The Filters We Need With Digital...

Started Oct 5, 2008 | Discussions thread
OP Joseph S Wisniewski Forum Pro • Posts: 34,130
The “Non-Filter” You Need, and the Filter You Don’t

The Lens Hood

While technically not a "filter", the lens hood improves your fall color shots dramatically. Even when you think you've got no light directly hitting the lens, there's always "stray light" that scatters inside the lens and produces "veiling flare" ("all over the image" flare, instead of streaks and spots of flare). If the stray light is clean and bright, the veiling flare simply erodes your contrast. If the stray light bounces off grass or leaves or has a lot of blue "sky light" in it, it tints your image most annoyingly. And since that tint is strongest in the shadows, it can be very hard to fix in post processing.

The Protection Racket

Well, what about the “protection” filter: be it the traditional “UV” or “haze” filter, or a so-called “digital” filter? The camera store salesman told you that you need one. He may even have said you won’t get a warranty if you don’t have one (a lie the smarmiest sales people have been using for decades).

I don't use common "protective" filters in the studio unless we're doing explosions or liquid splashes. (I lead an interesting life). I don't use them outdoors unless we're in a blowing sand or water spray environment, and sometimes, I don’t even use them in the nasty environments. My lenses are more exotic and expensive than those of the average photographer. I don’t “baby” the gear. I take good care of it, but it goes all over the place: into industrial, urban, and wild places.

At some point in time, you have to sit back and say “how serious am I about photography. Am I out to spend years at this and come back with the best lenses, cleaner and less scratched than anyone else’s, or am I out to come back with the best pictures, sharper, with less flare and more contrast, and more sellable than anyone else’s?”

Even the best and most expensive filters have parallel planes; light bounces back and forth multiple times between those planes and cause more internal reflections than the curved surfaces of the glass lenses. Some of this leads to “scattering” of light, reducing contrast. Some of the bouncing causes ghosts and lens flares. Even the best filters degrade the image. That's one reason why camera manufacturers now use permanently mounted “meniscus” (curved) protectors on their expensive long telephotos. These curved protectors don’t cause as many problems as a flat filter.

So, if you're competent at cleaning lenses, you're likely to get better pictures without filters, even in the most hostile conditions.

Safe In The Hood

So, how do you “protect” a lens? The best way is with a decent lens hood. The hood that’s made by the lens manufacturer to match a particular lens is typically very rugged, and it matches the focal length of the lens so that you get the maximum amount of flare protection without vignetting (dark corners in the image). Those filters securely “lock” to bayonets on the lens front, and you don’t need to unscrew the hood, screw on a filter, and screw the hood into the filter. The hood acts like a great big “bumper”, protecting the lens from fingers (or larger body parts), branches, or anything that might bump into the lens, or that you might bump into.

An aftermarket screw in metal hood or “snap in” metal or hard plastic hood is also excellent protection.

Given a choice between two different protection systems, I’ll pick the hood, which always improves the image, over the filter, which always degrades the image, every time.

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Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

 Joseph S Wisniewski's gear list:Joseph S Wisniewski's gear list
Canon EOS 5D Mark II Nikon D90 Nikon D2X Nikon D3 Nikon D100 +43 more
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