Thursday, 30 December 2010

AF speed, GH1 vs GH2

I have previously checked the AF speed of the Panasonic GH1, and the Panasonic GH2. However, the tests were done at different times, and with different setup, lightning, etc. Also, the GH1 firmware has been updated in the mean time. So I decided to check both cameras again, under exactly the same conditions.

Again, I set a LEGO figure in the centre of the image frame, and found the time from pressing the shutter release button to the camera taking the image. I turned on the camera just before testing the autofocus, which means that the focus is near infinity when first pressing the shutter release button.

I did the test under two different conditions. The first was in dim light, with a black background: There is artificial lights, and rather dim at around EV5. The distance from the camera to the LEGO figure was about 0.6m.

The second was with daylight coming in through the windows, and white background. The lightning was about EV9.

Here are a couple of examples:



Panasonic GH1, Lumix 20mm, dim lights, black background



Panasonic GH2, Lumix 20mm, dim lights, black background



Panasonic GH1, Lumix 14-140mm @ 140mm, daylight, white background



Panasonic GH2, Lumix 14-140mm @ 140mm, daylight, white background


And these are the timings I found:

LensGH1, dimGH2, dimGH1, daylightGH2, daylight
Lumix G 14mm f/2.5 pancake0.43 seconds0.43 seconds0.37 seconds0.20 seconds
Lumix G 20mm f/1.7 pancake0.57 seconds0.53 seconds0.53 seconds0.40 seconds
Leica Lumix DG 45mm f/2.8 macro1.07 seconds0.93 seconds0.73 seconds0.43 seconds
Lumix G 14-42 @ 14mm0.43 seconds0.33 seconds0.30 seconds0.20 seconds
Lumix G 14-42 @ 42mm0.47 seconds0.40 seconds0.37 seconds0.20 seconds
Lumix G HD 14-140 @ 14mm0.40 seconds0.33 seconds0.27 seconds0.17 seconds
Lumix G HD 14-140 @ 50mm0.53 seconds0.57 seconds0.40 seconds0.23 seconds
Lumix G HD 14-140 @ 140mm0.70 seconds0.53 seconds0.50 seconds0.33 seconds

What we see here, is that the timings are remarkably similar in the tests done with dim lights. The GH2 has a small advantage to the GH1, especially with the fast focusing zoom lenses. But in this test condition, there is little to gain by using the GH2.

On the other hand, when testing the cameras with more light available, the difference is larger. The GH2 really excels in this test condition.

My previous test gave a larger difference between the two cameras. However, the GH1 firmware has been upgraded several times since that test, and so has the lens firmware. It seems that the GH1, with the up to date firmware, is still very capable.

As for the accuracy of the focus, it is very good with both the GH1 and GH2. Both cameras use CDAF (contrast detection autofocus). This means that the image sensor checks the actual image for focus before the camera takes the picture.

In contrast to SLR cameras, which use PDAF (phase detection autofocus). This means that there are separate AF sensors behind the mirror, which check the focus in some spots in the frame. These sensors must be calibrated to the image sensor, a process which is costly and complicated. Users of SLR cameras often worry that the camera/lens combination is back-focusing or front-focusing, i.e., that the AF sensors are noe correctly calibrated. This is something that users of Micro Four Thirds don't need to worry about.

Modern DSLRs can also use CDAF, which is generally refered to as "live view". However, this focus mode is often quite slow on DSRLs, since few lenses are optimized for CDAF. All native Micro Four Thirds lenses, and some Four Thirds lenses, are optimized for CDAF.

Wednesday, 29 December 2010

Yearly sales statistics from Japan

It's time for the yearly sales statistics from Japan (from BCN Ranking). Here's the list of the 20 most sold system camera units, comprising DSLRs and mirrorless interchangeable lens cameras. I have included 2009 and 2008 for reference.


To make the table more readable, I have categorized the cameras into systems. This makes the following table, with slightly different principles going from 2006-2010. However, it still shows some clear trends:


Nikon had a good market penetration with the Nikon D40 back in 2006, however, since that time they have not been able to sustain the market share. These must be depressing statistics for Nikon.

Canon have been successful in the competition against Nikon the last years, however, in 2010 even they have seen a decline in market share. A decline which seems to have gone to the mirrorless cameras: Sony never got their DSRLs into the market as they wanted, but they've seen a much better penetration with the new Sony NEX mirrorless series.

And for the Micro Four Thirds cameras made by Olympus and Panasonic, the growth continues. From the monthly statistics, we can see that the Olympus E-P2 never was a big seller. It's predecessor, the E-P1, is still on the list of the twenty most selling cameras. People appear to prefer the E-PL1 (with built a in flash), or the E-P1 (for a lower price, at the end of it's product cycle).

Pentax are still succeeding well with their strategy of launching feature packed entry models at a reasonable price.

Saturday, 25 December 2010

GH1 vs GH2: AF during video

When the Panasonic GH1 was launched, it was the only consumer system camera to provide continuous autofocus during video recording. Since this time, several competitors have launched their own systems, with the same capabilities. To regain the throne, Panasonic's most recent GH2 model must improve upon the original GH1. How does it fare?

To test this, I made a LEGO contraption which moves a paper sheet back and forth. The paper sheet has a printout of a sharpness test pattern. Here's how it looks:



But filming this and seeing how well the camera AF can keep up, we can compare the performance of the GH1 versus the GH2.

Lumix G HD 14-140mm

I set the camera up with the Lumix G HD 14-140mm superzoom lens at f=100mm. My experience shows that the lens performs best in terms of AF in the shorter focal lengths, so setting it at f=100mm is extra challenging. Both cameras were left in iA (intelligent auto) mode. Both were filming in 25 fps, 1920x1080 pixels

The camera was mounted to a tripod, not entirely perpendicular to the paper. That way, the test pattern can be seen to move a bit sideways, and not only back and forth.

Here are the results:



Panasonic GH1



Panasonic GH2

Based on these videos, it's easy to see straight away that the GH2 can keep up the focus in a better way. However, I wanted to check more thoroughly. So I studied the frames to see which were reasonably in focus.

