Gold-Standard Slide Projector Lenses

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Only a few dozen of the 165 'alt-lenses' thus far graded as taking lenses have been slide projector lenses, but it's already been instructive for us to see how they compare to conventional lenses, as well as enlarger lenses deployed for this application.

Most will probably realise that slide projector lenses aren't as sharp as taking lenses, but they're still popular for their particular drawing style. You may have wondered when hearing users talk about being 'very sharp' in Zone A (centre frame) - how sharp, exactly? And how soft is Zone C (full frame corner)?

The full breakdown is more than I can sensibly communicate here (see Delta for details), but here's a quick hall of fame. I grade 'Gold-Standard' as reaching average scores of 9.0 across the frame at working apertures. Because most of these lenses are a fixed, wide aperture, no slide projector lens reaches Gold level. In fact, when you average it out, only the very best reach Silver (80-90%).

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Metric 1: Best overall performance
Averaging near and far-distance performance, across-the-frame sharpness, and smooth bokeh. With the exception of A, the following grades are for wide-open performance:

A. Schneider AV-Xenotar 90mm f2.4-8 (not exceptional wide open but extra marks for variable aperture): 85.3%
B. Leica Super-Colorplan-P2 90/2.5: 82.5%
C. Reflecta Agomar 90/2.4: 79.5%
D. Schneider Vario-Xenotar 70-120/3.5 at 70mm: 79.5%
E. Docter Doctarlux 150/2.8: 78.5%

All other slide projector lenses tested so far score Bronze for wide-open average performance. We expect the Rollei AV-Apogon 90/2.4 and 90/2.8, and Zeiss P-Sonnar 90/2.5 to join this elite group shortly. If you have a copy of these lenses you wish to loan or sell, please get in touch . . .

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Metric 2: Best Zone A (centre-frame) sharpness at near distance: Top 10 only.

Results in descending order of quality at 'maximum' (usually the only) aperture, with two other lenses for reference

Sigma 50/1.4 Art: 9.2
Leica Super-Colorplan-P2 90/2.5: 8.5
Rollei S-Projar 90/2.5: 8.4
Tamron G2 70-200 at 70/2.8: 8.3
Docter Doctarlux 150/2.8: 8.3
Leica Colorplan-P2 90/2.5: 8.3
Reflecta Agomar 90/2.4: 8.3
Rollei AV-Xenotar 90/2.4: 8.3
Schneider Vario-Xenotar 70-120/3.5 @ 70: 8.1
Carl Zeiss Super Talon 90/2.5: 8.1
Isco Cinelux-Ultra MC 60/2: 8.1
Agfa Agomar 85 (unmarked): 8.0

Likely to be included in this list when samples have been located are the Rollei AV-Apogon, Zeiss P-Planar and Zeiss P-Sonnar. If you have a sample you can spare or wish to sell, please PM me.

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Metric 3: Best corner performance (Top 10 only)

'Best' is here a loaded term: even the best projector lenses have lenses that are pretty dismal by the standard of enlarger lenses, which are usually outperformed at long distance (though often not under 1m) by modern taking lenses.

In descending quality order, these are the least worst, with two taking lenses for reference at f2.8:

Sigma 50mm f1.4 Art: 8.7
Leica Super-Colorplan-P2: 8.0
Schneider Vario-Xenotar 70-120/3.5 @ 70mm: 7.8
Reflecta Agomar 90/2.4: 7.7
Simda 85-150: 7.5
Schneider Vario-Xenotar 70-120/3.5 @ 120mm: 7.5
Docter Doctarlux 150/2.8: 7.4
Leitz Wetzlar Colorplan-P 90/2.5: 7.3
Tamron G2 70-200/2.8: 7.2
Leica Colorplan-P2 90/2.5: 7.1
Agfa Agomar 85 (unmarked): 6.9
Rollei S-Projar 90/2.5: 6.7

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The full list, with updates, is maintained in the Delta Lenses Hall of Fame.

