View Full Version : separation anxiety
johnielvis
20-Jul-2011, 04:53
anyone know if this can be repaired?--I suspect this will only get worse in time and totally spread throughout---or has anybody had something like this that just remained for years? There is a brown ring all around the periphery with these bubbles making their way in--I'm thinking this is separation? I've never seen anything like this before
I wouldn't want to try to do this myself--where can this be repaired if it's repairable?
cdholden
20-Jul-2011, 05:28
If it can be repaired, Focal Point is the place to send it.
http://www.focalpointlens.com/
don't bother. it will not affect anything. i have one that was WAY worse and i used it with zero issues. i have the lens 5 years and it never got worse.
yes, you can do it yourself. search here. steven tribe once had a good write up about how he did it.
eddie
johnielvis
20-Jul-2011, 09:01
I emailed the guy with a quote.
whether or not it gets worse, simple physics--this is between 10-20% of the glass area--this is a big bright lens--therefore, this will cause significant flare--I see no way around it. other than to use a shade to mask off that portion of the lens---in that case it won't cover 11x14, which is what I need....
no way am I going to try to fix this myself no matter how easy--it's too easy to make a mistake and these don't grow on trees
I'm with eddie--that amount of separation won't have any noticeable effect. Why don't you do some shooting before you drop a couple hundred bucks on a repair. I recently saw a a note from Andrew Moxom about Focal Point ruining his Dallmeyer 3B. They (over)heated the front group and the lenses oxidized--clouding over. They should have used a xylene soak to dissolve the balsam--it takes a couple weeks, but time is money, you know.
I recently saw a a note from Andrew Moxom about Focal Point ruining his Dallmeyer 3B.
Damn! are we sure it was toasted? that sucks!
If it was my 3B, I'd be the one doing the toasting and roasting...of Focal Point. Andrew mentioned something about them polishing it out, but that frequently leaves the lens messed up.
Steven Tribe
20-Jul-2011, 10:57
Edge balsam deterioration is quite stable and I have never seen further worsening of anything of mine.
Based on own experiences, I would never heat anything over 60 deg. C.
I, like the focal point example given, have had massive devitrification (devit) on a single lens when dying out the balsam. The opaque/crystalline layer extends well below the lens surface - strangely enough only on one side.
Peter De Smidt
20-Jul-2011, 11:53
I've had a lens with this, and I haven't noticed any change in the 20 years that I've had it. As others have said, trying photographing with it.
Mark Sawyer
20-Jul-2011, 12:41
If it were "stable", it wouldn't have happened in the first place. I suspect temperature and humidity (fluctuations and extremes) have a lot to do with it, but I also suspect once it gets a good foothold, the pressures exerted between the lenses by the existing separation may well exacerbate things.
It may or may not affect the image; the only sure way to tell is to make images, repair it, and make the same images for comparison. I'd guess iut may soften detail a bit at the edges and reduce contrast a touch (both effects fairly slight) when the aperture is wide open. Of course, if you repair the lens and find it does affect the image, you run the risk that you like the look with the separation ... :D
johnielvis
20-Jul-2011, 13:44
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
20-Jul-2011, 14:19
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
20-Jul-2011, 16:22
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!).
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
20-Jul-2011, 17:43
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.
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
20-Jul-2011, 18:30
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
20-Jul-2011, 19:43
Heat slowly until you see the separation disappears.
Steven Tribe
21-Jul-2011, 02:41
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
21-Jul-2011, 07:39
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.
Robert Oliver
21-Jul-2011, 09:23
Why did you post the question if you didn't want people's opinion. Focal Point can fix it, but not without risk or cost.
I think what everyone is saying is why not waste (test) a shot on a sheet of film to see if the quality loss is noticeable to you. If it is unacceptable fix it. If not, use the saved money for more film. This can be done with a textured wall to see what happens at the edges.
I personally don't mind a SLIGHT amount of darkening or fuzziness around the outside edges of an image, it helps bring the viewers eye into the center of your frame. I usually burn in the corners anyway.
I don't think it's a 'ticking time bomb'.... how long has it taken for the separation to cover this much of your lens?
Sounds to me like you are stressing out about what makes using these vintage lenses so unique and fun to use.... uniqueness. These lenses each have a unique signature. If you want perfect, buy a new modern lens.
NO NO NO---you guys don't have any idea...
:eek:
---I can make anything DO anything I want with sufficient effort......
eeeerrrr? okay? so it would not matter the tool then?.......
I was curious to see---not trying to DO anything. I play at this--
fair enough. :o
an entertaining thread for sure. thanks for the chuckles.
Sounds to me like you are stressing out about what makes using these vintage lenses so unique and fun to use.... uniqueness. These lenses each have a unique signature. If you want perfect, buy a new modern lens.
