kb244
Well-known
Hard to capture and I only really see it if I look at it from an angle against light rather than straight thru (also there appears to be a tiny pin prick size of a bubble inside the element)
Youtube Video : https://www.youtube.com/watch?v=ucUHFHZUyLA
Seems like it's in the middle of the rear element.
On the Canon 50mm f/1.8 Type-6 I just got.
Youtube Video : https://www.youtube.com/watch?v=ucUHFHZUyLA
Seems like it's in the middle of the rear element.
On the Canon 50mm f/1.8 Type-6 I just got.
Ronald M
Veteran
Small bubbles were common in optical glass 50 years ago.
This one was probably partially removed in the polishing/grinding process.
If you can get to it, a drop if india ink will render it inconsequential if it is not already which it probably is,
You have way too much light to check for fog. Keychain light is best.
Shine light at an angle thru front with lens against a dark field. If you can see element surfaces and not dust on them, a cleaning is in order.
This one was probably partially removed in the polishing/grinding process.
If you can get to it, a drop if india ink will render it inconsequential if it is not already which it probably is,
You have way too much light to check for fog. Keychain light is best.
Shine light at an angle thru front with lens against a dark field. If you can see element surfaces and not dust on them, a cleaning is in order.
kb244
Well-known
Doesn't look like bubbles (other than that one single pin prick), but rather like a film of sort that has circular patterns (most notable in the first few seconds).
The video is 1080p if you wish to fullscreen it for a closer look.
xayraa33
rangefinder user and fancier
I see a tiny double O Martin guitar there and some Don Ho type of tiny bubbles
Seriously, that could be anything, from globs of haze, to old lube oil spots to fungus.
kb244
Well-known
I see a tiny double O Martin guitar there and some Don Ho type of tiny bubbles
Seriously, that could be anything, from globs of haze, to old lube oil spots to fungus.
Basically anyone's guess. When I got the lens, it had a bit of heavier haze, but using this video where he simply takes the front element off, you can get at the rear of the front and front of the rear quite easily.
https://www.youtube.com/watch?v=qMRnqIysGAk
Then in this video of a 50/1.2 at around 2:24 it adds to my suspicion that there's actually 3 total pieces of glass in this 50/1.8, and that the haze/oil/etc could be sandwiched between there, especially since if I look towards the inner diameter of the lens there's a yellow sort of shellac/glue like crazing near the edge, so if it is something of an oil it could be from that.
https://www.youtube.com/watch?v=eGp0zR28-rw
I just need to pick up a spanner to be able to get to it.
nothing visible in that vid that will affect photos.
kb244
Well-known
Cool, least there's that.
I have a lens spanner on order, looking at some disassemblies, seems the remaining bit of 'whatever' is between the middle and rear element. With a spanner I can get at that relatively easy. (just not as easily as it was accessing the space between the front and middle element).
Essentially whatever is there is a 'light' version of what was between the middle-and-front where the aperture blades sit.
Digitally adapted (2.0x crop factor, so looking at center half of the lens), I can't really see anything that would suggest a hindrance to the optics even with a stronger backlight.
At ~ 3 feet / 1 meter (using a Fotasy LTM to Micro-4/3rd adapter)
Fotasy Adapter + short Extension tube (since that would usually exaggerate any anomalies)
Thru the back window, going from f/1.8 to f/16
kb244
Well-known
The spanner came today, so got that section cleaned, very easy lens to disassemble. When I was getting the inner ring off (the one that holds the rear element up next to the center element) I noticed that a lot of that shellac was crusting around the edges and it seems to be the stuff that may have left small deposits to the glass, so I blew that out real good so there wasn't any of that leftover "dust". I had the front portion set aside covered just in case (as not to let anything fall into the rear of the aperture assembly).
Got that all cleaned up, dried, and re-assembled, there's still a very very very very slight film that can only be seen at extreme angle now which is to be expected probably whatever the deposit took with it coating wise if there was any coating. But now it's so extremely negligible that I wouldn't have to worry about it and least know I know if there was anything in there, it's not there now.
I suspect since this was shipped to me from San Francisco, up to here in Michigan that any humidity that was trapped in there from a previous disassembly could have manifested itself when the temperature hit the dew point. And probably why the initial state of it went unnoticed until I got it.
For anyone curious for future reference, this version of the 50/1.8 disassembles exactly like the 50mm f/1.2 shown here.
https://www.youtube.com/watch?v=eGp0zR28-rw
Same as shown here
https://www.youtube.com/watch?v=qMRnqIysGAk
For just cleaning behind the front element and front of the center element (ie: around the aperture blades) you need only unscrew the little screw up front by the lip (not completely just enough to unlock the front) and that unscrews giving you access to the aperture blades. For between the rear and center element. You have to use a spanner to get the main black ring undone (with lens in infinity lock), which allows you to lift the back casing off the lens (don't lose the brass focusing washer), then you can take the rear assembly off the back by unscrewing it, and then taking the little ring off the back of that for the loose rear element to come out of. You can try to unscrew that without removing it from the whole assembly, but then the spanner might unscrew the thicker portion instead of just the little ring. Just remember which side is front/rear on that rear element.
