90mm 1:4 ELMAR scm

I have a 1937 90mm ELMAR that appears to have a light coating. I know that LEITZ did not coat lenses at that time but it does show some bluish color. I checked on heavily overcast days to ensure no blue sky and it still shows bluish. Could it possibly be bloomed?

I have the same lens, "Bloom" is not uniform over the front element.

If you see a uniform Blue, it could be that the lens was coated after manufacture. Many companies offered this service, some still do.

I have a 1937 90mm ELMAR that appears to have a light coating. I know that LEITZ did not coat lenses at that time but it does show some bluish color. ...

In fact they were [single] coated at the factory. But Leica's early coatings were very soft by today's standards.

 

It is possible your lens was recoated; although I am personally not a fan, there are outfits that do multi-coating of older lenses. Not a fan because polishing is involved and I've seen lenses - shall we say "changed" (that is - loose their original character) - as a result.

Edited October 21, 2020 by Bill Blackwell Images

In fact they were [single] coated at the factory. But Leica's early coatings were very soft by today's standards.

 

It is possible your lens was recoated; although I am personally not a fan, there are outfits that do multi-coating of older lenses. Not a fan because polishing is involved and I've seen lenses - shall we say "changed" (that is - loose their original character) - as a result.

Thank you, for clearing this up for me, I had searched websites, all said LEITZ lenses were not coated until after WW II.

I have both coated and uncoated Elmar 9cm F4 lenses. I've seen Black lenses that were coated, but these have a post-war SN. I have pre-war Zeiss lenses that are factory coated, they started doing this before Leica.

I have read that Leica did start coating lenses during WW-II- but only certain lenses. The first batch Summarit 5cm F1.5 comes to mind.

 

Sending an uncoated lens in to be coated does not involve polishing the glass, just removing the glass elements and placing them in the machine.

I've not read about Leitz coating their lenses until it became a thing during World War 2.

 

That said I have a 1937 sample of this lens as well that has been coated, but I always believed this was done in the post-war years when Leitz offered this as an upgrade service. I also have 2 uncoated samples from 1934 and 1936.

 

Alternatively it could be natural oxidation of the glass, though it would clearly not look as uniform as proper lens coating.