Zeiss Tessovar

[wstenberg]

IMG_0194.JPG (138.63 KiB) Viewed 4718 times

I'm working on a send for my Zeiss Tessovar lens system. As you can see, it's a work in progress. I'm trying to figure out how to connect a digital camera to it. The instructions show a Zeiss film camera, but I need to connect a modern digital SLR to it. There must be a special adapter that connects the Zeiss dovetails to the camera, but I don't know what it would be called.
I don't have the camera yet, but thinking of getting a Canon or Nikon, primarily for this application. Any help identifying the missing pieces would be appreciated.

Thanks!

[MichaelG.]

That looks a useful stand design, William

It must be nearly 30years since I made the camera mount for my Tessovar, but I do have the important 'tube length' measurement filed away somewhere.
Sorry, it may be New Year before I can access it.

I say 'important' because, although the Tessovar will produce an image at various distances, it behaves much better if the film/sensor is correctly distanced.

For convenience; I made mine with an M42 'Pentax' screw thread, which is then easily adaptable to most other camera mounts. A good alternative might be T2 [according to taste].

I will post some details when I can.

Best Wishes
MichaelG.

[zzffnn]

William,

Full frame sensors would offer the best optical match for Tessovar. They also have great auto focus and low light performance that smaller sensors (APSC or micro4/3) cannot match. Great for high speed (sports) too.

I heard Sony A7s, A7sII and A7RII all have silent electronic shutter, which is useful for high magnification. Nikon D850 has silent shutter too.

But note some (especially older) compound objectives (>=10x) won't cover full frame sensor very well. You need about matching projection eyepiece of about 2x in power (for compound objectives, not for your Tessovar). So corner image quality may not be good and sensor size is wasted.

For a good compromise, many Canon APSC sensor cameras that have silent electronic shutter would work well. You need matching projection eyepiece of about 1.3x, which may or may not be common though.

[wstenberg]

Thank you all for the assistance. I have found the M42 adapter and tubes on eBay. Just need to go camera shopping now.

I need to add a vertical focus adjustment on the stand. I can focus with the microscope stage adjustment, but I would like the option to move the lens up and down also.

[KurtM]

...the Tessovar ... behaves much better if the film/sensor is correctly distanced.

I've heard that. What I haven't heard is how the correct distance is determined? I use a Canon T3i, which is APS-C, with my Tessovar.

Good to hear there are other Tessy users out there, I thought I must the only one there for a minute.

[MichaelG.]

...the Tessovar ... behaves much better if the film/sensor is correctly distanced.

I've heard that. What I haven't heard is how the correct distance is determined? I use a Canon T3i, which is APS-C, with my Tessovar.

Good to hear there are other Tessy users out there, I thought I must the only one there for a minute.

I determined the correct distance by asking Zeiss UK
The answer was: Flange to Film Plane = 64mm +/- 0.1mm

Note: With a digital sensor, that tolerance might be a little loose;
+/- 0.05mm would probably be safer.

When it's right, the zoom operates with negligible focus shift.

MichaelG.

P.S. I currently use the Panasonic Lumix G1 body on mine.
.
Edit: Before anyone asks ... Here is a very useful list of 'register' distances
http://www.graphics.cornell.edu/~westin ... ister.html

[MichaelG.]

Thank you all for the assistance. I have found the M42 adapter and tubes on eBay. Just need to go camera shopping now.

I need to add a vertical focus adjustment on the stand. I can focus with the microscope stage adjustment, but I would like the option to move the lens up and down also.

William,

Although you could easily [?] cannibalise a microscope stand to do the job; the obvious answer is to use the Zeiss Supplementary Rack & Pinion:

Zeiss Part Number: 47 52 10

Tessovar_Rack.jpeg (418.85 KiB) Viewed 4628 times

If you are seriously interested, I may be prepared to sell mine, or trade it for something interesting.
... I have recently purchased a Wild stand with a built-in focus rack.

MichaelG.

Happy Christmas to all, and Best Wishes for 2018

[KurtM]

I determined the correct distance by asking Zeiss UK
The answer was: Flange to Film Plane = 64mm +/- 0.1mm

Very interesting. A quick Google session clued me in that the distance between a camera flange and sensor is known as "...the flange focal distance (FFD), also known as the flange-to-film distance, flange focal depth, flange back distance (FBD), flange focal length (FFL), or register..." (Dang - wonder why so many names for the same thing?!)

https://en.wikipedia.org/wiki/Flange_focal_distance

I then found that my number (Canon EF & EF-S) is 44mm, which means I need a 20mm spacer according to the 64mm value given above.

Thanks MichaelG! Now to give it a try...

[wstenberg]

Thanks everyone for all the help!