What I found, was that the GH1 cannot keep up the focus at all. Rather, only the frames in which the paper is close to the initial position are in focus. The rest are out of focus.

The GH2, on the other hand, manages to follow the sheet's motion. The frames in which the paper moves most quickly are out of focus, but the camera regains focus when coming near the end-points, in which the paper sheet moves more slowly.

Based on my simple study, it is clear that the GH2 continuous autofocus is better than that on the GH1.

Lumix G 45-200mm

Using the Lumix G 45-200mm f/4-5.6 lens at 100mm gave the same result:



Panasonic GH1



Panasonic GH2

It looks like the GH1 with the Lumix G 45-200mm f/4-5.6 keeps up the focus a little bit better than with the Lumix G HD 14-140mm. This is consistent with my previous experience, in which I found that the 14-140mm is a bit slow to focus in the longer part of the zoom range, and that the 45-200mm is very fast except in the very longest end.

Leica Lumix DG 45mm macro

I also did the same experiment with the Leica Lumix 45mm f/2.8 macro lens. However, the lens was not able to keep up the focus with either camera. It is clearly not as fast focusing as the Lumix G HD 14-140mm lens.

Thursday, 23 December 2010

Comparison: GH1 and GH2

When I first got the Panasonic GH1, I noted down some improvement areas for the camera. While it was a good camera, there where many areas where I felt it could be improved. Upon getting the GH2, I am happy to note that many the items have been ticked off.


Panasonic GH1 (left) and GH2 (right)

Some of the items I wrote down were very unrealistic, like implementing in body image stabilization. Panasonic have chosen their strategy, to implement image stabilization in some lenses only, not in the camera bodies. So this is not going to happen.

But a lot of other areas have improved. Here are some examples from my list:

  • The control wheel has been moved to the rear side, which I prefer.
  • The built in flash has become taller (as can be seen in the images below), meaning that the premium kit lens Lumix G HD 14-140mm casts a smaller shadow when using the flash.
  • The new camera does feature a simplified focus scale in the display when focusing manually with a Micro Four Thirds lens. This is not an absolute focus scale with measurements, but it tells you if you are moving towards the close or far end of the focus scale, for example.
  • The camera can autofocus with more Four Thirds lenses. For example the Olympus Four Thirds 50mm f/2 1:2 macro. However, the focus is slow for some of these lenses.
  • When using legacy lenses, you can access the magnified focus assist view by pressing the rear control wheel. On the GH1, you needed to press two keys to get this mode: First the left arrow key, followed by the down arrow key.

There are also some development areas that remain. For example, the buffer clearing speed is very slow when recording both JPEG and RAW images.





Physical appearance

The basic shape remains very similar. The shell has been made from a different plastic material with a "crinkle" appearance. While the majority of the GH1 body was covered with a rubber-like covering, the shell of the GH2 is more slippery.

On the other hand, the GH2 gains a more solid rubber grip. Somehow, I find that the rubber-like surface of the GH1 feels safe to operate: The camera is less likely to slip out of your hands. On the other hand, the GH2 has a better grip area for the right hand.

Some people have reported that early versions of the G1 had the rubber surface peeling off. This caused negative publicity for Panasonic, and may be the reason why they have chosen a plastic surface without the rubber coating for the GH2.


On the rear side, we can note some changes. The GH2 (left) has a more pronounced frame around the LCD, which I suppose is good for protection. The red video record button had to be moved to the top-side, since the space it previously occupied is now taken up by the thumb wheel.

A subtle, but good change, is that the display button has become flatter. On the GH1, it was easily pressed by a mistake, and now this is not a problem anymore.


From the side, we can see that the SD card compartment has been moved a bit inwards into the camera. My speculation is that this was needed to fit the extended processing power in the GH2 camera.

This placement makes the card a bit more awkward to extract: There is little space for your finger between the card and the compartment door.


As a consequence of the new SD card placement, perhaps, the battery needs to be slimmer. The GH2 battery (DMW-BLC12, left) is new, which has angered some fans. This means that you can not reuse your extra GH1 battery (DMW-BLB13) for the GH2.

In this view, we also see that the tripod mount has shifted backwards.


In this side view, we see that the new flash is taller, which is very good news. Ideally, the built in flash should be as far from the lens as possible, when extended.


Video quality

The GH1 was marketed as a hybrid stills and video camera, the first in it's class to have continuous AF during video recording. In the mean time, some competitors have launched their systems. So to regain the throne as the best video enabled system camera, the GH2 must excel in video quality.

My experiments so far indicate that the GH2 does indeed provide better video quality. I devised a simple test to compare the GH1 (hacked) with the GH2 in otherwise identical settings.

What I found was that the white balance and saturation of the GH2 is more pleasing, and also that the sharpness of the video is probably a tad bit better. But in my opinion, there was not a dramatic difference.

The GH2 features a much appreciated ETC (Extended Tele Conversion). This is essentially a digital zoom that works during video recording. So your lenses become 2.6 times longer, and you can still record at full HD 1080 resolution.

I've also checked the rolling shutter properties of the two cameras. I found that they were mostly identical in this respect. The GH2 might be slightly better.

Anyway, rolling shutter artifacts is not a huge problem with the GH1 and GH2 cameras. Unless you deliberately generate the artifacts, you're very unlikely to find this being a problem. This is in contrast to the Samsung NX10, which I found had significant rolling shutter artifacts.

Autofocus speed

While I had no problems with the autofocus speed of the GH1, I am still happy to see that they have further improved with the GH2.

I'm especially happy that the autofocus has improved when using the Lumix 20mm f/1.7 pancake lens, which felt a bit sluggish on the GH1. Here is a summary of my AF speed readings.

The GH2 appears to be better at continuous autofocus too, according to my test.

Taller built in flash

As mentioned above, the GH2 has a taller built in flash. In theory, this should be good for several reasons: Keeping the built in flash as far away from the lens as possible is generally a good idea. It makes the lightning more flattering when photographing people.

Also, it is a known fact that the GH1 built in flash casts shadow when using the premium kit lens Lumix G HD 14-140mm. Here's how the shadow looks using GH2 (left), and GH1, both at 14mm and having the lens hood attached.



