How do you tell if a lens is coated?

[traveler_101]

According to what I have read, if you shine a strong light on a lens you can tell if it is coated:

"Bring it under a light (Sunlight is best but a table lamp will typically work also) the coating usually has a different colored reflection then a plain glass lens. You may have to view it from multiple angles to see what I'm taking about."

Well I tried it with my modern Voigtlander lenses and it's pretty darned obvious that they are coated. Also, looking at my 1936 Summar I can tell that it is not coated.

However, I also have a 1946 Elmar which is harder to read. 1946 is around the point they began to coat the lenses. I see some coloured reflection, but it is subtle and I am not sure. I just took this photo which may, or may not, help. Most of what I see is a purple colour, some of which you can see in the photo.

Thanks in advance for any help.

https://www.flickr.com/photos/93975264@N05/15934165808/in/photostream/

 

[ray*j*gun]

Not all coatings are created equal.... early coated lenses are more subtle but if you put an uncoated lens next to one that is coated you will see the difference even if its subtle.

 

[f16sunshine]

In your linked image, I see different colored reflections from the same light source which is usually a good indication the lens is coated.

I'm far from an expert though. i have only 2 uncoated lenses. Niether reflect any other color than that of the light source.
All my coated lenses reflect 2 or 3 different colors depending on the angle one turns the lens toward the light.

 

[ottluuk]

Depends on the lens curvatures, too. Sometimes the reflections are just harder to see. My 1952 f/3.5 Summaron is pretty subtle (but obviously coated, as it should be). My 1950 9cm Elmar on the other hand shows its "blue" coating very clearly.

Old uncoated lenses tend to acquire a thin natural coating due to oxidation at the surface that also gives faintly coloured (usually bluish) reflections. Lenses with such patina were prized by connoisseurs.

I have a 1937 Welta with a 7.5cm f/2.8 Xenar that gives a pretty solid glint of purple, more than I'd expect from natural patina. The camera has been modified, probably in the fifties – a cold shoe added on top and DOF table relocated to the back. So maybe the lens has been coated as an aftermarket service...

 

[Monochrom]

it is very easy to check for coated lenses, look at the first element in a certain angle it will show blueish/purple or yellowish reflections, you can´t go wrong.

 

[Dralowid]

From your picture I'd guess yours is coated

Michael

 

[peterm1]

Early coatings were single-coated and also were very soft (and so on front and back lens surfaces, often get worn away by frequent cleaning). When you look at the front element of a lens with early coating the coating is less distinct and of a single color depending on the exact formulation used. Modern multi-coated lenses have much more obvious coatings which also change color when you hold them up to glancing light and move them around. I had such a coated Elmar (dated to 1936 but confirmed to have been sent back to Leitz in the 1950s to be coated) and I agree it was hard to tell if it was coated but when compared to an uncoated lens it is more obvious. Interestingly it is said that the idea of coating was developed in prewar days when it was realized that older lenses produced better images. This was because over time they tended to develop a natural coating from oxidization on the surface of the lens. German scientists studied this and began artificially coating lenses during the war I think. But it only became commercial later. I have some old Pentax Takumar lenses, all coated. But when I compare early single-coated lenses (usually having a reddish/ orange hue) with later multi-coated ones it is like comparing chalk with cheese. I also have a Russian 90mm f2 lens which looks almost uncoated but actually is. I am sure this is single coating using older technology and hence less obvious.

As to your color photos they look to me like images produced by a coated lens. Non coated ones produce less overall contrast in the image and quite often have obvious flares if there are any bright light sources. The mono ones are harder to characterize.

 

[traveler_101]

Thanks to all for your help. I think I can safely conclude that the lens is lightly coated.

 

[Richard G]

This will cover most of it in 35mm:
1. If it's black it's coated.
2. If it's very old and silver without cleaning marks it's uncoated.

 

[B-9]

My Summar has a blue cast, really easy to see in sunlight. Tells me its coated.

An uncoated elmar should be clear through and through. Ive owned both coated and uncoated Elmars. Easily tell the difference.

Goodluck!

 

[traveler_101]

My Summar has a blue cast, really easy to see in sunlight. Tells me its coated.

An uncoated elmar should be clear through and through. Ive owned both coated and uncoated Elmars. Easily tell the difference.

Goodluck!

This Elmar seems to have a purple cast, and I am virtually certain now that it is (lightly) coated, but I will check it in direct sunlight -- when the sun return to Scandinavia (lol).

 

[gb hill]

I have a Elmar from 1946 & it's coated. Put the elmar along side my Canon FD lenses it doesn't have the thickness of coating as the Canon lenses. Time of course might play a factor.

 

[iphoenix]

I have a 90/4 Elmar from 1942 and it is coated. I understand that during WW2, Leitz started coating lenses destined for the armed forces. Some are only identified by the coating.

 

[David Hughes]

Hi,

It might help: I had a Summar that was coated and the coating (blue) went across the lens and on to the metal of the mount on the rear element. Despite the coating it was a display only item and I got rid of it.

Regards, David

 

[grouchos_tash]

I have a 1930's Elmar that's coated, I know this because it's peeling off :/

 

[iphoenix]

Hi,

It might help: I had a Summar that was coated and the coating (blue) went across the lens and on to the metal of the mount on the rear element. Despite the coating it was a display only item and I got rid of it.

Regards, David

I have a 1930's Elmar that's coated, I know this because it's peeling off :/

There were a number of owners who had their uncoated lenses coated by Leitz and other technicians. I think we can assume that the quality of coating application on your lenses precludes any skill on the part of the persons doing the work.

 

[traveler_101]

I have a Elmar from 1946 & it's coated. Put the elmar along side my Canon FD lenses it doesn't have the thickness of coating as the Canon lenses. Time of course might play a factor.

I read somewhere that after the war coating was standard, but the source was not clear as to precisely when the coatings began to be applied.

Hi,
It might help: I had a Summar that was coated and the coating (blue) went across the lens and on to the metal of the mount on the rear element. Despite the coating it was a display only item and I got rid of it.
Regards, David

Hadn't paid so much attention to the rear element so I just checked. Same light purplish reflections as the front and no coating on the metal.

Summars were produced to 1939 so I think they were all originally uncoated. How irritating to have one where the coating was added later. It is hard to believe that the Leitz factory would do such sloppy work.

I have a 1930's Elmar that's coated, I know this because it's peeling off :/

There were a number of owners who had their uncoated lenses coated by Leitz and other technicians. I think we can assume that the quality of coating application on your lenses precludes any skill on the part of the persons doing the work.

Seems more likely that poor quality work was done outside the factory. How do we know that there weren't any number of camera shops offering coating at that time?
By the way, my Elmar is a very nice lens with good resolution -- just lower contrast than modern lenses.