Thursday, December 25, 2008

Canon Black Dot ... or Not

Canon Australia posts the following advisory about a curious anomaly some consumers have noticed with their new 5DMKII Digital SLRs:

Black dot phenomenon and Vertical banding noise

Posted on: December 17, 2008

To Owners of the EOS 5D Mark II Digital SLR Camera :
We have learned that some users of the Canon EOS 5D Mark II digital SLR camera have indicated two types of image quality phenomena that appear under certain shooting conditions.

“Black dot” phenomenon (the right side of point light sources becomes black)
Vertical banding noise
We are currently investigating ways to improve and/or mitigate these phenomena. An announcement will be made on the Canon Website when measures to address these phenomena have been decided.

The phenomena are likely to occur under the following shooting conditions.
“Black dot” phenomenon (the right side of point light sources becomes black) When shooting night scenes, the right side of point light sources (such as lights from building windows) may become black. The phenomenon may become visible if the images are enlarged to 100% or above on a monitor or if large prints of the images are made.
Vertical banding noise If the recording format is set to sRAW1, vertical banding noise may become visible depending on the camera settings, subject, and background. The following camera settings can reduce the phenomenon.
Set the recording format to RAW or JPEG.

Set C.Fn II-3: Highlight tone priority to 0: Disable if the recording format is set to sRAW1.

The vertical banding noise is not noticeable if the recording format is set to sRAW2, but please set C.Fn II-3: Highlight tone priority to 0: Disable if you are concerned about noise.

Canon always strives to provide the highest quality products to our customers. We apologize for any inconvenience these phenomena may have caused. We appreciate your kind patronage and support.

I took delivery of a Canon 5D MKII Christmas Eve. In the spirit of the holidays, and with curiosity about the "'black dot issue" I took this picture of a tree ornament.

I realized there would be lights in the background, the exact kind of pinpoint light sources that the Internet seems to be abuzz with. A perfect test for black dots. Here are screengrabs of a couple of different lights at 100%.

I shot in RAW, and I can't replicate the problem. I realize this is a cursory test, but I can't help but be amused that so much bandwidth and consternation is being directed at such a minor issue, that will no doubt be fixed by firmware anyway.

As for the 5d MKII, it is a very nice camera, extraordinary performance at a modest price, and I'm looking forward to the arrival of my Seacam 5D MKII housing in February. The first production housings will likely be shown at upcoming BOOT show, January 17-25 in Dusseldorf. 21 megapixel, Digic 4 processor, and HD movies ... This is going to be a serious tool for UW imaging.

Note - I heard from a friend who suggested that the issue would only show up at ISO 1600 to 6400. So, I took similar shots with both the 5DMKII and Canon 1DsMKIII. Regrettably, I did not mount the two cameras on a tripod, so there is variability in crop. After all, I did not start out to make this a scientific test, but more a matter of curiosity. (Focus was on the tree ornament, throwing the bulb slightly out of focus, as might happen in a normal night scene background)

This is the 5DMKII at 6400 ISO.

This is the Canon 5DMKII at 1600 ISO.

This is the Canon 1DsMKIII at 1600 ISO.

I'm very satisfied with what I see so far, not that this would likely be of any consequence to the kinds of things I normally shoot anyway. I'm far more eager to get the camera underwater and do real images with real subjects on a coral reef somewhere.

Click any of the images to see a more detailed/enlarged view.

Jan 9, 2009: Note that issue is now resolved with firmware update -

No comments: