Question for Yashica Mat owners

[davido]

Hello
I have a question for Yashica TLR owners: what is the distance from the rear lens element to the film plane (approximately). This would be with the lens set at infinity.
Odd question I know, but I am looking for a TLR camera To be adapted with a meniscus lens of 60-70mm FL.

Thanks for your help,
David

 

[Dan Daniel]

~66mm

 

[pagonzales]

I'm not sure if this will help, but 127/4x4 TLRs like the Yashica 44 and Baby Rolleiflex had 60mm lenses as standard. Maybe you can use 1 of those and just use cut down 120 or even 35mm film on 127 film spools. Most TLRs have around 75-80mm as nor
mal lenses. You can also try the Mamiya TLR series since they use a bellows system. The flange distance might be a little closer.

 

[davido]

~66mm

Thanks Dan for the measurement. Much appreciated!
Just one more thing: could you please measure the diameter of the lens element.

Cheers, David

 

[Dan Daniel]

Exposed glass- ~19mm
Outisde of mounting metal- ~23mm

All of these are rough, slop of maybe 1mm as I am eyeballing from 66mm (?) away with a ruler, then trying to check with calipers.

 

[davido]

Thanks Dan. much appreciated.
Which model do you own? I believe the Yashica TLR bodies are all the same size? But just in case.

David

 

[Dan Daniel]

Those measurements are from a YashicaMat 124 model.

Best as I know the basic lens formula of the Yashinon stayed the same throughout the life if the Yashicas. So the lens position at infinity should be the same. Looking at a Rolleicord which also has a Tessar-type lens, the measurements come out the same.

As to the overall body dimensions, I think Yashica didn't change he size over the years but I am not absolutely certain.

 

[davido]

Thanks Dan, this is much appreciated.
It seems that the film plane to flange distance might be fairly consistent from brand to brand as the design is so similar amongst many of these TLR's. You don't happen to have a Minolta Autocord do you? I've read that it's probably the smallest of the TLR's . It's also got a 75mm lens which may or may not make a difference in regards to the film plane to flange distance.

David

 

[Dan Daniel]

Autocord, like the YashicaMat, ~67mm. You're right, the Autocord and the Rolleicord are 75mm lenses, 80mm on the Yashica. I don't know enough to say why the back distance isn't 5mm different.

To be clear, my measurement of 66-67mm is from the back of the metal ring that surrounds the rear lens group.

 

[davido]

You have quite the collection of TLRs Dan!
Do you have an Argoflex?
Just looking at those and, though the quality is obviously much lower, they are apparently smaller than an Autocord. Though I do realize that any TLR has to be a certain amount to take into account the 6x6 ground glass at the top.
How are you measuring to to the film plane? Are you just measuring inside of back?
David

 

[davido]

Autocord, like the YashicaMat, ~67mm. You're right, the Autocord and the Rolleicord are 75mm lenses, 80mm on the Yashica. I don't know enough to say why the back distance isn't 5mm different.

Being that the lens has multiple elements, it's designed to adjust to actual distance by a certain percentage (I am not doing a great job explaining). But because I want to use a single meniscus lens it has to be the exact distance of its focal light to the film plane.

 

[Dan Daniel]

My measurement is from the back of the rear lens group- the metal ring holding the lens, which is just a bit above the glass itslef- to the film rail. A Tessar-type rear lens group is maybe 5mm deep? So if you can drop your meniscus into the back of the shutter block you might need to add 3-5mm to my measurements.

I am not certain what you want to do. Are you planning to mount your lens on the existing lens board? Behind the existing shutter? If so, I think you will have some serious vignetting, from both the shutter and the overall lens board/shroud. The lens board and shutter block/lens system sits mainly in formnt of the cast aluminum camera body. You might need to remove the lens board and mount your lens in the body opening. But the viewing lens will need a new mount, and you'll need a shutter?

I wonder if there's some overkill using a TLR body. What do you hope to gain from using such a body that you won't get from a Holga body or old Brownie-type camera?

 

[davido]

I was going to mount the new lens right behind the shutter (or 1mm or 2mm away from it). It shouldn't vignette, only if it were further towards the film plane.

What I hope to gain is more control than one gets from a Holga - exposure and focus control. Plus a ground glass to compose they image, over a very poor Holga viewfinder. I can also control the amount of edge blur using the aperture.

I have actually been looking at the Lubitel as a candidate. It should have a shorter film plane to flange distance as the body is only 95mm deep and the ground glass is smaller (4x4 I think). So, I am thinking it should be able to accommodate a meniscus lens under 65mm? Removing the two lenses also appears to be fairly straightforward. It's also a much smaller investment! And still a step up from the Holga.

Thanks, your measurement sounds good. I was thinking that it would be difficult working around the back door being open.

David