most useful filters for digital SLR

I use the Cokin P-series system of filters. They're not screw-on filters, however.

Most of my lenses DO have a screw-on UV filter, mostly for protection. The cokin filter holder then screws into that filter.

I frequently use a couple of graduated neutral-density filters. These are handy to slightly darken an overly bright sky, for example. With the cokin system, these square filters can be positioned within the holder to darken only as much of the frame as needed. Multiple filters can easily be stacked, as well. I suppose that this effect could be done in post-processing, but, like you, I prefer to work in the camera, not on the computer. Besides, my p-p skills are not that good.

Paul Noble

The only two filters I use for filtering light are an ND and a Polarizer. I don't ordinarily use a filter for protection unless circumstances warrant it and ultimate image quality is of secondary importance.

Godfrey

The use of Photoshop (or alternative) is a basic skill required for digital photography. If you have no interest or time to learn these skills, you will never see the real potential of the medium.

Filters are used mainly for color correction or, in black and white photography, contrast control. Color correction is much easier to attain and more precise in Photoshop than with filters. B&W filters are best emulated in Channel Mixer when converting from color. The only filter not possible in software is a polarizer, and to a lesser extent, an ND-grad filter. The latter emulation is easy enough by masking and possibly combination of two or more exposures. Multi-coating helps prevent flare and ghosting. Some coatings are so soft they quickly scratch due to cleaning.

B+W and Heliopan polarizers have very neutral color characteristics, and use the highest quality glass and brass mechanical parts. The B+W offers MRC coating, which is very durable and repels water. Hoya filters have excellent glass but use aluminum for the rings, which is weaker and tends to jam more than brass. Tiffen has a few good filters, but most are uncoated and have marginal mechanical quality - bargain-counter quality.

I use soft GND by Lee and Singh-Ray and a Variable ND, also CPL from B + W, get it right in camera, use CS3 to fine tune.

If you don't want to use Photoshop, which I certainly can understand, you should learn to use your camera's white-balance settings. This obviates the need for color-altering filters. Otherwise I agree with Godfrey, assuming he means ND-grad. The trouble with ND-grad is that often highlights are V-shaped etc. and do not fit the ND border. The UV filter is fairly useless unless you have a really cheap lens.

When I say "ND filters", I mean all types of ND filters. I tend to use grads less than others, but then I only do so much traditional landscape photography. I usually use 8x and greater ND filters so I can open the lens up a lot and still run relatively long exposure times.

If you're capturing in RAW format, white balance settings are of no interest, neither are any of the other image processing settings. Those are for JPEG (or TIFF) capture modes. For RAW capture, the only settings that explicitly change the image data are focus, exposure time, lens opening and whether noise reduction is enabled or disabled.

In the camera, at the time you take a picture, concentrate on proper focus, correct exposure and good framing. White balance, color correction, sharpening and contrast, saturation, etc etc are all best done in image processing post capture. Spectral adjustment (often mistaken for contrast...) and tonal control for B&W as well.

There are other filters that cannot be simulated in image processing:

- IR-pass :: filters to block visible light so you can record infrared light
- close-up lenses :: filters to allow closer focusing than the lens mount provides
- prismatic filters for special effects

I don't use these terribly often at all, personally.

Godfrey

"There are other filters that cannot be simulated in image processing:"

Also add to the list filters such as Singh-Ray's Vari ND and Mor-Slo - they allow much longer exposures in brighter conditions, for selected effects.

Cheers,

Colin

if you do indoor stuff, an 80A will help your sensor give the best ... shooting RAW or JPEG it won't matter