Underexposed

Updated 9:27 and 9:45 a.m. PST with further details from Canon USA announcement.

Canon has acknowledged the "black dot" problem that mars some shots taken with its new 5D Mark II camera and is preparing "correction firmware" designed to deal with the problem, the company said.

Canon's 5D Mark II full-frame SLR

(Credit: Canon)

"We are currently investigating ways to improve and/or mitigate these phenomena. An announcement will be made on the Canon Web site when measures to address these phenomena have been decided," according to a statement dated December 17 that appeared on Canon's Australian support and service Web site.

A later Canon USA service announcement was largely identical, but also said Canon is "examining measures to reduce or eliminate these phenomena by providing correction firmware."

Firmware fixes can be downloaded and installed, a much cheaper and easier process than the physical repairs the company undertook to help with Canon 1D Mark III autofocus problem.

Canon described the problem the same way many who've complained about it have: "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 percent or above on a monitor or if large prints of the images are made." For some examples, check farther down this post.

These magnified close-ups that Stephan Hoerold took with his Canon 5D Mark II show lights on a building at night. The dark spots appear to the right of the very bright areas. The three shots show images taken at ISO 100, ISO 200, and ISO 3,200. Photo used with permission.

(Credit: Stephan Hoerold)

The company also said it's looking into vertical banding noise that can show when shooting files in the sRAW1 mode, which produces a smaller file size than regular raw images.... Read more

Chuck Westfall

(Credit: Canon)

Some photographers have been frustrated with Canon's silence on the "black dot" issue that's afflicting its new EOS 5D Mark II camera, but the company plans to speak soon.

"Watch for an official Canon comment on this issue in the very near future," said Canon USA technical adviser Chuck Westfall in a Wednesday response to a question posted on his monthly question-and-answer column at The Digital Journalist.

The black spots appear to the right of very bright spots in some occasions, and many are wondering whether the issue is an unavoidable consequence of the sensor or something that can be altered with the camera's more mutable firmware.

Judging by Canon's earlier statements about issues such as the EOS-1D Mark III autofocus saga, though, it wouldn't be wise to count on a terribly revealing statement. This could well be at the stage of just acknowledging the issue still.

These magnified close-ups that Stephan Hoerold took with his Canon 5D Mark II show lights on a building at night. The dark spots appear to the right of the very bright areas. The three shots show images taken at ISO 100, ISO 200, and ISO 3,200. Photo used with permission.

(Credit: Stephan Hoerold)

The Canon 5D Mark II is the new fourth-place member of DxO Labs' test of image sensor scores.

(Credit: DxO Labs)

One verdict is in on Canon's EOS 5D Mark II: its sensor ranks very high on DxO Labs' test of sensor performance.

The black-spot issue notwithstanding, Canon's new full-frame SLR came in at fourth place with a score of 79.0, bumping Sony's 78.9-scoring Alpha A900 down a peg but still trailing Canon's top-end EOS-1Ds Mark III at 80.3. Nikon's D700, the closest rival to the 5D Mark II, is a notch ahead at 80.5.

More relevant for the potential upgrade market, new Canon SLR's score is significantly better from that of its predecessor, the 5D, whose score is 70.9. On a pixel-by-pixel basis, the 12.8-megapixel 5D's sensor actually has a lower signal-to-noise ratio, but when measured over an entire 8x10 print, the 5D Mark II's higher 21.1-megapixel resolution wins on that measurement.

The DxOMark Sensor test measures how well a camera's sensor fares when it comes to dynamic range, color depth, and low-light performance. The test doesn't measure any number of other camera issues such as autofocus, value, or image processing. But it's still useful given DxO Labs' engineering rigor and the central role a sensor plays in the abilities of a camera.

Pixel-peepers have been devouring DxO's new statistics; the curious can try this link to a comparison of the 5D Mark II, Nikon D700, and Sony A900. However, it should be noted, DxO Labs considers that scores must be at least of 5 points apart to be significant.

There's been much discussion about whether the $2,700 5D Mark II performs better than the $6,500 1Ds Mark III, which has the same resolution. The DxOMark tests give the edge to the top-end model based on its better color and dynamic range--the ability to capture both bright and dark regions--but the 5D Mark II wins out in low-light performance. Digging deeper into the charts, though, the 5D Mark II fares better in dynamic range at higher ISOs.

The sensor on Canon's 5D Mark II fares significantly better than that on the 5D. (Click to enlarge.)

(Credit: DxO Labs)

All these cameras perform better than the common herd by virtue of full-frame sensors measuring 36x24mm, the size of a full frame of 35mm film. Most digital SLRs have a smaller sensor that can't capture as much information overall, but those models are vastly more affordable.

Canon's EOS 5D Mark II

(Credit: Canon)

Some users have reported that photos taken with Canon's new $2,700 EOS 5D Mark II camera can be blemished with dark spots near areas with very bright highlights.

I first heard about the issue on the DP Review forums on Friday, but now one pixel-peeping user has come up with a fix spotlighted by Photography Bay: Disable for highlight tone priority, lighting optimizer, and noise reduction, according to commenter f_stops.

"No black dots," the photographer and new 5D Mark II owner reported on the posting, supplying before-and-after shots as proof.

Canon is checking into the issue. "We have been made aware of this and are looking into it," a Canon representative said Monday.

The spots appear on the right edge of some shots with very bright highlights.

One forum poster spotted a dark patch on a 5D Mark II video; it appears fleetingly at about 1:04 into the video.

Canon's EOS-1D Mark III

(Credit: Canon)

Hardware and firmware fixes have improved the autofocus performance of Canon's new EOS-1D Mark III camera, but it's still not up to the level of its predecessor, the photographer who first uncovered the issues in June said Monday.

Canon is offering some customers free adjustments to a mirror in the higher-end SLR and advising all customers to install updated firmware. The former improved the $4,500 camera's ability to focus on moving subjects in warm or hot conditions, and the latter helped when it's bright out, said photographer and consultant Rob Galbraith in a blog posting Monday. But problems remain, he said.

"In our view, there's more work to be done. In bright conditions, the EOS-1D Mark III still doesn't match the EOS-1D Mark II N; at times the two are close, and at other times the EOS-1D Mark III's autofocus performance is below what we consider acceptable," Galbraith said. "The culprit that continues to cramp the EOS-1D Mark III's autofocus style is bright sunlight."

Galbraith is based in Calgary, Alberta, but he made three trips to Phoenix in conjunction with Canon to test the camera in warm conditions. He's also shared innumerable photos with Canon engineers.

For all the gory details, check Galbraith's exhaustive 8,500-word piece, complete with high-resolution images and letter grades under different shooting circumstances.