Haze inside lens

[fix_se]

I am thinking about buying a LF-lens from the beginning of the 20th century. However, the seller says that there a some haze inside the lens. Is it (always) possible to get rid of the haze by cleaning the lens elements? If not, how do haze inside a lens normally affect the photographs?

[Peter De Smidt]

No. If the haze occurs between cemented elements, you won't be able to clean it off without separating, cleaning, and re-gluing the element. Haze will predominantly lower contrast and lead to flare.

[paulbarden]

No. If the haze occurs between cemented elements, you won't be able to clean it off without separating, cleaning, and re-gluing the element. Haze will predominantly lower contrast and lead to flare.

This is true, but I have found that 90% of the time the haze is a film of volatile compounds (from the lubricants in the shutter, usually) that have been deposited on the glass surfaces. As long as you know how to disassemble the lens groups to access the surfaces, they can be cleaned and the lens restored to fully functional. Only occasionally have I encountered a lens that had a problem with seriously fogged adhesive between glued elements.
So the answer is: it depends. It depends on what the lens is, what the manufacturer's track record is for aging of their lenses, etc. So it might be useful to know what manufacturer/model of lens is that you've got your eye on, then we can advise you better.

[fix_se]

Many thanks! It is a Voigtländer Heliar, barell, from the 1940s. What do you think of Haze in that lens?

[Steven Tribe]

Barrel Heliars are quite straightforward to clean all 6 glass surfaces. Not a usual victim of balsam/glue problems.

[paulbarden]

Many thanks! It is a Voigtländer Heliar, barell, from the 1940s. What do you think of Haze in that lens?

What Steven just said. A large format Heliar in otherwise good condition (no scratches to the glass surfaces) should be easy to disassemble and clean. There are often lubricants used in lenses/shutters that volatilize over time and that gets deposited on the glass surfaces. As long as there's nothing else wrong with the lens, this film is easily removed with a gentle solvent like Napthta (lighter fluid).

[tgtaylor]

Clean 'em right: https://skyandtelescope.org/astronomy-resources/caring-for-your-optics/

Thomas

[Bob Salomon]

Clean 'em right: https://skyandtelescope.org/astronomy-resources/caring-for-your-optics/

Thomas

This article does not have the “best” advice.
Depending on the type of plastic just putting a plastic bag or shower cap on the scope might end up with out gassing deposits on the lens. Something that may not be cleanable.
A good micro fiber cleaning cloth, kept clean properly, is far less likely to scratch then an old towel, cotton, etc..
It is better to blow the dust off first with a Rocket Blaster or clean compressed oil less air then brushing it off first. And canned air can not only spit but what it spits can be well below freezing. Plus they frequently have chemicals in them to inhibit inhaling.

[fix_se]

Thanks! Do you know if it is easy to get rid of oil on aparture blades, too?