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Helios 44m - strange "bubbles"
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PostPosted: Wed May 26, 2010 2:35 pm    Post subject: Helios 44m - strange "bubbles" Reply with quote

Hello everyone,

This is my first post as today I received my first ticket to the m42 wonderworld: a Helios 44M 58mm f/2 lens, that I'm going to try on my 7d as soon as the m42-eos adapter hits my mailbox.
Since I could still not shoot with it, this morning I played with it a bit, and examined it thoroughly. There seems not to be fungi or serious scratches - just some barely visible wear signs - but there are two or three "spots". I don't know how to describe them.. they seem as microscopic "bubbles" in the glass. Has this ever happened to anyone?
This evening, as soon as I get home from my office, I'm going to post some photos of the lens wide open, so that the "bubbles" are clearly visible.

thanks in advance for your advice and experience...


PostPosted: Wed May 26, 2010 3:58 pm    Post subject: Reply with quote

Glass bubbles are common in old russian lens. Some people think this is a sign quality glass.


PostPosted: Wed May 26, 2010 4:26 pm    Post subject: Reply with quote

Nothing serious, pretty common in early quality glass.

Klaus


PostPosted: Wed May 26, 2010 5:06 pm    Post subject: Reply with quote

Whew! that's a relief.
Anyway, i'm posting three shots of the little beast.
back, against the window so you can spot the bubbles.


side:


front - you can see the bubbles here, too


Then, I decided I cannot wait for the adapter, so I went for the cheapest adapter in the world: my left hand, holding the lens in front of the bare sensor - talk about handshaking! no IS here... Laughing





It seems bubbles aren't an issue here... QC Passed! What do you think?


PostPosted: Wed May 26, 2010 6:13 pm    Post subject: Reply with quote

As long as the lens' polished surface does not cut through a bubble, then it's fine; in fact you can use having bubbles in your lens as something to boast about! Razz


PostPosted: Wed May 26, 2010 6:28 pm    Post subject: Reply with quote

I think you should use the lens outside at F2. You'll get the swirly bokeh that many of us like and some detest. Laughing


PostPosted: Wed May 26, 2010 6:31 pm    Post subject: Reply with quote

blackrubystudio: Your results will improve.


PostPosted: Thu May 27, 2010 9:29 am    Post subject: Reply with quote

Seele wrote:
in fact you can use having bubbles in your lens as something to boast about! Razz


I will! thanks for the tip Very Happy


PostPosted: Thu May 27, 2010 10:04 am    Post subject: Reply with quote

calvin83 wrote:
Glass bubbles are common in old russian lens. Some people think this is a sign quality glass.


exaklaus wrote:
Nothing serious, pretty common in early quality glass.


What is it that would make bubbles be a sign of quality glass? Question

I would have thought the opposite....


PostPosted: Thu May 27, 2010 1:09 pm    Post subject: Reply with quote

Scheimpflug wrote:


What is it that would make bubbles be a sign of quality glass? Question

I would have thought the opposite....


Optical glass blanks need to cool at the right rates depending on the composition, some taking months to ensure the absence of internal stresses and complete eveness. This annealing process would not allow bubbles formed inside to escape.

Some decades ago the Japanese perfected the method of making blanks without bubbles, and the advent of techniques of molding lenses certainly make lens elements to be free from bubbles: better presentation indeed! But if you have bubbles, it means the optical glass was produced in the old-fashioned, all "kosher" way.


PostPosted: Thu May 27, 2010 1:31 pm    Post subject: Reply with quote

Interesting! Thanks for the detailed explanation! Cool

That brings up another question though- I'm assuming that the manufacturers noticed the bubbles... Did high-end lens manufacturers reject blanks that had bubbles? Or were they so common that this wasn't practical?


PostPosted: Thu May 27, 2010 1:48 pm    Post subject: Reply with quote

High-end manufacturers did not mind a few bubbles in a complete lens; if the quantities of bubbles would indeed have any measurable, or visible impact on the image quality, then the lens would not have been allowed to leave the front gate anyway. In fact, if the quantites of bubbles can have any impact on the image a lens produces, you would think you are looking through a glass of Perrier when looking through the lens!

At the optical glass factory, the molten glass is poured into a huge tray, and then it is put into an oven, where its temperature is lowered at an appropriate rate. When it has been cooled, it is taken out, and the quality inspector would look at the slab of glass, marking out the portions which are of sufficient quality to be used, while the other portions rejected. Less than a handful of lens manufacturers produce their own optical glass, but rely on specialist glass makers like Schott and Hoya, who would not dream of shipping out glass blanks which can be sub-standard in the first place.

In fact many high-end lenses I have had in my possession over the years got bubbles, and that never bothered me at all. These days, product presentation has to be perfect, and the salesmen cannot be entrusted to explain to the customers why bubbles should not matter. Along with the techniques to eliminate bubbles, the customers would not even know that they exist, so they would be surprised and alarmed to actually see them.


PostPosted: Thu May 27, 2010 2:26 pm    Post subject: Reply with quote

The Takumar glass were hoya made?


PostPosted: Thu May 27, 2010 2:37 pm    Post subject: Reply with quote

Bubbles in glass like this gives hope that to make this lens used old stock good quality glass elements. However chance is small, this Helios was made probably in 70/80. The best performance of Helios we have in aluminum lenses in M39 - in my opinion. I was always searching - older it means better. And regarding Russian optic - SN suppose to start with two zeros.


PostPosted: Sat May 29, 2010 12:55 am    Post subject: Reply with quote

I finally received the adapter!
here are three quick shots - minimal sharpening and color correction in PP.
All taken at f/2.







I think I can be quite satisfied with this lens. Very Happy
Thanks everybody for your contribution to this thread!


PostPosted: Sat May 29, 2010 6:15 pm    Post subject: Reply with quote

nice samples! No problems with bubbles in glass, dirty sensor could be worse that that.