Bubbles in lens element

olakiril

olakiril

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I need your input in this, so I can decide whether I should try another sample or appreciate what I already have.

The lens in question: VC snapshot 25 f/4.

The problem lies in one of the rear lens elements. It is not just one. Small bubbles are everywhere, although hardly visible with a naked eye. There are also some very faint lines all over that element too.

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How much of a problem is it? I didn't expect the highest image quality from that lens anyways, but if I can't resell it afterwards I am better off trying another sample.

What do you think?

Thanks for you input,
M.
 

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Bubbles used to be a mark of extraordinary glass but in a modern lens like your Voigtlander they may be some sample flaw. If it were an old Zeiss lens, I'd have no problem keeping it but seeing as it's quite modern, I'd return it, personally. If it makes good images though, it's probably perfectly fine.

Phil Forrest
 
Even today lenses that use a high refractive index and low dispersion glass normally have some air bubbles. QA is such that "sample variation" in modern glass or completed lenses all conform to the standards. If there are bubbles there, the manufacturer knows about it. Some put that information in their literature. Contact the maker if you are concerned. Don't ask a bunch of strangers on the Internet. But no, it will not make one bit of difference in your photos. Almost all of my lenses newer than 100 years old have bubbles. Some have lots of them.

From Schott: http://www.us.schott.com/advanced_o...es-and-inclusions-opt-glass-march-2014-us.pdf "Optical glass is remarkably free of bubbles. However, due to the glass composition and the need for an economical manufacturing process, bubbles cannot be completely avoided in glass."

From Sigma: "APO lenses use high reflective index and low dispersion glass in some lens elements. This special glass normally has some tiny air bubbles but it does not affect the optical performance of your lens. "
 
That looks like two elements coming uncemented from each other. Is bad news. No modern maker would let a lens out looking like that!
 
Doesn't look like separation at all.

ALL GLASS has bubbles. It's completely normal. I'm sure every lens is tested and inspected before it goes out too.
 
Phil_F_NM said:
Bubbles used to be a mark of extraordinary glass but in a modern lens like your Voigtlander they may be some sample flaw. If it were an old Zeiss lens, I'd have no problem keeping it but seeing as it's quite modern, I'd return it, personally. If it makes good images though, it's probably perfectly fine.

Phil Forrest
Click to expand...

I agree that this looks like a flaw (given it's a modern lens). As stated above old glass users regarded some bubbles as a sign of good glass (as back then the best optical glass could not be made without some bubbles). But in a modern lens bubbles of this magnitude are extraordinary. Personally I would return it. Given what appears in the photo you show I would expect some effects on images in some lighting. At the very least it will affect your resale value. So- return.
 
Peter, you are wrong. Read my links. Bubbles still occur, and are normal, in some optical glass. Don't start another internet rumor that is false.
 
It not like there are one or two bubbles .
There must be at least 50 of them in one glass .
Older nikkors often have a bubble or two .
It's not likely that the glass of a common 25 scopar
Is some exotic high index or low dispersion glass ,
If it's possible to return the lens I would attempt to .
 
OK, all you brilliant return advocates. What are you going to say when he gets another lens, and shines a bright light trough it the same way, and it has similar bubbles? Come on, what will you say then? We'll find out in a few weeks. Trying to show facts to this group is like trying to prove to the tinfoil hat contingent we landed on the Moon. I'm out....
 
goamules said:
OK, all you brilliant return advocates. What are you going to say when he gets another lens, and shines a bright light trough it the same way, and it has similar bubbles? Come on, what will you say then? We'll find out in a few weeks. Trying to show facts to this group is like trying to prove to the tinfoil hat contingent we landed on the Moon. I'm out....
Click to expand...

This is not a frequent occurrence with regard to CV lenses. That's why we're saying the OP should return it. I've owned numerous lenses of this brand and far more of other brands yet I've never seen a bubbling as severe as this example. I've also had a few lenses with some pretty significant bubbles but they were old Zeiss, Leica, Bausch & Lomb and Schneider lenses. Mostly uncoated to demonstrate how old they were.

I'm sure most users on this and other forums have had a similar experience.

Phil Forrest
 
Thanks everyone for your input. I contacted the seller and he agreed to return the lens.

Garrett, thanks for the links. I had read that few bubbles are expected, but I didn't know what is considered within specs. Of course I could contact the manufacturer but the strangers in this forum can be quite helpful ;). Moreover it provided me with a population sample of lens quality expectations had I decided to resell it later.

Miko, it is definitely bubbles, I checked it under a stereoscope. It is just hard to take a proper picture of them with my phone stack on one of the scopes eyepieces... Also it is not as bad as your sample was and I got it from a store in Japan.

Once I decide for another R-D1 I 'll try my luck again with another sample.

Best,
M.
 
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