How to clean Canon 50mm f1.4 LTM?

D

dagimage2

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I recently picked up one of these lenses for a decent price, and the test shots so far look pretty good, but it's got a lot of dust inside, which I think is contributing to veiling flare in some conditions. I've just noticed that the front of the barrel can be unscrewed fairly easily, and it looks like the front element would come with it. So I'm wondering if I can just unscrew that, blow out the dust, and screw that back in -- or if that might cause problems with focussing or anything else. What are the risks in doing this? Is there any place I can find proper instructions on how to clean this leans?

Also -- while we're on the subject: I've noticed that the images I take with it can have vastly different color casts (using auto WB on an RD-1) based on just the smallest difference in the angle of the light on the scene, or if I close the aperture 1/2 stop while everything else remains the same. Has anyone else observed this? Any ideas why this might be?

Thanks.
 
I don't own th 50/1.4, but a 50/1.2... I too want to know how to clean it by myself. Mine has a little haze in one of the elements and has a glu-like green goo at the rear element... how to clean? I read somewhere that the 1.4 and 1.2 are basically the same so I guess it's ok to ask here... if not, sorry dagimage2 to hijack your thread.
 
I have a Canon 50f1.4 and the images come out great but the focus ring seems loose somewhat and I am wondering if it can or needs to be tightened up? I have tightened the 3 screws on the back but it didn't seem to tighten the lens up. Maybe the lubricant would have made it tight but I don't want to spend much more on the lens.
Joe
 
retaining ring holds the Optics Module into the mount. Removes using an optical spanner. Be careful not to lose the Shim. Optics module drops out, and the rear optics can be removed using a spanner.
 
Brian Sweeney said:
retaining ring holds the Optics Module into the mount. Removes using an optical spanner. Be careful not to lose the Shim. Optics module drops out, and the rear optics can be removed using a spanner.
Click to expand...

Thanks, Brian, but I'm not even sure which part is the retaining ring. Is that the very font part of the barrel, in front of the aperture ring?

And is it going to be tricky to put back together correctly, or will it be obvious? Am I risking misalignment of anything if I take it apart myself?

Finally -- it looks like there may be one small patch of haze on one of the inner elements. Is this easy to clean off, and if so, how?

Thanks.
 
At this point I'm going to suggest letting a professional clean it. You need a specialized tool to remove the retaining rings. There are a series of them. I taught myself this stuff by buying junk lenses and taking them apart. After a while, i could actually put them back together. a Canon 50/1.4 is not the one to start learning DIY camera repair on. I have a box of unassembled junk lenses that can testify to that.
 
Brian Sweeney said:
I taught myself this stuff by buying junk lenses and taking them apart. After a while, i could actually put them back together. a Canon 50/1.4 is not the one to start learning DIY camera repair on. I have a box of unassembled junk lenses that can testify to that.
Click to expand...

Fair enough -- that's the kind of warning I was looking to see if I'd get. I have certainly taken apart more things than I've managed to put back together in my time.

Thanks again.
 
You've got a treasure. I echo Brian; send it to a qualified technician. You'll be happy you did.
 
Just wanted to follow up on this. I ended up returning the lens to the store because after examining some of my test shots I discovered that one corner was substantially softer than the other three corners. The lens was nice and sharp in the center, and pretty good in those other three corners, but the lower left quadrant was very blurry, and the difference remained as I closed the aperture. I was feeling that the purchase was a bit of an extravagance to begin with, and not confident that this defect could be repaired economically, so I opted to return it.

But I am curious whether this is the kind of thing that could have been fixed if I had sent it to a tech. Has anyone out there had that kind of defect repaired?

I don't know what cause was, but I'm wondering if it might have been a result of some 4 or 5 very small scratches that appeared as if they were concentric arcs on one quarter of the rear element -- maybe they were defocusing that quadrant of the image. Does that seem possible, or is it more likely some kind of misalignment?

Thanks to all who responded.

Dave
 
I few scratches would not cause this. Haze and/or etching on one part of the glass can cause this, but it would have been visible looking through the lens.

If one of the elements was mis-centered, or not in completely flat- you get a problem with the edge. This can happen from a bad repair job or dropping the lens.
 
It could also be that the lens mount on your camera isn't parallel to the film. Someone may have removed it, lost the shims, and put it back. Try the same test with another lens to be sure.
 
John Shriver said:
It could also be that the lens mount on your camera isn't parallel to the film. Someone may have removed it, lost the shims, and put it back. Try the same test with another lens to be sure.
Click to expand...

Interesting suggestion, but I've been using this particular camera for over a year with four other lenses, and haven't noticed this problem. When I was testing this lens, I was shooting the same shots with my 40mm Rokkor to compare the results -- and the pictures from the Rokkor don't show that problem. That's how I confirmed for myself that the problem was not that the camera was shooting at an angle to the test chart.

I think it's likely that something got jarred out of alignment at some point -- the filter ring had a couple of dents in it. They were minor, or had been bent back into shape, so you could still screw filters in -- but it was certainly not truly round.

So would this have been easily repairable by a good technician? I'm wondering, in case I ever encounter this problem in the future.

Dave
 
Canon 50 1.4 ltm Issues

Canon 50 1.4 ltm Issues

Hi
I have just purchased one of these in the knowledge it has slight haze on an inner element in the front group. As I understand I need to remove the tiny grub screw on the silver ring that supports the aperture ring, remove the front plastic retaining ring and then unscrew the front group?
I have discovered another problem in that the focus scale ring turns independent of the focus ring. It can simply spin freely in any direction. I have pulled down several ltm lenses in the past but I have never encountered an issue like this.
Any help would be gratefully accepted
 
Canon 50 1.4 ltm Issues

Canon 50 1.4 ltm Issues

Thank you for that, I have removed the grub screw and the front retaining ring and removed the front element but cannot get the front group to screw out, very very tight.
Guess I'll keep at it.
 
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