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TEST 2.8/21 Konica AR vs Mamiya CS vs Minolta AF 2.8/20
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PostPosted: Sat Oct 21, 2023 5:01 pm    Post subject: TEST 2.8/21 Konica AR vs Mamiya CS vs Minolta AF 2.8/20 Reply with quote
As requested elsewhere ...

jamaeolus wrote:
How does it [the Mamiya CS 2.8/21mm] compare with the Konica 21mm 2.8.


... here a short test of the two rare, expensive and difficult to find Konica AR 2.8/21mm and Mamiya CS 2.8/21mm lenses, plus a cheap and easy-to-get Minolta AF 2.8/20mm.

Both the Konica AR as well as the Mamiya CS lenses look "like new". They both come from their first and only owner, and they obviously were well treated during their entire life! The Konica has been owned by a civil engineer, together with a Konica Autoreflx T3 and a few other lenses, and served him well for many years as a professional gear. Sadly I don't know much about the Mamiya since I got it on-line from the french speaking part of Switzerland. The Minolta AF is one of my own samples, well worn and somehow battered, but still delivering fine images after >35 years of constant use.

Using the 24 MP FF Sony A7II, I checked all three lenses for ...

1) Center performance at f2.8
2) Field performance at f2.8, f5.6 and f11 (13.5mm from center)
3) Corner performance f2.8, f5.6 and f11 (21mm from center)

Center performance for all lenses is very good.
Field performance (13.5mm from center) is very similar with all lenses (therefore not shown here)
Corner performance is differing a lot.



It's clear that the Minolta AF 2.8/20mm (1987) is much better than the Konica AR 2.8/21mm (1979) and the Mamiya CS 2.8/21mm (1977 or 1978); however the two earlier lenses are much smaller than the later Minolta, of course. All three lens barrels are made of metal, BTW.

Given the fact that the Mamiya costs around CHF/EUR/USD 500.--, the Konica is about twice as much, and the Minolta is just 100.--, the obvious choice for users would be the Minolta. Both the Konica and the Mamiya are really beautiful small superwides, but they are collectors items for sure. I would never have bought them at today's prices, but I was lucky to find them - years ago - for a reasonable amount of money.

I hope this clarifies the original question Wink

S


PostPosted: Sun Oct 22, 2023 7:28 am    Post subject: Reply with quote
Thank you for posting these tests! Thank you!

How do the actual focal lengths of the three lenses compare? Looking at the center crops, it appears the Mamiya is a bit wider than the Konica, and then the Minolta, as labeled, is the widest of the three at 20mm.


PostPosted: Sun Oct 22, 2023 9:16 am    Post subject: Reply with quote
Surprised at the bad performance in the corner of the two older ones. I would expect them to be at 5.6 at least as the Minolta is at 2.8. But not even close. Is that drop in performance so evident only in the very far corners or does it extend way into the frame?


PostPosted: Sun Oct 22, 2023 11:48 am    Post subject: Reply with quote
Excellent info ! Like 1


PostPosted: Sun Oct 22, 2023 8:40 pm    Post subject: Reply with quote
Zamo wrote:
Surprised at the bad performance in the corner of the two older ones. I would expect them to be at 5.6 at least as the Minolta is at 2.8. But not even close. Is that drop in performance so evident only in the very far corners or does it extend way into the frame?


Wide open the low resolution extends quite a bit into the frame, at least 10% to 15% from each side I would say.
Below there's a corner crop with 1000x667 px (thus showing 20% of the frame). Mamyia CS 2.8/21mm @ 21mm, 100% crop from the corner of 24 MP FF JPG:



I am pretty sure that one can use the Mamiya wide open e. g. for reportage, though.

Below there's the other extreme - the Minolta AF 2.8/20mm @ f11 after removing CAs (RAW conversion with Photoshop):



S


PostPosted: Sun Oct 22, 2023 8:48 pm    Post subject: Reply with quote
the minolta AF wide angle it is not very common, at least , i have never seen it for sale around.
What about flektogon MC in M42 mount? would it do any better or at least the same as minolta af?


PostPosted: Sun Oct 22, 2023 9:09 pm    Post subject: Reply with quote
kiddo wrote:
the minolta AF wide angle it is not very common, at least , i have never seen it for sale around.
What about flektogon MC in M42 mount? would it do any better or at least the same as minolta af?


The Minolta AF 2.8/20mm is very easy to get here in Switzerland, usually for about CHF / EUR 100.--.

