Stephan’s Blog

Stock Photography

Posts Tagged ‘EOS 5D Mark II

EOS 5D Mark II: The ‘Black Dot’ Phenomenon

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My noise behavior photos have stirred quite some interest. I’ve uploaded these photos to my new blog on the day the camera was released to the public.

After pixel peeping, someone has discovered black dots right next to blown-outs. If they show, then they always appear a few pixels to the right of the blown-outs in landscape-oriented photos. The higher the ISO the more pronounced the effect appears to be.

Below is a crop of the ISO 3200 image that I’ve shown in my noise behavior post. You can clearly see these ‘black holes’. Some notes:

  • To the best of my knowledge, I turned off all in-camera processing such as picture style and noise reduction. I wanted to show results as close to the RAW file as possible.
  • I turned off all processing in ACR5.2 (Photoshop CS4 trial version), e.g. no ‘Recovery’ or ‘Blacks’ adjustments, no sharpening or noise reduction, no adjustments of curves or vignetting.
  • The same black dots appear in the results I get from the version of DPP that comes along with the EOS 5D Mark II.
  • To post it on my blog, I converted the results to JPG with the least amount of compression (setting 12 in Photoshop).
  • The crop below has been blown up by a factor of about 2.5 to clearly show the phenomenon.

Black dots in a night shot taken at ISO 3200

So what’s the problem? I don’t know but I hope it can be fixed in firmware. The sensor is supposedly identical to the one used in the Canon EOS 1Ds Mark III which doesn’t appear to show this behavior. Although the optics in front of the sensor has been changed to reduce the micro lens gap, I can’t imagine this is causing this phenomenon.

Another indicator that it is not a sensor issue is a shot taken at ISO 50. The same areas that show black dots in the ISO 3200 shot appear more like some sort of flare. I wonder if these flares are caused by the lens optics or by the sensor optics.


Same area at ISO 50

I’d like to contact a Canon representative who’s close to optics or firmware development, but don’t know who to get in touch with. So if you can give me a name, please post a comment. I will not publish it to protect the representative’s email address.

I should note that it is not only my camera that shows this problem. There is already a variety of examples shown on various other sites.


Written by glubsch

December 7, 2008 at 10:06 am

Albino Centipede?

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Today I discovered this little critter in a small canyon in Big Basin. The shot was taken at f/5.0, 1/60s and ISO 3200 (!). I must say I’m getting more and more impressed by the possibilities this camera enables. I read the RAW into ACR 5.2. No sharpening was applied but I set the luminance noise reduction to 50 and the color noise reduction to 25. This photo is quite usable, even though I couldn’t get the head quite sharp.

By the way, what sort of arthropode is this? Is this an albino or just a white centipede?

What is it? Is it an albino?

What is it? Is it an albino?

Written by glubsch

November 27, 2008 at 10:31 pm

First Shots with Canon’s EOS 5D Mark II

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Golden Gate Bridge, dreary weather

Golden Gate Bridge, overcast sky. Lens: 24-70mm/f2.8 @ 24mm. Camera settings: F9.0, ISO 100, Adobe RGB. Photo taken right after sunset. Click the photo for a full-size picture.

After I picked up my EOS 5D Mark II yesterday, I immediately drove to San Francisco to take some photos. I was mostly curious about the noise behavior at different ISO settings. Even though I didn’t read the manual, I was able to set up the camera within minutes. I changed it to store RAW files and turned the picture mode to neutral to make sure no in-camera manipulation such as sharpening takes place.

The weather wasn’t really the best but this was all about pixel peeping, right? Other than different ISO settings and the corresponding exposure time, the settings were the same. I used a tripod and mirror lock-up.

Since I shot the photos in RAW, I performed some adjustments in Photoshop. The curves were adjusted for more contrast. The white balance was set for a cloudy sky. The photo above is sharpened at 80%, 0.3 as it appeared rather soft as it came out of the camera. I didn’t apply any sharpening to the second photo.

ISO 1600

Basically the same settings as in the shot above, except that I changed the ISO to 1600 and that I didn't apply sharpening in Photoshop.

Written by glubsch

November 26, 2008 at 8:53 am