GH2
GH1

As you can see, the GH2 flash reduces the shadow cast a tiny bit, but the difference is rather subtle. On the other hand, you would probably not use the flash at 14mm focal length and 1 meter distance very often. And increasing either will reduce this problem. So for real life use, this is not that much of an issue.

Mirrorless cameras, like the GH1 and GH2, typically require a pre-flash to measure the intensity of the flash. This takes some more time than with DSLRs, since mirrorless cameras don't have a light sensor. They use the imaging sensor as a light sensor.


Battery life

Compared with most DSLR cameras, the battery life of the GH2 is not very impressive.  This is due to operating in live-view all the time.  DSLR cameras don't need the LCD for viewing during SLR mode, and save power that way.

With freshly charged battery, I found that I could record 144 minutes of video before needing a recharge.  This was with the LCD display on all the time. Using the EVF rather than the LCD probably gives better battery life.

It is possible to buy third party batteries for around US$20, but they give some reduced functionality.

Monday, 20 December 2010

GH1 vs GH2: Rolling shutter evaluation

Rolling shutter is the name of a type of mechanical or electronical shutter mechanism. In this type of shutter, the whole film or sensor is not exposed exactly at once, but rather, a shutter rolls across the frame and exposes it bit for bit. Rolling shutter is also the name of the distortion associated with this shutter implementation.

You can see this distortion for example when panning heavily during video recording. It looks like the scenery is "leaning" towards one side when panning. I tried the Samsung NX10, and immediately noticed that the viewfinder had much more rolling shutter artifacts than the Panasonic G-series.

This shutter implementation also leads to distortion to rotating elements. To test which camera has the most rolling shutter artifacts out of the Panasonic GH1 and GH2, I made a simple LEGO contraption which rotates a propeller at a constant speed. Then I videofilmed this with both cameras, using the Olympus 50mm f/2 lens.

Here are the two video streams:



GH1, ISO 1600, f/2, 1/500 second, 25p, 1080



GH2, ISO 3200, f/2, 1/1000 second, 24p, 1080

To more easily compare the rolling shutter artifacts, I have made similar framegrabs from both:


What we see here, is that the distortion is slightly smaller in the GH2 video stream. The shorter the distance between the two prongs to the left, the more the distortion.

So my conclusion is that the GH2 handles rolling shutter at least as good as the GH1.

For real life usage, rolling shutter is not a problem with GH1 or GH2 video. You can generate these effects by filming a rotating propeller, like I did here. Or by panning heavily. But most types of video footage will not display any noticeable rolling shutter artifacts.

As a side note, the amount of rolling shutter artifacts depend on the speed of the rolling shutter (in a mechanical implementation), or the speed of the sequential image data readout for a digital shutter. It does not depend on the shutter speed itself. Here is an illustration, where you can see three different shutter speeds generating the same amount of rolling shutter artifacts. But the amount of motion blurring is of course different.


Another term widely used is global shutter. This refers to a system in which the exposure values from the sensor are read all at once. Since the values are not read out sequentially, there are no rolling shutter artifacts with a perfect global shutter.

Before launching the GH2, a Panasonic representative was quoted saying that implementing a global shutter in Micro Four Thirds cameras is not coming soon: At the very earliest with the GH3. In retrospect, the the Panasonic GH3 did not introduce global shutter. And now, it looks like the GH4 (aka GH4K) is going to be more about 4K video than global shutter.

Thursday, 16 December 2010

Comparison @ 14mm

There's a number of Micro Four Thirds lenses which include the 14mm focal length. So it's natural to compare their properties at this focal length. I've compared these:

Lumix G 14mm f/2.5 pancake

Lumix G 14-42mm f/3.5-5.6 Mega O.I.S.

Lumix G HD 14-140mm f/4-5.8 Mega O.I.S.

I did the comparison by taking the same photo with all three lenses, at various apertures. The pictures were taken with the Panasonic Lumix GH2 camera on a tripod, at ISO 200. I used the self timer to avoid camera shake during the exposure, and disabled image stabilization. The pictures below were rescaled and sharpened. Here they are:

Wednesday, 15 December 2010

Video quality, hacked GH1 compared with GH2

I've tried to test the GH1 (hacked) and the GH2 under the same conditions. To make sure the conditions were the same in both tests, I made a rotating platform using Technic LEGO, and left it under artificial lights. To better be able to judge the quality, I put a sock on the platform. The sock has some texture, which will come in handy in the comparisons.

The lens used was the Panasonic Leica 45mm f/2.8 lens. The focus was put on the centre of the image, and I used f/6.3, ISO 400 for some depth of field.

Both videos are filmed in 1920x1080 pixel resolution. The GH1 is hacked to a maximum of 44Mbit max bandwidth, while the GH2 has the native firmware. The GH1 video stream is 25p, the GH2 is 24p. I used the new Cinema 24p mode on the GH2.

The GH1 stream is 11 seconds, 38.430.720 bytes, 3.5MB/s.

The GH2 stream is 10 seconds, 27.998.208 bytes, 2.8MB/s.

So there is more information in the hacked GH1 stream. However, this does not necessarily mean that it's better.

Here's the GH1 (hacked):



And the GH2:



It's not easy to make an objective comparison based on these YouTube videos. So to be more fair, I have made frame grabs from the video streams.

GH1 (hacked):


GH2:


To make the comparison even better, here are 100% views of two similar framegrabs (click for a larger version):


Conclusion

First of all, it is easy to conclude that the colour balance is different. I have the same saturation settings in both cameras (+1), and the lightning was the same. So the difference must be due to different implementation of auto white balance. Overall, I feel that the GH2 colours look more natural.  It's not strange that the cameras struggle with the colour balance here.  After all, there is artificial light, and the subject colours are rather strange.

When it comes to the sharpness, I think the conclusion is that the GH2 has better image quality. Even though the bandwidth is a bit smaller than in the hacked GH1.

I have also made a comparison of the GH1 video quality before and after the hack, in which case I found that the video quality was slightly better after the hack.

Sunday, 12 December 2010

GH2 touch screen AF (superzoom example)

I've previously tested the touch screen AF of the GH2, using the 45mm macro lens.

