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Using Black & White filters for digital.

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gurtch

Well-known member
I have had a set of yellow, orange, and red filters for sale very cheap on ebay forever, it seems and no interest. Does anyone know what would happen if I put one of these filters on a digital camera, then selected B&W as a film emulation, process the RAW images then converted to B&W using software such as Silver Efex Pro? If I were not so lazy (I am 86) I could try it myself, but I thought I would check to see if anyone else has tried it and prevented me from wasting my time.
Thanks in advance for those that respond.
Dave in NJ
 
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Paul Spinnler

Well-known member
B&W filters really make sense with a monochrome sensor; if you use a color sensor you can just emulate any filter with the B&W adjustment layer or in C1 or in any raw converter software there's typically a B&W conversion mode which lets you adjust the effect based on the colours. This lets you emulate any colour filter.
 
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gurtch

Well-known member
Thanks Paul. Yes, I agree one can emulate a color taking filter in Silver Efex. I was wondering if a color filter on camera would produce a different effect.
thanks for the input.
Dave
 
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gurtch

Well-known member
Thanks guys. Yesterday we had a thick rolling in fog close to dusk. We live on the sea coast. I remembered I had 52mm Nikon #1 and #2 Soft Filters. My lenses for my gfx100s take big filters ,so I grabbed my Sony A7Riv and Zeiss Sony 35mm f2.8 lens and headed to the beach. The view of the shrouded beach and fogged in ocean through the soft filter was amazing. I have simulated soft effects/blur with software, but the filter on camera looked really special through the finder. The auto focus and IBIS saved the day. I have not processed the raw images yet.

Dave
 
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Pieter 12

Well-known member
It will produce an effect, but probably not the one you expect, as the image will be captured in color first and any b&w or film emulations are done afterwards. I have no idea how a monochrome sensor would be affected by filters intended for b&w film.
 
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MartinN

Well-known member
Black and White film will be the last film to go away, if ever, so film photographers need filters very much, especially yellow, orange and red.
 
mristuccia

mristuccia

Well-known member
Maybe I'm wrong in what I'm about to say, but it seems to me that if one uses a real filter in front of the lens, the exposure compensation for it is accounted in the shot.

If one uses a digital filter, there is the risk of having more noise because the exposure compensation is done by increasing the level of some of the color channels in post.

At least theoretically. Never tested my hypothesis however. Just reflecting on this topic...
 
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MartinN

Well-known member
mristuccia said:
Maybe I'm wrong in what I'm about to say, but it seems to me that if one uses a real filter in front of the lens, the exposure compensation for it is accounted in the shot.

If one uses a digital filter, there is the risk of having more noise because the exposure compensation is done by increasing the level of some of the color channels in post.

At least theoretically. Never tested my hypothesis however. Just reflecting on this topic...
Click to expand...
Using a filter will overload a certain color of RGB pixels, and underuse other pixels. That is
proposed to be the worst effect of color filters.
 
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daz7

Member
The only colour filter I ever used was a red enhancer specialist filter to remove orange light pollution from evening or night sky.
Apart of that, colour compensation works much better in Photoshop.
Obviously with ND, IR/UV filters and polarizers that's a differnt story but colour filters in digital photography are not useful, really.
 
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ThdeDude

Active member
Possibility of strange and hard to predict interactions of the different transmissions of the individual color elements of color filter array and transmission of the color filter.
Once placed a red filter in front of my iPhone and recall not getting a good B&W image.
But perhaps using a pale yellow filter (#8 Wratten) could result in a superior B&W image since (theoretically) the image file is closer to the end product without drastically affecting image capture.

P.S. Based on the wording in first post "digital camera, then selected B&W " I assumed the question in this thread was asked in regard to a color camera.
 
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tcdeveau

Well-known member
For a color sensor I'd personally skip the filters on the lens and keep it simple. The advantage, to me, of silver efex and the like with color images is being able to select a filter in post after the fact...and it saves fiddling with them in the field.

Monochrom sensors are a different beast though and I find yellow/orange/red/IR filters necessary in the field for my intents and purposes. As Lou noted, red (or IR) when I want drama, orange or yellow when I want less of an effect but still want to increase contrast in the sky (for example, between the blue sky and clouds). Never really played with green or blue filters, but I find yellow/orange/red/ir/and various flavors of ND to be all I care to carry in the field.
 
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itsdoable

Member
B&W contrast filters cause more problems on cameras with Bayer CFAs as the demosaicing algorithm assumes a white balance. For instance, a deep red filter (ie: R2) causes the Green channel to extinguish. Since it is an important channel for interpolating pixel colors, this causes the algorithm to generate mosaic artifacts at the pixel level. It's better to color filter in post, and convert to B&W.

Achromat sensors need these filters for contrast control.

Foveon sensor work fine with these filters, but they don't add that much as you can filter in post.

These filters are still useful in B&W film, whcih seems to be getting more popular, But just about everyone that shot legacy B&W has a set of these filters, so there are probably a lot on the market.
 
Shashin

Shashin

Well-known member
A red filter is basically the same as the red bayer filter on the sensor, so using that would probably result in some noisy exposures.

Yellow and orange would give exposure across the red and green channels.

Personally, I think a channel mixer would be a more flexible tool. And you can just copy the image from the red channel if you wanted a deep red filter look.

The only filters I use now are for near infrared, which you cannot achieve using the camera color channels.
 
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Pieter 12

Well-known member
I believe there are several places that will convert a conventional color sensor to infrared, maybe monochrome infrared too. A one-way street, no going back, the camera would be an infrared-only camera.
 
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