OM-D EM-5 - High Iso Banding?

Started May 8, 2012 | Discussions thread
JL Auch
Forum MemberPosts: 84
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Re: OM-D EM-5 - High Iso Banding?
In reply to cbran, May 8, 2012

Okay. I have done extensive testing today to try and get to the bottom of this. I tested many variables. The best that I can come up with is this:

It seems to be related to the halogen light and/or electric box above the couch, that creates some sort of interference when the light is on. When I turn off the light, no banding with the 20mm. Also the banding seems most pronounced at 1/60sec and 1/30sec but it is still there at other shutter speeds.

Here is the kicker; I swapped lenses to the 14-42 kit lens, and bang! NO banding with the lights on at either 1/60sec or 1/30sec. The exact same lighting, tripod position, iso, and settings.

So I think cbran might be onto something. But if this is true, it is a real shame. The 20mm is a real gem of a lens and this is simply ridiculous.

I'll leave you to your own conclusions.

But what to do now? Return the 20mm lens?

-j

cbran wrote:

cbran wrote:

I noticed something similar yesterday when I used the 20mm on my OM-D and your thread prompted me to investigate more deeply.

MY CONCLUSIONS:

At high ISOs (primarily around 6400 for me) with RAW files I see banding ONLY WITH THE 20mm f1.7 LENS . Sometimes there is no banding at all, but most of the time it's there.

It is quite variable, however, both in distribution across the frame and in spacing .

For example, sometimes the banding affects the entire image; sometimes only the top 50%; sometimes only the top 85%. When looking at the thickness/spacing of the banding with 100% crops, sometimes I see 3 bands per inch on my monitor, sometimes 5 bands per inch, sometimes 8 bands per inch, and sometimes 15-20 bands per inch.

In addition to testing the 20mm lens, I tested a manual focus legacy lens (Zeiss 35mm f1.4) plus 3 other Panasonic lenses: the 14mm f2.5, the 45mm f2.8, and the 25mm f1.4. I also tested the Olympus 45mm f1.8. NONE OF THESE OTHER LENSES EXHIBITED BANDING in my tests.

Could it be that the 20mm lens itself is causing some kind of interference pattern? I haven't tested the lens at high ISOs in any other room than my office, but the fact that I don't see banding with other lenses suggests to me that any interference is coming from the lens itself, not other equipment in the room, though perhaps there is some weird interaction going on.

I will be happy to show crops of sample pictures as soon as I prepare some but wanted to share my results in the meantime.

I'd love to hear what others think about this and see results from other people's tests.

In reference to my post above, here are some examples of the banding using the 20mm f1.7 lens on my OM-D at iso 6400 (from RAW), 100% crops. The first picture shows the more widely spaced bands I referred to; the second picture shows more tightly spaced bands (spacing on other samples can be even tighter). The third picture shows how the bands are sometimes distributed over only the top part of the image.

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