Immense enlarger lens test database

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16-9
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Joined: Mon Jun 20, 2022 1:12 am
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Re: Immense enlarger lens test database

Post by 16-9 »

Lou Jost wrote:
Thu Nov 10, 2022 6:39 am
Delta doesn't measure CA or geometric distortion, and only mentions it in the review when it's severe.
Uhhhh, the CA is a big thing to leave out, and one of the most important and common lens defects. It's not that trivial to correct well, and any such correction could reduce resolution.
Point taken. And it's not the case that all enlarger lenses excel equally in this area, although the average standard is higher than taking lens of the period. I have more images to upload for tested lenses that show how they handle flare and render sunstars. It would certainly be possible to revisit the archive and also show examples where CA is problematic.

ray_parkhurst
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Re: Immense enlarger lens test database

Post by ray_parkhurst »

16-9 wrote:
Thu Nov 10, 2022 6:28 am
The PN105 is one of the my favourite examples of a lens that performs incredibly well for its intended purpose, and really terribly when asked to do anything else! My copy of that lens was a big inspiration to trek into the unknown and record the results in Delta.
Is your 105PN an "A" version, and if so what is its serial number? I am keeping track of the known 105PNA serial numbers and am hoping to hear of more lenses that fill in a gap in the numbers.

16-9
Posts: 12
Joined: Mon Jun 20, 2022 1:12 am
Location: London

Re: Immense enlarger lens test database

Post by 16-9 »

ray_parkhurst wrote:
Thu Nov 10, 2022 7:15 am
16-9 wrote:
Thu Nov 10, 2022 6:28 am
The PN105 is one of the my favourite examples of a lens that performs incredibly well for its intended purpose, and really terribly when asked to do anything else! My copy of that lens was a big inspiration to trek into the unknown and record the results in Delta.
Is your 105PN an "A" version, and if so what is its serial number? I am keeping track of the known 105PNA serial numbers and am hoping to hear of more lenses that fill in a gap in the numbers.
Sadly I no longer have it: I bought it from Pinewood when they closed the film mastering studio but sold it in 2015, I think. I'll trawl my records for a photograph. What's the highest and lowest serial you have at present?

ray_parkhurst
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Re: Immense enlarger lens test database

Post by ray_parkhurst »

16-9 wrote:
Thu Nov 10, 2022 9:31 am
Sadly I no longer have it: I bought it from Pinewood when they closed the film mastering studio but sold it in 2015, I think. I'll trawl my records for a photograph. What's the highest and lowest serial you have at present?
Here is the link to the thread where I am recording the serials...

viewtopic.php?f=3&t=43663

bbobby
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Re: Immense enlarger lens test database

Post by bbobby »

16-9 wrote:
Thu Nov 10, 2022 5:46 am
... two identical bank notes fixed sagittal/meridional on a plywood board close-lit by a single bare LED studio light in the dark. The scene is high contrast, with fine black markings added, to aid focus peaking.
"A picture is worth a thousand words" - it will be really helpful to see few images... I will really appreciate if you can share even a small crops of some of your images...

I tried quickly something with 2 banknotes today, just to have an idea... sloppy image, not really proud of it, but... Nikon d850 (45.7 megapixels) with similar sensor, 50 centimeters from the front of old Nikon 50mm f/1.8 Series E lens @ f/4... With this lens and working distance the magnification is about 0.1x (1:10). And this old "budget" lens outresolve the 45 MP in the center... which is clearly visible when I took picture with Sony A7R4 (61 MP), there was no need even to use pixel-shift... a newer design lens like Sigma Art 50/1.4 may or may not be better resolution-wise, and even if it is the sensor cannot record it... Which makes me wonder for 100-150mm lens even if the working distance increase to 80 cm the magnification will be more... like 1:8 or 1:6 or whatever and then the banknote itself maybe will not have enough small details...
On the other hand - and I will try it later tonight - increasing the distance 10 fold to 5 meters... means about 1:100... which for 50mm lens means so big depth of field that it will render bracketing not necessary, I am pretty sure... Not that bracketing is strictly needed even at 1:10, DOF should be more than few mm...