The first version of the Zeiss Flektogon 2.8/20mm was computed in 1967 (never produced, though); the computation of the second version was finished in 1971. To reduce costs, the lens didn't have floating elements, but that did require to add some additional coma (to get an acceptable definition from infinity to 1:10). And the lens specifically was computed to avoid high refractive glass, thus reducing manufacturing costs.

I highly doubt the Flektogon 2.8/20mm can compete with (let alone surpass) the Minolta AF 2.8/20mm which was computed 15 years later, using much more prowerful computers, and implementing both floating focusing (rear focusing) as well as high refractive glass.

But ultimately only a side-by-side comparison can show the differences.

S


PostPosted: Sun Oct 22, 2023 11:26 pm    Post subject: Reply with quote
Interesting results. Is there any field curvature? I am not actually asking for an excuse to be deployed for performance, or contextualize their legacy status. Just haven't done much lens comparison tests for this, and would want to see.


PostPosted: Mon Oct 23, 2023 2:38 am    Post subject: Reply with quote
eggplant wrote:
Interesting results. Is there any field curvature?

I haven't particularly looked into that - being primarily a landscape/architecture photographer, i?m interested in haveing good resolution over the entire image, and the specific type of aberration causing unsharp corners doesn't really bother me. Apart from astigmatism which simply doesn't look good ... But I can have a look into that.


eggplant wrote:
I am not actually asking for an excuse to be deployed for performance, or contextualize their legacy status. Just haven't done much lens comparison tests for this, and would want to see.

At least I can say it has nothing to do with an inaccurate length of the adapter used:

1) The Konica AR 2.8/21 does not have floating elements (so a inaccurate adapter length wouldn't matter anyway, but the adapter length is accurate), and
2) the Fotodiox adapter I use on the Mamiya CS 2.8/21mm precisely has the exact length needed.

S


EDIT
"Just for fun" I processed the image taken with the Minolta AF 2.8/20mm at f2.8 (wide open), and to my surprise it looks rather acceptable. Granted, both CAs and vignetting were removed, and sharpening was quite aggressive. Nevertheless such images could be printed in rather large sizes (again 100% crop from the corner of 24 MP FF):



S


PostPosted: Mon Oct 23, 2023 4:32 am    Post subject: Reply with quote
Thank you Thank you!

I recently replaced the loxia 21mm 2.8 that I had sold some time back to fund diving AF stuff for a trip I was taking. I purchased the first copy used it for 6 months and sold it for I think 15 more than I bought it right around 900 dollars. The recent copy I got was 400! It lives in my bag now replacing the olymus 21mm 3.5. I couldn't bring myself to carry my near perfect copy of the Konica all the time.


PostPosted: Mon Oct 23, 2023 2:34 pm    Post subject: Reply with quote
eggplant wrote:
Interesting results. Is there any field curvature?


I just checked the two lenses again, for field curvature.

At f2.8, the Mamiya CS 2.8/21mm has slightly "sharper" corners when focusing to the corners (insetad of the center).
Astigmatism is visible more clearly when focuing to the corners, though, and the image doesn't look better.

At f2.8, the Konica AR 2.8/21mm shows no obvious signs of field curcature.


jamaeolus wrote:
Thank you Thank you!

... the loxia 21mm 2.8 ... lives in my bag now replacing the olymus 21mm 3.5. I couldn't bring myself to carry my near perfect copy of the Konica all the time.


The Loxia 2.8/21mm of course is MUCH better than all three vintage superwide lenses tested here Wink ... on 24 MP FF perfectly useable even at f2.8.

S


PostPosted: Mon Oct 23, 2023 7:22 pm    Post subject: Reply with quote
Another lens I’d highly recommend is the Voigtlander Color Skopar 21mm f/3.5.

It has very good resolution at all distances, including at mfd (which btw is only 20cm). It has great colors, contrast, and very good flare performance. Low distortion, low CA’s, great sunstars and 10 blade aperture. Best thing is, it’s only just over 230 grams (for Sony). I don’t use this focal length very often, but because it’s so small and light, I can always bring it.

If weight/size is not an issue, there are several other great lenses in this focal length class. The Loxia is great of course.


PostPosted: Tue Oct 24, 2023 12:11 am    Post subject: Reply with quote
Yes, the Loxia is optically near perfect IMHO. It is just a tiny bit bigger than the Konica.

My only complaint is the finish is very slick and I fear my old man hands might drop it in a moment of inattention. I dislike the finish on my sony zeiss AF 90mm 2.8 macro for the same reason. I prefer the "splattered paint" effect of the G master 100-400. It looks nice but has enough texture not to slide in the dry skinned hands of an old man, such as myself. Still, all in all the Loxia is one of the finest manual focus lenses I have ever used.
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