This is a continuation of the thread found at:

http://forums.dpreview.com/forums/read.asp?forum=1032&message=33434923

Regarding low ISO banding issues on the 5d Mark II.

To briefly restate the problem, some 5d Mark II bodies may exhibit excessive crosshatched banding in the shadows at ISO 100 and 200. The banding is primarily contained in the red channel. This has been widely discussed on many forums including in numerous threads here on DPReview. The banding is not usually an issue at higher ISO's. Other camera bodies i.e. 1-series, xxxD series, xxD series, do not exhibit this behavior.

In my case, I had one of the first 5d Mark II's to arrive in the U.S. in late 2008. The excessive noise at the lower ISO's was something that I noticed fairly soon. I have been in contact with Canon off and on for the past several months and finally sent the camera in for repair last month after giving them sufficient correspondence and time to work on fixing the problem.

Here are some example photos, pre and post-repair, to hopefully illustrate the problem and demonstrate the apparent fix that was implemented. The repair consisted of replacing a circuit board, adjusting and recalibrating the camera. NO noise reduction was used on any of these examples. All shots were taken in RAW Neutral.

Pre-repair example:

Canon 5d Mark II
Canon EF 16-35mm f/2.8 L II @ 16mm
ISO 200

Original photo from RAW in DPP 3.7.2.0 - no adjustments other than sharpened:

http://farm3.static.flickr.com/2755/4082362037_38b7fc269c_o.jpg

100% Crop converted from RAW in DPP 3.7.2.0 - No adjustments other than sharpened

Please notice the reflection of the bridge in the water. The shadows have not yet been raised; however the reflection detail has been obliterated by the banding.

http://farm3.static.flickr.com/2678/4083078852_fc0439a8fd_o.jpg

Same photo, shadows raised 50% using Shadow/Highlight adjustment tool in Photoshop CS3. This better demonstrates the problem - again you can clearly see the detail obliteration:

http://farm3.static.flickr.com/2593/4083078548_58a68605b5_o.jpg

Now for some examples post-repair. I deliberately looked for very bright subjects with shadowed areas to test with.

Canon 5d Mark II
Canon EF 24-105mm f/4 L @ 105mm
ISO 100

Original photo from RAW in DPP 3.7.2.0 - no adjustments other than sharpened:

http://farm4.static.flickr.com/3491/4082319975_f03456f073_o.jpg

100% Crop converted from RAW in DPP 3.7.2.0 - No adjustments other than sharpened:

http://farm3.static.flickr.com/2522/4083080154_9fa6afecf5_o.jpg

100% Crop converted from RAW in DPP 3.7.2.0, with shadows raised 100% using Shadow/Highlight adjustment tool in Photoshop CS3. You will notice some noise but not banding. Remember the shadows have been raised TWICE as much as in the bridge example above - doubtful that I would ever do this other than for demonstration purposes:

http://farm3.static.flickr.com/2766/4082320175_ae331c9881_o.jpg


Here is another post-repair example, same lens and ISO:

Original 100% crop:

http://farm3.static.flickr.com/2608/4082319761_fe42d2fcff_o.jpg

Shadows raised 100%. Note that it was able to recover the top edge of the window frame that was completely blacked out in the original with acceptable noise that I could clean up in post if I wanted to - fairly impressive:

http://farm3.static.flickr.com/2575/4082319417_9e99927d87_o.jpg

For the final post-repair example I will show a foliage shot with deep shadows - a particular nemesis for banding on the 5d Mark II

Original shot

Canon 5d Mark II
Canon EF 16-35mm f/2.8 L II @ 16mm
ISO 100

http://farm4.static.flickr.com/3501/4083079380_ebfe48a8ce_o.jpg

Original 100% crop from lower left:

http://farm3.static.flickr.com/2709/4083079070_a5488b3c9f_o.jpg

Shadows raised 100%, again a little noise but not bad:

http://farm3.static.flickr.com/2735/4082318981_4fc612b76a_o.jpg

Raising the shadows in these post-repair examples, especially to this degree, would have been virtually impossible prior to the repair without getting the crosshatched red patterns. The post-repair examples were able to perform far better at recovery than before, even though the shadowed areas were MUCH darker than the pre-repair example shown.

Whether this repair will be available as standard issue for users experiencing the banding problems or not I couldn't tell you. Despite the fact that many reports have surfaced of users having the same problem, to date Canon has not officially acknowledged it.


--Bob