Canon 50mm f1.2 internal haze ... possible DIY?

[Keith]

A very strange thing has happened with my 1.2 Canon ... I haven't used it for a few months and last time I did use it, it was deinitely as clean as a whistle because I remember checking.

I've just taken it out of the cupboard and noticed it has a distinct build up of crud/haze on an internal element ... bad enough that I wouldn't contemplate using it like this. I'm puzzled that a lens can go from being relatively spotless to this state in such a short period of time though I do recall reading that this is a common problem with this Canon.

I gather these are relatively simple to clean provided you have the correct spanner to remove the retainers ... is this correct? Or am I better to entrust the work to someone qualified ... I'd hate to damage anything because the glass is absolutely pristine with no apparent cleaning marks on any surfaces that I can see.

 

[ferider]

I gather these are relatively simple to clean provided you have the correct spanner to remove the retainers ... is this correct?

Correct. There are detailed instructions somewhere if you search. It's pretty easy: take off the rear span ring, and then (by hand) un-screw the rear elements. You can also get to it from the front if you prefer: loosen a tiny visible lock screw in front of the aperture ring, and unscrew the entire optical block in front of the aperture.

Many of the 50/1.2 samples do fog up repeatedly. Something about lubes evaporating, I am guessing a professional cann't get rid of that either. Unfortunately, you are stuck with a lens that you have to clean every so often.

Roland.

 

[back alley]

i had one a long time ago, very nice lens, but it arrived with that haze. it cleaned up easily.
if i could do it then i see little problem for you keith.

 

[Keith]

Correct. There are detailed instructions somewhere if you search. It's pretty easy: take off the rear span ring, and then (by hand) un-screw the rear elements. You can also get to it from the front if you prefer: loosen a tiny visible lock screw in front of the aperture ring, and unscrew the entire optical block in front of the aperture.

Many of the 50/1.2 samples do fog up repeatedly. Something about lubes evaporating, I am guessing a professional cann't get rid of that either. Unfortunately, you are stuck with a lens that you have to clean every so often.

Roland.

All done and my favourite rangefinder lens is pristine once more ... a very simple operation. I was very impressed with the build quality of the internals while I had it apart!

Thanks Roland ... and Joe!

🙂

 

[Mephiloco]

What kind of cleaner do you use to get rid of haze? just methyl alcohol? peroxide?

 

[bobkatz]

Keith:
take a look here:
http://portretteur.nl/index.php?opt...12-rangefinder-lens&catid=37:lenses&Itemid=58
I have two of them nice lens indeed...Good luck
Bob.

 

[Mephiloco]

Blah, I got the spanner off, but the rear element is completely stuck, no amount on hand torquing is doing anything. Guess I can always try to figure out why the focus ring is sticking right before infinity until I can figure out how to get this element off

 

[Sonnar Brian]

The rear groups should come out as a module, a doublet and a single element behind it if I remember correctly. They are in a fixture together.

 

[kevin m]

It seems to be a persistent problem with these lenses. I had a cosmetically mint copy CLA'd by DAG, and still a year later I had to disassemble it and clean the haze. It was a very easy DIY, though.

 

[Steve Karr]

So what do you guys use to clean the inside & are there coatings to damage? I also have a 50DR that has some very slight haze, can this be cleaned by me without distorting the coatings and introduction friar?

Thanks!
Steve

 

[loneranger]

Is haze always just fog or some evaporated lube?
Is it ever more serious. I just bought a leica 50 collapsible summicron which is supposed to have a little haze, I am hoping it is not serious and could be cleaned off easily.

 

[Keith]

I definitely wouldn't be touching the internal surfaces of a DR myself ... far too easy to ruin I would suspect.

What do the pros like DAG etc use to clean these soft coatings ... I've often wondered?

 

[Charles Woodhouse]

Many years ago I was told that a phosphorous element in the helicoid grease caused the haze in Canon RF lenses so a few years back, after repeatedly cleaning the forward facing element behind the aperture in my 1.2, I stripped down the focusing mount, cleaned everything and regreased the helicoid with fishing reel grease. And the lens still fogs up after a year or so. And why is it always the same glass surface in Canon RF lenses that gets haze? And why is that same surface in 3.5/100 lenses so prone to cratering and becoming totally useless except for horrible special effects?Any answers please?

 

[Mephiloco]

Hey Brian. I was unable to get the rear element out through the back, it will not unscrew at all. Ended up going through the front with no problems, now I just have a problem with focussing to infinity (focusing stops just past 50ft, and wont move any faster, and takes some serious torque/screwdriver to get it to move at all). Not a huge problem, as I won't be shooting wide open at infinity, and the DOF at 2.8 covers infinity so stopped down it won't be a problem, but still.

 

[thomasw_]

I like it when things are simple to fix! Glad you are back in the clear with your favourite 50, Keith.

 

[Sonnar Brian]

I've always thought it was the specific lubricant used which reacted badly with a new type of glass that Canon used for the later Black lenses. I've cleaned a chrome 50/1.8 that was opaque- surface was perfect. Not so lucky on a Canon 50/1.8, 50/2.8, and 50/1.2.

On the Summicrons: I've cleaned the inner haze off of a collapsible, a couple of type 1 Rigid Summicrons, and a Summarit. I use ammonia based eyeglass cleaner, very small amount, on a qtip with Kodak lens cleaning paper over it. Very gentle swabbing. It worked for me.

On the stuck rear module- I've seen them cross threaded, and saw one welded in. I dremeled that last one out.

 

[Keith]

I like it when things are simple to fix! Glad you are back in the clear with your favourite 50, Keith.

The funny thing is I don't think I've used it since I actually cleaned it several months ago! 😛

It'll be sitting there quietly hazing itself up again no doubt! 😀

 

[Mephiloco]

I used Pancro to clean the insides, it worked ok, there's still some haze, but it's better than it was. I figure I'll source a good cleaner for internal use and order some of that. I figure if we use Pancro on $50k+ lenses, it should be fine on my sub $500 lens

 

[LeicaFoReVer]

it does not say in this tutorial that external shell can be put in back only in one direction, take care there is a groove to fit...

 

[Nokton48]

I opened mine up a couple of years ago, and did the entire thing in about thirty minutes. And I just checked, it's still clean as can be. And Yes, build quality of this lens is amazing.