X2D - Color Shifting Across the Image

[Reddott]

Hi, I'm new to this forum and will apologize for a rather long post in advance. I'm a very recent owner of an X2D along with the new 38mm & 55mm lens. While I'm still learning this camera, I'm not new to photography or post processing. This past weekend was blessed with some heavy fog and I took out the X2D to grab some shots around a local lake. Looking at the images in Phocus, I noticed a very consistent color shift from the edges of the frame compared to the center. All shots were taken with the 38mm lens. The day was very flat with no sun. I'm showing one of the shots (not a keeper but the best of the lot with the most even sky/lake tonalities), as my example of the color shifting I'm seeing. Today I took a look at this shot again in Phocus and exported jpeg images which are posted here. I brought them into PhotoShop to take CMYK readings across the image at the left, right and center (center/fog bank along the water edge). The images exported are numbered 0000, 0002 and 0004. The first being a straight export without any adjustments / no lens correction. The second with lens correction only and the last with lens correction and an adjustment layer in Phocus where a circular mask was applied and the tint adjusted to remove this color casting.
Today I shot a white wall with both the 38mm and 55mm and have included those as well (0007 & 0008). Both of those shots were brought into Phocus and had lens correction applied and exported as jpeg files. I brought these into PhotoShop and again took CMYK readings along the center of the images at the left, right and center points. The CMYK readings are included below.
Is this effect being caused by the lens or camera or possibly user error? The 55mm seems to be less affected by this than the 38mm. If you look at the images and the readings, the left side of all the images seems to be more saturated than the right side. I found this as well with the two images of the white wall. In fact all images seem to be the most saturated/darkest in the lower left hand corner. I do not have a science/math background and my tests are about as uncontrolled as you can get, but this is what I'm seeing simply using the camera. Is the sensor contributing to this effect or is this optics only? Do I have a bad camera or lens and what should be done? I would imagine I could create a simple correction mask and just apply it to every image that gets imported and that should solve it. I just don't know if the effect I'm seeing would be consistent across all images or varies under different shooting conditions.
I would greatly welcome some feedback and insight from this community.



View attachment bed9bc5635544e9ca0708b267b31b748.jpg
Image no correction exported from Phocus



View attachment b276edaa66ad4d489e8efb953f33d33c.jpg
Same image with lens correction applied and exported from Phocus



View attachment b83b1cf7873e4b599c5d28abee7b17bc.jpg
Same image with lens correction and mask applied to correct tint. Exported from Phocus.



View attachment 6635685d5d43490aa55104fd292112c5.jpg
White wall shot with v38mm. Lens correction applied and exported from Phocus



View attachment e83002480e524440b18416928706fa45.jpg
White wall shot with v55mm. Lens correction applied and exported from Phocus




CMYK readings taken in PhotoShop for each image.

 

[AZ Steve]

It is interesting nobody is commenting on this. At a minimum it looks like the 38mm lens is not delivering symmetrical illumination. Come on guys.

 

[JimKasson]

It is interesting nobody is commenting on this. At a minimum it looks like the 38mm lens is not delivering symmetrical illumination. Come on guys.

If you suspect a bad copy, and asymmetric illumination is an indicator, try this test:

Lens screening testing - the last word

Note: the best way to navigate this set of pages is to use the "Articles" section in the right-hand panel. It has links to all the pages and their titles. For the last few years, I have followed Internet discussions related to lens screening. By screening, I mean the process that a photographer...

blog.kasson.com

 

[yogi4fitness]

They both seem to have some light falloff on the lower left corner. 38 is worse. Bad copy maybe?

 

[JimKasson]

They both seem to have some light falloff on the lower left corner. 38 is worse. Bad copy maybe?

When two lenses show that issue, my first thought is to suspect the wall illumination.

Try rotating the camera 180 degrees..

 

[yogi4fitness]

They both seem to have some light falloff on the lower left corner. 38 is worse. Bad copy maybe?

When two lenses show that issue, my first thought is to suspect the wall illumination.

Try rotating the camera 180 degrees..

Thats an excellent suggestion. The likelihood of both lenses having light falloff in the same place is highly improbable.

--
https://blog.kasson.com

 

[Reddott]

It is interesting nobody is commenting on this. At a minimum it looks like the 38mm lens is not delivering symmetrical illumination. Come on guys.

If you suspect a bad copy, and asymmetric illumination is an indicator, try this test:

https://blog.kasson.com/lens-screening-testing/

Thank you Jim - I quickly read over this and will work on doing this as soon as possible. I've never had a lens exhibit a color shift like this. I've been using this new set up for the past 6 weeks. This past weekend was the first time I noticed this behavior and only because of the weather that day.

Thank you

 

[Reddott]

They both seem to have some light falloff on the lower left corner. 38 is worse. Bad copy maybe?

When two lenses show that issue, my first thought is to suspect the wall illumination.

Try rotating the camera 180 degrees..

Thats an excellent suggestion. The likelihood of both lenses having light falloff in the same place is highly improbable.

I'm sure this is the case and will quickly check this. I was more concerned about the color shifting issue. I will say that the picture of the lake also seems to exhibit the light falloff on the lower corner.

Thanks all for your feedback.

 

[yogi4fitness]

They both seem to have some light falloff on the lower left corner. 38 is worse. Bad copy maybe?

When two lenses show that issue, my first thought is to suspect the wall illumination.

Try rotating the camera 180 degrees..

Thats an excellent suggestion. The likelihood of both lenses having light falloff in the same place is highly improbable.

I'm sure this is the case and will quickly check this. I was more concerned about the color shifting issue. I will say that the picture of the lake also seems to exhibit the light falloff on the lower corner.

But I think that is in the scene. The fog is lighter compared to the ground in the lower corner.

Thanks all for your feedback.