Exposure Readings

Grayman

Grayman

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Graeme
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Hello folks,

I am trying to play around with exposure modes and in reading a photography magazine it said "The camera is set to manual exposure mode and I'm getting a reading for the background of xxxsec at fxx". My question is how does a person do that? I have tried all sorts in manual mode, but I can't seem to get any readings back, apart from the ones I set them at. I understand changing shutter speed and aperture to get a correct standard exposure level, but how can I meter so that the camera gives me suggested readings? I have tried RTFM, but can't seem to find the answer.

Hope this makes sense.

Thanks,
Graeme
 
In manual mode on the 40D the camera will show how much over or under exposure is expected (assuming you have pointed it at a mid grey subject) on the exposure compensation scale at the centre bottom of the viewfinder. This will move up or down when you change the various manual settings, SS, Ap or ISO.

Do not forget this is assuming that you are pointing it at a mid grey (between 12% and 18% depending on camera model) and if you are pointing it at any other TONE you need to compensate manually to counter the under or over exposure that will result.

Spot metering mode is best for this as it allows you to be more selective in your metering area!
 
Grayman said:
Hello folks,

I am trying to play around with exposure modes and in reading a photography magazine it said "The camera is set to manual exposure mode and I'm getting a reading for the background of xxxsec at fxx". My question is how does a person do that? I have tried all sorts in manual mode, but I can't seem to get any readings back, apart from the ones I set them at. I understand changing shutter speed and aperture to get a correct standard exposure level, but how can I meter so that the camera gives me suggested readings? I have tried RTFM, but can't seem to find the answer.

Hope this makes sense.

Thanks,
Graeme
Click to expand...

Graeme

I will attempt a reply but please bear in mind that I might be wrong and if that is the case then some more experienced person here will point us both to the right direction.
But the way I do it if I want to get a reading, considering that I think there are more than one way of doing it but if you want to put the camera to "M" mode (again not sure if other models do this but the 7D I have does it), while the M mode is active and you focus on a subject you will immediately notice the exposure meter either to the right or left, sometimes even so much that it disappears with an arrow pointing where it is. Then you have the options to use both dials for the aperture and ss to play around and attempt to bring the exposure meter to get to "0". The reading you get when the dial is at "0" is what your f/stop and your ss speed at that given point for the subject (background in your case as you are attempting to expose it). Obviously if you change the iso you will immediately be able to play around again with the settings. Keep an eye on the meter and you will see it flluctuating.

By the way, this is all in the manual :)
 
If you're in manual mode (M) you are essentially providing the reading to the camera. While in program (P), aperture priority (Av), or shutter priority (Tv) the camera will provide a suggested exposure based on what you have put in.
 
Thanks all for the advice. I don't know if it is the hangover, but I think I might have been reading too much into the article. I thought perhaps if I metered on the subject then the camera would automatically give me the readings (like a lightmeter?). I have been using the exposure comp scale as suggested, I just thought there was an easy-in-one solution to provide me the settings (lazy..I know). Guess I will be expecting my camera to make me a coffee next!
 
Grayman said:
Hello folks,

I am trying to play around with exposure modes and in reading a photography magazine it said "The camera is set to manual exposure mode and I'm getting a reading for the background of xxxsec at fxx". My question is how does a person do that? I have tried all sorts in manual mode, but I can't seem to get any readings back, apart from the ones I set them at. I understand changing shutter speed and aperture to get a correct standard exposure level, but how can I meter so that the camera gives me suggested readings? I have tried RTFM, but can't seem to find the answer.

Hope this makes sense.

Thanks,
Graeme
Click to expand...

Is there any preceding or succeeding text to that in the magazine? because its quite a vague statement. A reading is a very subjective thing, one should really point out what the camera is being at pointed and where the reading has been taken from, what the EV value is, and why that reading/EV value is important to them.

What they could mean is that they are getting EV0 in manual at those settings. When in manual you dont aperture/shutter readings, you get exposure values based on the settings applied.
 
Nawty said:
There is: P mode.

If you;re only going to replicate what the camera is suggesting anyway then why bother with manual?
Click to expand...

The article I was reading was about using off-cam flash and the bloke was metering for different parts of the scene using his camera to get the correct exposure for the background and subject.

Have never use P mode..prefer to play around in manual and TV/AV.
 
This sounds like confusion over metering mode and manual exposure which are different things.

Metering mode changes what part (or all) of the scene the camera checks the brightness of. Evaluative or matrix looks at the whole scene and chooses an average. Partial or spot just looks at the bit in the middle for a light reading.

So with the camera on spot or partial you can aim at the background in your example and adjust the cameras controls for an exposure based on that... then recompose for your subject.

My camera is always set to partial so i can meter off the part of a scene i choose.
 
hsuffyan said:
Is there any preceding or succeeding text to that in the magazine? because its quite a vague statement. A reading is a very subjective thing, one should really point out what the camera is being at pointed and where the reading has been taken from, what the EV value is, and why that reading/EV value is important to them.

