Canon 50/1.2

ChrisN

ChrisN

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I took a risk on ebay last week, and bid on a Canon P with a 50/1.2 lens. I'd planned to sell on the body and keep the lens. The body was very grubby, with a few scratches but it is very clean inside, the film advance is very smooth, the viewfinder is reasonably bright and the rangefinder image lines up well. So I might just find myself keeping this one for a while.

That 50/1.2 is big! It's in nice condition mechanically, smooth to focus, no oil on the iris blades and no scratches. However there's a fair bit of haze on one or other of the rear elements, and I suspect it might be within the compound element (in the canada balsam?). Anyone have experience with this? What does it look like to you?

Surprisingly the results are not as bad as I expected, if you stay away from very bright light sources. Better with colour than B&W. Not as contrasty as I prefer. I'll get it fixed in due course - can anyone recommend a good lens service person in Australia? I'll probably have to send it to the US if I can't get a good recommendation.
 
The element that is directly behind the aperture tends to cloud up on many of these lenses. Pretty easy to clean too, if you'd like to do it yourself. Take a look at this thread which made the rounds a few months back. Instructions on how to take apart this lens are included.

http://rangefinderforum.com/forums/showthread.php?t=5329

Jim Bielecki
 
so that was you that bid on it! lol. i was debating on wether i should bit on this one, or the canon 7. turned out the canon 7 won, but didnt have the 1.2. lol, oh well that issue is over and done with. ( as soon as i get my money 😉 )

the 1.4 seems big? haaaaaaardly so hehe, a noctilux is large, and on a different scale, the Canon 50mm f/1 for EOS cameras. that is teetering on the edge of gigantic.

big lenses strike my fancy, cant explain why, they just look and feel so much better to me.
 
If it's the element on either side of the aperture mechanism (these are most likely to fog due to evaporating lubricants) you don't even need to do that much to get at it. Unscrew the tiny setscrew in the side of the ring ahead of the aperture ring (it's roughly in the 7 o'clock position facing the front) and you can unscrew the whole front group by grasping around the filter ring and turning. The diaphragm blades now are exposed, and with them the two elements on either side.

If the diaphragm is open to f/1.2 (do this before unscrewing to reduce the risk of blades popping off) you can reach the back one through it, and the forward one is immediately accessible. If these are the foggy ones, clean them off using normal, careful lens-cleaning practice. The forward one is very deeply dished, but it's no problem to clean.

If the foggy elements are elsewhere, you're looking at more involved disassembly, for which the directions mentioned above should be helpful.
 
"the 1.4 seems big? haaaaaaardly so hehe, a noctilux is large, and on a different scale, the Canon 50mm f/1 for EOS cameras. that is teetering on the edge of gigantic."

compared to the 35/2 or 35/2.8 - even the 50/1.8 - the 50/1.2 IS big!
i'm in it for the size as much as anything else and while i'm getting used to the 1.4 it likely will be the biggest lens mounted on the p. even the 100/3.5 is less of a handfull & small & light to boot!

joe
 
Thanks for all that good info people - I'll get onto it later today and see what I can clean off myself. Have a good weekend!
 
jlw said:
If it's the element on either side of the aperture mechanism (these are most likely to fog due to evaporating lubricants) you don't even need to do that much to get at it. Unscrew the tiny setscrew in the side of the ring ahead of the aperture ring (it's roughly in the 7 o'clock position facing the front) and you can unscrew the whole front group by grasping around the filter ring and turning. The diaphragm blades now are exposed, and with them the two elements on either side.
Click to expand...

Mackinaw said:
The 50mm F1.2 is very simple to work on. If disassembled from the rear, just unscrew one retaining ring with a lens spanner and the entire focusing mount and distance scale part of the lens comes off in your hands. No need to worry about scribing anything, it only goes back in one way (has a notch which lnes up with a metal "block" on one side of the interior). The rear most lens group can be unscrewed using two fingers which exposes on more retaining ring.
Click to expand...

OK time for some more expert advice. Coming in from the rear, I can remove the focusing mount, but the lens thus exposed doesn't want to unscrew with finger pressure Is it locked in with those two little set screws in the shoulder of the aluminum body?

Attacking it from the front, I can remove the little set screw, but once again the front element group won't move, with finger pressure. This one doesn;t want to play!
 
If you don't have an optical spanner, or are nervous about using one so close to the glass, you might try using a sheet of rubber.

At good hardware stores you can get rubber insulating tape (NOT "electrical tape.") This is solid rubber, is about 1/16 inch thick, and has no adhesive; however, the rubber itself is naturally sticky, so there's a red liner applied to one side to keep it from adhering to itself. Peel off a piece long enough to wrap around the lens assembly, remove the red liner, wrap it around, and suddenly you find you have a mighty grip.

If you can't find this tape, look for a thin sheet of rubber in the plumbing department.

You may need to use the same treatment to get the front group off the lens; even after loosening the setscrew, it may be tight enough to be difficult to turn by hand. I still think this is the route you should be following at first, rather than taking individual elements out of their cells; the lens is designed so that the front and rear groups separate easily, and there's almost no way to get them misaligned when putting them back together.

I just put together a page for someone else wanting to disassemble a Canon lens. It's for a 50/1.4, but the 1.2 is very, very similar (especially in how the front group comes off.) Here's the link: click here.
 
Thank Brian and JLW. I've got some of that tape - we call it "self=amalgamating" - after you wrap a joint or connector the tape melds itself into a solid mass. Good stuff.

That optical spanner looks good - where do you get one of those from? At the front, the trim ring (with the lettering and serial number etc) unscrews easily, but there's nowhere else to go under it!

I gather it is the entire black housing I need to remove, after undoing the set screw.

I'll try the tape. JLW - great work on that instruction sequence!
 
ChrisN said:
At the front, the trim ring (with the lettering and serial number etc) unscrews easily, but there's nowhere else to go under it!

I gather it is the entire black housing I need to remove, after undoing the set screw.
Click to expand...

That's correct -- you need to grab the outside of the front rim, not the trim ring inside it. You might want to note its starting position relative to the main body of the lens, so you can get it back in the same position when you reinstall it.

"Self-amalgamating," huh? Now I'll know what to ask for at the hardware store, rather than "that sticky rubber tape"!
 
Tried the tape. Front element will not move. Just managed to unscrew the rear element, exposing the retaining ring beneath. Cover me - I'm going in!
 
Well. here's the result. I was about to write that the haze is embedded between the lens elements, but I've had another look and it might be a coating on the inside. I've tried iso-pro and optometrists lens cleaner fluid - what's next?

At least I've learned a lot about this lens today, and I've got some photos to send off to Essex for an estimate if I need to. I might be able to send just the lens group with the haze, which will save me a bundle on postage. 🙂

Looking at the lens like this, it amazes me that any light gets through to the film at all! I won't be so paraonoid about a few minor marks in the future!

Thanks for keeping me company on this journey of discovery!
 
Well, there may be another solution. I had solid white haze on a lens that did not go off with 'friendly' solutions. In the end I used steel fix, an extremely fine polisher. As a last remedy. First I tried it on a regular piece of glass to test.
I was relieved to find the lens clean! Afterwards a cleaning in a 'friendly' solution and voila.
The clean assembly was the next tricky part!

In Holland it is calles 'staal-fix', made by SC Johnson. The big chemistry company.
 
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