ROW VISIONAR 77/1.6 converted to E mount + Sony A7R

[chudy128314]

ROW Visionar 77/1.6 projection lens converted to Sony E mount with custom made step-down ring, M42 focusing helicoid and slim M42 -> E adapter. Fully functional.


It performs perfectly, sharp enough, little aberrations.
All samples without processing besides resizing, Sony A7R:

[sergtum]

it is very interesting solution. which focus range has the lens?

[chudy128314]

It focuses from less than 1 meter to infinity. It's fine solution for this lens, but for bigger and heavier projection lenses it's not good solution - the tension on helicoid makes it impossible to focus and whole construction begins to bend. Additionally you need some extra space between lens and sensor.
For bigger lenses I'm working on different kind of adaptation, without cheap, chinese helicoid. I hope te able to convert even my Visionar 200/1.9 to usable form .

[wolfhansen]

For the big ones i use Henrys SFT (velvet focus tube) - works great
i have three SFTs in 42,5mm, 52,5mm and 62,5mm for all common projector lenses.

Here a pic of my A7 with the heavy 1100gram Carl Zeiss Visionar 1.9/141mm in the 62,5mm SFT.

[chudy128314]

I've been searching on forum for any technical infromation about this tube and failed. Do you know where I can found any info? I'd like to see how similar to my idea it is.

[wolfhansen]

Have a look at Henrys Digicamclub - Site.
Please use Google to translate:

http://www.digicamclub.de/showthread.php?t=19738

[chudy128314]

Thanks, looks great.
However I''ll try to simplify things using only one additional element - aluminum tube with M42 or M39 mount at the end and machining shallow spiral groove on the lens' body. There will be pin in the tube fitted to the groove, turning the lens left/right will move it towards/against the sensor.

[sergtum]

[chudy128314]

Yes, but it's not very well corrected for close distance. It works the best as a portrait lens, when object is a few meters away.

[Sigurd Ruschkowski]

[sergtum]

[rebelstar]

My latest DIY helicoid adapter, fits any projection lens (52.5, 62.5, 82.5)
With 77-82mm thread adapter ring to screw CPL filter / hood
meopta 100 1.7

philips 100 1.5


using it for heavy visionar 141 1.9 as well

since I like to shoot at night with tripod, such heavy lens is not recommended for lens mount so I bought this tripod mount ring

[chudy128314]

Is there helicoid between the lens and mount? Does it take the space? When I tested some of my projection lenses I noticed if there was helicoid between lens and mount there was no infinity focus for M42 mount. That's why I want to adapt without external helicoid.

[rebelstar]

it's 17-31mm helicoid, I have infinity for all lens I own. Even for meopta 50 1.0 with extremely low working distance.

[chudy128314]

You have infinity with Sony A7. My idea is to get infinity focus with regular M42 adapter, so it will be usable not only with mirroless cameras, but also with DSLR (including Nikon when it will focus a bit "beyond" infinity). Off course a lot of projection lenses can't be adapted to M42, but some of them can be adapted only when there is no additional element between back of the lens and M42 adapter.

[rebelstar]

Its a pain to use manual/projection lenses with dslr because of optical viewfinder and no magnifier there. Live view is not a deal to use, so evf is perfect for manual work. Also shorter working distance. There are a lot of manual and projection lens which you cant use with dslr. Dslr is a good deal for AF native lens only.

[chudy128314]

I know, I don't even have DSLR and don't want one .
I just want to create the way of adapting that:
1) is the most versatile - having lens adapted to M42 is more versatile than Sony E
2) needs minimal amount of elements - tube with M42 back is simpler than reduction ring/tube + helicoid + camera mount

[rebelstar]

still can't get your point.
if you want m42 and have shorter working distance for e-mount probably you need this ring

[chudy128314]

If the lens is converted to real M42 mount (I mean taking into considertaion its 45.46 mm flange focal distance) you can use the same lens with mirrorless cameras using long adapters and with DSLR cameras using slim adapters. It's pure, elegant and it's a nice challenge .

[rebelstar]

but there are a lot of lenses which you can't convert that way since they will fit to mirrorless cameras working distance only.

[chudy128314]

Yes, I'm talking only about the lenses that can only be converted to M42 when you don't use additional helicoid taking valueable space.
Other thing is the weight of the lenses. When I tried Lomo 100/2 with helicoid between lens and mount the helicoid simply bent, it was impossible to control focus. Maybe I should try another, more expensive helicoid but there is another problem. When you focus with helicoid you don't hold the heavy lens at the most convenient point, the front of the lens. It's way easier to hold heavy lens when you hold it near the front (simple lever law).

Summing up - adapting projection lenses to M42 with focusing helicoid between the lens and mount is great for many lenses, but not for all purposes.

[rebelstar]

You just need some good helicoid, that's it. Because I use very heavy lenses with no problem ~1,2-1.5+ kg such as Visionar 141 1.9, 35KP 140 1.8
https://www.youtube.com/watch?v=YVyVejX30Ak&t=1s

[Attila]

[chudy128314]

[rebelstar]

It's custom made with helicoid thread inside from the telescope tube as donor, whole body made my lathe works buddy.