Here's another example using the touch screen AF with the Lumix G HD 14-140mm superzoom lens. The lens was set to 100mm focal length.



As you can see, the response is still somewhat slow, but the actual focus action of the lens is faster than when using the Lumix Leica 45mm f/2.8 macro lens.

I'm using the A mode on the mode dial. Using the iA mode typically gives me the focus tracking mode, in which the response time from touching the screen until the focus changes is a bit shorter.

When using the shutter button to trigger focus, the focus is very responsive, just like in my study of the GH2 autofocus speed.

When recording videos, you can change the focus areas using the touch screen as well. The response and speed is similar to this example.

I have also made an analysis of the focus speed of the GH2 for a number of lenses, and compared with GH1 for some of them.

Saturday, 11 December 2010

GH2 touch screen AF (macro example)

One of the new features of the G2/GH2, is touch screen LCD. Some fans have been negative about this feature, since they are afraid of losing the hard buttons on the camera body. It turns out that the touch LCD is an additional feature, and that it does not replace any hard button functions. So those who dislike a touch screen can ignore it, without losing any vital functionality.

One application where the touch screen makes some sense, is macro photo. It is rather quick to move the focus point around in the frame. Here is an example usage, with the Panasonic Leica 45mm f/2.8 lens:



You can doubleclick on the video to be able to view it in other sizes.

As you see, the response is not very quick. It takes a moment from changing the focus point until the camera actually starts changing the focus.

I'm using the A mode on the mode dial. Using the iA mode typically gives me the focus tracking mode, in which the response from touching until the focus changes is a bit faster.  So if you want the focus response to be quicker, set the dial to iA.

In the video, I am sliding my finger over the screen now and then.  This is not necessary. You can just point where you want the focus point.  My sliding finger action is probably something I've learned from using an Iphone.

This can also be done during video recording. The response speed is the same, as far as I can tell, during video recording.

Of course, the PL45 lens is not the quickest around in terms of autofocus. Using a quicker lens will make the response quicker as well.

I have also made an analysis of the focus speed of the GH2 for a number of lenses, and compared with GH1 for some of them.

Thursday, 9 December 2010

Panasonic GH2 autofocus speed

Update: Since this test, I have compared the GH1 and GH2 head to head under exactly the same conditions.

I have tested the autofocus speed for the Panasonic Lumix GH2 with various lenses. The test was done by turning on the camera (which leaves the lens at near infinity focus), and then pressing the shutter to see how long time it takes to reach focus. This was filmed using a GH1, and I played back the video in a video editing software, to read out the timings.

There is fairly dull indoor lightning. The lightning corresponds to around EV 6, the same as in my previous test of the GH1. A LEGO figures is placed in the middle of the camera frame, at around 45cm distance. The focus mode used is centre spot.

Here is an example test. In this test, I have the Olympus 9-18mm f/4-5.6 Four Thirds lens mounted to the camera, using an adapter. (Not to be mistaken with the Micro Four Thirds version of the lens.)



This combination gives a rather slow autofocus.

Another example using the Lumix G 14mm f/2.5 pancake:



As you see, the Lumix 14mm lens focuses very fast.

Another example, using the Leica Lumix DG 45mm macro:



This lens does not focus as fast as some of the other lenses, but it's still fair to say that the focus is not slow.

Summary

Here are the timings. I have included a column with the similar autofocus times for the GH1. You should note that the GH1 timings were done with early camera and lens firmware. Later firmware have improved the AF speed.

LensFocus time GH1Focus time GH2
Lumix G 8mm fisheyeNot tested0.24 seconds
Lumix G 14mmNot tested0.20 seconds
Lumix G 20mm1.23 seconds0.44 seconds
Leica Lumix DG 45mm macroNot tested0.60 seconds
Lumix G 14-42 @ 14mmNot tested0.28 seconds
Lumix G 14-42 @ 25mmNot tested0.20 seconds
Lumix G 14-42 @ 42mmNot tested0.44 seconds
Lumix G HD 14-140 @ 18mm0.53 seconds0.16 seconds
Lumix G HD 14-140 @ 50mm0.40 seconds0.40 seconds
Lumix G HD 14-140 @ 140mm0.68 secondsNot tested
Lumix G 45-200 @ 45mm0.33 secondsNot tested
Lumix G 45-200 @ 100mm0.36 secondsNot tested
Lumix G 45-200 @ 200mm0.87 secondsNot tested
Olympus ZD 4/3 9-18 @ 9mm2.90 seconds1.44 seconds
Olympus ZD 4/3 9-18 @ 18mm1.50 seconds1.36 seconds
Olympus ZD 4/3 50mm f/2No AF4.76 seconds

Conclusions

What we can see, is that the GH2 autofocus speed is very good. The Four Thirds lenses used on adapter are still slow, but they behave better. The Olympus 50mm f/2 macro lens can actually autofocus on the GH2, but the speed is very, very slow. It could be used for stationary objects, but for photographing people, the AF is more or less useless.

The Panasonic Lumix GH1, and the whole first generation of Panasonic G cameras, could not autofocus with the Olympus Four Thirds 50mm f/2 macro lens. This also applies to a host of other Four Thirds lenses that are not optimized for CDAF. The newer GH2 can autofocus with most Four Thirds lenses. However, the focus can be rather slow, as we have seen in this example.

Even the Four Thirds Olympus 9-18mm f/4-5.6 wide angle zoom lens, a fairly recent CDAF optimized lens, has an annoyingly slow autofocus. The AF is usable, but not as fast as we have become used to.

I am also rather happy that the autofocus speed for the Lumix 20mm f/1.7 pancake lens has improved a lot with the GH2. After all, this is a very good lens, and I find the AF speed to be important when photographing people.

As expected, the Lumix G HD 14-140mm superzoom lens remains very fast in terms of AF. It seems that the close focusing range differs for various focal lengths. The close focus range is specified at 50cm, however, it can focus a bit closer in the wide end of the zoom range. I was not able to test the lens in the longer range this time, since it would not reach focus there at 45cm distance.

