Gold-Standard Slide Projector Lenses

[16:9]

[16:9]

[16:9]

Just graded a new top-10 projector lens this morning: the Isco / Meridian 45mm f2.8 PC scored 8.45 for Zone A (centre frame) sharpness - placing it second on the list. Unfortunately, it's soft in Zone C even by the standard of projector lenses.

[16:9]

Meridian seem to be even bigger magpies than Vivitar: the same range consists of lenses made by Isco, Schneider and Docter. Information about them is thin on the ground, but they seemed to supply only lenses for Kodak slide projectors.

[16:9]

How about Metric 4: 'Best' Bokeh?

Fairly sure this isn't quantifiable, but here are a few I find pleasing - please add your own to taste.
NB: these are slide projector lenses only - not cine (so excluding the pretty f2 Isco/Schneiders)

1. All Leica Colorplan (especially Super-Colorplan-P2)
2. Agfa Color-Agolon 90/2.5
3. Agfa Agomar 100/2.5
4. Cabin 100/3.2
5. Docter/Meridian 60/2.8

[simple.joy]

[16:9]

The Color-Agolon 90 looks expensive . . . .

[16:9]

That Vario-Xenotar 70-120 is absurdly sharp for a projector lens - quite a lot sharper at the wide end, where it has sadly quite a lot of barrel distortion - and CA throughout. If you want a projector lens with barely any CA and even better Zone A sharpness, try the Reflect Agomar 90/2.4 (AKA Braun Ultralit). Not such a sweet drawing style, though.

Perhaps I'll send you my German CP90 v2: it's OK - maybe better than the Portuguese one?

Working on a comparison of all those 'elite' primes here:
https://deltalenses.com/index.php/2022/03/25/projector-lens-group-test-1-fast-90s/

[16:9]

I just noticed that Delta quantifies for sharpness the Vario-Xenotar 70-120 (at 70mm) with an overall grade of 80% - one of only two projector lenses so far to be awarded 'Silver'. The Leitz CP90 [V1] scores 73% and the Leica CP90 [V2] scores 75% - a more typical Bronze.

That zoom lens is exceptional, but if you wanted to try another very cheap lens that is a better than average (on par with the Colorplans) and draws quite sweetly, snag an Agfa Agomar 85mm [V2] - the all-plastic one without a marked aperture:
https://deltalenses.com/index.php/product/agfa-agomar-85-2-8-v2/
It scored 74% for me - lower than average contrast, but higher than average resolution for a triplet.

[eggplant]

[16:9]

I'm all for 'good' and 'bad' bokeh - modern lenses have smoother bokeh because they're better built and corrected: it's progress. In the mission statement, we specify this as our (technically justifiable) policy. In fact, early versions of Delta graded bokeh with a mark out of 10 for 'correctness', but we moved towards a more nuanced view by asking: is it always aesthetically justifiable? Does wonky bokeh sometimes make a better picture? And is a 'better' image always more desirable?

Film-makers have always used lenses, and now also LUTs, for a specific vibe - grungy, dreamy, vignetted, contrast-modified and colour-shifted, etc. In the end I felt it was more helpful to describe and illustrate how a lens draws than rate it numerically. One of my goals for Delta is that it becomes a 'library of looks', somewhat like a model catalogue - so visitors can come to a lens and ask 'Is this the right look for my project?', rather than 'Is she a 9 or a 10?' For PJ lenses more than enlarger lenses, this is probably a more important issue.

For other lens review projects, I had the goal of summarising all metrics to arrive at a single percentage mark - like Parker does for wine. But there's always the concern that it over-simplifies a more complex story - airbrushing important details.

The Delta article 'Reviewing the Reviews' shows arbitrarily different ranking systems yielding very different verdicts. I had a system ranking all aspects of lens behaviour - even though it involved debatable weighting of priorities - for instance, in Ctein's 1990s enlarger lens survey, some fine lenses were omitted because of vignetting issues. In 2020, using them as taking lenses, I would argue that light fall-off (and colour-fringing) is a trivial issue, practically speaking. Then again, I would be receptive to the argument that better-corrected lenses should score higher marks, and that digital correction is rarely lossless - and we segue into angels and pinheads. With 16:9, and now Delta, I have a 'tool-oriented' bias, focusing on what a lens does, more than what it is, or how collectable or valuable it may be.

In the end, I decided the first priority was to assess the basic utility of these optics in 2022 by grading the most common, most easily understood, most empirical, and least controversial metric: 'sharpness'. Even that's not clear-cut - gold standard MTF charts are still subject to manufacturer spin and inconsistent reporting. And without experience, it doesn't tell you how a lens really looks on a given camera, or describe all the aberrations that compromise real-world performance. The audio world is beset by similar issues. My take on this isn't without its own problems, but it's where we've begun.

We will take a deeper dive into some lenses, and groups of lenses, and compare all their properties. There's plenty of precedent for doing this well. But just at the moment our resources are invested in cataloguing and briefly assessing as many lenses as possible to gain a meaningful view of the big picture. This process is churning through a lot of glass, and churning to the surface lots of interesting stories. The coming YouTube channel should make this clearer.

