Question about Focus and Purple Fringing

[lct]

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[...] my purpose in posting (which I probably did not articulate very well) was to determine if the PF I was seeing with this copy of the lens was "typical" for the Summarit [...]

 

As far as my lenses are concerned, your 90/2.4 has more CA and is then more prone to fringing than 90/2 v2, 90/2 apo, 90/2.8 "thin", 90/4, C 90/4 and 90/4 macro but less so than 90/2 v3, 90/2.8 v1 and is more or less in par with 90/2.8 v2 so your lens is in the average from this viewpoint. Nothing to worry about IMHO. 

[jmahto]

Thanks to all the posters, really, my purpose in posting (which I probably did not articulate very well) was to determine if the PF I was seeing with this copy of the lens was "typical" for the Summarit.

 

I realize the degree to which PF (and other lens characteristics) bother people is personal:  I recall reading a thread on these boards (when I searched) about a "famous" PF problem with a 50mm lens (don't recall if it was a Noctilux or Summicron or what). Yet many people love that lens regardless. I also use Olympus and in that world there is a famous question of PF with Pana-Leica lenses on Olympus bodies, the prescription often given is to use a particular type of UV filter. Now the Summarit sample(s) I posted were exported from Lightroom after the 90mm Summarit Lens Profile was applied (with Chromatic Aberration checked) so this is about as good as it's going to get, unless there's an additional way to correct for PF in LR that I'm not seeing.

 

Again, I realize how you react to this issue is personal, so instead of asking "is this acceptable" (although that's maybe how it came out) I just wanted to know if this degree of PF was what I normally would expect with the Summarit. I could then make my decision as to whether the pluses outweighed the minuses.

 

Addressing the highlighted question. LR does a good job in removing the fringing. Below is the example from 28Cron ASPH at f5.6 (it is an excellent lens ) with sever fringing on the top right corner. See LR settings and how it gets removed in step by step process.

 

One word of caution is that removing fringing, also affects the colors in other part of the picture which doesn't have fringing (most of the times it is subtle but sometimes not acceptable). Therefore be aggressive in removing fringing only when it bothers you at the image size you intend to use.

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[jmahto]

Additionally you can use the fringing removal tool as below:

 

Pick the fringing color

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Final picture

[nlk10010]

jmahto:  Thanks for the work you put in posting that info. As I mentioned, the pix I posted ALREADY had the "Remove Chromatic Aberration" box checked in the "Lens Profile" section. Once I figure out how to get to the "Defringe" tool I'll see how that works as well.

[nlk10010]

As far as my lenses are concerned, your 90/2.4 has more CA and is then more prone to fringing than 90/2 v2, 90/2 apo, 90/2.8 "thin", 90/4, C 90/4 and 90/4 macro but less so than 90/2 v3, 90/2.8 v1 and is more or less in par with 90/2.8 v2 so your lens is in the average from this viewpoint. Nothing to worry about IMHO. 

lct:  Well, as I say, I don't have it yet. What I need to do is ask myself if the PF I see in a pix like the one I uploaded, which is after applying the LR CA Lens Correction, is OK to my eye. If it is then I'll probably purchase the lens, otherwise I'll forego it; after all, a 90mm isn't the easiest to RF focus or hand hold at lower shutter speeds.

 

Thanks for the info.

[Ko.Fe.]

Thanks to Jayant! I never seen how to deal with PF this easy before.  Next to red eye removal. 

I might reconsider, re-buying some less expensive M-mount lenses.  

[jmahto]

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Thanks to Jayant! I never seen how to deal with PF this easy before.  Next to red eye removal. 

I might reconsider, re-buying some less expensive M-mount lenses.  

 

Yes, some of my old lenses get a new lease of life due to digital miracle.

 

..but.. (there is always a but)

 

It doesn't come without a price. The downside of digital defringing is less accurate colors on rest of the picture. As I said earlier, this is very subtle (and affects colors only in fine texture) but you need to look at the rest of the picture to make sure you are not too aggressive with correction. In one of my pictures I lost the colors from the stripes in a remote US flag due to defringing. Just be warned.

 

In the worst case, I aggressively correct the aberration in LR and then take the corrected and non-corrected files in PS as layers and apply corrections only in selective places (by selectively erasing the non-corrected layer). That way the correction is only limited to the areas I want (it is like local processing for defringing, I wish LR had that). I should mention that use of PS is needed only in extreme cases.

 

Enjoy your old legacy lenses.

Edited March 9, 2018 by jmahto

[pgk]

In the worst case, I aggressively correct the aberration in LR and then take the corrected and non-corrected files in PS as layers and apply corrections only in selective places (by selectively erasing the non-corrected layer). That way the correction is only limited to the areas I want (it is like local processing for defringing, I wish LR had that). I should mention that use of PS is needed only in extreme cases.

 

That was going to be my suggestion - only when its really extreme though.

[adan]

Just FYI, the 90 Summarit is essentially a tweaked revival of the optical formula of the last 90mm Summicron non-APO (1980-98). Which itself was well known for purple fringing (longitudinal CA) both at wider apertures and in OOF areas.

 

And in my experience, your results look normal - for a given value of "normal." I.E. given the conditions. APO it ain't. Lovely bokeh though.

 

(scroll to the very bottoms of both pages to find the optical diagrams - 5 elements, 4 in front of the aperture, one behind, ++--|+

 

https://photographylife.com/lenses/leica-summarit-m-90mm-f2-5

 

http://www.xingzhelitao.com/?p=7588

Edited March 10, 2018 by adan