[iangreenhalgh1]

In my experience, projector lenses can be, and often are, very sharp when used as taking lenses.

By far the best I have encountered are the Schneider-Kreuznach series for professional 35mm and 70mm movie projection, closely followed by the ISCO range.

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That seems to be true . . . I'm conscious that the only cine projector lens we've properly graded so far is the Isco Ultra-MC 60/2, and that there are very interesting optics in this ballpark.

The Cine PJ section of the Delta archive (600 entries) feels some way behind the enlarger (1300 entries) and slide projector (600 entries) categories. By all means have a look at see what we're missing, and if you have any experience with using them, or want to highlight any standout models, please chip in a review or sample pic for reference. I'm struggling to locate these lenses in any quantity, though I keep an eye on eBay.

[kds315*]

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That's a great selection of lenses-in-action, Klaus, and some lovely images - particularly if you like flowers.

Once the enlarger lens archive hits 1500 entries, I'm looking forward to devoting time to the cine projector lens section. Shame I'm late to the party: a few years ago they could be picked up for pennies; now their virtues are well enough known to make them valuable.

[iangreenhalgh1]

I have picture samples from quite a lot of projector lenses, including some very unusual ones ripped out of data projectors, most of it is on my old PC which I really must get aroundto removing the hard drives from to copy the data to my new PC.

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That would be brilliant, if you could - they deserve to be seen. Data projector optics would be a whole new category . . .

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I don't have enough test data yet for a 'Gold standard cine projector' thread, but surely that's in the pipeline . . .

[iangreenhalgh1]

You're more than welcome to make use of any of my images or data, let me know how to best serve them to you.

[eggplant]

I am just curious- for deltalenses.com, where did you manage to gather all the data from for the slide projection lenses?

Because whilst lists are out there, it seems like some of these had to be manual entries


Anyway- I do think, atleast for slide projection lenses, we do not need to list every single one in existence, to know what optical design was used or it's likely performance.

Based on the age and targeted price point (economy vs luxury), we can see whether one is a triplet derivative (mostly Cooke), or a Double-Gauss derivative (e.g. Xenotar, Colorplan). The Hektor could be considered an old but still luxury design. Petzvals not seen here as not a sufficient anastigmat. Shorter than 50mm a class of it's own.

Now there is probably room for some sort of innovative projection lens made somewhere between 1950-1970 that bucks the trend. But I have not seen it yet..

This is absolutely not a dig at the website- just another way to think about it.

But that being said, I do think the wilder digital projection lenses ian mentions would do very well on this website. I also think the 'straight' projection triplets made faster than f2.8 will be of note too.

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Thanks for your feedback. There appear to be countless plastic-barrel triplet slide PJ lenses out there, and - you're right - there wasn't a central information source from which to catalogue them. There is now, because we're building it, one lens at a time - manually - the hard way.

As for there being 'no need to list every one in existence' - well, perhaps not a 'need'. Then again, we can't all be paramedics.

Delta started as the 'Digital Enlarger Lens Test Archive', and it became increasingly hard to draw a line around what to include and what to exclude. John Jovic's Big List at photocornucopia.com has been a great resource, and initially I wanted to combine his list with our tests, but John's interests have moved on somewhat and I think he's drawn a line under it. It's been a daunting amount of work for him to catalogue almost 400 lenses, documented with approximate years of production, focal-flange distances, pictures, filter sizes, lens schemes, etc.

As I got interested in some of the stories behind these lenses, and connections between them, I became conscious of gaps in what I'd naively assumed was a definitive list. Starting from a spreadsheet that initially consisted of notes for about 20 enlarger lenses I owned, during lockdown we've grown the catalogue from scratch to almost 1,300 enlarger lenses. We're still missing several hundred models. More importantly, I wanted to collect serial numbers, built accurate timelines, and offer a guide to identification. The YouTube channel will be crucial to what we're doing, too, because there are great stories to tell about things and people that have been forgotten. Mathieu Stern is a kind of funkier, pain-au-chocolat version of the bread-and-butter werreting and ferreting we're doing at Delta.

