Need some help in Sigma FP Color Shading corrections

[Chris DC]

Hi All:

I also posted this thread in the "Adapted Lens" forum:

I finally got some sun around home and tried out my newly acquired Sigma FP with my old Leica M39 LTM lenses made back in the 1950's; the 3.5cm. F3.5 Summaron and the 9cm Leica Elmar M39 lens.

Overall I am pleased with the results. Both lenses give interesting looking images and are plenty sharp in the center. The Summaron 3.5cm shows significant purple coloring especially in blue skies around the extreme left and right edges of the frame. I took a picture of a white wall and set a custom color shading setting for this lens. I needed to add(?) some red and some blue to get the white wall to be monotone but the correction is not perfect.

Then when shooting with the lens (3.5cm Summaron) I choose this custom color shading profile. In my view it is only marginally better. I suppose I'll have to play around more with settings. I wish the manual was more detailed in this feature.

Here are some shots with the Summaron and the 9cm Elmar. The Elmar has no edge color problems.


Lots of purple edges on the 3.5cm Summaron

View: original size


Less purple edging when the sky is less blue

View: original size


Less purple edging when stopped down too.

View: original size


This is a white wall after selecting the custom color shading profile-Not perfect!

View: original size

And here's the 9cm Elmar's performance:


9cm Elmar-A little vignetting but no color shift.

View: original size


9cm Elmar does well on distance landscape shots.

View: original size

Overall I am having fun and that was the point of this acquisition. The camera is neat and the EVF is very helpful.

I can say that the dust on the sensor is annoying and something I am not used to seeing. I've been an Olympus mFT for nearly 20 years and never once had to clean dust off my sensors. Oh well.

Anyhow, if anyone can chime in and explain the right way to use the color shading feature on the Sigma FP I will be grateful.

CDC

 

[D Cox]

The examples look like ordinary vignetting to me. You could try the vignetting fix in your processing software. I may be wrong.

I have not been troubled by dust on my fp. I always give a puff with the Rocket when changing lenses.

Don

 

[zstekar]

Other than with my Leica 50 f/2 on the Sigma fp l, I could never attain a pleasing color cast-free with the Leica 28 f/2.8. The green would show up more often than not, based on indoor vs outdoor for instance. I could never get rid of it fully. What helped the best was to take a picture of a monotone surface in a controlled environment.

 

[Chris DC]

Yes. I suppose it is tough to get past the physics of light.

The old adage..."better, cheaper, faster...choose any two" applies.

Small, fast, abberation free...you can have one or two of these lens characteristics but not all three!

Perhaps I will come across a smallish sized 35mm or 28mm lens to find that will behave a little better on the FP than the tiny Summaron I have.

Till then, I will keep the Summaron set a t F8 when blue skies are in the image!

CDC

 

[D Cox]

Yes. I suppose it is tough to get past the physics of light.

The old adage..."better, cheaper, faster...choose any two" applies.

Small, fast, aberration free...you can have one or two of these lens characteristics but not all three!

Perhaps I will come across a smallish sized 35mm or 28mm lens to find that will behave a little better on the FP than the tiny Summaron I have.

Till then, I will keep the Summaron set a t F8 when blue skies are in the image!

CDC

I have the Sigma 24mm f/3.5 which is small and aberration free. You could consider that.

Does a 24mm need to be fast ? You can use it with a fairly slow shutter speed.

Don

 

[Chris DC]

Thanks for the idea Don. It looks like a great companion to the FP. I will keep an eye out for one sometime.

On the other hand, I already have a very complete mFT system with lenses from 7-300mm. I got the FP specifically for my vintage film lenses and plan to acquire more vintage lenses as they come across my path (cheap!). I am quite satisfied by the optical performance on the FP overall.

I am having fun!

CDC

 

[Chris the Novice]

You could try the Voightlander 2.5 35mm Skopar - it's not vintage, but is very compact, good optics, and a pretty good price brand new.

 

[Chris DC]

I will definitely add this lens to my list to look for. Rather than going online to buy one, I think I'll just sit back and see what I stumble across in my travels. When I find something interesting, I'll post some samples.

CDC

 

[Chris DC]

Hi All:



Here's an update on the purple corners I have noticed when using the Sigma FP with an old 35mm rangefinder lens, the Leica 3.5cm Summaron.

It appears that perhaps the Sigma FP is a bit prone to the issue. I took essentially the same image with both the old Summaron 35mm and the new Sigma 45mm lens. With a vertical camera orientation, the uppermost blue sky at the edges of the frame looks purple with both lenses.

My other camera is a mFT Olympus which uses a 4:3 image format and I've never seen purple sky edging.

Here's the two images:




Taken with the Sigma FP and SIgma 45mm contemporary lens. The top edge has a purple tint.




Taken with the Sigma FP and the old Leica 35mm Summaron. More noticeable purple top edge.

I think I am beginning to like the unique character of this camera

CDC