I see "Location: London" and although I was in England for almost an year (and few times in London) 15+ years ago I do not remember what the English banknotes look like - not that you mentioned anywhere what kind of banknotes you are using. Maybe they have more details that the dollar bills...
16-9banknotes.jpg
bd.jpg
bd1.jpg

16-9
Posts: 12
Joined: Mon Jun 20, 2022 1:12 am
Location: London

Re: Immense enlarger lens test database

Post by 16-9 »

One wrinkle applicable to this conversation is that there are controls over digital reproduction of banknotes. When I started, I immediately hit problems using Photoshop, which spotted the images were fivers and wouldn't let me open them. My B-kit Affinity Pro has been handling viewing and saving duties.

The most recent near-field test batch compared Schneider Apo-Componon 60/4 HM, Beseler ColorPro (Kowa version) 50/2.8, EL Omegar 50/3.5, Taylor Hobson Ental II 50/3.5, Meogon 50/2.8, Meogon 50/5.6, Meogon 60/5.6 and Tominon 58MC.

At f4, the Apo-Componon's Zone A is judged 9.2. This crop has been compressed with Lanczos-3 Separable at an 86/100 quality setting for upload and display, and so is compromised compared to the original TIFF.
_1026539-crop.jpg
This f4 Zone C crop is from the Kowa/ColorPro 50/2.8 and was judged 8.2. Same compression for upload and display.
_1026492-crop2.jpg
Splitting the difference, the Meogon 50/5.6 gave some of the best Zone C results. Here, not quite at its peak, f5.6 was graded 8.8.
_1026460-crop.jpg
It's hard to 'speak' about resolving the sensor. What 'looks' fully resolved can turn out by comparison with a sharper lens not to resolve the sensor fully at all. Your crops appear to show a sensor in want of more, but it's only a hunch: without being party to the whole image capture and without US currency to hand for inspection, I don't know what I'm looking at. Which I appreciate has been your problem with my comments so far in the thread!

To say for sure, we'd need to shoot specific lp/mm charts and have a long conversation about Nyquist v Kell, and at the end of the day make some guesses anyway. But comparison power: the Apo Componon Zone A/f4 is pretty sharp: excellent, in fact – and you might think that's what a full resolved sensor looks like – until you see the Meogon 80/2.8 or Sigma 50/1.4 at peak apertures. That's partly why the scale runs to ten, but the results never reach it. I can't guarantee an outcome is limited by the sensor, not the lens. I have to assume somewhere out there, perhaps in the future, a lens will be mounted on this body and I will see imperfections in my Sigma 105/1.4, and realise that even if I had 'resolved the sensor' before, the new, better lens looks sharper. There is no perfect. Nothing's ever 100%.

Which is (not) why I view images at 200% or better: details that appear samey at actual pixels reveal larger differences on expansion.

If you look at the Hall of Fame, you'll see evidence of bunching around the 90-92% mark where I'm reluctant to award higher marks, and don't see major improvements. However, comparison with the Sigma primes shows that we haven't reached the sensor limit here (whatever that is). At some point, I have earmarked to do a large reshoot with the G9, and may be able to stretch those results up to 95% if the elite enlarger lenses compare well with the benchmark M43 lenses. Fun fact: the Panasonic 75-100/2.8 scored 93% for far-field f4-f8 average vs the best enlarger lens in that category (Apo-Rodagon-N 105) which scored 87.8%.

You'll quickly realise if you try yourself to grade those crops that it's not entirely obvious in some cases how to balance resolution v contrast, and trade the pros and cons of different types of aberration – especially when a lens demonstrates wide divergence in its sagittal and meridional MTF. This is the curse of a simplified 'sharpness' metric, and the point on which the reader is asked to trust my judgment; where an element of subjectivity enters proceedings. Down the line, when I dig into differences between one or two lenses in articles and videos, it will make sense to display results and allow viewers to make their own judgment but at present the priority is to generate a large matrix of grades as an introductory survey.

A confession: if I'm in a rush I don't often shoot at f11, and I don't include that aperture in the averaged grading. If you have an f8 capture, you can surmise with confidence what f11 is like: as before, but slightly softer – and if the corners were poor, fractionally better in Zone C. At f11 you're capturing an image of diffraction more than a test target.

mjkzz
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Re: Immense enlarger lens test database

Post by mjkzz »

wow, that is a lot of work, thanks for the compilation.

I was just thinking to get rid of the EL Nikkor 50/F2.8, it is not very good at 3x or above, maybe I should give it a try at less than 1x.

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