Help with lens evaluation please.

[tedwin]

I am going to have a look at a lens that is for sale this morning. It is a Leica Elmarit-M 90mm f2.8 lens which the current owner bought new in 1995. He has listed it quite cheaply on an auction site as it clearly has ALOT of small bubbles in the second element from the front. I assume this has been the case from new, and I also assume that it probably doesn't affect images all that much as is shows some 'brassing' ie he's used it often for 13 years. My question is is this. Is there something specific I can snap that will highlight any possible problems? I was going to shoot, backlit, and bright light source high contrast shots with a colour film, wide open. But I don't want to take a bunch of shots that have unrealistic expectations from a perfect version of this lens. Is it a question of just suck it and see? Should this lens have comparable contrast and sharpness to a current 50mm Summicron (my only other leica lens for comparison) Anyone else used a lens with a similar problem? Any thoughts?

Any replies would be greatfully appreciated within next few hours, as I have to head of and play with it.

Thank you in advance.

Ted.

 

[payasam]

What I'd suggest is a range of shots at different distances and different apertures, in different kinds of lighting. My guess is that the lens will be less contrasty than your Summicron. It should be sharp, though.

 

[tedwin]

Thanks for replying.

Have been and looked at it. They are not bubbles, but a load of what looks like white microfibers (but obviously are not) As I understand it, this lens has no cemented elements, so its not weird looking separation, they are not bubbles, and not fungus. If you can imagine a good amount of dust on an internal element when shining a torch through the camera, then on closer inspection the 'dust' actually being tiny little white curves or lines, like I said like tiny fibers (?!) sorry, but its really hard to describe! I have been researching the web for hours and can find no description of anything similar. I have spoken to the local repair man, he too had spotted the advert and also has no idea what it could be (but suggested I steer clear) I'm persevering as its a lens I would love, but couldn't normally afford. So its really tempting!

Anyone else got any ideas? The guy selling it is a lifetime pro, has owned from new and was unaware of 'issue' until deciding to sell it.

Thanks again,

 

[colyn]

Thanks for replying.

Have been and looked at it. They are not bubbles, but a load of what looks like white microfibers

This is fungus.

Fungus can be spider webbing or small fuzzy looking balls or spots.

I'd stay away from it...

 

[tedwin]

Each filament (for the want of a better word) is on its own, there are none connected. There is no pattern of growth, no dots with legs etc. I am 95% sure its not organic.

 

[colyn]

Each filament (for the want of a better word) is on its own, there are none connected. There is no pattern of growth, no dots with legs etc. I am 95% sure its not organic.

The most common form of camera lens fungus is spider webbing however fungus can also take the form of non-connected fuzzy balls. If they are a whitish color then it's fungus. Growth pattern is usually random and only becomes connected once growth covers most of the lens element..

 

[tedwin]

There are no fuzzy balls, no fungus is present.
Another way to describe it would be small ellipses of dust. If you have seen the marks a rotary sander can leave if used with too coarse an abrasive, then imagine those marks appearing as dust. Anyway, if I can get it cheap enough I must just buy it anyway, then I will take a picture of the phenomena and post here for opinions! Would be interested to know what it is, but it is obviously too hard to describe without a picture.

 

[35mmdelux]

I would pass... Use your money on good glass. Frankly, I don't like the representation. If he bought it "new" with bubbles why not simply return it for a good example?

 

[colyn]

There are no fuzzy balls, no fungus is present.
Another way to describe it would be small ellipses of dust. If you have seen the marks a rotary sander can leave if used with too coarse an abrasive, then imagine those marks appearing as dust. Anyway, if I can get it cheap enough I must just buy it anyway, then I will take a picture of the phenomena and post here for opinions! Would be interested to know what it is, but it is obviously too hard to describe without a picture.

If the issue is nothing more than bubbles then you would only see round or oval shaped spots without any "load of what looks like white microfibers".. Dust appears as dark spots.

Since you described the appearance as "white microfibers" then it has to be fungus. I would pass on the lens..