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Author Topic: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!  (Read 6525 times)

simplify

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I just received my Sony Nex-7 and Zeiss 24mm 1.8 lens.  I have been doing some testing and am noticing some very disturbing chromatic aberration when the lens is wide open, or close to.  I will attach images.  What is weird about this CA is it is in the middle of the image - as well as towards the edges. Unfortunately at this time Lightroom doesn't have any lens profiles for this lens, and doing manual CA adjustment does not fix the CA in the middle of the image, just on the sides.  Has anyone noticed these CA problems with the lens and camera.  I will be returning this setup to Sony unless I can figure out a way around this.  Its very disturbing that it happens in the first place, it really makes me question the quality of the lens.  I see images from hundreds of camera's a week (I work at a lab) and have never seen CA this bad.
Here is a link raw image for a challenge to see if you can fix this easily.  http://dl.dropbox.com/u/21236009/_DSC0143.ARW
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SpiritShooter

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #1 on: March 08, 2012, 09:45:10 pm »

I opened your image in Capture One.

With no fringing correction applied, none of the CA that I see in your examples is there, except for the very edges of the papers. C1 usually does an excellent job with CA, but in this case, it is leaving a very slight amount at the paper edges. I has C1 analyze the image for CA and turned on the Purple Fringing filter. The result was only a very slight decrease at the paper edges but overall the images looks very nice.

simplify

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #2 on: March 08, 2012, 10:08:53 pm »

Thanks for the advice.  I use capture one every day for my phase one P 45+ files. I will try processing some of these nex-7 files with C1.  I am still a little turned off by the look of these files in Lightroom.  I can't wait for my fuji x-pro so I can sell this Sony.
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simplify

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #3 on: March 08, 2012, 10:51:52 pm »

I would like to hear if anyone else with this lens and camera combination have seen this weird chromatic aberration at wide open apertures, when processed in the latest version of Lightroom 3. Let me know, thanks
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madmanchan

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #4 on: March 08, 2012, 11:16:36 pm »

This is standard longitudinal / axial CA that many fast lenses exhibit at wide apertures.
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Eric Chan

simplify

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #5 on: March 08, 2012, 11:29:35 pm »

Why do the chromatic aberration sliders not fix this if it is standard?  I've used a lot of fast lenses on Leicas and Zeiss for Nikon and i have never seen anything like this.  Maybe the camera profile for Lightroom isn't quite there yet.
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ErikKaffehr

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #6 on: March 09, 2012, 12:03:45 am »

Hi,

Longitudinal chromatic aberration is very different from the more common lateral chromatic aberration, it is caused by light of different colors being focused in different planes. Therefore the CA sliders are not going to fix it. The problem is not unique to NEX-7 and the Zeiss lens. Almost every large aperture lens suffers from it. Stopping down to around f/4 usually solves the problem. Your test, photographing high contrast monochrome text with different amount of defocus is a well known way to illustrate the problem, by the way.

I don't know how Capture One may get around this, I guess it would be by desaturating color around high contrast edges if the image is predominantly monochrome.

You could check this article for detailed explanation (page 32) http://www.smt.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf
Note: you need to cut and paste the adress to get it working!

Some screen dumps from the article and from Photozone.de included.
Best regards
Erik


Why do the chromatic aberration sliders not fix this if it is standard?  I've used a lot of fast lenses on Leicas and Zeiss for Nikon and i have never seen anything like this.  Maybe the camera profile for Lightroom isn't quite there yet.
« Last Edit: March 09, 2012, 12:40:10 am by ErikKaffehr »
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Erik Kaffehr
 

kuau

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #7 on: April 12, 2012, 09:27:07 pm »

I am renting this lens right now to use with my NEX7,
Though my gripes is with using the lens at infinity, F5.6
Very sharp in the center 2/3 of the image then at both ends the detail really falls off.

Steve
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douglasf13

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #8 on: April 12, 2012, 11:35:41 pm »

Hi,

Longitudinal chromatic aberration is very different from the more common lateral chromatic aberration, it is caused by light of different colors being focused in different planes. Therefore the CA sliders are not going to fix it. The problem is not unique to NEX-7 and the Zeiss lens. Almost every large aperture lens suffers from it. Stopping down to around f/4 usually solves the problem. Your test, photographing high contrast monochrome text with different amount of defocus is a well known way to illustrate the problem, by the way.

I don't know how Capture One may get around this, I guess it would be by desaturating color around high contrast edges if the image is predominantly monochrome.

You could check this article for detailed explanation (page 32) http://www.smt.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_30_MTF_en/$File/CLN_MTF_Kurven_EN.pdf
Note: you need to cut and paste the adress to get it working!

Some screen dumps from the article and from Photozone.de included.
Best regards
Erik



+1.  This LOCA is common to many fast lenses.  My Zeiss 85 had it really bad.
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Paul2660

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Re: Sony Nex-7, Zeiss 24mm 1.8 - Disturbing Chromatic Abberation!
« Reply #9 on: April 13, 2012, 09:26:14 am »

I am renting this lens right now to use with my NEX7,
Though my gripes is with using the lens at infinity, F5.6
Very sharp in the center 2/3 of the image then at both ends the detail really falls off.

Steve


Steve:, 

I have not used the Zeiss 24mm, E mount, but if you are getting that much fall off at F5.6 Infinity, I would consider
trying another version.  That sounds way off.  I use the Sony/Zeiss 16-80 Zoom on my Nex7 and at 24mm and 5.6
the results are stellar.  At the price point of the 24mm E mount, you should be getting a better image IMO. 

So far the Sony 16-80 has been a really amazing lens, one that will get some amazing details out of the Nex7.

Paul
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Paul Caldwell
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