Panasonic 20 banding on Olympus bodies - Fact / Fiction / Definable formula?

davidzvi

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There have been several threads over the years, but I'm not sure I've really seen one on 20mp Olympus bodies.

Also I'm not saying it's a fact or fiction. But I thought it would be nice to see from those that have experienced banding to post images and setting. Maybe if we get enough examples we can see if there's a repeatable recipe that causes it so we might be able to avoid it.

No I don't have the P20, but I have two 20mp bodies and am considering one.
 

davidzvi

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Fiction, I've used it extensively on all my oly bodies with no banding or purple haze...

Must not smoke enough...?
I know of at least one member that would disagree. But we were chatting in a PM, so I will leave it up to them if they want to reply.

Personally I think it may be something like the GX8 shutter shock issue. "If you do this with these settings you might see it". Which is why Panasonic released a FW update to switch to E-Shutter under those specific conditions (as I understand it, I'm not a GX8 user so I didn't really follow it that closely).
 

Machi

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It's different for every body. I did in the past tests for E-M10II and banding was dependent on ISO.
Now I'm simply not using ISO at which banding occurs (from 800 to 1600) and everything is fine.
Unfortunately I still don't have 20mpix body so I cannot comment on that but it looks (from the lack of complaints) that new cameras should be OK.
 

agentlossing

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When I used the original EM10 and P20 combo, there was 100% banding in the files whenever I tried lifting shadows. Anyone who would say there wasn't was smoking something. But I have no experience with Oly 20MP sensors, and since the banding only appeared to me in PP, it's certainly possible that more flexible RAW files could fix the issue. It's certainly there for older 16MP sensors though, unless you never wanted to edit the RAWs.
 

Egregius V

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It's been quite a while since I've seen a new thread about this problem, David!

Yes, it's a real problem. Olympus acknowledged it in 2012 and claimed to be working on a fix. Panasonic also acknowledged the problem in writing. Neither company has shown any interest in the problem since then.

I tested the problem extensively a few years ago on five camera bodies and am happy to share my findings in summary. Others will have different experiences and conclusions because of different testing methods and conditions.

The banding with the 20mm f/1.7 and bodies with a 16MP Sony sensor is 100% reproducible under the right conditions. One way is to underexpose and lift shadows. If you really want to try that, a very reliable approach is to shoot in a dark room with a bright light source in the frame, preferably a window with venetian blinds, because it's a source of strong natural light and creates the contrast needed to reproduce the problem. Expose as you wish and lift the shadows in post to make noise more visible. If you stage and meter the scene correctly, you'll get your banding in the shadows. But this same approach can also reproduce the banding with correct exposure and even low ISO. The super-high contrast of the scene is the key here. For reliable production of banding, the scene must have very high dynamic range and a big enough region of shadow that you can see a noise pattern in it. And to further complicate matters, I've discovered that the span of the noise pattern across the sensor will vary from camera to camera. My E-M10 showed the banding only across the top and bottom regions of the frame (landscape orientation). My E-M5 II shows it nearly across the whole frame, except for a gap along the top of the frame where there is very little. My E-PL5 showed a slightly different configuration as I recall. (I still have the images showing all of this, but am not willing to fetch them and start cropping them for demonstration right now.)

Despite many claims, including from Olympus, that the problem is dependent on ISO, I found that this is generally not the case in controlled testing. Maybe my test method was flawed - I don't know. But for me, the visibility of the problem was actually more dependent on aperture. In a controlled test, all else being equal, the problem is nearly invisible at f/1.7 and becomes more visible as the aperture is stopped down. Changing ISO while keeping the aperture the same doesn't change the noise pattern or make it more or less visible. I believe that in practical shooting conditions, due to exposure decisions being made, there is often a correlation with high ISO - but I don't think it's a causal relationship. The fact is that lifting shadows effectively makes noise more visible, and high iso tends to produce more noise.

I'm not saying the problem isn't visible at f/1.7. Nor am I saying that the problem only occurs with very high contrast/HDR. It can be very visible at f/1.7 if one really tries to lift the shadows to make noise more visible. And it can show up in low-contrast scenes (I've seen that myself). I'm talking about a series of controlled tests that enabled me to reproduce the problem very reliably. In these tests, I exposed correctly for a very difficult indoor scene and closely examined the RAW and JPEG images from the camera. I did not have to elevate the shadows in post to see banding.

In short, with the 20mm lens, banding can be reproduced very easily at any iso and aperture once you know how. Interestingly, the same noise pattern can also be seen with the 14mm/2.5 pancake - but I found the problem so hard to reproduce with that lens (and so hard to see) that I had to shoot at iso 6400 or above, with shadow areas lifted strongly due to severe underexposure. It's possible to uncover banding with a few other lenses, but doubt very much it's the same banding with the same cause. I read one report years ago of a user seeing a banding pattern in noise with an Olympus 75-300 II. I have never been able to reproduce that in tests or in practical situations.

So what are the solutions with the 20mm lens? I found several:

- Use an electronic shutter if your camera has one. While a certain kind of banding can occur with e-shutters from rapidly-changing artificial light sources and even in skies sometimes, I have thus far not been able to reproduce the banding pattern that is characteristic of the 20mm lens when using e-shutter. I've seen a few claims that it can be done, but am not convinced it's a cause for concern.

- Use exposure bracketing to capture a very high dynamic range, then merge the frames in HDR software to taste. Solves the problem very nicely, unless there's movement in the scene.

- Use a different sensor. So far, I haven't reproduced the problem myself with a 20MP sensor (E-M1 II) or with the 16MP sensor in my Panasonic GX85. The few reports I've seen of banding with the 20MP sensor and the 20mm lens haven't been backed up with enough evidence to convince me it's a concern.

- Try to remove the banding using Dfine 2 in the Nik Collection (the old, free Google release or the current DxO release - doesn't matter). It's pretty good at handling this type of banding in noise.

Sorry - I haven't tested hi-res modes or a variety of 20MP cameras. I'll leave all that for someone else if you don't mind. :laugh1:
 
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mfturner

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@Machi , thanks for linking to your older reviews, which also linked to the dpreview thread. I love the idea of this lens, but have never bought one because of uncertainty of this issue. I've enjoyed getting away from my old Canon's read pattern noise. However, with my PM1, the p20 would be a nice lens, and I've not read of complaints with that combination.

Reading the old dpreview thread, i don't think they got quite to the bottom of the issue, but they might have gotten close. The competing EMI/ supply noise hypotheses are strong candidates, and either would explain the variability in the effect's presentation. They might also explain why multiple Olympus bodies might have a similar interaction, since supply regulation is often relatively unchanged between similar products. If i had this lens, and the effect bothered me, i might acquire a 10mm extension tube to use as a sacrificial socket, to see if separation of the supply (or just altering it with, i dunno, a 1uf cap) might affect it. It would be funny if a tube alone would be enough to make it go away, I've not seen discussion on that.

Edited, ignore the below, i just recalled that if they disconnect electronics in the lens, the problem goes away...

[I never quite understood why they gave up on optical possibilities so quickly, a diffraction interaction with sensor specific microlenses whose effect varies with color and light intensity for example. I might imagine that this may give more complex banding patterns, but i dunno.]
 
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davidzvi

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Thanks for the details and links to older threads. No I haven't seen much about it lately and have been thinking the P20 would go very nicely on my Pen F.
 

rezatravilla

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Thanks for the details and links to older threads. No I haven't seen much about it lately and have been thinking the P20 would go very nicely on my Pen F.
same here. Well between P20 or PL15mm actually.
 
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