Does anybody here still use B&W lens filters, such as these
http://www.bhphotovideo.com/c/product/811187-REG/Hitech_HT100BWKIT_100_x_100mm_Black.html
And no, not because you are nostalgic for the film days, but because you honestly get better results using filters in combination with Photoshop B&W conversion techniques? Everyone I talk to says B&W contrast filters are useless with DSLRs, but I'm still not convinced they have no benefit when it comes to color channel noise reduction and highlight clipping control. I'm tempted to buy a set for what the hell, but thought I'd ask first.
Hi,
Depending on the Bayer CFAs on your camera, there may be a slight noise benefit because you can expose Red or Blue Channels a bit longer. That works if you strictly adhere to the Expose to the Right (ETTR) doctrine.
Whether that applies to your camera is easy to determine by shooting a spectrally neutral grey or white surface without filter under the type of lighting you intend to use for the actual exposure. You then need to use a utility that allows to view the Raw data histogram, e.g. RawDigger, that shows the relative exposure level of the R/G/B channels. In many cameras that will reveal that the Red and Blue channels are relatively somewhat less exposed. In that case, using i.e. Orange or Red filter will reduce Green and Blue exposure relative to Red, and the underexposed Red channel can be boosted more without risk of clipping the other channels.
This of course does assume you have already determined that the specific filter is optimal for the scene. It often is not! You get much more flexibility in optimizing tones in a Black and White conversion when all channels are available and equally well exposed (which might call for a Magenta filter). Also do not forget that the three noise patterns of the R/G/B channels will be combined in a weighted average, and when combining 3 independent noise patterns, total noise is reduced due to the weighted averaging.
So total noise may only be improved marginally by using a filter, but flexibility will suffer. If I were you, I'd not use more than say a deep Yellow or Orange filter to reduce sky blue, or freckles on a face, but you may need to take a close look at the noise contribution of the other even more underexposed channel(s).
Cheers,
Bart