Graflex.org Forum Index Graflex.org
Get help with your Graflex questions here
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

lens problem

 
Post new topic   Reply to topic    Graflex.org Forum Index -> Lenses Help
View previous topic :: View next topic  
Author Message
slikj



Joined: 21 Mar 2009
Posts: 17
Location: Australia

PostPosted: Sat Mar 21, 2009 3:29 am    Post subject: lens problem Reply with quote

I recently bought a crown graphic 4X5 on ebay, together with a CALTAR II-E MC 210mm lens, both from the same vendor. I thought I may have problems when the polaroid and film pack holders sold with the camera were found to be obsolete. I discovered today from the camera technician I had employed to fit the caltar lens that the lens is faulty, it will only focus at about 3'.
Does this ring a bell with anybody? Could it be right that a lens, with good cosmetic appearance could be so out of whack? Or does the technician not know the system? He has a good reputation and seems confident about this. What might be going on here?
I haven't got the camera back yet, he is also fixing a Fuji G690 for me, so I can't have a look at it myself.
I have since bought a pair of Grafmatic holders, so the film holder problem is fixed.
I do not expect any help from the vendor as he never replied to my comment that it would have been fairer to state the obsolescence of the film holders supplied.
I am now looking for a Fuji portrait and WA lens.
Can anybody throw any light on this?
Back to top
View user's profile Send private message
Les



Joined: 09 May 2001
Posts: 2682
Location: Detroit, MI

PostPosted: Sat Mar 21, 2009 12:47 pm    Post subject: Reply with quote

I'd like to have the repairman explain that to me. I have yet to see a lens that can only focus at one point.

The focus of a large format lens depends entirely on where the object is and where the ground glass is. Put the ground glass one focal length away from the lens, then an object at infinity will be sharp. As you move the ground glass away from the lens, objects closer to the lens will come into focus.

So you can see any largeformat lens has a range of focus. Perhaps the repairmen meant that it focuses at 3' when it should be focused at Infinity??


Here's the caveats to that rule:
    Somebody added a close up filter to the lens, either the screw on kind, or at least in one reported case, cemented directly to the lens.

    The lens is in the wrong shutter. (It should be in a Copal #1) Cell spacing can effect focus. If the lens is in a too thick shutter, or they lost shims that are between the lens and shutter, this will effect focus to some degree, but more often overall performance (it's not sharp anywhere) Also the missing washer problem would be considered a slight shift. One missing shim will not cause a lens to focus at 3ft when it should be focused an inf.

    The lens cells are not matched. Somebody swapped the rear from another lens, possibly a different focal length lens. Not all manufacturers do this but some will put the last 3 or 4 digits of the serial number of the front cell on the rear cell. If I were forced to guess the problem without more information, This is would be my guess.
[/list]
_________________
"In order to invent, you need a good imagination and a lot of junk" Thomas Edison
Back to top
View user's profile Send private message
DHF845



Joined: 20 Jul 2008
Posts: 93
Location: Hudson Valley Area, Upstate NY

PostPosted: Sat Mar 21, 2009 8:23 pm    Post subject: 8x10 and wet plate supplies Reply with quote

Everything Les said is spot-on.
I'd like to add my own two cents: No such thing as a Crown Graphic that only focuses at one point! Doesn't sound like your "technician" knows how to work on old style press cameras!
Could be a rangefinder problem: You didn't state whether your Crown has top-mount rangefinder or side-mount Kalart rangefinder. Rangefinder may need the right cam (top-mount rangefinder); or infinity, mid-point & close-up adjustments (side-mount Kalart type).
Other simple answers: The infinity stops are in the wrong place, the focusing lock is locked, the track isn't moving because the helical shaft is stuck.
Good Luck! Keep us informed.
_________________
Got first Speed Graphic at 15 (1976).Other kids were using 35mm SLR's. I ran around with flashbulbs and sheet-film holders, I wanted to be Weegee (#2084).
Back to top
View user's profile Send private message
slikj



