[Spodeworld]

Does anyone know if using a multi-coated filter reduces reflections on a lens that is non-multi coated?

[ripit]

I have been wondering the same thing. My understanding is that multi coating has more to do with accurate light transmission. It reduces separation of the different colors of light. With that said, if the filter has much better anti reflective properties I would think it might reduce strong glare and let more light enter the lens. The problem is, light coming in at an angle might just go through the filter, hit the front element at an angle and reflect causing the same problem. If you are shooting in bright enough light, I would think a polarizer would work much better. In theory, it eliminates light coming in at an angle which is more likely to reflect. Maybe someone with real world experience could offer an opinion. Personally I'm just going to try it next chance I get (bad weather and I'< looking for a bright sunny day that I have free to go shoot). I hope my filters are good enough to let me find out.

[JinDesu]

I would doubt it'd reduce reflections inside a non-coated lens. Multicoating effective reduces the refraction differences between the glass and everything else (air). With just air and glass, the refractive index difference makes it so reflections occur more easily. Multicoating (or at least Pentax SMC) reduce the difference in refractive index from the glass to the air with the coatings. So having a SMC filter means you wont' have reflections off the SMC filter, but it would not change how the light interacts with the remaining glass elements inside the lens.

[dms]

(To add some info--but not based on firsthand experience) multi-coating reduces the amount of reflected light--so if light is reflected by the camera/shutter/ lens components and is leaving the lens back out the front--any additional glass surface will cause some to be reflected back in. This is the reason why it is not a good idea to add a filter when not needed--multi coating is much better--but it still is a detriment.

If there is a potential benefit it has to do with incoming stray light at a wide angle--I don't know if the additional multi-coated fillter has any beneficial effects--either due to the coating, blackened edges, etc. My sense/gut feeling s not. (ANYONE HAVE THIS INFO?).

What I would do is to use a good/efficient lens hood (rectangular/tulip, etc.) and not use a filter.

BTW super takumar lenses are double coated--truly uncoated quality lenses (from any vendor) are likely 60+ years old. And for non-zoom lenses with only a few lens elements multi-coating is not a major improvement. Many of my lenses are pre-multi-coating and they do just fine.

[JinDesu]

Well as you said, hood would block stray light. A SMC filter would allow more light from odd angles through than a non SMC filter (which would let it in, and reflect internally), and that light would then (hopefully) be absorbed by the internal baffles of the lens. But that doesn't change the fact that any light that could normally reach the front element with the hood on would still reach the front element.

[ripit]

I would think a polarizer would be the best thing to try. It is not going to stop light from reflecting but it will cut out a lot of the light coming in at an angle which is what I would think would cause the most problems.

[mysticcowboy]

Even with a non-multicoated lens, if you use a filter, it should be multi-coated. You don't want to introduce any extra reflections into your photos.

[Wheatfield]

Even with a non-multicoated lens, if you use a filter, it should be multi-coated. You don't want to introduce any extra reflections into your photos.

^^This^^ plus a million^^
Coatings are designed to reduce reflections.
Putting a better filter on a poor lens doesn't improve the poor lens, but it doesn't make it especially worse, either.

[RioRico]

No matter whether the lens is coated
AND
No matter whether the filter is coated
ALWAYS
Use a lens hood
OR
Do a lot of PP to fix the results.

[D1N0]

When I put my multicoated 1:1 diopter from my cosina 100mm F3.5 Macro, on my 1976 Jupiter 9 (not coated) which has a terrible soft haze wide open, it makes the haze completely disappear. This ofcourse is a lens, and not a filter, but maybe that would work the same way (since both are a piece of glass).

[newarts]

When I put my multicoated 1:1 diopter from my cosina 100mm F3.5 Macro, on my 1976 Jupiter 9 (not coated) which has a terrible soft haze wide open, it makes the haze completely disappear. This ofcourse is a lens, and not a filter, but maybe that would work the same way (since both are a piece of glass).

I'll bet the diopter is acting as a hood & shielding the lens from side-light. If so, a few extension rings or short tube might do wonders for your Jupiter 9's contrast in general.

[D1N0]

Nope, stopping down is the only other thing that helps. The diopter would actually have to act as an aperture, or the coating helps. (Hard toch check, since it can only focus very close.)

[dadipentak]

No matter whether the lens is coated
AND
No matter whether the filter is coated
ALWAYS
Use a lens hood
OR
Do a lot of PP to fix the results.

Amen!

[newarts]

Nope, stopping down is the only other thing that helps. The diopter would actually have to act as an aperture, or the coating helps. (Hard toch check, since it can only focus very close.)

I thought you said that putting on the diopter helped the contrast. - if so, as you say, the diopter may act as an aperture, its ring defining the aperture - if so, what role does the diopter lens itself play?

[D1N0]

Great, a bunch of seventh day hood evangelists. Well sometimes a hood does'nt cure lens softness. Later Jupiter Nines with multi coating usually are sharp wide open. Do all lenses need to be coated or, just the front and back one?