NX200 colour cast

Started Feb 29, 2012 | Discussions
Zdman
Regular MemberPosts: 195
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NX200 colour cast
Feb 29, 2012

So the NEX7 has a serious problem with some manual wide angle lenses and a magenta colour cast which is speculated to be a micro lens or IR filter problem (the NEX 5n doesn't though). This caused a bit of concern with me as the NX200 at 20mp was also nearing the NEX7 pixel count and I like using manual lenses. At first I saw nothing with the NX200 so I relaxed but the other day when taking a picture of a grey tile I noticed something and set about experimenting further. The NX200 seems to have a similar problem but to a much lesser extent. This is one of about 50 shots I took of a concrete wall testing but all the rest have almost the same shift in color from magenta to green from left to right.

You might not notice it at first but I've put the NX100 picture below (which shows no colour shift although maybe a bit from top to bottom).

The last photo is the NX200 one with high saturation to make it easier to see.

Now I've checked and this happens for multiple lenses (less sevre with telephotos but still there) and I suspect its my IR filter thats out of alignment. I'd be interested if other users of the NX200 with some manual glass could do a similar test to see if this is NX200 wide problem or limited to my copy. Strangely its almost absent on the native lenses (20-50 and 30mm) but you can see a consistent pattern when you turn up the saturation so perhaps the camera is doing something to reduce it then?

Samsung NX100 Samsung NX200 Sony Alpha NEX-7
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jj74e
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Re: NX200 colour cast
In reply to Zdman, Feb 29, 2012

oh wow, smart move to add in that high saturation photo- i was going to say that it might just be our eyes playing tricks on us before i saw it.

but interesting find....though i'm sorry to say i can't say anything about it since i don't use manual lenses.

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Mescalamba
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Re: NX200 colour cast
In reply to Zdman, Feb 29, 2012

Yes, camera can do something to reduce that (and most likely does). You can too, there are few ways. One is CornerFix, another one is colorshift profiling in Capture One software.

Native lens are probably profiled and designed with this in mind (although they perform rather poorly in corners on NX200 so I guess profiling wasnt perfect).

Color shift is caused by lens design causing light rays to reach sensor in too sharp angles. It can be cured by either lens profiling (thats what Leica did with M9), or with aligned microlens (Ricoh did that with M-module).

Or simply use some SRL lens that have long flange-focal-distance. Best choice would be probably Nikon F mount and similar. Longer flange-focal distance means that rays simply cant go in wrong angle (cause they would hit lens mount :D).

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Zdman
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Re: NX200 colour cast
In reply to Mescalamba, Mar 1, 2012

Mescalamba wrote:

Yes, camera can do something to reduce that (and most likely does). You can too, there are few ways. One is CornerFix, another one is colorshift profiling in Capture One software.

Native lens are probably profiled and designed with this in mind (although they perform rather poorly in corners on NX200 so I guess profiling wasnt perfect).

Color shift is caused by lens design causing light rays to reach sensor in too sharp angles. It can be cured by either lens profiling (thats what Leica did with M9), or with aligned microlens (Ricoh did that with M-module).

Or simply use some SRL lens that have long flange-focal-distance. Best choice would be probably Nikon F mount and similar. Longer flange-focal distance means that rays simply cant go in wrong angle (cause they would hit lens mount :D).

Actually this is from an R mount lens and the Nikons behave the same. I imagine it would be worse for an M mount though. I was unaware that Capture One had that profiling so I'll investigate that. I'd be interested to see if others have a similar pattern.

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Ariston
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Re: NX200 colour cast
In reply to Zdman, Mar 1, 2012

I have no chance of trying it out on M mount lenses, but I'll see if I could get an R mount lens or Nikon one.

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Zdman
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Re: NX200 colour cast
In reply to Ariston, Mar 1, 2012

Seems Rawtherapee has a tool to correct this called flat field correction. I still have to give it a try though.

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Mescalamba
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Re: NX200 colour cast
In reply to Ariston, Mar 1, 2012

M-mount lens doesnt fit, flange focal distance is too long. Its possible if you dont care about replacing whole mount. But Im afraid color shift will be as bad as in NEX-7.

If it produces color shift with Leica R lens it does prove something I thought for long time now. Samsung sensor is too "deep" or thick if you want. Which most likely means, its not classic CMOS (those are quite flat). Im pretty sure previous 14 mpix Samsung isnt "true" CMOS, but most likely hybrid between CCD and CMOS. Cause it does behave like CCD. Perfect color separation, great resolution at base ISO. Not so good high ISO. And takes pretty good long exposures during night. Which all seem much more like CCD than CMOS. I guess Samsung suceeded where Panasonic failed, and thats in mixing together best of CCD and CMOS.

Ariston wrote:

I have no chance of trying it out on M mount lenses, but I'll see if I could get an R mount lens or Nikon one.

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Zdman
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Fixed with RawTherapee
In reply to Mescalamba, Mar 2, 2012

Managed to fix it with RawTherapee's flat filed correction. All I need is a shot of a solid colour like white, unfocused and at the same aperture and point RT to it and it fixes it. RT really is impressive.

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hpchan
Contributing MemberPosts: 640Gear list
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Re: NX200 colour cast
In reply to Zdman, Mar 7, 2012

Try some Nikkor AFS lenses that have recent design for flare free control.
All old lenses included nikkor AF near all have flare problems if unmodify.

The case seem to be multi reflection leak at lenses core as silver metalic build inside for the days there were no high iso over 400. Now we have 128,000/256,00 high iso sensors.
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