Metering

Creed

Creed

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Ok forgive me for this, I understand what metering is to some degree, I'm pretty sure there are 3 types, one that monitors the full frame, one that gives priority to the centre of the image but does account for the surrounding areas (centre weighted is it?) and then spot metering that only looks at the centre of the image.

so knowing that, and having a 300D I am struggling to find out how to put this into practice as it were, from a 'looking through the viewfinder' point of view what do I need to be looking for, can the 300D do all three types and if so where do I change the setting..

I misplaced the manual but can't remember there being much in there about it.

I didn't know if it was one of those things like exposure compensation that since I'm forcing myself to use manual doesn't matter.. spent ages on my camera trying to figure out who to dial in exposure compensation in M before realising I just had to manually under or over expose depending on what I wanted.
 
300D has centre weighted, evaluative, and partial.

The simple way to meter is to use the palm of your hand. Make sure it's in the same light as the subject and take a reading from your palm using partial metering. Now depending on your skin colour you'll need to adjust the exposure by some amount but it will always be the same amount so once you've worked out the right value for your palm you can always get the right exposure by taking a reading and adjusting that amount. The camera will never "guess" wrongly and you won't have to work out how much EC you need, etc.

The only time it needs to be more complicated is when you're using flash as well.
 
pxl8 said:
300D has centre weighted, evaluative, and partial.

The simple way to meter is to use the palm of your hand. Make sure it's in the same light as the subject and take a reading from your palm using partial metering. Now depending on your skin colour you'll need to adjust the exposure by some amount but it will always be the same amount so once you've worked out the right value for your palm you can always get the right exposure by taking a reading and adjusting that amount. The camera will never "guess" wrongly and you won't have to work out how much EC you need, etc.

The only time it needs to be more complicated is when you're using flash as well.
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Thanks for the reply.. but I still don't completely understand it.... I know I should go and research it but having trouble finding what I need....

For example you say meter from your palm... ok then, on my 300D what exactly would I do (apart from the obvious of putting my palm in front of the lens) also what would I see in the display regarding the metering? what does it affect?..... I was thinking that it affects what the camera judges as the ideal exposure (i.e. the little green arrow I am trying to align to when changing my settings) ... is that correct?
 
Basics first: you need to adjust your exposure settings because the range of brightness in a scene, from sunny by the sea to a black cat in a coal cellar, is vast. Cameras can only record a small part of that range, and the camera's exposures controls adjust the light level so the important bits that you want to record are within the range of the sensor (called the dynamic range).

All in-camera metering systems work by measuring the light reflected back from the subject (that's called a reflected light reading) but the fundamental problem here is that bright subjects reflect more light than dark ones, and so will give different exposure settings when in fact both subjects require the same exposure. What you really need to do is measure the level of light falling on the subject (known as an incident light reading).
This is what you are doing when taking a reading off the palm of your hand and so long as you adjust that from skin tone to mid-grey, your exposure will be correct. In practise, take a reading off your palm, then add 1.3 stops to the exposure and you're there. Taking a reading off grass is another method, and if you take a reading off an 18% grey card the exposure should be absolutely optimum, without any adjustment necessary.

The various methods you've described, like average scene metering, centre weighted, spot, partial, selective, semi-spot etc are ways that you and the camera try to work around the light subject/dark subject problem. Used with some skill, they work well. But the easiest method is to use evaluative, matrix, multi-pattern metering (names vary) and all these methods take multiple readings from the scene, often dozens of them simultaneously.

The camera then knows the range of brightness in the scene, and how large an area each brightness covers. It then compares this information to data from many thousands of images programmed into its memory, and decides what the best exposure will be. For example, if it sees lots of bright areas in the top of the frame, it knows this is sky, compares this with the darker foregound, and takes a stab at modifying the exposure for the result you want. And it works amazingly well :)

One of the blesings with digital is that you can check the exposure immediately on the camera's LCD. If it looks right then it is probably not far off at all, but then switch to the histogram and you can see exactly the range of tones that have been captured, and where on the scale the camera has placed them. You can then take a view on whether the camera has got it right, and give it a tweak lighter or darker as you like.

If you shoot Raw, there is a slightly greater range of subject brightness contained in those files than there is in JPEGs, so there is a bit more room for manoeurve/rescue in post processing.
 
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