PDA

View Full Version : Who has an optical bench and can service view lenses?



Don Dudenbostel
17-Feb-2016, 11:05
I have a Fiji 180mm NW that needs optical service. Wide open it's quite soft and blooms around the highlights. there's no haze and no evidence of physical damage. I did a comparison between it and my 150 Symmar S and there's no question the Symmar S is much sharper and no bloom. Even stopping down 2 stops on the Fuji it doesn't get sharp. Can anyone suggest a repair company that has an optical bench? I called SK Grimes and they don't have a bench and have a call into Schneider's optical service but haven't had a response. I also don't know if they service any lenses other than Schneider. I tried Fuji but they never imported them and getting to someone that knows anything is a problem. I'm guessing that shims have been lost at some point. Any thoughts?

Randy Moe
17-Feb-2016, 11:25
Buy another one. Probably cheaper.

http://www.thalmann.com/largeformat/fujinon.htm

Don Dudenbostel
17-Feb-2016, 11:46
At the suggestion of the person at SK Grimes I unscrewed the front cell a half turn and did another test. It's noticeably better which suggests shims are missing. Who might have a set of shims?

Randy Moe
17-Feb-2016, 12:17
At the suggestion of the person at SK Grimes I unscrewed the front cell a half turn and did another test. It's noticeably better which suggests shims are missing. Who might have a set of shims?

I doubt anybody has those shims now.

At my former employer we made custom shims all the time, for internal product testing purpose, not optical work.

Our custom department would use a Laser to cut perfect circular shims from 0.001 and thicker up to 8" diameter and with narrow width.

I would use them to adjust diesel engine cylinder liner height for testing head gaskets.

They were very thin and floppy, probably cost $100's each. I went through lots of them.

Find a place that Laser cuts very thin brass or we used stainless.

I cannot access them now.

plaubel
17-Feb-2016, 12:17
First I would check if the rear element is the right one, because I have had trouble with a wrong element in one case.
Somebody gave a good description of finding the right distance between the elements.
I'm not sure either in this or in another forum...

Ritchie

djdister
17-Feb-2016, 12:19
I have a Fiji 180mm NW that needs optical service. Wide open it's quite soft and blooms around the highlights. there's no haze and no evidence of physical damage. I did a comparison between it and my 150 Symmar S and there's no question the Symmar S is much sharper and no bloom. Even stopping down 2 stops on the Fuji it doesn't get sharp. Can anyone suggest a repair company that has an optical bench? I called SK Grimes and they don't have a bench and have a call into Schneider's optical service but haven't had a response. I also don't know if they service any lenses other than Schneider. I tried Fuji but they never imported them and getting to someone that knows anything is a problem. I'm guessing that shims have been lost at some point. Any thoughts?

I have a Fujinon W 180mm that was giving me massively soft focus results (see photo below) even when stopped down. Turns out that a small inner lens element in the rear lens assembly (closest to the shutter) was turned around the wrong way (this smaller, dime sized lens cell has a bevel on one edge). After flipping the small lens element around everything is sharp and normal again! As far as I can tell, the front lens assembly also has a smaller lens element closest to the shutter which could also be turned around the wrong way - so you might need to check both front and rear lens assemblies.

146753
Fuji W 180mm with inner lens element facing the wrong way

Randy Moe
17-Feb-2016, 12:23
If the lens is missing a shim, One method of measure MAY be done by using this. I have also used this stuff a lot. It is like rubber plastic and only a tiny amount is needed. It's not oily, but brittle and dry and is easily removed.

Of course I used in linear crushing situation and this is rotational. ymmv

http://www.plastigaugeusa.com/

plaubel
17-Feb-2016, 12:27
Thinking about...
I believe it was a years old article in the german LF forum...
If I remember right, for finding the distance in approximatively this way:

- focusing to the center while the edges are not sharp
-screwing ot the front lens, refocusing
- at some point the whole lens become sharp.

I hope, that this may help a bit,
Ritchie

Don Dudenbostel
17-Feb-2016, 14:08
Thanks for all the ideas.

I spoke to Grimes again after doing another test by unscrewing the front group a half turn and shooting a neg as well as one all the way in. After unscrewing it a half turn there was a marked improvement. This leads me to believe it's a shim missing. Grimes said for me to determine through this method how many or fraction of a turn it takes and let them know. they can figure the thickness and make a shim. The thread pitch is a known so they can figure from that.

My friend Steve hamlet suggested putting a digital back on the camera but I sold my back. I might see if I can mount my DSLR on the graflok back and use that as a test with live view.

I'm still waiting to see if Schneider / Century optical will do it. They used to do this sort of thing.

Thanks!

Don Dudenbostel
17-Feb-2016, 14:17
I just reached Schneider and since it's probably a matter of focus / spacing adjustment between the shutter and the lens cells they are willing to do it.

ic-racer
17-Feb-2016, 15:23
buy another one. Probably cheaper.



^^^
this

Nodda Duma
20-Feb-2016, 03:43
Don sounds like Schneider will help but if not let me know and I can take a look at it.

Don Dudenbostel
20-Feb-2016, 15:18
Don sounds like Schneider will help but if not let me know and I can take a look at it.

Thanks! Much appreciated.