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Mamiya Sekor C 4/210mm apochromatic correction?
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PostPosted: Mon May 07, 2018 7:43 am    Post subject: Mamiya Sekor C 4/210mm apochromatic correction? Reply with quote
Some months ago I got a tilt/shift adapter for my Mamiya 645 lenses. Some preliminary test gave excellent results for the Mamiya telephoto lenses, but not so for the Mamiya Sekor C 3.5/35mm (for which a shift adapter would make sense). Therefore I forgot a bit about using these Mamiya Sekor C lenses on my A900.

A few days ago i checked a Leica 3.4/180mm APO Telyt on 24MP FF - with stunning results; the lens is even a trace better than the Minolta AF 2.8/200mm APO G.

This gave rise to a small test of a few fast 180mm / 200mm lenses. Out of curiosity I did include the Mamyia Sekor C 4/210mm.

The results of the Mamyia were stunning as well; this lens obviously is very well corrected - certainly better than the AF ED Nikkor 2.8/180mm, and at f8 it has less CAs than the Minolta AF 2.8/200mm APO.

Below are 100% crops from the corners; the JPGs are directly out of the Sony A7 (24MP FF).


Canon new FD 2.8/200mm IF: The optical performance of this lens is the worst of the bunch tested here. As others have mentioned, its CAs are pretty hefty, and focusing is not as precise as with non-IF lenses (the same is true for the AF Nikkor 2.8/180mm; the Minolta AF 2.8/200mm APO, however, has a more precise IF mechanism). We can an assume that the nFD 2.8/200mm has two large lenses out of LD glass (Abbé number 70) - at least the nFD 4/200mm, nFD 4/200 Macro, and the nFD 4/300 (non-L) do have them. Obviously this is not sufficient to give a good color correction.


Konica Hexanon AR 3.5/200mm (latter version): medium performance; less CAs than the Canon nFD 2.8/200mm IF and the Pentax SMC 2.5/200mm, but more CAs than the Mamiya/Minolta; good details, but lowest contrast of the six lenses tested, and not-so-good colors (especially compared to the Minolta AF 2.8/200 APO).


Mamyia Secor C 4/210mm: What a surprise! At f8 the best color correction of all lenses tested here, and absolutely comparable to the legendary Leica APO Telyt 3.4/180mm. The Minolta APO may have slightly betters colors, though (more "punchy"). Details are excellent (also at f4; not shown here).


Minolta AF 2.8/200mm APO: slightly more CAs than the Mamiya, and slightly better colors / contrast I would say. Please note that the crop shown here was taken at f4 (and not at f8 as the others) - I simply had forgotten the f8 shot. Together with the Mamiya Sekor C 4/210mm this is the best lens of the bunch. Easy and quick manual focusing without any play (the Nikkor AF and the Canon nFD are much worse in this respect!).


Nikkor AF 2.8/180mm ED (newest version): medium performance; detail resolution not as good as with the Minolta AF 2.8/200 APO and the Mamiya Sekor C, but better corners than the Canon nFD 2.8/200 and the Pentax SMC 2.5/200. The same is true also concerning the CAs. Manual focusing is a bit annoying since the focusing mechanism has quite a bit of "play" (a problem that plagues also the Sony Zeiss ZA 1.4/85mm and ZA 1.8/135mm).


Pentax SMC 2.5/200mm: Quite a bit of CAs (less than the Canon, though) and a relatively low resolution, even at f8. Slighty better than the Canon, and a bit faster than the others, of course.

And now an important technical remark about testing: The E-mount bayonet of the Sony A7 series is very badly made. Whne attaching a fast / heavy lens, the mount will easily tilt about 0.5mm - which makes lens testing meaningless. I have reduced this problem by not using a tripod; instead i put the camera and lens directly on a stable basis.

Of course now we all are curious about the Mamiya Sekor C 5.6/300mm...


