Why identical lens on Mamiya TLR?

[Eugen Mezei]

Hello!

I just wonder why the taking and viewing lens of the Mamiya C series TLRs are identical. Other companies put a cheaper, not so well corrected, but also faster lens in the viewing position. This worked fine, even on the original TLR, the Rolleiflex.
Why did it Mamiya different? (More expensive, more dark, etc.) Can anyobody enlighten me about the advantages?

 

[KoNickon]

One advantage is that if the filter threads of the taking lens get damaged (very easy), you can simply swap the lenses. I've done it more than once.

 

[joachim]

Hello!

I just wonder why the taking and viewing lens of the Mamiya C series TLRs are identical. Other companies put a cheaper, not so well corrected, but also faster lens in the viewing position. This worked fine, even on the original TLR, the Rolleiflex.
Why did it Mamiya different? (More expensive, more dark, etc.) Can anyobody enlighten me about the advantages?

Hi Eugen,

Not sure, have been wondering the same, here are two possible reasons, I could think up:

• Rejects. Lenses they manufactured but turned out to be sub-quality would still be good enough to serve as viewing lenses
• The Mamiyas focus extremely close. To get good agreement in focus between viewing and taking over this wide variation in distances, they need to be very well matched. This concerns not only the focal length but also the other optical parameters, such as the distance of principle planes. At some point it becomes just easier to use the same design twice, than matching two very different designs (e.g. triplet viewing and Tessar/Planar taking on Rollei).

Perhaps other have different insights here.

J.

 

[graywolf]

I doubt that they are different lenses on any of the better quality TLR's. First, they have to be matched exactly in focal length. Second, the fraction of a stop faster is probably just because there is no diaphragm in the viewing lens. In some cases the fraction of a stop probably only exists in the advertising departments minds. I do not actually know that they are the same, but the cost factor of production suggests that they are, if they were entirely different lenses they would have to be produced on different production lines. It was hard enough to get to matching lenses off the same production line, much less off of two entirely different production line. Rollei may have done it, but I kind of doubt that anyone else would have even tried.

 

[farlymac]

I doubt that they are different lenses on any of the better quality TLR's. First, they have to be matched exactly in focal length. Second, the fraction of a stop faster is probably just because there is no diaphragm in the viewing lens. In some cases the fraction of a stop probably only exists in the advertising departments minds. I do not actually know that they are the same, but the cost factor of production suggests that they are, if they were entirely different lenses they would have to be produced on different production lines. It was hard enough to get to matching lenses off the same production line, much less off of two entirely different production line. Rollei may have done it, but I kind of doubt that anyone else would have even tried.

I'm not that familiar with the newer Rollei TLR's, but on my Automat Model 1, the viewing lens is a Heidoscop-Anastimat, while the taking lens is a Zeiss Tessar. Joachim has the right idea about the Mamiya set-up, seeing as you could do very close-up photography without the need for auxilliary lens units, due to the extension of the bellows mount. By matching the two lenses, you could get a precise focus and field of view in the viewing lens, then just crank up the camera with the Parramender, and take your shot. And with a Porroprism meter finder, you were taking a reading of the actual scene that the taking lens would be seeing.

Man, I miss my C330F.

PF

 

[oftheherd]

I think I once read that the wider open viewing lens was to aid in focus.

 

[joachim]

I think I once read that the wider open viewing lens was to aid in focus.

It also helps the brightness of the finder image!

 

[Spavinaw]

Yes, I've given this twin lens situation some thought in the past. I figure the Mamiya lenses are obviously identical twins. Ricohflex lenses with same f-stop but different formula would be fraternal twins of same sex, and Yashica lenses with different formula and different f-stops would be fraternal twins of different sex.
Yeah, I know, someone is going to think, how can I waste my time with stuff like this. When you're a retired engineer you have plenty of time, it's not hard to do, and it helps keep the brain active! Your situation may be different.

 

[Jamie123]

Yes, I've given this twin lens situation some thought in the past. I figure the Mamiya lenses are obviously identical twins. Ricohflex lenses with same f-stop but different formula would be fraternal twins of same sex, and Yashica lenses with different formula and different f-stops would be fraternal twins of different sex.
Yeah, I know, someone is going to think, how can I waste my time with stuff like this. When you're a retired engineer you have plenty of time, it's not hard to do, and it helps keep the brain active! Your situation may be different.

Sounds like all you think about is sex 😉