Haze & Cleaning Marks, How much do they really afftect image quality?

[existrandom]

hi folks,

of course we want that 50 years old lens "mint" and "like new" as it were just fresh out of the factory,

but i just wonder, how far cleaning marks and haze, or perhaps other defects on the glass would REALLY affect image quality in 90 - 95% of our shooting?

for instance, i just bought a "mint" zuiko 28/2.8 for my brother from the EEEEbay, only to find out that there is a light haze/ clouding in the internal element when i look through the lens with a flashlight... should i have it CLA'd, or should i just let it be... or should i tell my brother in the first place?

would love to hear you folk's opinion and experience

thanks for viewing!

lee

 

[Sonnar Brian]

It is amazing how a lens still performs with "imperfect" glass.

Check out this lens:
http://www.rangefinderforum.com/photopost/showphoto.php/photo/10031/sort/1/size/medium/cat/859/page/

And its Results:
http://www.rangefinderforum.com/forums/attachment.php?attachmentid=2674
http://www.rangefinderforum.com/forums/attachment.php?attachmentid=2675

 

[doubs43]

That is pretty amazing, Brian. What's even more amazing is that some lens in perfect order won't do as well.

Walker

 

[existrandom]

thanks for the reply, those are amazing shots! perhaps that special dreamy effect are on account of the cleaning marks?

what about haze? haze bothers me, will it develop and turn worse like fungus?
is there haze that are not cleanable by the usual CLA procedure? how to tell?

thanks!

 

[thmk]

The haze on older lenses is due to aging processes (coating/glass). In the worst caes lense elements have to be recoated and polished. That is a very expensive task and it is hard to find someone who will do this.

 

[Nikon Bob]

I just had an old Elmar cleaned internally as it was a bit hazy and it now performs much better. It is old enough not to have been coated originally. I also have seen lenses with ugly looking front or back lens surfaces that performed surprisingly well.

Bob

 

[Meleica]

<<<The haze on older lenses is due to aging processes (coating/glass). >>>
not quite true. Most haze comes from gases and condensation from lubricants used internally in lenses. Leica lenses from the 40's to late 60's are notorious for having haze. It is directly attributed to gases given off by the lube used inside the lens. In fact, its so common that I estimate 80 to 90% of ALL Leica lenses in this period will have some level of haze inside.

 

[Meleica]

PS - if you have noticed, there are some makes that dont ever seem to have haze... I find that Nikon lenses, of this period, generally have far less issues with haze and Canon more than Nikon but less than Leica. Same goes for cleaning marks - Leica's very soft coatings make cleaning marks very common while Nikon and Canon are MUCH less likely to have marks due to harder coatings...

 

[thmk]

I read about this haze problem with Leica lenses from the 50's shortly and it was reported that it is not due to lubrication gas but to the types of glass which were used. But as often I assume that opinions differ. I will check if I can find the link to the text again.

 

[thmk]

Ok, found it:
http://www.cameraquest.com/mlenses.htm
I mean the chapter "Fogging".

Cheers
Thomas-Michael

 

[Meleica]

Here is part of a conversation I have had with Don Goldberg DAG

"Dan,

............The inner coatings are soft unlike the outer coatings, metals in the lens elements / lube produce gas that find their way out through the element coating & deposit a "fog" on the outside of the lens coating & start braking down the coating. If this becomes bad enough no matter how carefull you are the coating will come off when you clean that element- but optically its much better to have that fogged coating off. I've talked to many people in the optical industry about this & they all said that it's better to remove the fogged coating of an inner element than to leave it on. If this was not the case then no one would ever go into a Leica Lens to clean the fogged elements,

Don
DAG"

 

[Sonnar Brian]

Here is a previous thread on cleaning marks, which includes my before and after test of an M-Mount Summarit that was CLA'd by Essex. They did a great job, and managed to leave the inner coating intact. They CANNOT promise that every lens will come out as good. On the 2nd Summarit, Ian called me at the house to explain that damage to the coating would occur and the lens would not be 100%. It came out fine. And I much agree with the prior post, it is much better to remove a coating completely and incur the 3% transmission loss than it is to leave the haze on a lens.

http://rangefinderforum.com/forums/showthread.php?t=391&highlight=summarit+kitty

 

[Sonnar2]

depends on... there is haze easily to recognize with naked eyes.. I think this lowers contrast in nearly every picture. Very often "haze" isn't removable.. this was with my first Canon 1.8/50 (sad to say, this is often offered with "haze")

If you need a light to see the "haze" or cleaning marks well, then you should use this lens carefull with backlight or high-contrast, always with the proper hood (which BTW isn't a bad idea with *every* 1950's oder 1960's lens). In most if not all pictures you won't see a lowered contrast.

Bad cleaning marks alone can reduce the $$-value to 1/2 or 1/3, but I think it don't will lose more than 1/3 of picture quality. Sadly, more often than not cleaning marks, haze, ugly apperience, and other mistakes come together.. ;-)

Frank