PostPosted: Mon May 07, 2018 10:08 am    Post subject: Re: Mamiya Sekor C 4/210mm apochromatic correction? Reply with quote
stevemark wrote:
Some months ago I got a tilt/shift adapter for my Mamiya 645 lenses. Some preliminary test gave excellent results for the Mamiya telephoto lenses, but not so for the Mamiya Sekor C 3.5/35mm (for which a shift adapter would make sense). Therefore I forgot a bit about using these Mamiya Sekor C lenses on my A900.

A few days ago i checked a Leica 3.4/180mm APO Telyt on 24MP FF - with stunning results; the lens is even a trace better than the Minolta AF 2.8/200mm APO G.

This gave rise to a small test of a few fast 180mm / 200mm lenses. Out of curiosity I did include the Mamyia Sekor C 4/210mm.

The results of the Mamyia were stunning as well; this lens obviously is very well corrected - certainly better than the AF ED Nikkor 2.8/180mm, and at f8 it has less CAs than the Minolta AF 2.8/200mm APO.

Below are 100% crops from the corners; the JPGs are directly out of the Sony A7 (24MP FF).


Canon new FD 2.8/200mm IF: The optical performance of this lens is the worst of the bunch tested here. As others have mentioned, its CAs are pretty hefty, and focusing is not as precise as with non-IF lenses (the same is true for the AF Nikkor 2.8/180mm; the Minolta AF 2.8/200mm APO, however, has a more precise IF mechanism). We can an assume that the nFD 2.8/200mm has two large lenses out of LD glass (Abbé number 70) - at least the nFD 4/200mm, nFD 4/200 Macro, and the nFD 4/300 (non-L) do have them. Obviously this is not sufficient to give a good color correction.


Konica Hexanon AR 3.5/200mm (latter version): medium performance; less CAs than the Canon nFD 2.8/200mm IF and the Pentax SMC 2.5/200mm, but more CAs than the Mamiya/Minolta; good details, but lowest contrast of the six lenses tested, and not-so-good colors (especially compared to the Minolta AF 2.8/200 APO).


Mamyia Secor C 4/210mm: What a surprise! At f8 the best color correction of all lenses tested here, and absolutely comparable to the legendary Leica APO Telyt 3.4/180mm. The Minolta APO may have slightly betters colors, though (more "punchy"). Details are excellent (also at f4; not shown here).


Minolta AF 2.8/200mm APO: slightly more CAs than the Mamiya, and slightly better colors / contrast I would say. Please note that the crop shown here was taken at f4 (and not at f8 as the others) - I simply had forgotten the f8 shot. Together with the Mamiya Sekor C 4/210mm this is the best lens of the bunch. Easy and quick manual focusing without any play (the Nikkor AF and the Canon nFD are much worse in this respect!).


Nikkor AF 2.8/180mm ED (newest version): medium performance; detail resolution not as good as with the Minolta AF 2.8/200 APO and the Mamiya Sekor C, but better corners than the Canon nFD 2.8/200 and the Pentax SMC 2.5/200. The same is true also concerning the CAs. Manual focusing is a bit annoying since the focusing mechanism has quite a bit of "play" (a problem that plagues also the Sony Zeiss ZA 1.4/85mm and ZA 1.8/135mm).


Pentax SMC 2.5/200mm: Quite a bit of CAs (less than the Canon, though) and a relatively low resolution, even at f8. Slighty better than the Canon, and a bit faster than the others, of course.

And now an important technical remark about testing: The E-mount bayonet of the Sony A7 series is very badly made. Whne attaching a fast / heavy lens, the mount will easily tilt about 0.5mm - which makes lens testing meaningless. I have reduced this problem by not using a tripod; instead i put the camera and lens directly on a stable basis.

Of course now we all are curious about the Mamiya Sekor C 5.6/300mm...


The Sekor N 300/5.6 has less chromatic aberration than bot the the N Sekor 210/4 and Leitz Apo Telyt R 180/3.4 on the Sony A7/7R/72.

I got all the lenses tested/mentioned above,save the Minolta 200/2.8.Sekor N 300/5.6,though not as sharp as The Apo Telyt R 180/3.4,is the best apo corrected lens of them all.