Reassembly as shown in the video is just the little ring, the rear assembly back in, then placing the casing back on matching the notch up to the lock inside, then the black spanner collar to tighten it back down. That one black spanner is all you would need if you wanted to just get at the shim or the aperture 'clicks' (such as for video conversion to go clickless).
Got that all cleaned up, dried, and re-assembled, there's still a very very very very slight film that can only be seen at extreme angle now which is to be expected probably whatever the deposit took with it coating wise if there was any coating. But now it's so extremely negligible that I wouldn't have to worry about it and least know I know if there was anything in there, it's not there now.
I suspect since this was shipped to me from San Francisco, up to here in Michigan that any humidity that was trapped in there from a previous disassembly could have manifested itself when the temperature hit the dew point. And probably why the initial state of it went unnoticed until I got it.
For anyone curious for future reference, this version of the 50/1.8 disassembles exactly like the 50mm f/1.2 shown here.
https://www.youtube.com/watch?v=eGp0zR28-rw
Same as shown here
https://www.youtube.com/watch?v=qMRnqIysGAk
For just cleaning behind the front element and front of the center element (ie: around the aperture blades) you need only unscrew the little screw up front by the lip (not completely just enough to unlock the front) and that unscrews giving you access to the aperture blades. For between the rear and center element. You have to use a spanner to get the main black ring undone (with lens in infinity lock), which allows you to lift the back casing off the lens (don't lose the brass focusing washer), then you can take the rear assembly off the back by unscrewing it, and then taking the little ring off the back of that for the loose rear element to come out of. You can try to unscrew that without removing it from the whole assembly, but then the spanner might unscrew the thicker portion instead of just the little ring. Just remember which side is front/rear on that rear element.
Reassembly as shown in the video is just the little ring, the rear assembly back in, then placing the casing back on matching the notch up to the lock inside, then the black spanner collar to tighten it back down. That one black spanner is all you would need if you wanted to just get at the shim or the aperture 'clicks' (such as for video conversion to go clickless).
xayraa33
rangefinder user and fancier
"I noticed that a lot of that shellac was crusting around the edges"
Make sure it is not lens element separation.
To the novice eye lens element separation looks like yellowish crusty shellac particles around the circumference edge of the glass.
Make sure it is not lens element separation.
To the novice eye lens element separation looks like yellowish crusty shellac particles around the circumference edge of the glass.
kb244
Well-known
Hrm, well... around the edges that's exactly what it looks like, a crusty yellow ring for that center element (though I can only see that edge when looking in thru the front at an angle)
Edit: Phone Pics
xayraa33
rangefinder user and fancier
Hrm, well... around the edges that's exactly what it looks like, a crusty yellow ring for that center element (though I can only see that edge when looking in thru the front at an angle)
Edit: Phone Pics
Yup, the beginning of lens element separation, that is the tell-tale crusty balsam sap accretion around the edge circumference of the lens elements.
Very common problem on Canon LTM lenses, and kind of rare on FSU lenses for some reason....Soviet Stalin balsam strong as bull.
kb244
Well-known
So.... overpaid at $189?
Edit: Seems as you said 'common', there's a very tiny outer ring of 'gold shimmer' that I can see in the back of my Canon Serenar 35mm f/2.8, but I see nothing of the sort on my Industars or Jupiters.
Edit #2 : seems there are ways to repair it, but I would wonder who in the professional repair industry would re-glue elements in an LTM lens.
http://www.largeformatphotography.info/forum/showthread.php?65756-One-way-to-fix-lens-separation
xayraa33
rangefinder user and fancier
Yes and no.
I foolishly paid 100 dollars in 1987 for that same lens, and it was full of fungus... which cleaned out nicely.
I could have used that same 100 dollars at that same camera show to buy a minty in the box Yashica YF.
Which it turned out was one of the last cameras made by Nicca (and costly and rare now) and it had a very newish Canon 50mm f1.8 lookalike lens on it, probably made for Yashica by Tomioka, that is very rare and good optic, so I learnt a valuable lesson to do my homework before spending money with very little knowledge... and that was a priceless lesson in life.
kb244
Well-known
I'm curious as to how many years I have with it before the separation starts to seep into the visible portion of the optics, particularly if I keep it out of hot conditions.
At the time of getting it (new years day), my choices for strictly US sellers was mostly around 150 for 50/1.8s or 200-ish for 50/1.4s many of which either had haze or possible fungus/etc. This one appeared at least in the picture to be the cleanest example out there and the bonus was that it was a type 6 with the 8 aperture blades.
So... 30-40 over what my other choices were, and the haze/condensation portion being relatively easy to clean up, with any luck I got 5~10 years before it starts ringing into the visible portion of the picture (more if adapted to digital since that goes down the 2.0x crop of the center).
