Sigma DP1 - "green vignetting"

Started Feb 26, 2008 | Discussions
n1x0n Regular Member • Posts: 220
Sigma DP1 - "green vignetting"

Have anyone noticed the strange greenish vignetting in almost all Sigma DP1 samples?

http://www.sigma-dp1.com/sample-photo/

Most obvious in DP1-015, DP1-010, DP1-014...

Inspectoreleven Forum Member • Posts: 65
Re: Sigma DP1 - "green vignetting"

I can sort of see what you might be talking about it #010, but it could very easily be natural coloration in that one, and I don't see anything in any of the others. I think you're imagining things.

SandyF Forum Pro • Posts: 14,962
Re: Sigma DP1 - "green vignetting"

if you're referring to the blowing sand/haze/coloration of the distance in the sand dune photo #10, I believe the photo was taken at an extremely windy time on the sand dunes... one might say in a sand storm...

as a side note, when I was on the dunes the next morning, all was still... and the ripple patterns were still undisturbed by footprints.
Best regards, Sandy
http://www.flickr.com/photos/sandyfleischmann (Death Valley, work in progress)

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Kendall Helmstetter Gelner Forum Pro • Posts: 20,587
Re: Sigma DP1 - "green vignetting"

n1x0n wrote:

Have anyone noticed the strange greenish vignetting in almost all
Sigma DP1 samples?

http://www.sigma-dp1.com/sample-photo/

Most obvious in DP1-015, DP1-010, DP1-014...

I don't think so, I don't see this at all in 015 when I measure the corners. 014 looks a little like that is occuring, but that could easily be misleading because of the terrain - the center is very white from salt minerals but the surroundings are more of the earthen color in that area of Death Valley, which actually has a lot of green color to it (lots of copper all around).

In 10 it's hard to tell, but as Sandy said in the distance you have haze from all the wind blowing sand all over, and even in the foreground sand is continuously blowing across the dune. The light on sand can change depending on angle... only the lower right corner looks to have any extra green in it to me, and again I could see that being the angle of the sand at that point. The sand to the far left looks completely fine.

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Jonathan Demarais Veteran Member • Posts: 3,607
Re: Sigma DP1 - "green vignetting"
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Oh yeah! Looks like that angle of incidence problem is plaguing them.

'I cried because I had no E-3. Then I met a man with no E-510'

(unknown member) Veteran Member • Posts: 3,441
Re: Sigma DP1 - "green vignetting"

Have anyone noticed the strange greenish vignetting in almost all
Sigma DP1 samples?

Yep there must be a problem with the Lens...

ShutterFlutter Regular Member • Posts: 225
Re: Sigma DP1 - "green vignetting"

glaucoma?

Kendall Helmstetter Gelner Forum Pro • Posts: 20,587
Give an example then

Carsten Pauer 2 wrote:

Have anyone noticed the strange greenish vignetting in almost all
Sigma DP1 samples?

Yep there must be a problem with the Lens...

Except that f you look at the images, there is nothing consistent as far as a green tint.

Therefore there must be a problem with the conclusion more than the lens...

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Robert F. Tobler
Robert F. Tobler Senior Member • Posts: 1,149
The original poster is onto something...

The original poster is onto something.

A lot of the sample images exhibit the
problem. It can be most easily measured
in image 15. Open the image in Photo-
shop, run a gaussian blur with radius 30
over the image, and then use the pipette
in the Adjustment > Levels tool to set the
color balance based on various points in
the image. [You can also just read off the
numbers as you run the cursor over the
parts of the blurred image without using
the Adjustment Levels tool, but the numbers
are not as easy to compare...]

You will notice a significant shift from
reddish to greenish color balance, based
on the location of the sample in the sand
that should have the same whitish color
across the image. And this shift is due to
a reddish center and greenish corners of
the original image.

Once you see the problem in this image,
you will notice it in quit a few of the
others. It is also very obvious in images
20, 21, and 34...

Greetings
--
Robert F. Tobler
http://ray.cg.tuwien.ac.at/rft/Photography/

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Robert F. Tobler
Robert F. Tobler Senior Member • Posts: 1,149
Please ignore (nt)

Greetings,
--
Robert F. Tobler
http://ray.cg.tuwien.ac.at/rft/Photography/

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brittonx
brittonx Senior Member • Posts: 2,445
Re: Give an example then

I'm wondering if any of the following could have been the issue:

A.) Impact from lens hood (if it was used)
B.) Something smudged on the lens
C.) Technical issue with a pre-production camera (Wonky sensor etc...)
D.) Some other thing we can't think of.

