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recently I acquired a sony ar7ii and have done about 2k photos with it. works amazingly, but occasionally i see these black bands.

i have no idea what is causing it, and how to prevent it. any insight would be appreciated! (

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The horizontal light and dark bands looks like a flickering issue, which is common with many artificial light sources. Some cameras have an anti-flickering setting. If such a setting is not available, you can try dropping the shutter speed to something like 1/40. If the problem goes away, you can gradually increase the shutter speed until just before banding reappears.

The problem is often associated with electronic rolling shutter. Unfortunately, the solution would be to adjust the readout time, which is out of your control.

Here is another effect associated with electronic rolling shutters:

image

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  • \$\begingroup\$ thanks!!! i've also noticed this effect outside, but it was at night so possibly caused by one of the street lights ? \$\endgroup\$
    – Sonic Soul
    Commented May 17, 2019 at 18:09
  • \$\begingroup\$ +1 for amazing info! but the other answer suggest possible solutions which appear to be reasonable :) \$\endgroup\$
    – Sonic Soul
    Commented May 17, 2019 at 18:25
  • \$\begingroup\$ Banding at night could be street lights, but would have to see the picture. Camera settings would also be helpful. \$\endgroup\$
    – xiota
    Commented May 17, 2019 at 23:31
  • \$\begingroup\$ I don't think the other answer is entirely accurate. At best, it contains some red herrings, such as the link to banding caused by fixed-pattern noise. Did you actually try the "solutions" to see if they work? Not marking an accepted answer is also an option. \$\endgroup\$
    – xiota
    Commented May 17, 2019 at 23:34
  • \$\begingroup\$ no i have not tried those things yet, answer unmarked \$\endgroup\$
    – Sonic Soul
    Commented May 30, 2019 at 20:57
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The banding seems similar to that from "rolling shutter", where parts of the image sensor are scanned sequentially during the flickering of fluorescent and LED lighting.

A few ways to avoid, or at least reduce, the problem:

  • Use fill light from a source that doesn't flicker, such as daylight or incandescent lamps.
  • Use a flash, either direct or bounced.
  • Adjust the shutter speed to get a full cycle of AC power, which is 50 Hz in many countries, but 60 Hz in North America. I.E., Use 1/25 or 1/50 second most places, 1/30 or 1/60 second in N. A.

Experiment taking photos with your camera of a plain white surface lit by fluorescent or LED lamps, using different shutter speeds, to confirm if that is the issue and to see how best to fix it. N.B. Some LED lamps are more prone to flicker than others. Also, some fluorescent tube phosphors have longer persistence than others, so you might observe slightly colored bands.

This may be similar to another question about banding, though.

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  • \$\begingroup\$ Using flash won't fix the banding problem in this question. Flash can also have its own banding problems. The banding in this Q is not at all related to banding caused by fixed-pattern noise. \$\endgroup\$
    – xiota
    Commented May 17, 2019 at 23:25

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