At the beginning of December, users of Canon new Mark II 5D  DSLR have reported an issue with the camera which produces fine black dots on the right side of bright spots in images shot at night and at high ISO levels. The dots only become visible if the images are enlarged by at least 100 percent on a monitor or large-format prints are created. The problem was acknowledged by a Canon back on December 8th.

Canon posted a statement on its Australian support site acknowledging the problem, promising it is looking into the phenomenon to discover ways to improve and mitigate the issue.

Some Canon Mark II 5D users have found a workaround to eliminate the black dots, suggesting photographers disable the highlight tone priority, lighting optimizer and noise reduction.

The photographer, Stephan Horold, who is believed to have shot some of the very first photos that demonstrated the issue, believes the issue stems from different optics used in the 5D Mark II, as the 1Ds Mark III DSLR uses the same sensor and does not have the black dot issue. Horold goes on to say the black dot effect gets more pronounced as ISO levels increase.

Canon also announced it is looking into another 5D Mark II concern regarding vertical banding noise showing up when shooting images in sRAW1 mode. The setting produces file sizes smaller than regular RAW images. Before a definitive fix is found, Canon did suggest ways to eliminate this issue. It gave users three suggestions that will not produce the issue. They consist of setting the recording format to RAW or JPEG instead, setting C.FN II-3 highlight tone priority to 0: Disable if shooting in sRAW1 or using sRAW2 and setting C.Fn II-3: Highlight tone priority to 0: Disable.

Canon has promised that any permanent fix for either issue will be posted via a firmware upgrade on its global websites.

Via Electronista