I'm thinking that Canon changed lubricants in the late 1950s, into the production of the Black lenses. I have an early 50/1.2 that has perfect glass. I've taken apart 4 later Canon 100/3.5's- all had haze, all had some level of damage to the surface behind the aperture.
peterm1
Veteran
Yes I also have a 50mm f1.2 and an early 100mm f3.5 and both are without serious haze issues (same for the other Canon LTM lenses I own). But I also own the black model 100mm f3.5 and it has unremovable haze so I suspect you may be right. What's more I have an FL Canon 100mm f3.5 and it also has the same hazing as the late LTM version.
nikon_sam
Shooter of Film...
Here's my version...not the LTM but I understand its the same lens...
Found it at a local camera swap meet, traded a Nikon F2 prism for it.
The lens was covered in dust and at first glance looked old and used...but after a quick cleaning it looks like new...the glass is perfect and images are very sharp...it can be slow to use but so worth it.
I sold the A-1 so I use it on the Sony a6000...
Pretty sure this was with the 100mm...
Found it at a local camera swap meet, traded a Nikon F2 prism for it.
The lens was covered in dust and at first glance looked old and used...but after a quick cleaning it looks like new...the glass is perfect and images are very sharp...it can be slow to use but so worth it.
I sold the A-1 so I use it on the Sony a6000...
Pretty sure this was with the 100mm...
aoresteen
Well-known
Back around 1982ish I bought a Canon 100mm f/4 from the Shutter Bug NEWSPAPER. I used it and loved it as it was light & sharp on my M3. When I needed speed I used my Canon 85mm f/2. When I bought a Telle-Elmarit 90mm f/2.8 I stopped using the 100mm and sold it in the late 80's. Dang, now I got GAS and need to find the f/4 version. It could be worse. I could be GASing for a 100mm f/2 
peterm1
Veteran
This lens is so good I have two. Let me explain. A few years ago I found a cosmetically nice, but fogged, all black version on eBay. The seller was candid about this and the price cheap so I bought it assuming I would be able to clean the fog. I was wrong. Though the lens is easily disassembled to get at the optics, the fogging can be impossible to remove. The lens is still usable with the normal caveats about its lowered contrast and the added problems of backlighting, so I felt, fair enough I will take it on the chin. The lens is, after all every bit the performer that others have claimed. Eventually I some years later I found a nice black and chrome one on the same site at a good price and bought that. It was much cleaner. It's is a superb little lens. What more can I say. Perhaps it lacks a little in character in the sense that it lack flaws that might give "character". But for what it is - a tiny, sharp, contrasty lens with excellent color rendering I can not add any thing more to what others have said about it. I did at one time (many years ago) also own the all chrome version of this lens. This was before I really knew anything about such lenses. Like an idiot I sold it I think because I was using it on my Leica M3 at the time and felt I wanted to "upgrade" to a Leitz 90mm. I kick myself now if only because that Canon lens too, was cheap and very good.
peterm1
Veteran
Here's my version...not the LTM but I understand its the same lens...
Found it at a local camera swap meet, traded a Nikon F2 prism for it.
The lens was covered in dust and at first glance looked old and used...but after a quick cleaning it looks like new...the glass is perfect and images are very sharp...it can be slow to use but so worth it.
I sold the A-1 so I use it on the Sony a6000...
Pretty sure this was with the 100mm...
I also own this lens and like it. But mine has some fogging on some elements that I have not been able to clean. Never the less it is a fine performer. I would not be surprised if this FL mount lens has the same optical design as the equivalent LTM lens. I believe that the same can be said for the FL mount versions of the 85mm f1.8 and 100mm f2. At least I think that is what I have read somewhere. I can vouch for the FL mount 85mm f1.8 being excellent though I unfortunately do not own the 100mm f2.
Mackinaw
Think Different
Not sure if the FL versions of these two lenses used the same optical formula as the screwmount lenses, but the "R" lenses, for the Canonflex, used the same optics. I have a R 100/2.0, and it is a superb lens.
Jim B.
I used the element behind the aperture to replace one in the LTM lens- might be a very slight difference, but it works. I had to slightly adjust the shim of the LTM after the swap.
james.liam
Well-known
It could be worse. I could be GASing for a (LTM) 100mm f/2
How about the 100/2? That's one lens I've thought about in the past. Anyone out there ever lay hands on one?
BTW, can't say I particularly love the color images from the 100/3.5. B&W seems to suit it (much) better.
peterm1
Veteran
I cannot comment personally about the 100mm f2 but everything I have read about it is excellent (in all versions). But all versions tend to be reasonably expensive though the R (Canonflex version) is somewhat less so.
If you want a really affordable Canon 100mm option for use with mirrorless, I frequently use the Canon FD "Chrome Nose" 100mm f2.8. I love it. It has very nice rendering that is perfect for portraits and is not really an expensive lens by any means. The f2 version of the same lens is rated even higher of course but is much more expensive as I mentioned above. All I can say is that thef2.8 version does everything I could want of it.
Some samples (bear in mind I have fiddle-faddled with these a bit in post).
Pretty Girl, Dinner al Fresco by Life in Shadows, on Flickr
Pretty Girl, Dinner al Fresco 2 by Life in Shadows, on Flickr
One Moment of Time on the Street by Life in Shadows, on Flickr
WJJ3
Well-known
The Canon LTM 100/2 is a great lens. It has very nice imaging, being sharp from f2 with pleasing out of focus areas. And for what it is, the size and weight are very reasonable. I came across one at a second hand shop in Nagano one day, mounted on a Canon 7 for ￥25,000. I bought it, sold the body for ¥5000, and kept the lens. After a few rolls, and then shooting it on my M9, I came to the determination that it was front focusing a bit, so I paid Kanto Camera ￥10,000 to adjust it for me. Now focus is spot on, but depth of field wide open is so narrow it requires careful use. I mostly shoot it on my M9 with a UN brand 1.25x magnifier.
A few shots from this summer. All @ f2
james.liam
Well-known
Impressive sharpness on center for such an old design and wonderfully soft bokeh! Can't remember the last time I saw one for sale though.
Darinwc
Well-known
I have both the chrome/black and all black versions of this lens. Neither have haze and they are both fantastic.
Costo Kim
Established
canon 3.5/100 ltm (old silver/black version) on a sony a7rII
canon ltm 3.5/100 mm by bokeh hunter, on Flickr
canon ltm 3.5/100 mm by bokeh hunter, on Flickr
Costo Kim
Established
canon 3.5/100 ltm (old silver/black version) on a sony a7rII (with macro-rings)
canon ltm 3.5/100 mm by bokeh hunter, on Flickr
canon ltm 3.5/100 mm by bokeh hunter, on Flickr