Canon 50mm/1.5 Rear Element Haze

[dyao]

Hi all,

Bought a 50mm/1.5 about 6 months ago with heavy haze on one of the elements towards the rear of the lens, had it cleaned and (possibly) CLA'd (not sure what exactly the tech did). Cleaned up really nicely.

A few months later, I noticed that haze has returned on the same element. I suspect it's from the lubricant. Can't see any effect on photos - contrast is good, lens is sharp. Do you think it would be worth having it cleaned again? I recall reading on these forums that 50mm/1.5's are particularly susceptible to reoccurring haze.

I'm worried that if I don't get it cleaned, eventually it will etch the glass.

 

[John Shriver]

Yes, you should have it cleaned again. Foolish not to with the lens getting so valuable. Ask them to completely clean and re-lubricate the focusing helical as well, and the iris mechanism, to eliminate the source of the haze.

 

[dyao]

OK, I think that's what I will do. Are there any places that specialize in Canon lenses? I remember people sending their Canon lenses to Essex in NJ. Would that be a good option?

 

[John Shriver]

Well, is the prior repair covered by any warranty?

Certainly Essex can do this work.

 

[dyao]

Nah, it's a local guy...

 

[ferider]

Welcome to the Canon LTM world. Other Canon lenses (50/1.2, 100/3.5, etc) do that too, quite frequently.

I recommend to get a spanner and do it yourself regularly. It's quite easy.

Other than that Don, Essex or John certainly can replace the lubricant with a different type.

 

[Frontman]

Welcome to the Canon LTM world. Other Canon lenses (50/1.2, 100/3.5, etc) do that too, quite frequently.

I recommend to get a spanner and do it yourself regularly. It's quite easy.

Other than that Don, Essex or John certainly can replace the lubricant with a different type.

You don't need a spanner to disassemble most Canon LTM lenses, just some micro screwdrivers. On many of the normal length lenses there is a set screw on the outside of the filter ring, just above the focusing ring. Remove this screw and you can twist out the front element group, which will give you access to the hazy rear element.

Remember that the coating on the inside of the elements is very thin and fragile, and can be damaged if you clean too aggressively. Use only pure cotton swabs, and clean gently.

The lens should be sent out for a proper CLA, and lubricated with a more modern lubricant which does not generate haze.

 

[dyao]

Well I had it cleaned by Essex two months ago and I asked them to replace the lube. The haze is coming back unfortunately. I know I'm covered by their 12 month warranty but shipping costs will add up. Thinking about spending the shipping money on spanners instead and doing it myself.

Question: From the rear, there are two sets of rings that you can use spanners on. Which one controls access to the lens, the inner or outter one?

 

[peterm1]

I have to disassmble and clean my Canon 50mm f1.2 soon.

I had looked on ebay for a lens ring spanner, but find that the better ones are quite expensive (conisdering I would only use it once in a blue moon) and the cheaper ones (still only about half the price) look, well, cheap and I am not certain they will function as well as they are supposed to especially if they have to be twisted strongly to under a tight ring.

I have considered buying a cheap sliding gauge (something like this one) and modifying the tips to use as a lens spanner. They can be had for as little as five bucks. Has anyone tried this?

http://us.123rf.com/400wm/400/400/b...ll--vector-illustration-isolated-on-white.jpg

 

[Sonnar Brian]

I have an ancient set of calipers that work as a spanner. BUT: they will not apply as much force as the real thing. "Work in a pinch".

 

[mahleu]

I have a variety of different dividers which work well although on a really tight ring they don't do so well.