How do you correctly meter a shot?
- Thread starter Prophet
- Start date
you cant manually meter with the camera, if this is what you want to do.
With its metering modes it does it for you. you can however adjust it! so if it tends to underexpose keep it to the right hand side and visea versa for over exposing.
there are some situations where the meter is useless - i.e for exposure of more than 30 secs etc
With its metering modes it does it for you. you can however adjust it! so if it tends to underexpose keep it to the right hand side and visea versa for over exposing.
there are some situations where the meter is useless - i.e for exposure of more than 30 secs etc
You have three metering modes on your 350D; evaluative, centre-weighted and partial. Successful metering is a combination of knowing which mode to use at a given time and how to use it.
Evaluative metering divides the frame into sections and each one is analysed and the exposure calculated for the entire image. The camera's meter asseses each segment individually and uses various algorithms to calculate the optimum exposure. Evaluative is good for most situations and a useful 'standard' to keep as the default.
Centre-weighted calculates the exposure from light over the whole frame but gives precedence to light in the centre. Generally a good mode to use for your typical outdoor scenes.
Partial takes a reading from a smaller area in the centre of the frame (but not a very small area as you'd find with a camera that can spot meter) and calculates exposure accordingly. The most common example for using partial metering would be shooting a backlit scene - i.e. taking a photo of someone with their back to the sun.
Understanding Exposure would be the perfect book to pick up and help you through the learning process of understanding the theory behind metering and how to get the best results. Couldn't recommend it enough.
For now though, take your camera on a day out and test the various metering modes for the same scenes. Set your tripod up, compose your shot and then stick your camera on either Av or Tv (or M if you're comfortable using it) and shoot three exposures - one for each metering mode.
You'll be able to see the differences between the exposures instantly, but it might take some checking on your PC and comparing histograms to really understand what's going on.
One final point. I'd recommend setting your exposure compensation dial for anywhere between 1/3rd and 1 full stop of underexposure. It can be a pain in some situations, especially where light levels are low and you need a specific shutter speed/aperture, but it will reduce the danger of blowing your highlights through accidental overexposure. Shooting in RAW will also help immeasurably.
Soldato
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I would say, go outside use manual mode and partial metering. Now looking in the viewfinder, point the camera at the floor, preferably grass or tarmac and notice the light meter. Its most likely way too high or way too low depending on your shutter speed and aperture.
Change your aperture and shutter until the meter settles in the middle, where the camera "thinks" the exposure is correct. Take a picture.
Now point the camera up in to the sky and notice how the light meter suddenly jumps up shouting, "OMG, IT'S SO OVER EXPOSED!". Take a picture with no adjustments.
With your camera still looking at the sky (not the sun!) you can now adjust your aperture/shutter again to get the meter back in the middle (i.e. where the camera "thinks" the correct exposure is). Take another picture of the sky.
Point the camera back at the ground and take another picture without changing anything.
You should now have 4 pictures:
Ground "correctly" exposed
Sky over exposed
Sky "correctly" exposed
Ground under exposed
I guess what I'm trying to say with the above is that the overall light hasn't changed in the scene but the light meter is jumping all over the place. If you put the viewfinder so its half on the sky and half on the ground you should find it's near enough in the middle of both the light meter readins for sky and ground. That's because again, it's taken half of the sky and half of the ground and mixed them up together to produce a middle shade.
What you need to know is that the camera takes what it sees in its metering mode and mixes all the shades around like a paintbrush mixing loads of colours in to one shade. Based on this shade, the camera then adjusts the exposure to make the shade 18% grey so that either makes the image darker or lighter and for a good amount of scenes it's not far off being correct.
However, classic examples are a black cat in a coal bin, the camera sees all the shades of black, mixes them together to get the average and surprisingly it's well, basically black. The camera then thinks, I need to lengthen the exposure to get enough light in to make it 18% grey (which for a normal scene would basically be correct exposure). But by doing this your black coal and cat become grey!
Same thing goes for a white rabbit in snow. The camera sees all the white and thinks it's over exposed and pulls back the exposure which means all your whites become 18% grey! You'll notice this a lot with peoples snowboarding holiday snaps.
So, to get round this you can use EC (exposure correction) in aperture or shutter priority modes, minus for blacks and plus for whites. The more white the more you go plus and the more black the more you minus. So black is black and white is white.
In a normal scene, when the camera takes all the shades and mixes them up in to one shade it's usually going to be around 18% grey so it's near enough fine. However, if you want consistent exposures and less post processing then learn how to operate in manual modes. That's not to say manual is always the best mode just that it should take preferance as much as possible imo.
Hope this helps but I'm not very good at getting what I mean across, it may be confusing, sorry. Hope it helps, exposure is one of the things I still find the hardest to nail every time and is also one of the things to master to really make the most of your shots.
Change your aperture and shutter until the meter settles in the middle, where the camera "thinks" the exposure is correct. Take a picture.
Now point the camera up in to the sky and notice how the light meter suddenly jumps up shouting, "OMG, IT'S SO OVER EXPOSED!". Take a picture with no adjustments.
With your camera still looking at the sky (not the sun!) you can now adjust your aperture/shutter again to get the meter back in the middle (i.e. where the camera "thinks" the correct exposure is). Take another picture of the sky.