What they could mean is that they are getting EV0 in manual at those settings. When in manual you dont aperture/shutter readings, you get exposure values based on the settings applied.
Click to expand...

Fair point mate. The article was about 'adding drama by using flash in daylight' and the writer was taking a picture of his spaniel in the back garden. Took a reading of the spaniel and the sky. Having read the article again it seems to make more sense.
 
gnom said:
If you're in manual mode (M) you are essentially providing the reading to the camera. While in program (P), aperture priority (Av), or shutter priority (Tv) the camera will provide a suggested exposure based on what you have put in.
Click to expand...

Sorry, but this is completely wrong!

Whilst in manual mode you are providing the settings to the camera, the camera meter provides a reading dependant on what tone it is aiming at, which you may or may not act on.

In the auto modes the camera provides an exposure setting based on the reading of the meter again dependant on what tone it is aimed at and taking into account any manual setting of a variable SS, Ap or ISO that you have manually set. Again you may well need to override the setting to get the correct result.
 
EdBray said:
Sorry, but this is completely wrong!

Whilst in manual mode you are providing the settings to the camera, the camera meter provides a reading dependant on what tone it is aiming at, which you may or may not act on.

In the auto modes the camera provides an exposure setting based on the reading of the meter again dependant on what tone it is aimed at and taking into account any manual setting of a variable SS, Ap or ISO that you have manually set. Again you may well need to override the setting to get the correct result.
Click to expand...

:)

It's essentially what I meant, but I expressed it a very alternative way!
 
Grayman said:
Hello folks,

I am trying to play around with exposure modes and in reading a photography magazine it said "The camera is set to manual exposure mode and I'm getting a reading for the background of xxxsec at fxx". My question is how does a person do that? I have tried all sorts in manual mode, but I can't seem to get any readings back, apart from the ones I set them at. I understand changing shutter speed and aperture to get a correct standard exposure level, but how can I meter so that the camera gives me suggested readings? I have tried RTFM, but can't seem to find the answer.

Hope this makes sense.

Thanks,
Graeme
Click to expand...

Adding a few words, what the author is saying is "The camera is set to manual exposure mode and, when I point it at the background and adjust the shutter speed and aperture dials so that the needle in the viewfinder is zeroed, I'm getting a reading for the background of xxxsec at fxx".

That reading will be subject to all the variables that always affect exposure meters and their various modes (light, dark, 18% grey whatever, and spot/evaluative etc) but that's not what he's talking about.

What he appears to be doing is measuring the light in the background, presumably in order to know what to set on the flash gun to balance the flash and ambient light levels.

A rather easier way of doing it is to simply pop up the flash on any of the auto modes (Av gives most control) and just point and shoot. The camera will do all the balancing tricks for you in an instant! It will quite likely be more accurate than trying to calculate it manually, but if you don't like the balance that the camera has selected, you can adjust both the ambient and flash exposure levels with the +/- compensation controls.

The other major advantage of using E-TTL for this kind of thing is that it will automatically adjust the flash output if the shooting distance changes. Flash is very sensitive to distance and when you're shooting close for a portrait or small group, if the distance changes by only a foot or so that will have a noticeable effect on the exposure (inverse square law effect).
 
HoppyUK said:
Adding a few words, what the author is saying is "The camera is set to manual exposure mode and, when I point it at the background and adjust the shutter speed and aperture dials so that the needle in the viewfinder is zeroed, I'm getting a reading for the background of xxxsec at fxx".

That reading will be subject to all the variables that always affect exposure meters and their various modes (light, dark, 18% grey whatever, and spot/evaluative etc) but that's not what he's talking about.

What he appears to be doing is measuring the light in the background, presumably in order to know what to set on the flash gun to balance the flash and ambient light levels.

A rather easier way of doing it is to simply pop up the flash on any of the auto modes (Av gives most control) and just point and shoot. The camera will do all the balancing tricks for you in an instant! It will quite likely be more accurate than trying to calculate it manually, but if you don't like the balance that the camera has selected, you can adjust both the ambient and flash exposure levels with the +/- compensation controls.

The other major advantage of using E-TTL for this kind of thing is that it will automatically adjust the flash output if the shooting distance changes. Flash is very sensitive to distance and when you're shooting close for a portrait or small group, if the distance changes by only a foot or so that will have a noticeable effect on the exposure (inverse square law effect).
Click to expand...

Thanks Richard, that is exactly what I was looking for. Reading your post is a much easier explanation than what was given in the magazine.
 
Grayman said:
Thanks Richard, that is exactly what I was looking for. Reading your post is a much easier explanation than what was given in the magazine.
Click to expand...

Cheers Graeme :)

I seem to have written a lot about fill-in flash in the last week or so. Search my user name if you're interested.
 
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