Maybe next year I'll get a newer 50/1.4 LTM.
At the time of getting it (new years day), my choices for strictly US sellers was mostly around 150 for 50/1.8s or 200-ish for 50/1.4s many of which either had haze or possible fungus/etc. This one appeared at least in the picture to be the cleanest example out there and the bonus was that it was a type 6 with the 8 aperture blades.
So... 30-40 over what my other choices were, and the haze/condensation portion being relatively easy to clean up, with any luck I got 5~10 years before it starts ringing into the visible portion of the picture (more if adapted to digital since that goes down the 2.0x crop of the center).
Maybe next year I'll get a newer 50/1.4 LTM.
xayraa33
rangefinder user and fancier
It is hard to predict how far the separation will increase or not.
You could use the lens regularly for the rest of your life and it could remain in the same condition.. and you know it preforms very well as seen by your test shots.
The Canon 50mm f1.8 lens is a very common lens and it still not overpriced, you can find another in better condition for not much more or you can buy another model of lens later on for something different than you have now.
kb244
Well-known
Speaking of test shots. This is after I got that little bit of condensation-like residue out of between the rear and middle.
My general critique of it is that it's not as sharp in the center as my Canon Serenar 35mm f/2.8 lens, but it has overall good clarity from edge to edge (least on the digital testing). At f/1.8 it's sharper/clearer than say my Pentax-M 50/1.4 (which by comparison is pristine compared to all my other used 40+ year old lens).
The 35/2.8 is quite sharp in the center even wide open, it just gets funky/fuzzy/distorted at the edges (and this is in the digital testing so I'm curious to see how it is full frame), but that just seems to be the "character" of the optics which I kind of like depending on the subject.
I'll likely be using the 35/2.8 on my Canon 7 for the class, but got the 50/1.8 so that I had the two most common focal lengths to use for film photography. A wide and a Normal.
And who knows, maybe it's appearance on 35mm film and printed traditionally will be much more pleasant than what my Olympus E-M5 digital sensor produces, since it's not like the vintage glasses was designed to direct light at a picky sensor.
xayraa33
rangefinder user and fancier
Speaking of test shots. This is after I got that little bit of condensation-like residue out of between the rear and middle.
My general critique of it is that it's not as sharp in the center as my Canon Serenar 35mm f/2.8 lens, but it has overall good clarity from edge to edge (least on the digital testing). At f/1.8 it's sharper/clearer than say my Pentax-M 50/1.4 (which by comparison is pristine compared to all my other used 40+ year old lens).
The 35/2.8 is quite sharp in the center even wide open, it just gets funky/fuzzy/distorted at the edges (and this is in the digital testing so I'm curious to see how it is full frame), but that just seems to be the "character" of the optics which I kind of like depending on the subject.
I'll likely be using the 35/2.8 on my Canon 7 for the class, but got the 50/1.8 so that I had the two most common focal lengths to use for film photography. A wide and a Normal.
And who knows, maybe it's appearance on 35mm film and printed traditionally will be much more pleasant than what my Olympus E-M5 digital sensor produces, since it's not like the vintage glasses was designed to direct light at a picky sensor.
It appears that it is a keeper of a lens, judging by that image seen on a computer monitor screen.
I would not get rid of that lens or be quick to replace it with the same model, as it produces very pleasant images, element separation or not.
kb244
Well-known
Oh guess what. The Industar-61L/D (55/2.8) I have has it. Though it's not balsam sap or anything, just a sort of 'hovered' separation in the rear element. Rarely ever used it ever since the focus ring got super stiff (so more than enough reason to get it apart). But just thought I'd point out, I got least one FSU lens with separation, though it would explain some of the interesting focus results I had in the past from it. I mainly just stick to the Industar-10 50/3.5 collapsible I have on the Fed-2A (which focuses correctly on the Fed, but not quite on non-FSU naturally) which I just recently cleaned of strong haze.
So guess it does manifest in FSU lens, just differently.
xayraa33
rangefinder user and fancier
Rarely ever used it ever since the focus ring got super stiff (so more than enough reason to get it apart). But just thought I'd point out, I got least one FSU lens with separation, though it would explain some of the interesting focus results I had in the past from it. I mainly just stick to the Industar-10 50/3.5 collapsible I have on the Fed-2A (which focuses correctly on the Fed, but not quite on non-FSU naturally) which I just recently cleaned of strong haze.
So guess it does manifest in FSU lens, just differently.
Yes it can manifest on FSU lenses but still not as common as on Canon lenses.
The I-61 l/d lens is a breeze to clean and lube the focus helical, second only to the
I-22 in simplicity.
kb244
Well-known
I might have to pick up some of the super-cheap 61L/Ds on ebay in the future from Ukraine's down the road just to swap out elements between the best of them.
Trying to remember what kind of grease was best for the focusing helical. Lithium?