The Nikon Z 50mm 2.8 Macro Mystery

NCV

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Just replaced my venerable 60mm Nikon macro with the new Z 50mm macro for slide and negative copying mostly.

To my surprise when I opened the test shots in DXO, DXO asked me if I wanted to install the Sigma 50mm macro lens profile.

A Nikon lens made by Sigma?

I wrote to DXO and they replied:

"Hello

Thank you for writing. What you are seeing is an event called ambiguity in the program. In very rare cases, the optical qualities of one lens can be very close to, or exactly the same as, one or more other lenses. PhotoLab does not just use information stored in the file about the camera and lens, but it also does an extensive analysis of the optical characteristics of each image input into the program to determine exactly what correction code to use.

When you have images where your lens model is not yet available in the program for use with your camera, which appears to be the case here, and another lens module is used in its place, this is caused by the ambiguity. For these types of instances, we offer the following information for your consideration.

Until a correction module for your exact lens and camera combination is available, you might want to consider using the module selected by the program to get very good results.

As you may know, we are constantly updating our database with new modules. Several years ago we added another lab to increase our capacity to provide more modules. You can always get information regarding new modules we are working on and current cameras and lenses supported at the following web address:"


In fact the pronounced pincushion distortion that the non software lens corrected has, dissapears.

Who knows!
 

Butlerkid

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So it appears that DxO is simply suggesting an alternative lens profile that is similar until they have updated their data base to include the new Nikon lens.

"When you have images where your lens model is not yet available in the program for use with your camera, which appears to be the case here, and another lens module is used in its place..."
 

NCV

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So it appears that DxO is simply suggesting an alternative lens profile that is similar until they have updated their data base to include the new Nikon lens.

"When you have images where your lens model is not yet available in the program for use with your camera, which appears to be the case here, and another lens module is used in its place..."

Yes, and it seems to be an almost perfect fit, as without a lens profile this lens has quite pronounced pincushion distortion.

I mostly use Capture 1 which uses a Nikon profile.

A rather sad picture I used to try the lens out, so forgive for the bad colour and dust.
DSZ_8284_DxOsmall.jpg
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Capture 1, nice and distortion free.

DSZ_8284 3.jpg
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Capture 1 uncorrected. look at the border

DSZ_8284_DxOsmall.jpg
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DXO with profile
 

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It strikes me as odd that a Nikon micro lens has obvious distortion, they are traditionally flat field with low distortion since they are used for copying. But I guess they reason that distortion is easily corrected in post processing.

Why not find and compare the cross sections for each lens, or just find the number of elements and groups and the types. The Nikon has ED and aspherical elements. It’s interesting that the Nikon is not internal focussing (IF), IF designs can lead to higher CA, but don’t pump dusty and damp air in and out.
 
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I had been noticing that suggested Sigma lens profile, too, and I have not installed it, thinking I would wait for the correct Nikon profile. After your communication from DxO, I think I will try the Sigma substitute.

I don't think the 50 MC has significant distortion. How are you photographing these slides?
 
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I just downloaded and applied the Sigma lens profile to an image I processed yesterday without it. What do you think?

_JZ66189.jpg
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_JZ66189corr.jpg
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The only difference between the two is that I applied the auto distortion correction and lens sharpness after downloading the Sigma profile.
 
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Try photographing something like a book of stamps, so that a straight edge lies along the edge of the frame. That will make distortion easier to see.

As an aside there is a review of this lens on ephotozine:

https://www.ephotozine.com/article/nikon-nikkor-z-mc-50mm-f-2-8-macro-review-35518

It looks excellent even though it’s not an S lens. I have copies of the AFD and AFS 60mm micro lenses, and they are both superb. Is there a reason to ‘upgrade’?

Incidentally, does anyone know why my signature takes me to two different web sites, depending on where I click?
 
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Try photographing something like a book of stamps,

I may try that, but if the lens displays "pronounced pincushion distortion " it would certainly be visible in that perfectly round coin.

I've seen two detailed reviews of the lens, and neither has mentioned any kind of distortion. I believe Nikon Ricci said it was "minimal" or "virtually undetectable".
 
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I may try that, but if the lens displays "pronounced pincushion distortion " it would certainly be visible in that perfectly round coin.

I've seen two detailed reviews of the lens, and neither has mentioned any kind of distortion. I believe Nikon Ricci said it was "minimal" or "virtually undetectable".
The review I linked to states 0.71% pincushion distortion, I don’t know at what distance that is measured. There is a sample image of some text, and the distortion is obvious. Ricci might have been referring to infinity focus, or perhaps he has Nikon software with an automatic correction applied.
 
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The review I linked to states 0.71% pincushion distortion,

I can live with that.

_JZ66196.jpg
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_JZ66197.jpg
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_JZ66198.jpg
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It looks excellent even though it’s not an S lens. I have copies of the AFD and AFS 60mm micro lenses, and they are both superb. Is there a reason to ‘upgrade’?

So long as you're happy with the lenses you have , then probably no reason to upgrade.

I personally prefer to use native mount lenses on the Z bodies. I currently have 2 macro lenses with Z mounts, and IMO they are much nicer to use than their f mount equivalent's via the FTZ adapter. Maybe its the adapter.
 

NCV

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From the reviews I I read, the consensus is that with the Nikon lens profile, which my Capture One reads by default, distortion is very low.

I did read a review which I cannot find again, the reviewer said that without software correction there is a lot of pincushion distortion. The Sigma "stand in" profile seems quite good.
 
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The pictures I posted (#13) were uncorrected. I see no distortion that I would bother to correct. Maybe those were not appropriate examples, but I don't expect to be photographing anything more likely to be distorted.
 

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