Exposure compensation

LivingLarge

OK...quick search gave no results. I have been learning (experimenting):wink with full manual on the mode dial (50D) and with all the winter snow I want to add exposure compensation to get "white" snow. In other modes I can dial in over\under exposure. Do I just set the exposure using the small meter at the bottom of my viewfinder and when it reads 1-1.5 EV "over" am I good to go?

Richard

LivingLarge wrote:

OK...quick search gave no results. I have been learning (experimenting) with full manual on the mode dial (50D) and with all the winter snow I want to add exposure compensation to get "white" snow. In other modes I can dial in over\under exposure. Do I just set the exposure using the small meter at the bottom of my viewfinder and when it reads 1-1.5 EV "over" am I good to go?

More or less. Chimp a few shots to see whether you are compensating enough.

Scott_Quier

When shooting full manual mode, there is no such thing as exposure compensation (EC). EC is you over-riding the exposure calculated by the dumputer in the camera when you shoot in Av or Tv.

Your technique is good for the situation you are describing when you are shooting in manual mode. You simply adjust the ISO, shutter speed, or aperture (or some combination of them) to get the exposure you want. Take a shot, look at the histogram and compare that to the image in the LCD. If there is snow in the image, then you should have a spike very close to the right edge of the histogram. If it's not there, add more exposure. If you have blinkies, back down the exposure.

LivingLarge

Scott_Quier wrote:

When shooting full manual mode, there is no such thing as exposure compensation (EC). EC is you over-riding the exposure calculated by the dumputer in the camera when you shoot in Av or Tv.

Your technique is good for the situation you are describing when you are shooting in manual mode. You simply adjust the ISO, shutter speed, or aperture (or some combination of them) to get the exposure you want. Take a shot, look at the histogram and compare that to the image in the LCD. If there is snow in the image, then you should have a spike very close to the right edge of the histogram. If it's not there, add more exposure. If you have blinkies, back down the exposure.

Thank you Scott, that is what I was thinking and just needed confirmation.

jfriend

Scott_Quier wrote:

When shooting full manual mode, there is no such thing as exposure compensation (EC). EC is you over-riding the exposure calculated by the dumputer in the camera when you shoot in Av or Tv.

Your technique is good for the situation you are describing when you are shooting in manual mode. You simply adjust the ISO, shutter speed, or aperture (or some combination of them) to get the exposure you want. Take a shot, look at the histogram and compare that to the image in the LCD. If there is snow in the image, then you should have a spike very close to the right edge of the histogram. If it's not there, add more exposure. If you have blinkies, back down the exposure.

I agree with what you have said, but thought I'd add a few places where EC might still creep into the equation, even when the camera is set to manual exposure.

On my Nikon D300, if you look at the light meter reading in the viewfinder to see what it thinks, that value is affected by the EC reading, even when the exposure mode is set to manual. It's not affecting what shutter speed or aperture is being used because you still pick that with your manual settings, but if you are using the meter as a guide in anyway, that info is affected by the EC setting.

And, if you have auto ISO on (which isn't really full manual mode), even though you are in complete control of aperture and shutter speed, the camera will still adjust ISO to try to get a "proper" exposure and that exposure will be influenced by the EC setting.

Richard

jfriend wrote:

On my Nikon D300, if you look at the light meter reading in the viewfinder to see what it thinks, that value is affected by the EC reading, even when the exposure mode is set to manual. It's not affecting what shutter speed or aperture is being used because you still pick that with your manual settings, but if you are using the meter as a guide in anyway, that info is affected by the EC setting.

Interesting...does anyone know whether Canon cameras work the same way? I always assumed that in manual the viewfinder display on my 20D was not biased by any previous EC setting. There doesn't seem to be a way to set EC in manual and AFAIK, exposure settings do not carry over when you switch from one mode to another.

Scott_Quier

Richard wrote:

Interesting...does anyone know whether Canon cameras work the same way? I always assumed that in manual the viewfinder display on my 20D was not biased by any previous EC setting. There doesn't seem to be a way to set EC in manual and AFAIK, exposure settings do not carry over when you switch from one mode to another.

You are correct in your assumption. There is no EC when shooting in manual mode on a Canon xxD camera. In manual mode, the light meter reads true .... or at least as true as these things can get.

Richard

Scott_Quier wrote:

You are correct in your assumption. There is no EC when shooting in manual mode on a Canon xxD camera. In manual mode, the light meter reads true .... or at least as true as these things can get.

Thanks, Scott. I was getting nervous there for a moment. :whew

pathfinder

Scott, It would matter whether you are using the spot meter versus the evaluative meter wouldn't it? How the meter reads, is what I am referring to. No different than other shooting modalities, just the way the meter readings are obtained. Even though the aperture and shutter speed are fixed in manual mode?

In the end it comes down to the 3 channel histogram for a final evaluation of exposure.

But you probably do not want to use spot metering unless you have an thorough understanding of the zone system or a similar exposure plan.

Interesting, I hadn't really thought what Auto ISO might do when shooting in Manual Mode either - the AUTO ISO decision does depend on the light metering decisions made by the camera.

Scott_Quier

pathfinder wrote:

Scott, It would matter whether you are using the spot meter versus the evaluative meter wouldn't it? How the meter reads, is what I am referring to. No different than other shooting modalities, just the way the meter readings are obtained. Even though the aperture and shutter speed are fixed in manual mode?

Here's what I think is happening (so I could be wrong)...

The amount of over/under exposure indicated by VF lightmeter is the result of a computation involving

• How much light is received in the "sensitive area" of the frame (spot, evaluative, etc)
• User selected ISO
• User selected aperture
• User selected shutter speed

The dumputer in the camera takes these values

• works black magic to come up with a value,
• compares this value against a value for it's idea of a 18% scene,
• and then moves the light meter indicator off zero by a displacement, in some way, related to the difference between these two values.

Anyway, that's what I think might be going on. But, for all I know, the dumputer in the camera is generating a random number, squaring it, using that as a lookup into the Farmer's Almanac, extracts a temperature, divides that value into Avogadro's number, taking the remainder as an EV value and adding/subtracting a fudge factor. :lol4

As for Auto ISO - I have no clue as I have never even read about it in the manual. I like control.

pathfinder

Scott_Quier wrote:

. But, for all I know, the dumputer in the camera is generating a random number, squaring it, using that as a lookup into the Farmer's Almanac, extracts a temperature, divides that value into Avogadro's number, taking the remainder as an EV value and adding/subtracting a fudge factor. :lol4

That's been my suspicion for some time

Richard

Scott_Quier wrote:

But, for all I know, the dumputer in the camera is generating a random number, squaring it, using that as a lookup into the Farmer's Almanac, extracts a temperature, divides that value into Avogadro's number, taking the remainder as an EV value and adding/subtracting a fudge factor.

If Microsoft ever builds a camera, that's the way it will work.