The new kit zoom Lumix G 14-42mm is also a very competent lens when it comes to focus speed. I think this was to be expected, after all, it is a brand new kit lens, and focus speed is one of the important factors when people buy camera kits.

Sunday, 5 December 2010

Lens hoods

Frequent readers of my blog will know that I like to tinker with lens hoods. Here is a summary of some of the lens hood solutions I like.

Panasonic Lumix G 20mm f/1.7 pancake

This lens does not come with a hood at all. While a hood is probably not much needed from a stray light perspective, I still like to put a hood on my lenses for protection against objects accidentally touching the front lens element.

My favourite solution is to put a 46mm to 37mm step down ring as hood. This gives some basic protection of the front lens element, while keeping the overall package compact.


I've checked that there is no extra vignetting caused by the step-down ring.

In addition, you'll need a 37mm front lens cap. Both can be gotten from various auction sites for about US$10 in total.




This lens features a traditional focus mechanism, in which the whole lens assembly moves back and forth. Adding extra weight to this assembly is generally not a good idea. However, the step-down ring doesn't add that much weight. Less than a glass filter would, anyway.

Another solution is to get a 46mm metal screw in hood designed for Leica Summicron:


While this hood looks stylish, I think it adds too much bulk. Besides, you might not be able to fit the front lens cap inside it.



Panasonic Leica Lumix DG 45mm f/2.8 1:1 macro

This lens does come with a hood, however, I am sad to say that I find the hood completely hideous:


This hood does look stylish, and reminds me of the older Leica hoods. However, it is much too wide, and could have been used for a wide angle lens. But this lens is a short tele. So the hood does not do a good job of keeping stray light out.

I prefer a hood that is a narrow as possible, while still not inducing any extra vignetting. I found the solution I like by adding three extra elements to the front lens thread: First a 46mm stand off ring (glassless filter), then a 46mm-37mm step-down ring, and finally, a 37mm-28mm step-down ring:


I was almost a bit surprised when I verified that this combination does not add any extra vignetting. But the front lens element of the 45mm macro has a rather narrow diameter, so I suppose it makes sense.

This "hood" does not add any extra diameter to the lens, which is good. In addition, you'll need a 28mm front lens cap. Such a cap is pretty inexpensive.





Olympus M.Zuiko Digital 45mm f/1.8

In a move which has annoyed quite some fans, this lens is not sold with a hood included. There is a hood you can buy from Olympus, which fits in to the bayonet mount. However, it is quite expensive.

I bought a collapsible rubber hood for screwing into the 37mm front threads. It works great:


This rubber hood cost me US$13, including shipment from China.



Panasonic Lumix G 14mm f/2.5 pancake

Just like the 20mm pancake, this lens does not come with a hood. Again, I've used the same solution as with the 20mm pancake lens: A 46mm to 37mm step down ring as hood:


In this case, I had bought a grey ring by a mistake, so I had to paint it black with enamel paint. No big deal.




This lens features internal focusing, so I am not afraid of putting some extra stuff onto the front lens thread.

Panasonic Lumix G 45-200mm f/4-5.6 Mega O.I.S.

This lens does come with a hood, and I think the hood is very well designed:


The only problem I can see, is that it is awkward to insert and remove the front lens cap.

I still changed this hood, since it was a tad bit too long for my camera bag. I got a 52mm screw in metal hood:


This alternative hood is probably not as good for protection, but is is more practical to use, and it's easier to add the front lens cap after use.



Other lenses

The kit zoom lenses generally have well designed hoods, and I see no reason to replace them.

Wednesday, 1 December 2010

Testing the effect of the GH1 hack

For a while now, it has been a well known fact that the Panasonic Lumix GH1 firmware can be adjusted to yield higher video bitrate, among other things. This is referred to as using "the hack", or "hacking" the GH1. Similar adjustments can also be done to the GF1 and G2 cameras.

I wanted to test the effect of the hacked GH1. Is it possible to measure the improvement of the video after installing the hack? I know many people have praised the quality of the hacked GH1 video before, but I wanted to make sure this test has exactly the same moving subject and lightning before and after installing the new firmware.

Test setup

Here is my test setup:


The camera is on a tripod, with the Leica Lumix 45mm f/2.8 macro lens. The camera is set to f/5, 1/60s, ISO400. The LEGO figure is on a platform that rotates at a constant speed.

I recorded one video file before installing the hack, and one after. When adjusting the firmware, I upped the max bandwidth from 16,000,000 to 50,000,000. Both videos were recorded at Full HD, 1920x1080 pixels. This can only be done using the AVCHD format. My camera is the PAL version, meaning that I get a framerate of 25fps.

The first video is 11s, and 20,754,432 bytes, 1.89MB/s. The second video is also 11s, and 31,395,840 bytes, 2.85MB/s, 50% higher than before the hack. So already here there is an indication that the hacked video contains a higher bandwidth.

Video examples

Here are the videos. You can double-click on the video to get to the YouTube page, where you can see them in higher resolution, up to 1080p.

Before the hack:



After the hack:



Of course, just watching the videos on YouTube isn't enough to judge the quality. For an extra test, I have made some framegrabs from the videos, to compare the quality.

First, two full size framegrabs from the video.

Before:


And after:


It's still difficult to compare the quality of the images. Here are 100% crops from the 1920x1080 framegrabs. I chose four consecutive frames from each video stream. Click on the image for a larger version.


Conclusion

Based on these screenshots, I believe it looks like the there is some more clarity and sharpness in the hacked video stream. Also, the colours are more washed out without the hack. The hacked video stream is better. But from my experiment, I don't see a dramatic difference.

Other effects

After recording the second video, I was not able to playback the videos any more. Just showing the thumbnail in the viewer was enough to freeze the camera. To reset it, I needed to remove the battery. Just flipping the on/off switch was not enough. This is, of course, quite annoying.

Sunday, 28 November 2010

Lumix 14mm, insufficient distortion correction

Just like a host of other Micro Four Thirds lenses, the Lumix G 14mm f/2.5 pancake lens utilizes in camera distortion correction.

However, when using the lens on the Panasonic GH1 camera, I've noticed that the distortion correction is not sufficient. There is still some residual barrel distortion after the in camera correction.