+1
johnielvis
21-Jul-2011, 10:18
totally agree--I do try to get new/like new for that reason
and when I buy well used/old I buy what I think is 100% functional (these days---I haave bought fixer uppers in the past and that phase is on hiatus)--I was mistaken is all--I screwed up and didn't look closely enough -- thought it was 100% but when I finally got it I found it wasn't---it was my fault--I didn't look closely or ask questions--but still wanted to make it work...you know....I will buy what I think works-----I am through with the junk/projects/fixer-uppers/not100% stuff...
I just wanted to MAKE it work...see...the way I WANTED it to work...and it just wasn't in the cards that's all. I'll have to wait for another one to play with another day.....
I'm curious--what was the lens anyway?
johnielvis
21-Jul-2011, 11:12
I must remain silent on specific lens info for now...sorry...
Hang on a minute.... I never said ANYTHING about Focal Point toasting my lens.... It's a long story, and John at Focal Point is a professional... He never made any bones about the risks involved with fixing 150 plus year old lenses!!!
Long story short, the Dallmeyer 3b had a major 3/8" seperation/yellowing at the edge, and issues even further inside that were just starting that would eventually have led to image degradation. I had to do something.... I worked with the seller who was willing to take the lens back, and they were also good enough to meet me halfway with the repair costs... In hindsight, I'd never do that again. I'd return it. It was me taking all the risk... cost of a lens, additional repair cost, and nothing but a paperweight if it went tits up. At any rate, I rolled the dice, and off it went to Focal Point.
I get an email just after it arrived, and John said, it's an older lens where the front doublet has been rolled into its mount from the back. It's unlike the darlot's or other lenses that simply unscrew from their mounts. The rolled over edge needs to be carefully pryed back while holding the doublet in a lathe chuck!! There is a risk of breakage in this step and FP told me this could happen. They were successfully able to roll open the lip without breakage... Then comes the actual seperation of the doublet. They use a small oven to bring the lenses slowly up to around 300 deg f to melt the balsam, separate it, and let it cool to avoid cracking. Again, breakage can occur here too. It separated fine, but..... during the heating, one surface of the crown glass glazed over, and also to a degree on the edge on the other side of it. As I understand it, it can be caused by having 150 old VERY soft glass.
Again, John said he could polish it out, and the 2 lenses he has had that oxidized on him before have been fine after polishing. He said it should work, but does not mean that they could necessarily do that to my lens, but at this point I have paper weight. So we went ahead with the polishing. I was told it's a surface treatment only and would not impact the lens design/optical parameters at all! So it took 3 weeks to hear. One side is done with no issues, and was assured that John thinks we are going to be successful and told me to hang in there.. The reason it takes so long is the set up time and testing that the polishing was good. It's mounted, polished, dismounted, cleaned, checked, re-mounted and very tedious. So one side down, and I am hopeful the next side goes as good. Then we are on the home stretch.
Many will chime in saying that why didn't they use Xylene, or acetone and heat is BAD etc..etc... Focal Point came highly recommended, and I believe they will make it right. However, they are doing CYA about the very real potential for breakage of these older lenses.... I trust them and appreciate the up front nature of the way they do business.
Am I concerned about my lens... I sure am.... It cost me a kidney, and a spleen in repairs, but I am hopeful it will be restored and will NEVER be a problem again. No matter what the lens is, it is a gamble, and anyone who attempts these steps themselves may get lucky especially if you use xylene/acetone to separate the lens. In this instance, I did not have the tooling to open the rolled in lens, and it would have cost me minimally more to have them do all of it, so why not I thought?? At any rate, it is what it is... Focal Point has been totally professional so far. I would have likely made a pigs ear of it trying it myself. You pays your money, you makes your choice...End of Story.... Will update this thread on the overall outcome. At this stage it's looking good!
Steven Tribe
21-Jul-2011, 14:11
Sorry to hear about your problems, Andrew.
Turning the brass lip back on a lathe is the only way to do it! This is exactly the method Dallmeyer used to turn down the lip in 18xx. Many makers used this system(quick, cheap and reliable in skilled hands) for achromats , especially RRs - they were thinking of decades of use - not centuries!
The only way to polish a lens is to make a 3 dimensional tool which has the exactly the form of surface to be worked. Two sides of a lens means two special made tools are usually necessary! I don't know whether modern numerically controlled machines could produce these from the precise radius of the original surface. I know that this seems a lot of work for "just" polishing but there is tendency to remove too much glass at the edges without a convex/concave tool.
Steven, that is why it is taking so long. They are being VERY diligent about removing too much material. I had a friend who has an old Leica Summitar lens fixed there and, polished/re-coated. Granted, those lenses were not anywhere near as old, but the coatings of the day were VERY soft. The machine that is used to mount the lens for polishing will scratch the older softer coatings, so BOTH sides needed to be polished out before coating. His lens turned out in superb shape, so I don't doubt Focal Point knows what they are doing... I guess I'll just have to wait and see..... keep my fingers crossed that I don't have a paper weight, and I've learned VERY expensive lesson about lens buying....
johnielvis
21-Jul-2011, 15:36
yeah--mee too!!!!
one thing for sure....if they don't outright say the glass is clear, it ain't--you must ask.