We're resting here on that slippery slope, but I'm conscious we're only a short slide from archiving cine camera lenses, CCTV lenses, microscope lenses and digital projector lenses. We're already close to crossing the line to include large-format taking lenses.

However, it's becoming increasingly obvious that there's no need to test every projector lens, because (as you say) those of a similar scheme perform similarly (badly). In fact, we can now quantify that precisely in comparison with other lenses. As you allude to, the fast 90mm lenses are much more interesting.

However, there are still differences in rendering styles - for instance, not every triplet gives strong or attractive bubble-bokeh. Those that do are more desirable for those seeking such an effect.

This information is already disappearing: the people we're interviewing for first-hand information are old - some we'd like to speak to are dead. Other information sources are still uncatalogued and inaccessible in museum vaults. No-one is placing a high priority on these old optics, which is why I thought we should. Fortunately, this forum, Photrio, and the specialist photographica press hold a wealth of information - but it's scattered, hard to access and often inconvenient to browse. That's our remit. There's a growing community - many of you here - that for at least.a decade have been having fun in this large playground of 'alt-lenses'.

I'm talking about it now because the resource would benefit from multiple inputs. When I put the idea out there, only one person was on the same page. He's somewhat publicity shy, so if I don't mention him, it's not because I'm ungrateful for his help - he's been a tremendous collaborator. But I never conceived it as a one-man show - it needs peer review and a knowledgeable panel of contributors to weed out errors, and widen its breadth and depth.

[eggplant]

Sorry, I wasn't trying to poo-poo this effort- I will be contributing myself We are on the same page and I do the same things anyway, archiving eBay listings of lenses I deem abit uncommon.

If anything I envision a couple of different ways to browse the website which query the big list. I will think on it.

Some ideas come to mind- imagine a slider for the intensity of bubble bokeh which recommends you a lens at each intensity(!)

You're completely correct about disappearing information. I consider some of the most valuable stuff I own to be printed ephemera about lenses. Maybe one day I will get to see a copy of "Put the future in focus with Rayxar f/0.75 superspeed anastigmats"? https://www.worldcat.org/title/put-the-future-in-focus-with-rayxar-f075-superspeed-anastigmats/oclc/66003747

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No worries at all: your comments were inoffensive and obviously well-meant. I've had a lot of practice at not getting offended by criticism. All input is welcome, whether directed constructively or otherwise.

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Scanning back through previous posts, I've denigrated the Zone C performance of projector lenses, but a plastic-barrel Schneider Vario-Xenotar zoom lens (worth about £25) actually has sharper corners at 70mm that the current Tamron G2 70-200/2.8. Who knew? Shame about the barrel distortion is all.

[eggplant]

Another question is copyright. I have some pretty valuable articles I've downloaded, alot from the SMPTE Motion Imaging Journal - too many to count now. But lots with indispensable diagrams, MtF charts, period-correct comparisons/discussions.

Examples include








The simple data about dimensions, MtF charts can be copied, but alot of this is freeform discussion. Some of it is really quite old and I'm unsure who else is reading it.

I would personally be in favour of reproducing them as they seem pretty 'low priority' stuff, and I think alot of people would be interested to know there's stuff like this out there. I note Mike Eckman will link Herbert Keppler articles sometimes in full.

[e6filmuser]

[eggplant]

OK- well fortunately the website may only need simple numbers and data, and you can link below to "discussion about this lens was covered in the following article available on archive.org". That should do it

[RokkorDoctor]

Just posted this in another thread, but seems relevant here as well:

I am surprised they (projector lenses used as photographic lenses) work as well as they do; projector lenses are usually designed in conjunction with the condensor of the illumination system which (generally speaking) projects an image of the light source in or near the optical centre of the projector lens hence no adjustable aperture (it wouldn't do much really). The illumination when used as a photograpic lens is quite different to what they were designed for and therefore the addition of an aperture quite beneficial...

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[eggplant]

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