PostPosted: Mon May 07, 2018 10:37 am    Post subject: Reply with quote
Quote:
And now an important technical remark about testing: The E-mount bayonet of the Sony A7 series is very badly made. Whne attaching a fast / heavy lens, the mount will easily tilt about 0.5mm - which makes lens testing meaningless. I have reduced this problem by not using a tripod; instead i put the camera and lens directly on a stable basis.


One of the first things I bought for my A6000 was the Fotodiox Tough E Mount, It's a huge improvement and worth every penny.

https://www.youtube.com/watch?v=2H5EZP9Cf8E


PostPosted: Sat Mar 26, 2022 6:48 pm    Post subject: Reply with quote
A word of caution abut the Mamiya Sekor C 4/210mm: Obviously its front lens is made from a sensitive fluoride (or even fluorite??) glass.

My sample of the said lens has turned "blind" (fogged) on the outer surface of the front lens, after prolonged storage without front cap. I have never seen such a problem with any other lens. This seems to indicate the use of special fluoride glass, which is more sensitive to moisture and pollutants than "normal" glass.

Luckily I could buy another beautiful Sekor C 4/210mm today, and just for the fun of it I checked its performance. Here we go:

(CLICK TWICE ON THE IMAGE TO GET THE FULL RESOLUTION)



There's no doubt that the Mamyia Sekor C 4/210mm is on par with its famous APO / ED cousins from Minolta and Nikon - maybe even slightly better (and slower, of course).

If you need an excellent and cheap 200mm lens for landscapes - this is it!

S


PostPosted: Sat Mar 26, 2022 8:12 pm    Post subject: Reply with quote
I don't waste time with looking at the corners wide open, that is for anal idiots.

But from actually using the lenses, I would say that the Bronica Zenzanon-PE 200mm f4.5 is much better on my a850.


PostPosted: Sat Mar 26, 2022 8:54 pm    Post subject: Reply with quote
kiddo wrote:
Steve, what adapter are you using for the mamiya c lenses to Sony? Is the ze working or not? Thanks


I have a beautiful Zörk tilt/shift adapter (Sekor C => Minolta AF) which allows shifting and tilting on the Sony/Minolta DSLRs. The adapter is a masterpiece of fine mechanics since the difference between Minolta AF (44.5mm) and Mamiya 645 (63.7mm) is just 19.3mm. While the adapter is a mere 19.3mm thick, it has three functions:

1) shifting +/- 15mm (the 2022 version seems to have even +/- 20mm)
2) rotation 360°
3) tilting 30°

For connecting the Mamiya Sekor C lenses to the Sony E bayonet I use an additional MinAF => Sony E adapter (no-name in this case).

S


PostPosted: Sat Mar 26, 2022 10:04 pm    Post subject: Reply with quote
stevemark wrote:
A word of caution abut the Mamiya Sekor C 4/210mm: Obviously its front lens is made from a sensitive fluoride (or even fluorite??) glass.

My sample of the said lens has turned "blind" (fogged) on the outer surface of the front lens, after prolonged storage without front cap. I have never seen such a problem with any other lens. This seems to indicate the use of special fluoride glass, which is more sensitive to moisture and pollutants than "normal" glass.

S


It is fluorite (with a t), the name for calcium fluoride (with a d).

You can flummox people by mentioning that one of the elements in your expensive APO is made of a salt, rather than of glass Wink

However, I would be very surprised if the front element of the Sekor was actually made of fluorite. Fluorite is soft, fragile, and susceptible to water damage, which is why all camera lenses with a fluorite element that I have ever seen have had their sensitive fluorite element protected behind a regular glass front element (which is not to suggest that camera lenses with exposed fluorite front elements don't exist).

Having said that, owners of the Takahashi FS series telescopes, which do have fluorite front elements seem to have no issues with them. I believe that is because they finally managed to apply hard coatings to the fluorite element, something which had always been a problem. Not sure when they made that breakthrough though.