AND...just because SOME flaws are pointed out, that don't mean that ALL the flaws have been pointed out!!!!! you MUST ask the questions and assume nothing!!!
just like cars---if they don't mention the milage--it's very high
if they don't mention the price---it's high
if they don't mention the recent exhaust work, the muffler is gone
etc
Louis Pacilla
21-Jul-2011, 16:34
Why did you post the question if you didn't want people's opinion. Focal Point can fix it, but not without risk or cost.
I think what everyone is saying is why not waste (test) a shot on a sheet of film to see if the quality loss is noticeable to you. If it is unacceptable fix it. If not, use the saved money for more film. This can be done with a textured wall to see what happens at the edges.
I personally don't mind a SLIGHT amount of darkening or fuzziness around the outside edges of an image, it helps bring the viewers eye into the center of your frame. I usually burn in the corners anyway.
I don't think it's a 'ticking time bomb'.... how long has it taken for the separation to cover this much of your lens?
Sounds to me like you are stressing out about what makes using these vintage lenses so unique and fun to use.... uniqueness. These lenses each have a unique signature. If you want perfect, buy a new modern lens.
+2
johnielvis
21-Jul-2011, 16:53
hey guys---I wants what I wants and don't want what I don't want
I see nothing wrong with having higher standards than someone else.
Actually once I had deliberately bought a sironar 210 with separation, to test my ability to fix separation. I did it. I could have done it much better if i had those V tools to squeeze the lenses in between in order to have them alligned centered on top of each other.
This is how to do it.
1) Buy some Methylene chlorid based paint remover. They are hazardous fluids though. It boils at 40C (103F) If you leave it in a hot place, the increasing gas preassure inside the tin can blow it's cap and you won't enjoy stoping it with your face.
2) Submerse the group with separation into this fluid and wait for 2~3 days. Until they break apart.
3) Get some Optically Clear UV Glass Adhesive.
4) Get an UV lamp
5) Place the lens element flat on table and apply glue on tip of it.
6) Place the other lens on top of it. When you press evenly the glue shall spread and cover the whole contact surface evenly.
7) Place the lenses inside two V shaped metal thingys those i don't have and don't even know how to search for.
like this <O> so that the lens' optical axis become congruent.
8) When you are happy with the lens's allignment apply UV light and the glue will cure in seconds.
9) Paint the side black to prevent lateral insider reflection. But don't paint too thick since it wont fit in the barrel that it came from.
10) Test your lens.
P.S. The methylene chlorid based paint remover and Optically Clear UV cure Glass Adhesive and UV Lamp are easily available. Google is your friend. Anybody who knows how to find those V thingys please let me know.
Peter De Smidt
22-Jul-2011, 03:36
Like this? http://www.edmundoptics.com/products/displayproduct.cfm?productid=1688
Like this? http://www.edmundoptics.com/products/displayproduct.cfm?productid=1688
Hey...! exactly and exactly..! That's the right tool you need if you have intentions to run above procedure.
E. von Hoegh
22-Jul-2011, 07:30
Hey...! exactly and exactly..! That's the right tool you need if you have intentions to run above procedure.
You can also use a surface plate and a couple V-blocks, probably a bit more precise. McMaster-Carr will have both, they're used in toolrooms.
Jason Greenberg Motamedi
22-Jul-2011, 07:52
I read once about using a laser pointer for aligning the elements, has anyone ever tried this?
I think this is called collimating the lenses so that they are in perfect alignment.
alex from holland
22-Jul-2011, 09:04
be aware that once glued with Optically Clear UV cure Glass Adhesive it is almost impossible so separate it in the future.
so if something goes wrong in this process ......
Alex
be aware that once glued with Optically Clear UV cure Glass Adhesive it is almost impossible so separate it in the future.
so if something goes wrong in this process ......
Alex
That is not 100% true. You can get them apart by soaking them. Not an easy thing but very doable.
Okay, so the best news I've heard in about 6 weeks after purchasing a Dallmeyer 3b came in today!!!
Focal Point have successfully renovated my front Doublet, that's the machining out of the actual lens elements from the mount, separation of elements, cleaning, polishing, and re-cementing, re-mounting of the lens back into the brass housing and rolling the lip over. John emailed me and said I will VERY happy with the way it turned out!! I will know for sure when it arrives on August 1st! It's been a stressful 6 weeks waiting for this thing.
That is not 100% true. You can get them apart by soaking them. Not an easy thing but very doable.
Actually that is not as hard as splitting a epoxy age (forties to mid seventies) lens group. With the move over from epoxy to cyanacrylate lens cements, chemical separation has become easier - epoxy needs pretty strong and hard to obtain solvents (though I'd stay clear of anything as nasty as methylene chloride - DMF is both more harmless and more effective), while cyanacrylate will dissolve in regular acetone.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions Inc. All rights reserved.