Is Cosina Voigtlander Allergic to f/2 Lenses?

antiquark said:
I've read somewhere on the internet that CVs design philosophy is to create a lens using the best possible components, then replace the parts with cheaper versions to bring down the cost. That seems to be a logical engineering process, but the problem would be that the final lens wouldn't meet the original specifications.

What follows is total speculation...
Maybe CV designs lenses with standard apertures (1.0, 1.4, etc) but after the "cheapening phase" the aperture is a little "off". So for the 50/1.5 maybe they initially designed a 50/1.4 which ended up with a 1.5 aperture after development. Maybe the 35/1.2 was initially a 35/1.0, and so on.

That might even explain why their only 1.4 lens is a 40mm... maybe it was initially designed as a 35.
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AH, AH, I don't think so.
 
No, I think the optical design and specifications remain constant from beginning of the design phase to the end. Perhaps in the engineering and assembly some economies are factored in.
 
Here's the article I mentioned:
http://keppler.popphoto.com/blog/2006/05/the_contrary_mi.html#more

"Usually we first design the very best possible lens, regardless of glass price," explains Kobayashi. "Then we try to substitute less expensive elements wherever possible without noticeably affecting quality. We stop when we have lowered production costs sufficiently, but have retained quality, and where the difference from our original lens will be negligible to the user."
 
antiquark said:
What follows is total speculation...
Maybe CV designs lenses with standard apertures (1.0, 1.4, etc) but after the "cheapening phase" the aperture is a little "off". So for the 50/1.5 maybe they initially designed a 50/1.4 which ended up with a 1.5 aperture after development. Maybe the 35/1.2 was initially a 35/1.0, and so on.

That might even explain why their only 1.4 lens is a 40mm... maybe it was initially designed as a 35.
Click to expand...

That would be funny if it were true. 😀

Cosina is not being so precise with their aperture designations. They aren't calling a lens f/1.9 of f/2.5 because they were forced to by the results after the design & manufacture process.

Peter & Blakley hit the nail on the head the first time this thread ran - product differentiation. They were trying to create a niche for themselves by offering something a little different.

For a long time almost all of the lenses were designated on the "5's" - 1.5, 2.5, 3.5, 4.5. This was not because this is what these lenses actually were. Check the Popular Photography lens reviews. The 50/1.5, for example was actually 1.6. The 75/2.5 & 35/2.5 were actually 2.7. (Anyone else would have called them 2.8 & let it go at that.) The 50/3.5 was actually 3.7. Even when they weren't on the 5's, they were off the stated spec. The 35/1.7, for example, was 1.8. Pop Photo didn't test the 28/1.9, so I don't know what it actually measures, but my guess is that another manufacturer wouldn't have quibbled over f/1.9 vs f/2, but for Cosina it became "the fastest 28 ever made."

Cosina isn't the only one whose lens measurements don't match the spec. The Leica pre-ASPH 35/1.4, for example, is actually 1.6. What makes Cosina different is that they "ballpark" their specs at exotic designations. My problem with it is that it leads to specualtion such as yours, which essentiall says: "The spec must really be what it says it is & there must be an explanation for it. Why else would they be so precise?" No one is surprised when a 50/2 is a little off the stated focal length or maximum aperture. Hec, we've come to expect it. There is a small variation in almost all lenses from the spec, but we accept that if you're looking for a "standard 50", this is "ours" - even though it may actually be 53/2.1 (M-Hexanon). What we don't expect is for manufacturers to be "rounding off" at f/2.5 or f/3.5.

To be fair to Cosina, they didn't invent the game of seeking attention by stating exotic specs rather than using full or half apertures. If you look back, you can find other companies who have done the same. I think that it is an indication that Cosina now seems to feel established in this niche that they have not been doing this with their more recent new lenses. The 40/1.4 used a full aperture stop for its designation. (It actually is 1.4) They finally gave us a "standard 50" - the 50/2 Heliar. Although they are replacing lenses of the same designation, the new 21/4 & the 25/4 are spec'd at full aperture stops as well.

I like this latest trend from Cosina. They have enough standing in the rangefinder world that they no longer have to play the game of 5's with "gimmick" designations.
 
Silva Lining said:
The old voigtlander made plenty of 50mm f/2 ultrons !! Maybe Cosina Voigtlander don't believe in history repeating itself! 😉
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hello, did you forget? The 50mm f2 was brought out with the R2/3M and now you can get seperately.
 
Just an aside: the 50/2 Heliar has come down in price a fair bit. Cameraquest has it on sale, I think $400? Comparable to their LTM $350 offerings if you plan to use it on an M and factor the adapter cost. I haven't seen a lot of samples though.
 
Peter - you are brilliant - you should go work for RAND or some other think tank.

Cheers,
Alex
 
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