Looking at the various DP1 samples across the web, the color issue at the one edge is not a common or systemic issue.

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rjjr Forum Pro • Posts: 14,769
Re: Sigma DP1 -

I'm surprised no one took a picture of a well lit blank wall to check the wide angle lens for vignetting.

OP n1x0n Regular Member • Posts: 220
Re: Give an example then

Kendall, glad to have you here! Thats what i call "first hand information"

Don't get me wrong, i've waited for camera like DP1 for years and i'll be more than happy to find out that there's nothing wrong with it.

Still i trust my eyes... no glaucoma here, thank you ShutterFlutter and my calibrated monitors.

Here are files in question, the only "tweak" is levels adjustment to stress the issue:

Does anyone find that normal?

OP n1x0n Regular Member • Posts: 220
Re: Sigma DP1 -

Well, technically it's not vignetting... it's more like color cast without any measurable density falloff.
See the images in my previous post.

Graystar Veteran Member • Posts: 8,373
Re: Sigma DP1 - "green vignetting"

Is the DP-1 too sharp? Interesting thing about DP1-015...to me the photographer has a cut-&-pasted quality.

Could also just be me

Sarah J Connor Regular Member • Posts: 130
So you processing the pictures to get these

so called green tint/cast? you can alter anything from an intended use by any kind of tweaking, I can put noise in a Canon, like wise make Nikon sky red by post processing. These pictures that you just show do not resemblant any that I see at the official site, they had been altered to fit your argument. Look more like a witch hunt to me, pardon my expression. Some people just out right weir.

n1x0n wrote:

Kendall, glad to have you here! Thats what i call "first hand
information"

Don't get me wrong, i've waited for camera like DP1 for years and
i'll be more than happy to find out that there's nothing wrong with
it.

Still i trust my eyes... no glaucoma here, thank you ShutterFlutter
and my calibrated monitors.

Here are files in question, the only "tweak" is levels adjustment to
stress the issue:

http://img153.imageshack.us/img153/416/sigmadp1015sek9.jpg
http://img238.imageshack.us/img238/1731/sigmadp1020spk6.jpg
http://img153.imageshack.us/img153/1377/sigmadp1008scd5.jpg

Does anyone find that normal?

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Sarah

Joseph S Wisniewski Forum Pro • Posts: 34,888
Effect of the IR filter...

n1x0n wrote:

Have anyone noticed the strange greenish vignetting in almost all
Sigma DP1 samples?

http://www.sigma-dp1.com/sample-photo/

Most obvious in DP1-015, DP1-010, DP1-014...

That's a common effect when you have a dichroic IF filter in front of a sensor and the lens's exit pupil is too close to the sensor.

At this level, it's a pretty trivial software fix. I wouldn't worry about it.

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Normally, a signature this small can't open its own jumpgate.

Ciao! Joseph

http://www.swissarmyfork.com

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alisD Contributing Member • Posts: 627
Re: Sigma DP1 - "green vignetting"

Graystar wrote:

Is the DP-1 too sharp?

you might be on to something there. but you could easily take your screen protector off the lcd screen and glue it over the sensor. should return some new users to comfortable territory

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my makeshift collection of photographs:

http://flickr.com/photos/56776653@N00/

Kendall Helmstetter Gelner Forum Pro • Posts: 20,587
Not systematic though...

n1x0n wrote:

Here are files in question, the only "tweak" is levels adjustment to
stress the issue:

http://img153.imageshack.us/img153/416/sigmadp1015sek9.jpg
http://img238.imageshack.us/img238/1731/sigmadp1020spk6.jpg
http://img153.imageshack.us/img153/1377/sigmadp1008scd5.jpg

Does anyone find that normal?

Some of it no, but I would note that it doesn't always occur in all corners, nor does it seem to happen in all images. It could be a lot of different things, but I don't think it's something that's a general case. It could even be related to the nature of pre-production equipment...

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rjjr Forum Pro • Posts: 14,769
Yes, but...

That simple test for optical vignetting would also any color cast issues on the edges.

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