Guidance needed on use of color filters.

[Bill wrs1145]

I need guidance on the following:

1 stop for yellow reduction
2 stops for orange "
3 stops for red "

My question is from what? To what? How many feet per second?

Also, some state that reducing shutter speed is an alternative, but again how much?

I would appreciate your guidance.

Thanks,
Bill

 

[lynnb]

I need guidance on the following:

1 stop for yellow reduction
2 stops for orange "
3 stops for red "

My question is from what? To what? How many feet per second?

Also, some state that reducing shutter speed is an alternative, but again how much?

I would appreciate your guidance.

Thanks,
Bill

From what? From the recommended exposure reading (which is the exposure needed to correctly expose the subject, as measured by an exposure meter, or from your experience estimating exposure eg. by using the Sunny 16 rule).

For any given ISO, exposure is set using a combination of aperture and shutter speed, each of these usually being adjusted in one “stop” increments. [a stop refers to an f-stop… each adjacent aperture f-stop lets in either half as much light, or twice as much light depending on whether you are opening the aperture up or closing it down. An aperture of f/4 lets in twice as much light as f/5.6]

Note: some exposure meters read the light through the lens (and therefore through the filter) so no exposure adjustment is needed for the filter when your camera’s exposure is measured with a through the lens (TTL) meter. Some rangefinder cameras measure light TTL, others don’t, and others don’t have an exposure meter at all (which is why people use hand held exposure meters or learn to estimate exposure in their head).

Shutter speeds also adjust the amount of light reaching the film or sensor: 1/125sec will allow twice as much light (ie. +1 stop) than 1/250sec., and conversely, 1/250sec admits half as much light (-1 stop) as 1/125.

A “stop” in general terms refers to an increment of half or double the exposure. “Plus one stop” means letting twice as much light to the film or sensor, whether by adjusting the aperture or by adjusting the shutter speed to the next incremental setting.

So for any given ISO, you can use a combination of aperture and shutter speed to arrive at or adjust the exposure. Different combinations can achieve the same exposure, which gives you a choice between depth of field (controlled by aperture, as well as by distance to subject), and motion stopping ability (controlled by shutter speed, a faster shutter speed of say 1/500 will “freeze” motion better than a slow (1/30sec or slower) shutter speed, which would allow some motion blur of many moving subjects.

Say the exposure meter (not one operating TTL) says correct exposure should be 1/500 @ f/5.6. If you mount a yellow filter (that reduces the amount of light by one stop), you can either correct for that by either opening up the aperture 1 stop to f/4, or by increasing the amount of light through the shutter by using 1/250 instead of 1/500. In the above scenario an orange filter that reduces the amount of light by 2 stops would require any of the following combinations to get the correct exposure:
1/125 @ f/5.6 (shutter speed adjusted by +2 stops)
1/250 @ f/4 (shutter speed +1 stop and aperture +1 stop)
1/500 @ f/2.8 (aperture +2 stops)

I hope this helps.

Edited several times to clarify.

 

[peterm1]

Does your camera meter through the lens? If so it will automatically give you the correct exposure when a color filter is fitted on the lens as it will meter thu the lens and the filter. You can see this in action - If you meter when the filter is off then again when it is on, you will see that there is a one stop difference when a yellow filter is fitted, two stops when an orange one is fitted etc, and no adjustment is needed as the internal camera meter automatically allows for it. But if you have a hand held meter you should take the reading and then just adjust the camera settings by opening up the aperture (or slowing the shutter speed) by one stop for yellow etc. If you are estimating the exposure based on the "sunny 16 rule" for example (on a sunny day set the aperture to f16 and the shutter speed to the reciprocal of the film sensitivity) you similarly just open the aperture by one stop and instead set the aperture to f11 when using a yellow filter.

Sunny 16 rule - Wikipedia

en.wikipedia.org

 

[Retro-Grouch]

From what? From the recommended exposure reading (which is the exposure needed to correctly expose the subject, as measured by an exposure meter, or from your experience estimating exposure eg. by using the Sunny 16 rule).

For any given ISO, exposure is set using a combination of aperture and shutter speed, each of these usually being adjusted in one “stop” increments. [a stop refers to an f-stop… each adjacent aperture f-stop lets in either half as much light, or twice as much light depending on whether you are opening the aperture up or closing it down. An aperture of f/4 lets in twice as much light as f/5.6]

Note: some exposure meters read the light through the lens (and therefore through the filter) so no exposure adjustment is needed for the filter when your camera’s exposure is measured with a through the lens (TTL) meter. Some rangefinder cameras measure light TTL, others don’t, and others don’t have an exposure meter at all (which is why people use hand held exposure meters or learn to estimate exposure in their head).

Shutter speeds also adjust the amount of light reaching the film or sensor: 1/125sec will allow twice as much light (ie. +1 stop) than 1/250sec., and conversely, 1/250sec admits half as much light (-1 stop) as 1/125.

A “stop” in general terms refers to an increment of half or double the exposure. “Plus one stop” means letting twice as much light to the film or sensor, whether by adjusting the aperture or by adjusting the shutter speed to the next incremental setting.

So for any given ISO, you can use a combination of aperture and shutter speed to arrive at or adjust the exposure. Different combinations can achieve the same exposure, which gives you a choice between depth of field (controlled by aperture, as well as by distance to subject), and motion stopping ability (controlled by shutter speed, a faster shutter speed of say 1/500 will “freeze” motion better than a slow (1/30sec or slower) shutter speed, which would allow some motion blur of many moving subjects.

Say the exposure meter (not one operating TTL) says correct exposure should be 1/500 @ f/5.6. If you mount a yellow filter (that reduces the amount of light by one stop), you can either correct for that by either opening up the aperture 1 stop to f/4, or by increasing the amount of light through the shutter by using 1/250 instead of 1/500. In the above scenario an orange filter that reduces the amount of light by 2 stops would require any of the following combinations to get the correct exposure:
1/125 @ f/5.6 (shutter speed adjusted by +2 stops)
1/250 @ f/4 (shutter speed +1 stop and aperture +1 stop)
1/500 @ f/2.8 (aperture +2 stops)

I hope this helps.

Edited several times to clarify.

About as clearly stated and concise an explanation as anyone could hope for. My hat is off to you! And where were you 60 years ago when I needed this?