Home
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

35KP 70/1.8 + Sony A7R
View previous topic :: View next topic  


PostPosted: Fri Sep 08, 2017 7:57 am    Post subject: 35KP 70/1.8 + Sony A7R Reply with quote

35KP 70/1.8, soviet projection lens I converted to M42 with focusing:



I'm in love with these projection lenses, it's really something different to regular photo lenses.
Sony A7R, no post-processing besides resizing:





PostPosted: Fri Sep 08, 2017 7:57 am    Post subject: Reply with quote

One thing keeps me interested. There are many fast projection lenses (faster than photo lenses) with great image quality, significantly better than a lot of corresponding photo lenses. For instance, comparing this 35KP 70/1.8 to Jupiter-9 85/2 is crushing for Jupiter. You can also have 120/1.8 with better image quality than most 135/2 photo lenses.
What's so special about projection lenses? Often they're not bigger. Maybe they were super expensive then?


PostPosted: Fri Sep 08, 2017 9:16 am    Post subject: Reply with quote

lower production numbers with better quality control?


PostPosted: Fri Sep 08, 2017 9:35 am    Post subject: Reply with quote

Quote:
One thing keeps me interested. There are many fast projection lenses (faster than photo lenses) with great image quality, significantly better than a lot of corresponding photo lenses. For instance, comparing this 35KP 70/1.8 to Jupiter-9 85/2 is crushing for Jupiter. You can also have 120/1.8 with better image quality than most 135/2 photo lenses.
What's so special about projection lenses? Often they're not bigger. Maybe they were super expensive then?

My guess it that these lenses are optimized for top performance at maximum aperture (do they even have irises for stopping down at all?) while photographic lenses are optimized for top quality at working aperture which is typically a few clicks down from max. Remember, the old school of photography teaches that for examples portraits should be taken at f/5.6 to f/11 and a wide maximum apertures in a portrait lens was there just for the sake of a brighter viewfinder and occasional low light shot where you don't expect good quality anyway. The fascination with thin DOF and bokeh is a relatively modern invention.


PostPosted: Fri Sep 08, 2017 10:12 am    Post subject: Reply with quote

chudy128314 wrote:
Maybe they were super expensive then?


When you think of the soviet economic system, I think they had no price at all? They were just delivered where the movie projection committee saw suitable.


PostPosted: Fri Sep 08, 2017 12:35 pm    Post subject: Reply with quote

Miran, fast (and only, no iris!) aperture optimization seems reasonable.
Moreover, old cameras nof often had 1/4000 or 1/8000 s shutter needed in a sunny day, so it was more natural to stop down. And focusing was not as easy as today with mirrorless cameras. Fast aperture and thin DOF (and all consequenses) can indeed be better handled nowadays.


PostPosted: Sun Sep 10, 2017 10:15 am    Post subject: Reply with quote

Yes, using projetion lenses is a good way to get good result with fast lens, at low price (if you can adapt it).

I have the 75mm version, also converted, with internal diaphragme ( https://www.youtube.com/watch?v=7fNBDQL5aOI ). Talking about competition with Jupiter-9, it is indeed a pretty good competitor.


And if you close a bit diaph :


PostPosted: Mon Sep 18, 2017 11:13 am    Post subject: Reply with quote

I tried mine 35KM140 1.8 2 weeks ago, 1.5kg. some photos and no more fitness needed. No problem with the focusing with focus peaking Magic Lantern on 6D. Outsite ND can be helpful, if one dont want do lose the bokeh by using diaphragm. The optical resolution however Im not sure is so big, but the image circle isbig and because of this we are not working with the periferic part. Tripod needed, colar 66mm with some insider 1mm ring (still waiting my collars, cannot be sure). some 12-13mm of the rear barrel must be cut to get infinity, if chinese helicoid is used. Toys for boys hahaha...

Cheerz!