lumix GF1 colour shift with Nokton f1.5

[leon]

HI

I'm very new to digital cameras as a whole. I've got a lumix GF-1 that I'm using an adaptor to mount my CV 50mm nokton f1.5 on. I'm usually a MF and LF film user, but I have to say this camera and lens combo has really re-ignited my interest in smaller camera-photography.

I'm noticing that, when in auto white balance mode, images get progressively cooler as the aperture gets smaller.

f 1.5- f5.6 on the nokton show roughly the same colour rendition the kit zoom that came with the camera, but f8 and above are markedly cooler.

This isn't really a huge problem as it works fine when I set the white balance mode manually, but it's irking me a bit as to why it might happen.

the Kit zoom keeps a steady colour rendition throughout no matter which WB mode I select so I doubt it's a fault with this particular camera?

 

[khaki8]

Don't have an answer for your question but am curious about how accurate your focus is with the manual lens. Using the same camera with a Sonnar M. I like using this setup as I can see immediately what the aperture setting is doing unlike my film cameras. By the time I get film back I never know what the setting was.
I just ordered another adaptor as the one I have wobbles a bit and I think it does not focus well at infinity.

 

[leon]

no problems with focusing Khakhi8. And the shallow DOF at f1.5 is superb for portraits. I 'm struggling with no viewfinder though - need to get an EVF.

 

[JoeV]

This is a total SWAG (Scientific Wild-A@@ed Guess), but perhaps there's a white balance sensor mounted on the periphery of the imager chip itself, that's getting some stray reflection from the lens and/or adapter. You could try fashioning a rectangular light baffle at the rear of the adapter, permitting light from the lens to strike the imager but not any wider than its edges.

I've also heard of some type of chromatic aberration that colors the image (secondary CA??), but I wouldn't expect it in this quality of lens.

Again, both of these are mere suppositions, but there you have it.

~Joe

 

[leon]

Thanks Joe. the lens is fine with colour print/ slide on my bessa r3a, so it's got to be something to do with the AWB functioning.

A guy on another forum reminded me that the dedicated AF lenses dont stop down until the exposure, so the scene is always metered at full aperture. Whereas, with the manual "legacy" (I hate that term!) lenses, the camera has to meter when stopped down. This must be throwing the AWB out somehow making it think the scene is warmer than it is and setting a cooler tone to compensate. I think you might be on to something with the sensor idea.

I think I'll email panasonic to see what they have to say (should have thought of that first!)

Either way, it's just a quirk really. Interesting non-the-less though.

 

[spiderfrank]

I didn't notice this with my Nokton 50/1.5 on the Olympus E-PL1, but I seldom go more close than f5.6 (on a micro 4/3 it's like an f11 on a 24x36 mm, so it give a lot of dept of field ), but I want to make some test, one of these days

 

[ampguy]

Your lumix is probably fine

Your lumix is probably fine

I've noticed some odd color shifts with the Nokton 50/1.5, on film and RD1s, so it's probably best used as a b/w lens.

Also, on AWB, I've generally found Canon, Fuji, and Nikons to work better in tricky lighting than Panasonics.

Your lumix is most likely fine. You may want to get a coffee filter AWB portable setup, or a commercial white balance filter.

HI

I'm very new to digital cameras as a whole. I've got a lumix GF-1 that I'm using an adaptor to mount my CV 50mm nokton f1.5 on. I'm usually a MF and LF film user, but I have to say this camera and lens combo has really re-ignited my interest in smaller camera-photography.

I'm noticing that, when in auto white balance mode, images get progressively cooler as the aperture gets smaller.

f 1.5- f5.6 on the nokton show roughly the same colour rendition the kit zoom that came with the camera, but f8 and above are markedly cooler.

This isn't really a huge problem as it works fine when I set the white balance mode manually, but it's irking me a bit as to why it might happen.

the Kit zoom keeps a steady colour rendition throughout no matter which WB mode I select so I doubt it's a fault with this particular camera?

 

[Paul T.]

My uneducated guess would be that part of the programming for AWB relies on the fact that, in low light levels, the light source is more likely tungsten.

 

[ferider]

What Paul said.

 

[leon]

My uneducated guess would be that part of the programming for AWB relies on the fact that, in low light levels, the light source is more likely tungsten.

superb point Paul. that explains it perfectly. thanks.