Below is a question I wrote, then answered myself. I've kept the question in case it helps others. ~~Question~~ Please reassure me. Below is a crop from the eighth photo (taken as a JPG at iso1600 with the kit zoom) I took on my shiny new E-PL5. Is that banding an issue, or is it something I can resolve? Subscribe to see EXIF info for this image (if available) (pixel perfect version at Snapshots - Stuart's Photographs ) It's not all photos. A pic at 1/5s f3.5 iso1600 is fine, another pic identical but at 1/20s is not. So it could just be the under-exposed ones that are the issue and the bands are a natural consequence of demanding more than the sensor can manage (although it begs the question why the camera didn't auto-ISO above 1600 - although at that point it may have been set to a max of 1600). However, I have just taken another picture with the Panasonic 14-42 X at iso 5000 (1/3s and f3.5) and that same issue has occurred. The reason for trying again is to avoid interference from my PC (which was nearby in the first photo, but not in the one I just tried). Sadly I'm waiting for Lightroom to update before I look at any raw images, so can't check whether it's occurring with those. ~~Answer~~ Ok, I've been writing this note for 45 minutes now. In that time I've had a play with the Noise Reduction (NR) and the Noise Filter (NF) settings. Eight photos, all of the same scene (shot handheld, so minor differences), a dark room with lights behind the window, all at 1/3s f3.5. With NR set to "Auto", I sometimes get those bands, and sometimes don't. With NR set to "Off", I always get those bands, whatever NF is set to. With NR set to "On", I never get those bands, whatever NF is set to. This basically suggests that forcing NR to 'on' will remove those artefacts from JPGs. I'll probably find out that this is all JPG artefacts and no issue at all once I start using the RAW images, so I'll experiment again once I can process the RAW images. erm. ORF images. Incidentally, NR 'On' and NF 'Low' gave a different interference pattern that's not visible in the JPG at full size, but which my graphics viewer of choice created as part of rendering at screen size (rather than full size). Finally, in a very subjective interpretation of which settings work best, I prefer NR 'On' and NF 'Off' - but with NR 'On' and NF 'High' as second favourite, so I suspect other factors are at play here However, this impromptu test has made one thing clear: If you're doing low-light photography, set Noise Reduction to 'On'. Note : If you're not doing low-light photography, it may be better to leave NR on 'Auto', as the manual notes that it "requires about twice the time needed to record the image". However, I was still getting the 7-8 fps shooting in RAW so in real use it's not going to impact me. Anybody had similar or divergent results? Is this related to the (lack of) AA filter? Am I just weird?