Joined: 21 Mar 2009
Posts: 17
Location: Australia

PostPosted: Sun Mar 22, 2009 2:30 am    Post subject: Reply with quote

Thanks Les and DHF845. I need to get a better explanation from the technician. He did suggest that what might have happened is that someone may have dis-assembled and re-assembled incorrectly. It's difficult for me to question his knowledge as he has already told me he knew the camera and also I have very little knowledge myself!
The model is a top rangefinder with the rangefinder not functioning. I plan to use for portrait so I don't think the rangefinder will be any good to me anyway. I instructed the technician to leave it alone.
I'm keen to get the camera back and have a fiddle myself. I'll let you know any developments. Thanks again.
Back to top
View user's profile Send private message
slikj



Joined: 21 Mar 2009
Posts: 17
Location: Australia

PostPosted: Sun Mar 22, 2009 2:31 am    Post subject: Reply with quote

Oh and I did ask the technician to set the infinity stops for the caltar lens. He said he could do this, bit I don;t know yet if he got to that point after discovering the lens problem.
Back to top
View user's profile Send private message
glennfromwy



Joined: 29 Nov 2001
Posts: 903
Location: S.W. Wyoming

PostPosted: Sun Mar 22, 2009 3:58 am    Post subject: Reply with quote

I have a couple of those lenses. They are an extremely sharp lens at f/16. If someone disassembled one of the lens cells and put an element in backwards it could cause the problem, as could mixing cells from another unknown lens. I think you should ask that technician exactly how he determined his data. Even if the assembly was missing a shim, it shouldn't be that drastic. If the seller put a IIE front cell on a shutter with someone elses rear cell in it, in order to pass it off as the Caltar, I would be very upset.
_________________
Glenn

"Wyoming - Where everybody is somebody else's weirdo"
Back to top
View user's profile Send private message
slikj



Joined: 21 Mar 2009
Posts: 17
Location: Australia

PostPosted: Sun Mar 22, 2009 5:08 am    Post subject: Reply with quote

Thanks Glenn, I'm going to put these scenarios to the technician and see what he comes back with. If someone has tried to misrepresent, I'm going to take it up with the vendor.
Back to top
View user's profile Send private message
slikj



Joined: 21 Mar 2009
Posts: 17
Location: Australia

PostPosted: Sun Mar 22, 2009 5:38 am    Post subject: Reply with quote

Just in case there is a clue visible, I have posted the original ebay images on this lens to Flikr. Here is the link:
http://www.flickr.com/photos/john_mayger/sets/72157615652488955/
Back to top
View user's profile Send private message
glennfromwy



Joined: 29 Nov 2001
Posts: 903
Location: S.W. Wyoming

PostPosted: Sun Mar 22, 2009 7:19 pm    Post subject: Reply with quote

Well, to my eye everything looks okay. I still wonder about how the tech got that 3 foot focus figure. For that lens to focus down to 3 feet, the bellows would be way out there. Infinity focus would place the lens 8 1/4 inches from the ground glass, more or less. Maybe I'll get out the Speed that has one on it and see if it's even possible to focus it at 3 feet. Something sounds strange. Maybe he was trying to say it would only focus as close as 3 feet, which sounds more reasonable.
_________________
Glenn

"Wyoming - Where everybody is somebody else's weirdo"
Back to top
View user's profile Send private message
slikj



Joined: 21 Mar 2009
Posts: 17
Location: Australia

PostPosted: Wed Apr 08, 2009 2:13 am    Post subject: All now working. Reply with quote

Finally got to Sydney to pick up my Crown Graphic and lens from the repair shop, and the news was good!
The original finding was that the lens only focussed at one point. Suspecting that it had been dis-assembled and assembled again incorrectly he took it apart and re-assembled. This fixed the problem and now all is working perfectly. Thanks for your interest and responses. I'm now looking for a lens board for a Rapax shutter with Raptar WA. My measurement tells me a 32mm hole will do it as I measure the flange at 31mm.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Graflex.org Forum Index -> Lenses Help All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group