[Beginners]Colored Filters

[lostinasia]

Hello all,

I have been given a yellow color filter for my DSLR's lens, but I am not exactly sure under which circumstances I should use it.

Is it good for portraits?

If I use it for B&W photography, since I shoot in RAW format, how should I proceed for the black and white conversion in order to retain the yellow filter "influence" on my images?

Thank you in advance for your help ;-)

[ravncat]

There is very little reason to use color filters with DSLR`s (note that I do not say none) The effects of just about any color filter can be done in post production - through hue adjustments - colorization adjustments, filter adjustments and white balance adjustments.

It can be used to warm a scene - White balance should be set before using the filter - otherwise, automatic white balance can "undo" the visual effects of the filtration.

Traditionally, such a filter would be used to warm scenes - or affect the lightness of tones in a black and white image. Warming can be useful for portraits. I wouldn`t let the digital-ness of your camera preclude you from using the filter for creative effects - unless you are worried about ultimate image quality.

Digital sensors function on R G and B - and a color filter will adjust how much exposure each channel receives. The use of a minus green (magenta) filter in combination with uniwhitebalance can be used to equalize exposure between channels to reduce noise.

As for using the filter with RAW in black and white image conversion - I suspect you`ll not need to do anything else to "keep it`s effect" so long as you make sure to set white balance before shooting the image - and do not select auto white balance after the fact - you`ll want to use a preset - or as shot.

[lostinasia]

Thank you for the reply.

When you talk about setting the white balance, do you mean it should be manually set?

[dcclark]

White balance should be set by whatever means you can, before using filters. If it's on "auto", then your auto white balance will try REALLY hard to correct for the yellow cast -- resulting in something less yellowish than you probably intended.

So, for what reason do you want to use colored photos? If you want to change the warmth or tone of the image, then this really isn't the right way to do it. Get the white balance right in camera, or edit it later if you shoot in RAW -- or just find a time and place with better lighting. That's part of the art of photography.

[ravncat]

It should be set with a preset - or a custom white balance (manually set) - not Auto. course - if you play with it, you`ll see what happens really quickly - I fully recommend experimenting - memory is cheap

[lostinasia]

Thank you for your reply, dcclark.

Originally Posted by dcclark

So, for what reason do you want to use colored photos? If you want to change the warmth or tone of the image, then this really isn't the right way to do it. Get the white balance right in camera, or edit it later if you shoot in RAW -- or just find a time and place with better lighting. That's part of the art of photography.

I apologize for my ignorance, but I am not sure of what you mean here. I would like to use the yellow filter to affect my black and white photos. I read this can be done in post-processing, of course, but how can I do it with a "true" filter? Does it make any sense, anyway?

Thank you again.

[lostinasia]

Originally Posted by ravncat

It should be set with a preset - or a custom white balance (manually set) - not Auto. course - if you play with it, you`ll see what happens really quickly - I fully recommend experimenting - memory is cheap

I definitely will, thanks a lot

[dcclark]

Originally Posted by lostinasia

I apologize for my ignorance, but I am not sure of what you mean here. I would like to use the yellow filter to affect my black and white photos. I read this can be done in post-processing, of course, but how can I do it with a "true" filter? Does it make any sense, anyway?

Thank you again.

First, I made a mistake by typing "colored photos", not "colored filters". Oops!

Yes, colored filters can help on black and white photos. However, with digital cameras, there are much better ways to do it.

Your camera will always capture color data. If you use the camera's built-in functions to convert the image to black and white, you'll get some sort of average, uninteresting, automated black and white conversion.

However, try taking a color photo and bringing it in to Photoshop or Gimp. Use the Channel Mixer (available in both of them) to "mix" the red, green, and blue channels together in different amounts, forming a black and white image. The result can be quite stunning. For example, if you have a very blue sky, but use none of the blue channel in your conversion, you'll get a deep black sky.

You can do similar things with colored filters, but it will be much harder, and you'll have much less control. I find that this post-processing method is much more effective than carting around a bagload of colored filters!