What about dust in a schneider lens

[glrerun]

I have been looking at a lot of large format lenses on Ebay. I have noticed that a lot of Schneider lenses have dust noted by the seller. Many of the sellers make the statement that there is no effects to image quality, but the question is why are there so much more dust in Schneider lenses than other lenses. Also, where does this dust come from and what can be done about it?

[Dan Fromm]

Its time for a cold shower.

As far as I know all lenses are equally attractive to dust.

The environment is dusty. Dust settles on lenses' outer surfaces. In infiltrates through the shutter. LF lenses' cells are usually well sealed, so dust that infiltrates through the shutter can settle on the glass surfaces that face the shutter but doesn't often get inside the cells. Live with it or unscrew the cells from their shutter and carefully brush it off.

Some photographers think they're birds and take dust baths with their gear. Don't take dust baths with your gear even if you' are a bird.

You can't be too careful. Don't buy any photographic equipment. If you want to capture images, learn to paint. Painting is more contemplative and slower than photography, a soul-less mechanical process.

[glrerun]

I hope that you are correct, but my understanding was that the dust was in-between the glass elements, not reachable by the user. Otherwise why not just clean the lens. I also rarely see the dust notation on lenses other than the Schneiders's and a few Goerz. even on older or more complex lenses by other manufacturers.

[BrianShaw]

It seems to take a whole lot of dust before it really matters.

Dust notation, as you call it, is probably more a function of the seller than the make if the lens. Some sellers describe and justify every possible isue, real or imagined, that a buyer might later criticize. Some buyers seem to think all old stuff should be as good or better than when new so u can't blame the seller who errs on the side of too much information, whether pictures or description.

[ic-racer]

For dust not on the outer surfaces of the front and rear cells, I'd worry about lenses that have been tampered or perhaps put together wrong. Otherwise, as Dan pointed out already, dust usually done not settle on those surfaces. Also, "fungus" can become "dust" in some sellers descriptions.

[Jim Galli]

Schneider also used suspect black paint on the inner surfaces. The infamous Schneider-itis comes from the crappy paint. Sometimes so called dust between the elements is paint letting go. But trust me, it doesn't show up in the pictures. It has no optical effect and whatever percentage of light it might by blocking is infinitesimal. So find the one with the most mention and price detraction because of the "dust" and buy it and go make pictures. I bought a gorgeous f5.6 Symmar S recently for $72. Heck, I could beat the glass out of it with a hammer and make a profit on the Copal 1, but it's a magnificent lens.

[Kevin Crisp]

Some people mention dust to be thorough, and some people can't (or won't) distinguish between dust and fungus. Typically dust is on the outside of the front element, or on the back of the back element. If "interior," then on the back surface (inside) of each lens group. How does it get there? Maybe when mounting the lens on the board, if the rear element has to come off to get the retaining ring off. It takes a ton of dust to make any difference. The dust rarely accumulates within the front or back group in the air space (unreachable without disassembly) and certainly not in volumes that make a difference. Dust WITHIN a cemented lens group can't happen if the cement is intact. If it isn't, you've got bigger problems.

[Bob Salomon]

Some people mention dust to be thorough, and some people can't (or won't) distinguish between dust and fungus. Typically dust is on the outside of the front element, or on the back of the back element. If "interior," then on the back surface (inside) of each lens group. How does it get there? Maybe when mounting the lens on the board, if the rear element has to come off to get the retaining ring off. It takes a ton of dust to make any difference. The dust rarely accumulates within the front or back group in the air space (unreachable without disassembly) and certainly not in volumes that make a difference. Dust WITHIN a cemented lens group can't happen if the cement is intact. If it isn't, you've got bigger problems.

It probably got there during assembly at the factory. When I watched the Linhof test procedure at the factory this was one of the main reason that more Schneider lenses failed the test then other lenses. If the dust was inside the lens group it went back to the Schneider factory as a Linhof reject.

[Pfsor]

If "interior," then on the back surface (inside) of each lens group. How does it get there? Maybe when mounting the lens on the board, if the rear element has to come off to get the retaining ring off.

How does the dust get there? Probably in the same way as fungus spores - a minimal crack in sealing can act as an entry port. It's the similar process as with sealed windows - you buy them nice and clean. After some year you wonder how dust could come inside, where you cannot clean it. The constant atmospheric pressure differences make small cracks in sealing act as a miniature hoover sucking up air and dust pollutants present in its vicinity. Fungus spores get there and their nutritive dust too.

[Lee Hamiel]

I like this thread ...

I've been away for a few years and seeing all of the respondent's names thus far it's like the all-star team of different voices with a certain patience and continuity combined with good information for the OP

There is a lot at play here - I totally agree that it takes a lot of dust to impact an image - conversely it (at the right ratio) may be the analog version of un-sharpening - your choice - Brian's response is a good one

The OP may be like me when years ago I labored in order to have immaculate lens surfaces early on to the point that I could have used a clean room to be satisfied - I was cleaning lens caps afterwards better than most people clean actual lens surfaces

Jump ahead 40 years - I don't care the same way I used to

Dan nailed it - As an illustrator I'm too shaky to do it anymore though ...

I owned two Schneider lenses like Jim referenced and they had no impact on image quality & no complaints by the buyers

Regarding Bob's comments I will say that I understand the Linhof Select Lenses are/were culled from the Schneider assembly line for inspection and are adjudged as being the best off the line

As a seller I have always included the "may be slight dust" comment as it only takes light intensity to show something eventually at a given angle - best to describe as virtually no dust or slight dust or whatever it looks like honestly - A lot of buyers expect in as new condition & expect totally dust free elements which is near impossible

LF lenses are so much easier to get clean as opposed to MF & 35mm - I had to return 3 new Nikkor 105 f/2 DC lenses to B&H due to not only dust but literally small clumps of dust in the lens assembly - they were great & took care of it - only took a month or so ...

Back to the OP - Buy the lens you want & allow for a CLA to put it in shape for use if unhappy with the bargain

Regards

[Bob Salomon]

How does the dust get there? Probably in the same way as fungus spores - a minimal crack in sealing can act as an entry port. It's the similar process as with sealed windows - you buy them nice and clean. After some year you wonder how dust could come inside, where you cannot clean it. The constant atmospheric pressure differences make small cracks in sealing act as a miniature hoover sucking up air and dust pollutants present in its vicinity. Fungus spores get there and their nutritive dust too.

One major way is when the clean rooms aren't as "clean" as they should be at the factory.