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Visible dust spots and air bubbles in lens: should I buy?
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PostPosted: Tue Sep 04, 2018 9:23 pm    Post subject: Visible dust spots and air bubbles in lens: should I buy? Reply with quote
Hi,
I found a Meyer-Optik Görlitz lens on ebay, which is sold to a cheap price, but the seller warns that it comes with some "visible black dust spots and some air bubbles in the glas". Indeed I can see both on the pictures provided.

Assuming I am going to shoot practically always WO, as I am interested in the bokeh effect, do you think it is safe to buy? In other words, do the problems mentioned above impact the picture when shooting WO?

Thanks.


PostPosted: Tue Sep 04, 2018 11:16 pm    Post subject: Reply with quote
It is very unlikely that you will see anything of that; just make sure the rear lens is in order, as this may show.


PostPosted: Wed Sep 05, 2018 8:35 am    Post subject: Re: Visible dust spots and air bubbles in lens: should I buy Reply with quote
wolan wrote:
Hi,
I found a Meyer-Optik Görlitz lens on ebay, which is sold to a cheap price, but the seller warns that it comes with some "visible black dust spots and some air bubbles in the glas". Indeed I can see both on the pictures provided.

There was a time when Carl Zeiss Jena actually informed possible customers abot air bubbles in some of their very best and most expensive lenses: Bubbles in their lenses were seen as sign of high quality!

Why?

In pre-WWII-years, some new high-refractive / low dispersive (and expensive!) glass types with a very high melting point were introduced at Zeiss. There were no meams to thorougly stir the molten mixture, and to remove all bubbles. These bubbles therefore were seen as inevitable signs of expensive Zeiss glass, and even advertised as such!

I have added the corresponding page from the Zeiss Ikon publication "Ten Contax Lenses" (1935) which i got from Henry Scherers excellent Contax site (contaxcamera.com).

Stephan



PostPosted: Wed Sep 05, 2018 9:07 am    Post subject: Reply with quote
Bubbles are typically not an issue. Spots depends on how many / how big, and on what element(s); usually the effect is negligeable.

Maybe you can use these "flaws" to negotiate a lower price Smile or maybe not...


PostPosted: Wed Sep 05, 2018 12:25 pm    Post subject: Reply with quote
Air bubbles are there since the lens left the factory. Usual thing in Soviet lenses, I won't bother about it.
Dust has no effect on pictures, but haze can decrease contrast.
Black dust, depends... I found that in a few lenses without any effect, but it was just a few specks.
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