Point the camera back at the ground and take another picture without changing anything.
You should now have 4 pictures:
Ground "correctly" exposed
Sky over exposed
Sky "correctly" exposed
Ground under exposed
I guess what I'm trying to say with the above is that the overall light hasn't changed in the scene but the light meter is jumping all over the place. If you put the viewfinder so its half on the sky and half on the ground you should find it's near enough in the middle of both the light meter readins for sky and ground. That's because again, it's taken half of the sky and half of the ground and mixed them up together to produce a middle shade.
What you need to know is that the camera takes what it sees in its metering mode and mixes all the shades around like a paintbrush mixing loads of colours in to one shade. Based on this shade, the camera then adjusts the exposure to make the shade 18% grey so that either makes the image darker or lighter and for a good amount of scenes it's not far off being correct.
However, classic examples are a black cat in a coal bin, the camera sees all the shades of black, mixes them together to get the average and surprisingly it's well, basically black. The camera then thinks, I need to lengthen the exposure to get enough light in to make it 18% grey (which for a normal scene would basically be correct exposure). But by doing this your black coal and cat become grey!
Same thing goes for a white rabbit in snow. The camera sees all the white and thinks it's over exposed and pulls back the exposure which means all your whites become 18% grey! You'll notice this a lot with peoples snowboarding holiday snaps.
So, to get round this you can use EC (exposure correction) in aperture or shutter priority modes, minus for blacks and plus for whites. The more white the more you go plus and the more black the more you minus. So black is black and white is white.
In a normal scene, when the camera takes all the shades and mixes them up in to one shade it's usually going to be around 18% grey so it's near enough fine. However, if you want consistent exposures and less post processing then learn how to operate in manual modes. That's not to say manual is always the best mode just that it should take preferance as much as possible imo.
Hope this helps but I'm not very good at getting what I mean across, it may be confusing, sorry. Hope it helps, exposure is one of the things I still find the hardest to nail every time and is also one of the things to master to really make the most of your shots.
I know a few guys who are mega serious Medium/Large format shooters, who all use expensive handheld light meters and sun charts and various other stuff, to get their exposures absolutly perfect.
For me, I tend to use centre weighted evaluative metering most of the time, i've learnt it so well that I can predict exactly how it'll behave in a certain situation, this allows me to dial in exactly how I want it with exposure compensation.
With my wildlife portraits etc, its critical to get the correct exposure in one shot for the simple reason that 99% of the time it doesn't stay in a particular pose for long, sometimes I use manual mode and spot-metering with the metering locked to the focus point, so I can meter off the darkest area of the subject by moving the single focus point around, then guesstimate the correct exposure with the manual controls.
Another method to "fool" the meter into getting a more accurate exposure, is to set your lens to manual focus, twist it all the way to infinity to everything is a total blur, activate the metering then hit exposure lock, recompose focus and shoot.
The idea behind that method is that because your turning the scene into one big blur, the camera averages out the exposure more evenly, making it less likley to drastically under/over expose the picture.. I'd say this is useless for landscapes though, which would require good filters or multiple exposures.
As other people have said, I think the best way is to just go out and try as many methods as possible, certain things work well for certain people but not others..
For me, I tend to use centre weighted evaluative metering most of the time, i've learnt it so well that I can predict exactly how it'll behave in a certain situation, this allows me to dial in exactly how I want it with exposure compensation.
With my wildlife portraits etc, its critical to get the correct exposure in one shot for the simple reason that 99% of the time it doesn't stay in a particular pose for long, sometimes I use manual mode and spot-metering with the metering locked to the focus point, so I can meter off the darkest area of the subject by moving the single focus point around, then guesstimate the correct exposure with the manual controls.
Another method to "fool" the meter into getting a more accurate exposure, is to set your lens to manual focus, twist it all the way to infinity to everything is a total blur, activate the metering then hit exposure lock, recompose focus and shoot.
The idea behind that method is that because your turning the scene into one big blur, the camera averages out the exposure more evenly, making it less likley to drastically under/over expose the picture.. I'd say this is useless for landscapes though, which would require good filters or multiple exposures.
As other people have said, I think the best way is to just go out and try as many methods as possible, certain things work well for certain people but not others..
Soldato
- Joined
- 5 Nov 2004
- Posts
- 9,302
as far as getting your exposure right the best thing you can do is just take a step away from the camera and look at your natural, and or forced light sources. There is no magic setting on a camera.
any metering mode is either going to give you one of the following based on light data fed into the camera:
Expose according to exposure.
over expose
under expose.
The very best shots come from knowing your external light sources.
any metering mode is either going to give you one of the following based on light data fed into the camera:
Expose according to exposure.
over expose
under expose.
The very best shots come from knowing your external light sources.
Yes? You can keep a rough benchmark in your head and extrapolate from that--ISO100, 1/100s @ f/16 for a sunny day, for example, the same but f/8 for overcast weather, extrapolate to ISO100, 1/1000s @ f/5 on a sunny day, etc. etc. etc.
Of course in-camera meters are now so good as to render it obsolete but it's useful to have a concept of it in your head.