Here are a couple of examples. First, let's look at an example at a close focus distance, close to the minimum focus distance of the lens:

Corrected JPEG
Uncorrected RAW

In this example, even when looking at the small image (above, left), it is easy to see that there is still some barrel distortion in the upper, horizontal line. The line is not straight. You can click on the image to view a larger version of it.  The corrected image to the left is the JPEG output from the camera.

The right image shows the image as captured by the sensor, without any distortion correction at all.  I used the UFRaw RAW processing software.  But any software that allows for disabling the distortion correction could be used for this purpose.

And one example with a longer focus distance:

Corrected JPEG
Uncorrected RAW

In this latest example with a longer focus distance, it appears that the remaining distortion is not so significant. I added a red, straight guideline to the left in the JPEG image, above left. You can see that there is some barrel distortion still, but not much.

Conclusion

It appears that when using the Lumix G 14mm f/2.5 pancake lens on a Panasonic GH1 camera, there is some residual barrel distortion. This is most apparent at shorter focus distances.

One could speculate why this is so. I don't think it is a firmware issue, since I have the newest firmware available for my camera.

Another speculation is that Panasonic chose to not correct all the barrel distortion, since that would have decreased the diagonal angle of view. The diagonal angle of view for this lens is specified to 75°. Further correction of the barrel distortion would reduce this figure, albeit with a small margin.

The Lumix G 14mm f/2.5 pancake lens uses internal focusing, and it is not uncommon that these designs lead to changes to the distortion properties, and field of view, at closer focus distances.

Saturday, 27 November 2010

Camera sales statistics from Japan

Update: There is newer sales data from the end of December 2010 here.

BCN Ranking provides monthly sales statistics for various items in Japan. One of them is system cameras, which includes DSLRs and mirrorless systems.

Here is the most recent sales statistics for Micro Four Thirds camera systems. The number in the graph is the ranking the given month. So a "4" means that the specific model was the fourth most sold model during that month. In the first two places you typically find the basic kit models from Nikon and Canon.


There are a lot of interesting findings here.  For example, two Panasonic models have had a second birth: Both the GF1 and GH1 have seen an increase of sales, probably due to the discounted prices awaiting the arrival of the newer models GF2 and GH2.  This also applies to the Olympus E-P1 camera, which saw a significant sales increase in the third quarter of 2010.

Another finding is that while the Panasonic Lumix G1 sold pretty stably, it was the Olympus E-P1 which made a big difference in the Japanese market.  This is consistent with what I saw in the Nordic market.  Even though the G1 has, in my opinion, better photographic functionality, it was the E-P1, with the retro styling, and somewhat slimmer body, which got the landslide sales.  The E-P2 never was a big seller, it seems.

In the mean time, some competitors have also launched systems. I was not able to find statistics for the Samsung NX system, but the Sony NEX was easy to find.  In the diagram below, it is apparent that the Sony NEX was a big hit in Japan.


The top model Sony NEX 5 got an impressive second place in June 2010, and retained the third place in July and August.

Saturday, 20 November 2010

Using the 8mm fisheye lens as a macro lens

Using a fisheye lens as a macro lens is probably a very strange idea. But the Panasonic Lumix G 8mm Fisheye lens has a remarkably short minimum focus distance, so it actually makes some sense.

The closest focus distance is specified as 0.1m. However, this is measured from the sensor plane. So the distance from the front element is about 0.02m, or 20mm.

This corresponds to a magnification of 0.20x, or 1:5, which is not very impressive. We should keep in mind, though, that the field of view is more compressed in the corners, hence this magnification measure doesn't make much sense for the fisheye lens.

Here's my setup for photographing a LEGO figure at the closest focus distance:


The camera is on a tripod, and the figure is about 2cm from the front lens element. At this close distance, it is inevitable that the lens casts some shadow on the subject.

And here is the resulting image, taken at ISO 100, f/5.6, 1.3 second exposure:


The very close focus distance possible with the Lumix 8mm lens can be used to make interesting compositions. Especially when combined with the deep depth of field associated with a wide angle lens.

Friday, 19 November 2010

Measuring the field of view of the Lumix 14mm f/2.5 pancake lens

There has been some uncertainty as to the actual field of view of the Lumix 14mm f/2.5 pancake lens. While I personally don't doubt Panasonic's specifications, I decided to make my own measurement.

I placed the camera level, facing 90° towards a window. On the window, I placed a measuring band. The distance from the camera's mount to the measuring band is 870mm. This means that the distance to the sensor is 890mm, since the register distance of Micro Four Thirds is 20mm.

Here is the setup:


And this is the resulting image, after in-camera distortion correction:


It's easier to measure the width when looking at 100% crops of the endpoints:


We can see that the total horizontal distance is 1039mm.

Doing the basic trigonometrical calculation, we get the horizontal angle of view to be: 2*arctan((1039mm/2)/890mm)° = 60.5°.

Now, we want to find the diagonal angle of view. The diagonal width is sqrt(10392+(1039*3/4)2) = 1298.75. Hence, the diagonal angle of view is 2*arctan((1298.75mm/2)/890mm)° = 72.2°.

Panasonic's specifications state that the diagonal angle of view is 75°. However, we know that the angle is specified at infinity focus. And in my case, the focus is just below 1m. It is also a fact that the angle of view can change with the focus, especially with internal or rear focusing mechanisms. So this is probably the explanation for the difference.

Thursday, 18 November 2010

Lumix 14mm distortion correction

Just like most other Micro Four Thirds lenses, the Panasonic Lumix G 14mm f/2.5 pancake lens is corrected for barrel distortion in camera. This is applied when looking through the viewfinder, when producing JPEG images or videos, and when using some RAW converter programs. So many users are probably not aware of this at all.

It is easy to see the effect of the distortion correction when opening the RAW image file in a converter program that allows for not applying distortion correction. One such example is UFRaw.

Here is an example image. It was taken at f/2.5, ISO 400, 1/13 second exposure. Both the out of camera corrected JPEG, and the non-corrected RAW image are shown below:

Corrected JPEG
Uncorrected RAW

It is apparent that there is some barrel distortion in the RAW image. To correct this requires about -14.5 adjustment in the Lens Distortion filter within The Gimp image processing software. This is slightly more than for the Lumix 20mm lens, for which I found that -13.5 was an appropriate adjustment.

