separation anxiety

[johnielvis]

Thanks all....

Well, all I can go by is what I see. And what I see is a reduction in coverage--very noticable on 11x14--there is an opaque "ring around the collar" that physically obscures the image circle--so there's THAT that I've ALREADY noticed without shooting. I need as much coverage as I can get. Second--when I look through it in the light them things light up---this will cause fog that I can't afford to have--I'm doing reversals and bleaching away fog is the only option--there is no "printing through" the fog. Extra fog will result in lower dmax/contrast--so I just can't use it like it is.....Or i can black it out or shade it out---this cuts out my coverage even further.

Also--this is a ticking time bomb in my opinion---once things go bad they tend to go from bad to worse--usually at the worst time.

thanks again.

[Jim Jones]

I'd try two things before expensive repairs. First, make a mask that fits immediately in front of the lens with a round aperture that prevents image forming light from reaching the damaged area. Second, use a large efficient lens shade, something like a compendium shade, to minimize all extraneous light. The round aperture in the mask might not cause vignetting at small f-stops, even though it will show with the lens wide open.

[johnielvis]

right, I know all the trix

but I have now relieved myself of the dilemma....

you know, now I can truthfully say that I once had a lens EXACTLY like that and I never noticed image degradation on any image I ever shot with it (seeing as how I NEVER shot it---HA!).

[eddie]

you should try it anyway.....just to be sure. you never know.

are you shooting portraits or landscape? if you are focusing closer it may not be noticeable? what lens?

[johnielvis]

If I had the time to mess around testing and trying to determine if it's the lens or something else doing what I don't want, I would, but I ddon't wanna

the only way to compare is to have a perfect one to compare to and I ain't got one.

I'll now never find out if it actually will work out--its now gone and out of my hands

and I never noticed a difference from a perfect one.

[eddie]

the only way to compare is to have a perfect one to compare to and I ain't got one.

No the only way to tell is to shoot it and see if it does what you want it to do. That is the only way to know......

[Mark Sawyer]

No the only way to tell is to shoot it and see if it does what you want it to do. That is the only way to know......

What Eddie said!

[daytona]

Heat slowly until you see the separation disappears.

[Steven Tribe]

Heating a complex lens in order to remove or reduce the discoloured edge separation is not a good idea for old balsamed lenses.
What has happened around the edge is a combination of oxidation, evaporation of the various organic/aquous solvents from the balsam through the existing tiny gap between the cemented lenses. This eventually leads to solids being formed on both internal surfaces. These are actually white - the tobacco-like colour is due to a component, probably an oxidation product, which stays in the small amount of liquid phase in the attacked area.
This white deposit is unfortunately, pretty well, undisolvable in anything. I have always had to remove it mechanically in rebalsaming exercises.

Even gentle heating with aged balsam is likely to increase the discoloured area as the yellow/brown pigment will migrate into the old, but now softened, clear balsam.

Canada balsam is very much a natural product - with a complex mixture of dozens of organic and inorganic compounds. Like wine, there are differences between the annual harvests (vintages) and actual tree source (Vineyard of origin)!

[johnielvis]

NO NO NO---you guys don't have any idea...

I don't have a pre-conceived notion of what I WANT the thing to do---I can make anything DO anything I want with sufficient effort--and so can you.

what I want to do is to see WHAT this particular type of lens does. I never used one before--and looking at other peoples pics don't help me at all..not one bit---I have to USE them to see what they do when I use them the way I use them...BUT--I can't determine what something does if I don't know if it's functioning properly---no way to tell that except to compare to a perfect one, like I said. I thought this was a-ok and then when I got it the story turned out to be otherwise. That's all...I still wanted to play though so I was thinking of repairing it--then I wised up and figured my time is more valuable....just wait for a good one I guess...plus...if the repair guy messed it up, I'd be back in the same boat, right...never knowing and always suspecting.

I was curious to see---not trying to DO anything. I play at this--I do not work--this is not a profession for me. I like to mess around, but without any futzing around wasting unnecessary time.