Bear in mind that some "regular" glass compositions used in camera lenses can also be susceptible to the formation of a surface haze/fogging; alkaline ions can leach out of the glass during prolonged periods of condensation on the glass, the concentrated alkaline solutions then erode the silica gel layer of the polished surface. When the condensation evaporates, silicon ions and alkali are then deposited on the glass surface leaving a hazy film that cannot be removed by wiping. ("Optical Glass", T.S. Izumitani, UCRL-Trans-12065, LLNL, 1985; referenced in "Fabrication Methods for Precision Optics", H.H Karow, Wiley-Interscience, 2004). Of course the way you stored the lens may well have prevented any condensation, in which case this is irrelevant.


PostPosted: Sat Mar 26, 2022 10:22 pm    Post subject: Reply with quote
stevemark wrote:
kiddo wrote:
Steve, what adapter are you using for the mamiya c lenses to Sony? Is the ze working or not? Thanks


I have a beautiful Zörk tilt/shift adapter (Sekor C => Minolta AF) which allows shifting and tilting on the Sony/Minolta DSLRs. The adapter is a masterpiece of fine mechanics since the difference between Minolta AF (44.5mm) and Mamiya 645 (63.7mm) is just 19.3mm. While the adapter is a mere 19.3mm thick, it has three functions:

1) shifting +/- 15mm (the 2022 version seems to have even +/- 20mm)
2) rotation 360°
3) tilting 30°

For connecting the Mamiya Sekor C lenses to the Sony E bayonet I use an additional MinAF => Sony E adapter (no-name in this case).

S


Fotodiox do something vaguely similar with their ROKR adapters (tilt & shift adapters for mounting medium format lenses on 35mm FF cameras.)
I have one of those for Bronica PS lenses, but the engineering accuracy of the Fotodiox ROKR adapter leaves a lot to be desired (bottomed-out screws, mount not parallel to film plane at zero tilt, no mount springs thus a rattling lens, no facility to lock the PS lens shutter open once mounted with spring loaded accessories such as bellows, TC's extension tubes, etc. etc.) I had to make quite a few modifications to get it to work properly.


PostPosted: Sat Mar 26, 2022 11:50 pm    Post subject: Reply with quote
RokkorDoctor wrote:

Fotodiox do something vaguely similar with their ROKR adapters (tilt & shift adapters for mounting medium format lenses on 35mm FF cameras.)
I have one of those for Bronica PS lenses, but the engineering accuracy of the Fotodiox ROKR adapter leaves a lot to be desired (bottomed-out screws, mount not parallel to film plane at zero tilt, no mount springs thus a rattling lens, no facility to lock the PS lens shutter open once mounted with spring loaded accessories such as bellows, TC's extension tubes, etc. etc.) I had to make quite a few modifications to get it to work properly.


Ouch. The Zörk is really very well machined. Of course there are quirks in handling, but that's a result of squeezing so many functions in an adapter with just 19.3mm thickness.

S


PostPosted: Sun Mar 27, 2022 8:44 am    Post subject: Reply with quote
I have th Tilt ROKR for Mamiya 645 and it is not too bad, just needs a setting before the lenses stop to slide down.


PostPosted: Sun Mar 27, 2022 10:17 am    Post subject: Reply with quote
Slalom wrote:
I have th Tilt ROKR for Mamiya 645 and it is not too bad, just needs a setting before the lenses stop to slide down.


I'm sure they also have some good models.

Judging from their promotional product shots, they made some improvements to their ROKR adapters which didn't make it into the particular one I got (Bronica-PS to Nikon-F). Probably a matter of low demand and old stock.

I have one other Fotodiox adapter as well. TBH, going by the two samples I have in my possession I do not understand the price premium for the Fotodiox Pro adapters. They look good and cosmetic finish is quite good, but when you start taking them apart for modification the engineering shortcuts, mistakes & faults become clear. IMHO, it is a lot more money for only a modest improvement over the generic cheap adapters as far as production quality is concerned.

Both the Novoflex and Rayqual adapters that I also have are significantly better made (apart from the mount pressure spring design, which seems to be a common issue with ALL adapter makes I have seen so far.)
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