This picture shows what sensor area is lost during this conversion: The area outside the white frame is unused when applying the distortion correction.



This corresponds to around 12% of the sensor area, and hence you lose around one megapixel of resolution with the normal 12 megapixel sensor. This is nothing to worry about.

The upside is that if you need a wider field of view, you can use the whole sensor output from the RAW file. The normal diagonal field of view for this lens is 75°. Using the extra sensor area output to the RAW file gives you around 80° field of view. Of course, this will not be distortion corrected, but as long as you don't photograph any straight objects, this shouldn't be any problem. For nature and people, this might not be an issue.

Framing your picture will be difficult, though, since the viewfinder only shows the image after the distortion correction. And you might experience more vignetting in the extreme corners.

Insufficient distortion correction

To my surprise, I noted that the distortion correction is in fact not fully sufficient. After the in camera distortion correction, there is still some residual barrel distortion, especially at shorter focus distances. You can note this in the top left image: The pillar to the left is not entirely straight. Also, the ceiling is slightly distorted.

It could be that newer cameras do a better job of correcting the distortion.

Saturday, 13 November 2010

Panasonic Lumix G 14mm f/2.5

The Panasonic Lumix G 14mm pancake lens is the long awaited miniature standard wide prime. Some people have been disappointed by the aperture: The max aperture is f/2.5, which is a tad slow for primes. On the other hand, it is clear that size was important when designing this lens, and a moderate max aperture is needed to design a small lens.

To further reduce the overall size, it comes with new slim line, low profile front and rear lens caps:


Example video capture, GH1+Lumix 45-200mm

This recording was done in Union Square Park using a Panasonic GH1 and a Panasonic Lumix G 45-200mm f/4-5.6 zoom lens.





In this example capture, you can see that the camera jogs the focus back and forth now and then, probably to verify the correctness of the focus. Also, while zooming, the focus is lost for a short period. The newer Lumix G 100-300mm f/4-5.6 lens is said to have some technology to prevent the loss of focus during zooming.

The recording was done in 720p, and converted/edited using HandBrake and Kdenlive.

Of course, one should be very careful with zooming during video recording. It is almost impossible to get the zooming smooth and undistracting. When zooming is done by professional videographers, the usually use a dedicated zoom motor, which attaches to the zoom ring and rotates it smoothly.

This video example illustrates how you can achieve a nice background blur using one of the cheapest lenses available. The possibility to blur the background to enhance the foreground subject is one of the reasons why some people like using Micro Four Thirds for filming.

Here is another example video capture:





This was filmed using 720p, 50 fps. I set the focal length to 120mm, which corresponds to 240mm on a traditional 35mm film camera.

The camera was not on a tripod, but I rested it against a fence for extra stability. Still, it was difficult to keep it entirely stable. You can see that there is some camera shake.

Tuesday, 9 November 2010

Lumix G 8mm f/3.5 Fisheye

The 8mm fisheye lens is a specialized lens, meaning that it is not a lens that most people would use a lot. One can imagine several reasons why Panasonic still chose to develop this lens, e.g.:

  • The short flange distance for the Micro Four Thirds system means that wide angle lenses can be made very compact, illustrating the strengths of the M4/3 concept.
  • Videographers commonly use fisheye lenses for skateboard, BMX and other types of sports events.
  • When panning with a rectilinear wide angle lens, the objects can appear as if they change size as they move across the frame. With a fisheye lens, this can look more natural. Hence, some videographers prefer fisheye for wide angle videos, as opposed to traditional wide angle lenses.
  • Fisheye lenses can be used to make "cute" images and videos, e.g., novelty images of animals where the nose appears very large.

Anyway, the user is of course free to choose what to use this lens for, and does not need to be restricted by the items above.

I have made a comparison of the sharpness and other aspects of the Lumix 8mm fisheye lens compared with the Olympus Zuiko 9-18mm f/4-5.6.

In 2011, the Samyang 7.5mm f/3.5 fisheye lens was announced. It is a fisheye lens with fairly similar specifications as the Lumix G 8mm f/3.5. The Samyang is a manual focus lens, with a manually operated aperture ring. My study has shown that it has remarkably good optics, in terms of sharpness and CAs. It also has somewhat less distortion than the Lumix G 8mm lens.




Type of fisheye lens

Most fisheye lenses fall into two categories: Circular fisheye lenses, and full frame fisheye lenses. Circular fisheye lenses cover the field of view of 180° in all directions, and only expose a disc in the centre of the frame. Full frame fisheye lenses, on the other hand, expose the whole sensor area, but only cover 180° in the diagonal.

The Lumix G 8mm fisheye lens is a full frame fisheye lens. A circular fisheye lens on the Four Thirds format sensor would probably have a focal length of around 3-4mm.


Physical appearance

The lens comes with a built in, non removable, hood. The hood also protects the front lens element against objects touching it accidentally. Due to the hood, you can place the lens upside down on a table without the glass touching anything.



The front lens cap is unusual. Rather than the pinch centre caps that we are used to, this one is more like a lid which slides onto the outside of the hood. It is held in place by friction. The outside of the hood is around 61mm wide. You better take good care of the lens cap, since replacing it can cost around US$40.

Comparing the fisheye lens with the Lumix 20mm f/1.7 Pancake lens, reveals that it's size is small:



The Lumix 20mm is seen here with a "home made" low profile hood.

Quality wise, the lens gives a very good impression. There are no moving parts on the outside (beyond the focus ring), due to the internal focus mechanism.

The aperture can be set from f/3.5 to f/22. Changing the aperture gives a small "click" sound. It is not as silent as the Lumix G HD 14-140mm superzoom lens, but still, I hardly think anyone will find this problematic.

There is no geometric distortion correction in software when using this lens.  As opposed to most Micro Four Thirds lenses, which utilize geometric correction in post processing, e.g., the Lumix G 20mm and Lumix G 14mm pancake lenses.

