focusing to infinity impossible with fujinon 1,8/75 on nex

psy501 · Expire: 2015-04-15

..hello..this is my first post in this very fine forum which i have been following passively for quite a while..

..please know that its all your fault that i have spent quite some money on some fine lenses during the last six months based on the information provided here and that i will spend some more, im afraid.. Smile

..thanks for providing all the knowledge and therefore providing all the fun i have with my lenses..

..now i need some help..

..i got me a nice fujinon as stated in the header for use with two c-mount adapters on my two nexes (7 and c3)..
..the adapters seem fine as far as i can tell but i am not sure as they came with my two fujian lenses via hongkong and are cheaply made..with one adapter i can focus a bit more to infinity than with the other..
..the lens came with a small distance ring that i took off as with the ring attached i was only able to really focus close..

..there is information on the net that this lens should focus to infinity without problems (i think it was getdpi) and as far as i have learned by now with a focal length of 75 mm there should be no problem..

..do you have some hints for me..?

..thanks in advance..erik..

..ps: do you know a 25 mm cine lens that will cover an aps-c sensor..it seems that this is not possible immanent to the system but maybe there is the ONE lens i have not researched.. Laughing

..thank you very much..

Phenix jc · Joined: 19 Dec 2009 Posts: 398 Location: France

(Welcome here)
If you want to get some help, the best thing is to publish a picture of your own lens.
With a close-up on the rear mount.
You have to know that there is (at least), two traps with the c mount : CS mount and not C mount (same mount but a different register), and C mount lenses with a too large rear mount, so you can't thread them deeply enough in the adapter (fot mFT, or Nex).
It's fixable...or not.

IAZA · Joined: 16 Apr 2010 Posts: 2587 Location: Indonesia

like Phenix jc said, many cine lenses.
for c mount, there are lenses for 8mm cine vedio and 16mm video. in APSC be sure you get 16mm video lenses.
8mm video lenses will vignete very deep, for sample some Zeiss Tevidon lenses.

About your Fujinon.
since many c mount variants, the register different tooo, adpter sometime not match in infinity, maybe just slightle past infinity or not reach infinity. I experience this with my Cosmicar 75/1,4, so I add a seal tape ( usually being used for faucet). it works

iangreenhalgh1 · Expire: 2014-01-07

I've had two copies of the Fujinon 1.8/75, they both focussed to infinity on my NEX-3.

I'd suspect your adapter rather than the lens.

Hope you can get it working as it's a great lens, it has a Biotar formula.

psy501 · Expire: 2015-04-15

..thanks for the helpful responses..after trying out one or another adapter i also think that its the adapter thats..hmm..faulty.. Smile

..do you have any suggestions where to get a good c-mount adapter that fits my fujian 35, fujian 50 and fujinon 75..?..(because obviously the chinese adapters are fine for that they are more or less for free but seem to have rather big tolerances..?

..also do you know any 25 mm cine lens that more or less covers aps-c..?..after a long research i havent found one..

..thanks a lot..