2
\$\begingroup\$

I have a Canon 10D DSLR. Sometimes I get weird patterns in my pictures. What causes this pattern, and how can I eliminate or prevent it?

enter image description here

Improve this question
\$\endgroup\$
3
  • 1
    \$\begingroup\$ Which ISO was selected ? Does it appear only in low light situation ? Do you see this pattern, after taking an image with the cap on the lens (no light coming to the sensor, close your viewfinder) and having in post increased the exposure ? \$\endgroup\$
    – Olivier
    Jan 16, 2017 at 18:36
  • \$\begingroup\$ Did you rotate the original image? Could it be related to the issue discussed here? \$\endgroup\$
    – osullic
    Jan 16, 2017 at 23:47
  • 1
    \$\begingroup\$ Sorry for late reply but apparently there is no pattern in the original picture. It looks like some transfering methods are causing this problem. (Computer to phone) \$\endgroup\$
    – Darkerthanapoem
    Jan 17, 2017 at 16:29

3 Answers 3

Reset to default
2
\$\begingroup\$

I might be wrong, but unfortunately I think that is just the pattern of your sensor's noise, meaning sensitivity of your sensor was so high, it captured byproduct of it's overheating.

This happens because camera wants to compensate for low light, making sensor more sensitive to capture more details. Sensitivity of a sensor is regulated by ISO, higher the ISO, higher the noise.

This is normal and every camera has this when using too high ISO. Only way to fix that is shooting in conditions with more light, so your camera doesn't have to use high ISO.

If you take a picture in conditions with more light, but the problem persists, then it might be a problem with the sensor.

Improve this answer
\$\endgroup\$
3
  • \$\begingroup\$ If the above answer were correct, this problem would be endemic to every astrophotographer, and it's not. To me, it looks like some sort of constructive interference, though I can hardly figure out which. That's certainly weird! \$\endgroup\$
    – Knob Scratcher
    Jan 16, 2017 at 18:33
  • \$\begingroup\$ @KnobScratcher some cameras are more prone to pattern noise than others. Apparently, part of the problem is poor or too-aggressive algorithms in noise reduction, in dark areas of images that are underexposed. \$\endgroup\$
    – scottbb ♦
    Jan 16, 2017 at 19:45
  • \$\begingroup\$ Higher ISO isn't the only way to take pictures in the dark. Astrophotographers will make good use of aperture and shutter speed. They may also make use of cameras that have much better high-ISO performance. Take a look at the exposure triangle: photo.stackexchange.com/questions/6598/… \$\endgroup\$
    – laurencemadill
    Jan 17, 2017 at 10:00
2
\$\begingroup\$

I believe this is what's called a Moiré Pattern. That's when two patterns--the background you're shooting and the camera's sensor--are overlaid and produce a third pattern. I'm guessing the background has some sort of texture that doesn't line up with the camera's sensor pattern, so in some places the sensor picks up the pattern and in others, it doesn't, thus producing the Moiré pattern. It's worth noting that the Canon 10D had a resolution of 6.3 Megapixels, which may be course enough to produce some Moiré patterns.

If the background in question did not have any pattern or texture, however fine, then this is wrong. If so, I can retract it.

Improve this answer
\$\endgroup\$
2
  • \$\begingroup\$ It's a pretty regular pattern if it is indeed Moiré. Most Moiré has at least some bit of irregularity. \$\endgroup\$
    – scottbb ♦
    Jan 16, 2017 at 19:48
  • \$\begingroup\$ @scottbb, yeah; the camera and background would have to be almost perfectly aligned. It could be a combination of noise and Moiré, which I didn't think of when I posted this. \$\endgroup\$
    – BillDOe
    Jan 17, 2017 at 20:38
2
\$\begingroup\$

I found this problem fascinating enough to research a suitable answer.

1) This is NOT Moire interference; as was mentioned above, the grid is far too regular (in both vertical and horizontal direction.

2) This is also NOT noise banding resulting from working the sensor too hard. The banding, again, is far too regular and nothing in the image suggests an unusual exposure which, in fact, looks pretty typical.

3) Some internet sleuthing suggests that this " Grid Banding" processing artifact plagues a few generations of Canon CMOS sensors, going as far back as 2008 and the 5D Mark II (see this link for a cursory description: https://blog.kareldonk.com/canon-eos-5d-mark-ii-barely-worth-it/. According to several users, this grid banding shows up in relatively underexposed parts of an image at fairly low ISO (like the OP's image) and is even worse when recording video.

This link (http://www.dvxuser.com/V6/archive/index.php/t-207542.html) describes a 7D users experience with this problem and what Canon did to repair this "unbalanced A/D channels" issue....at least partially. Apparently, there is no "user error" in creating this artifact, it is a known issue with Canon CMOS sensors, and may be repairable by Canon, or at least partially mitigated.

Improve this answer
\$\endgroup\$
0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.