Autofocus

This lens has a very quick autofocus system. Except when photographing very close objects, you barely notice the focus at all: It appears to be in focus instantly when half pressing the shutter.

Here is a comparison of the focus speed for various lenses on a GH2. In this study, the 8mm fisheye lens has a very quick timing.

Moreover, the autofocus is virtually inaudible. It is barely noticeable in use.

I would recommend using multi point AF with this lens. The spot autofocus can be a bit awkward, with the very wide angle of view.

The closest focus distance possible is very short, specified to 0.1m. Keep in mind, though, that this is measured from the sensor, meaning that the minimum focus distance is very close to the front lens element. At this distance, it is ineviteable that the lens casts some shadow on the subject.

Here is an example use of the lens for macro purposes.

Manual focus is possible by using the focus ring. It is made of ribbed plastic, and for that reason it is not as easy to operate as a rubber ring would have been. On the other hand, the plastic ring is probably much more solid, and will not wear out any time soon. The ring feels fairly dampened and smooth, about the same as the Lumix 20mm focus ring.

Sharpness

My experience so far indicates that the sharpness is very good, even at f/3.5.

The typical way to evaluate the sharpness and artifacts of a wide angle lens, is to take a picture of foliage with the sky in the background. So here they are:

f/3.5, 1/13000, ISO 200
f/5.6, 1/500, ISO 200

To better evaluate the sharpness, let's look at some 100% crops from certain areas in the image (click for a larger image):



As we see from these crops, the image is very sharp from f/3.5, even in the corners. When stopping down the aperture to f/5.6, the corners sharpen up even more.

I have made a comparison of the sharpness and other aspects of the Lumix 8mm fisheye lens compared with the Olympus Zuiko 9-18mm f/4-5.6.

Here is another sharpness comparison with the Samyang 7.5mm f/3.5 fisheye lens.

My study of the chromatic aberrations (CA) artifacts reveals that the lens has around 2-3 pixels wide red/green fringing in the corners of the frame, caused by high contrast areas. This is corrected by post processing software in the camera, and by some RAW converters. There is still some residual purple fringing in the corners after this in camera image processing, but it's mostly not a problem.

Flare

The Lumix G 8mm fisheye lens covers a very wide field of view. For this reason, it can be difficult not to have a strong light source in the frame, e.g., the sun. Hence, it is important that the lens handles flare well. Otherwise, one strong light source could ruin your shot.

I have included an extreme example below. Here, the sun is in the centre of the frame, just behind the figures.


And here is an enlargement of the persons, who has the sun just behind them. This is a 100% crop, meaning that it has not been resized:


Here we see that the sun does indeed reduce the contrast. However, considering how difficult this scene is to render, given the very high contrast, I think the lens does a good job. So flare is not a big problem with this lens, I would say.

Example images

This specific fisheye lens is the full frame type, meaning that the image fills the entire rectangular frame. The diagonal coverage is stated to be 180°.

A fisheye lens generates images that are not rectilinear, as we are used to, but rather hemispherical. This looks like an excessive amount of barrel distortion.

This distortion is very apparent when photographing rectangular shapes, like, for example, the Apple store in New York:



However, when photographing organic forms, the distortion might not be a huge problem. Here is the sled dog Balto, the only one to get a statue in Central Park while still being alive:



It is easy to see that the head is too large, and that the hind part of the dog is too small. This is due to the fisheye distortion. But on first glance, the shapes do not look very wrong. Only when the intention is an anatomically correct image, would the distortion be a problem.

Fisheye lenses can be defished, i.e., transformed to a rectilinear projection. In this example, I used the program Hugin to do the transformation. The original picture of the Tourneau store was taken with a 16:9 aspect ratio:


The diagonal field of view is 180°. In the 16:9 aspect ratio, the ratio of field of view becomes even more narrow, due to the curvature of the projection. The field of view is 136° horizontally, and 76° vertically. Here's how the defished image looks:


You'll note that there is some residual barrel distortion even after the defishing process. This is because the Lumix G 8mm f/3.5 fisheye lens gives somewhat more distortion than what is common for a fisheye lens. Here is a distortion comparison with the Samyang 7.5mm f/3.5 fisheye lens.

Example video

Here's an example video, filmed at 720p with the Panasonic Lumix GH1. It was filmed while holding the camera above my head at arms length, so it is a tad shaky. Doubleclick on the video to go to the YouTube view, which may work better than this embedded view.



Compared with the Lumix G 7-14mm f/4

It is natural to compare this fisheye lens with the Panasonic Lumix G 7-14mm f/4 ultra wide zoom lens. They are both extremely wide lenses, and their pricing are fairly similar.

When it comes to the lens construction, the 8mm fisheye lens is a much simpler design. It features 10 lens elements in 9 groups, while the 7-14mm zoom has 16 lens elements in 12 groups. In terms of exotic elements, it is also simpler: 1 ED glass element (4 in the 7-14mm), and no aspherical elements (2 in the 7-14mm).


There's no significant difference in the speed. The wide angle zoom has a maximum aperture of f/4, which is only slightly smaller than f/3.5. While the fisheye wins in this respect, the difference is hardly significant.

The fisheye lens has a close focusing distance of 0.1 meter, which is very, very close. The corresponding distance is 0.25 meter for the 7-14mm zoom, which is also close, but still not comparable. While you may not use this close focusing distance a lot with the fisheye, the front lens element is less than an inch from the subject at this distance, it can still be used for some interesting effects.

In terms of overall usefulness, the 7-14mm zoom wins, no question about it. In the longer end, it becomes a "normal" wide angle lens, useful for a lot of shooting situations. The fisheye lens, on the other hand, remains an exotic, specialized lens all the time.

The 8mm fisheye lens is still attractive due to it's very wide angle of view, and the small size (37% shorter and 45% lighter).

Conclusion

This is a very good and compact lens. But it's usefulness is a bit limited for most people, and it is expensive.

Due to its lower cost and good optics, the Samyang 7.5mm f/3.5 fisheye lens can be a good alternative to the Lumix G 8mm f/3.5 fisheye lens.

The Samyang lens also has a more common fisheye projection model, and is easier defished, in my experience. If you plan on doing that, then the Samyang may be a better choice.