View Full Version : Lens elements reversed?

Calamity Jane
22-Jun-2005, 18:40
The shutter on my new/old Conley was slow so I took the lense off the camera and found the lens information was on the REAR element - no wonder I didn't see any info!

Would there be any valid reason to reverse the front and rear lens elements????

The lens is marked "5x7 LUXAR ANASTIGMAT F:7.7 EQ FOCUS 8 IN. No 425"

BTW: For whoever posted the suggestion of using lighter fluid to clean a shutter, THANK YOU! It rejuvinated the old Wollensak Regno just fine! Saved me the cost of a commercial cleaning :-)

Ernest Purdum
22-Jun-2005, 19:15
If a lens is asymmetrical, reversing the cells is the thing to do when the image is larger than the subject.

Maybe a previous owner was doing macro work.

Jim Galli
23-Jun-2005, 10:26
On old lenses like symmetrical Rapid Rectilinear types the 2 are identical and if one had pits and scratches and the other didn't you might want to have the best in the back. O/W it would make no difference. If the 2 cells are different focal lengths a previous owner may have been using the front group at the back singly and just left it that way. You really shouldn't notice any difference reversing them back. A 7.7 lens is usually either a very early Dagor rype or a Protar type that has 2 size differences between the 2 groups. You can shine a penlight cell in and count bright and dim reflections to find out.

Mark Sawyer
23-Jun-2005, 11:06
"Would there be any valid reason to reverse the front and rear lens elements???? "

Probably not the situation with your lens, but if you reverse the elements and mount the board backwards (shutter/barrel inside the camera), it can give you a recessed lensboard. Of course you'd have to adjust the f/stops by removing the camera back, and if you want to fire the shutter, you'd need to drill a little hole in the board for the cable release to pass through, and of course make it light tight. Not an issue with barrel lenses or if you normally have long enough exposures to use a lenscap.

One can also use recessed boards backwards to gain an extension for long lenses or macro work on some cameras. Depends on the lensboard design...

Mike Phifer
23-Jun-2005, 13:47
There could be an optical reason for doing this. A symmetrical lens is optimized for a 1:1 (a one to one) magnification, yet works very well at distant objects also. If the cells are "Absolutely Identical " to each other, the order will not matter. However, if they are not exactly the same, there will be an order that performs better for distant objects. This may, or may not be the case with your lens.

Ron Wisner wrote about this several years back in his lens series in one of the Photo Mag's. (I have it somewhere???) He even described how to check by focusing on the filament of a distant clear light bulb using a loupe (with out the ground glass, i.e. focus on the areal image), to see which way would be best. Of course it might be negligible as was my DAGOR when I checked it.

I hope this helps, Mike

Alan Babbitt
24-Jun-2005, 08:15

Did you just squirt lighter fluid into the shutter without disassembling it?

The lighter fluid does a very good job of loosening up the old sticky grease and oil in the mechanism, but if you do it without disassembling the mechanism and the blades, you are likely to still have dirt and grit and old lubricant trapped in there which are likely going to cause you grief later on. You have also probably washed away lubricant from the places where it is required inside the shutter. It's also possible that you may have washed lubricant into the contact points for the flash sync (if there is one on that particular shutter).

The shutter probably seems fine right now, but I would recommend that you give it a proper cleaning and lubrication sooner rather than later. It's a job you can do yourself, if you are careful and patient and meticulous about noting how everything goes together as you disassemble the shutter. If you can find a service and repair manual for that shutter, then it will simplify the job greatly. Basically, you take it apart, clean all the parts with lighter fluid, let them dry and reassemble. Some parts need to be lubricated(this link (http://presscameras.graywolfphoto.com/graphex.html) will give you a pretty good idea of where you need to add lubrication). Expect your first shutter cleaning job to take about 4 to 6 hours.

James E Galvin
24-Jun-2005, 10:27
When taking a shutter apart, I scan it at each stage. Just put it upside down on your scanner. The scanner depth of field is enough to get a picture good enough to see where all the parts (especially the little springs) go. I use plastic trays from frozen dinners, one tray for each subassembly, to keep the parts and their springs and screws together. To clean the pivot holes for the gears, sharpen a wooden toothpick and twirl it in the hole. The shutter blades might be blackened brass, or painted plastic. Not knowing what will disolve them, I wipe them with a tissue moistened in alsohol. As even the slightest oil makes them stick together, I handle them with tweezers after cleaning (one fingerprint might be too much sticky). I use watch oil on the light bearings, watch grease on the heavier ones (like the cocking lever). I use graphite on the ring that moves the blades (just write on the contacting surfaces with a soft (HB) pensil) Use VERY LITTLE lubricant, a tiny drop thrown on the blades sticks it.

Calamity Jane
24-Jun-2005, 12:19
Yes Alan, I did the "closed case flood". Worked all the actions, flooded again to wash out the crud, shook out the excess, and then set it aside to dry.

I know this will leave everything bone dry but I don't have the time right now to do it properly. It was running WAY slow and the slow speeds wouldn't even finish their cycle but the lighter fluid bath got everything working well again. Come fall, when things slow down, I'll probably treat it to a professional CLA.