I'm open to input of ideas, but wanted to set out my stall so you understand Delta's objectives - key among which is to be useful. As I've said before to 'simple.joy': “If this doesn't make sense, please talk me out of it.”

[16:9]

Bastian's article is a great overview, by the way - his examples are well chosen. One thing he doesn't mention is that optical vignetting decreases with increased focal length and image circle size: it's not just a correction or construction issue. But this is very true:

“The thing is, unlike MTF (contrast and resolution), bokeh cannot easily be measured. It is possible to compare lenses and you might find you like one more than the other, but at a different focus distance or with a different background you might prefer the lens you have dismissed before. "

Enlarger lenses have a tendency toward over-correction of spherical aberration, and therefore harsher bokeh, whereas projector lenses have no correction for anything* and do all manner of craziness.

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* Hyberbole alert

[RokkorDoctor]

[16:9]

To bridge the discussion we're having elsewhere, it seems to be that what cinematographers like about anamorphic lenses can often be accomplished with greater ease and wider versatility with enlarger and projector lenses, which offer a wide array of cosmetically appealing aberrations without introducing distortion.

[16:9]

[16:9]

Time to stop asking questions and start sharing answers. I'm closing in on the final stages of the overview of slide projector lenses.

At this point, there's a well-defined list of 'Gold Standard slide projector lenses' - but the best only reach Silver when judged on the same scale as other taking lenses, just as only the top enlarger lenses scrape into Gold territory when compared to modern primes at normal working distances.

Two slide projector lenses have risen to the top of this elite group and are (technically) clearly the most sophisticated designs. If I describe these Kings of the PJs, see if you can guess what they are:

Joint Winner A:
Extremely high centre-frame resolution, comparable to Sigma primes at the same aperture, scoring in excess of 9.0 – far better than any other slide PJ lens. But Zone C (full frame corner) only reaches 7.6. Good multicoating. Excellent colour rendition but low-to-moderate CA. Mild bubble bokeh (moderately smooth). Higher than average mechanical vignetting (cat-eye/swirl). Performs similarly at all working distances. Very expensive when new.

Joint Winner B:
Good centre-frame resolution (8.6) and better Zone C than any other slide PJ lens - full frame corners reach 8.0. Good multicoating and flare resistance. Excellent colour rendition and very low CA. Extremely smooth bokeh (no bubble). Lower than average mechanical vignetting. Performance tapers off at long distance. Very expensive when new.

Which sounds most attractive?

[D1N0]

The Leitz Colorplan 90/2.5?

[16:9]

The Leitz ColorPlans are good, but distinctly behind these top two.

One caveat - thank goodness for 'peer review' - there is another candidate that slipped through the net that could join them.

On this lens - the Braun Ultralit 90/2.4 MC - does anyone have a copy they know well or have tested? We'll be getting a copy in soon, but I'd previously been misled by the Reflecta website and catalogue that shows a picture of the Ultralit under a caption 'four element lenses' - which encouraged the view that it was identical to the Agfa-made Reflecta Agomar 90/2.4 MC (which we know well)

However, I received a message that the Ultralit isn't four element. On closer inspection, there seem to be a number of differences - and of course the Ultralit name is more usually associated with Staeble. Doubtless Klaus had one, has a lovely portfolio of images shot with it, and has several samples gathering dust in his archive! Input welcome on this lens . . .

[D1N0]

I have a Braun Super-Paxon 85mm F2.8 (multi-coated) that came from my multi Paximat (that is still in the attic) and Picked op a Kindermann Color-Germany 90mm 1:2.8 MC at some point

[simple.joy]

[D1N0]

They both have nice bokeh but prettty soft. I have only free lensed them so not a very reliable review.

Braun https://www.flickr.com/photos/randomdump/albums/72157681757459016

Kindermann https://www.flickr.com/photos/randomdump/albums/72157714769563822

Kindermann looks a bit better to me

[kiddo]

AV Apogon/AV Xenotar?
maybe 2.8 should be sharper ?

[simple.joy]

[16:9]

In general the f2.8 versions are simple triplets, with the typical performance limits, but I've not yet played with the Kindermann 90/2.8, or even established whether there are multiple variants.

In 1997, Chasseur d'Images ranked it 1 out of 5 and the f2.4 version 4 out of 5.

Only three lenses reach 'Silver' level in the Delta ranking of average sharpness across the frame. In a category of their own, the Leica Super-Colorplan P2 and the AV-Apogon are neatly ahead of all those tested so far (which doesn't yet include the Ulltralit - previously thought to be identical to the Reflecta Agomar 90/2.4).

As I suggested above, the comparison between this pair is interesting: the Rollei is the most 'projector-like' projector lens - the fullest expression of the varietal, if you will. The Leica is the projector lens least like a projector lens: so well corrected it's like a modern prime - a remarkable achievement that for some may defeat the purpose of owning one.

Here's a zoomed-in crop of a handheld shot using the AV-Apogon.

[simple.joy]