Metering?
- Thread starter mrbez
- Start date
- Messages
- 7,179
- Name
- Edward Bray
- Edit My Images
- Yes
The flippant answer would be turn the camera on, take the lens cap off, point it at something, half press the shutter and you are doing it!
Metering is the process of measuring the amount of light either falling on it (incident) or reflected from it (reflected).
Cameras as standard use reflected light readings as normal (although gizmos can be bought to measure incident light)
The main things to know about metering is that there are various different metering modes (spot, evaluative, centre weighted, average) and that the meter does not know what you are pointing it at!
See this thread for more info!
Metering is the process of measuring the amount of light either falling on it (incident) or reflected from it (reflected).
Cameras as standard use reflected light readings as normal (although gizmos can be bought to measure incident light)
The main things to know about metering is that there are various different metering modes (spot, evaluative, centre weighted, average) and that the meter does not know what you are pointing it at!
See this thread for more info!
- Messages
- 568
- Name
- Matt
- Edit My Images
- Yes
Metering is measuring the light to get the correct exposure for your photographs. Your 40D will do it automatically unless you're shooting on manual mode, which if you're asking this question is unlikely.
If shooting on manual metering mode then you need a seperate light meter to correctly read the light and tell you what settings to use.
If shooting on manual metering mode then you need a seperate light meter to correctly read the light and tell you what settings to use.
- Messages
- 11,626
- Name
- Janice
- Edit My Images
- Yes
Great tutorial, Ed. Peeps should be forced to look through those and the basics section, and do a search before being allowed to ask a question!! Wonder if that would work!!
- Messages
- 7,179
- Name
- Edward Bray
- Edit My Images
- Yes
Great tutorial, Ed. Peeps should be forced to look through those and the basics section, and do a search before being allowed to ask a question!! Wonder if that would work!!
Thanks!
- Messages
- 122
- Name
- mark
- Edit My Images
- Yes
[Are you jesting? I cant believe you have made 240 posts and are asking this question!! ] bit of a tough reply if his camera does it auto he wouldnt now he was doing it he was only trying to learn more. but your right about doing more seaching
Great tutorial, Ed. Peeps should be forced to look through those and the basics section, and do a search before being allowed to ask a question!! Wonder if that would work!!
Sarccy!
OP
- Messages
- 1,034
- Edit My Images
- Yes
Actually, I wasn't "jesting".
I'm assuming that you are "jesting", when basing a persons knowledge of a subject on their overall post count.
If that is the case, you must be a genius.
I have heard people say that they will meter from the sun, meter from the subject.
Is this basically just half pressing the shutter whilst aiming at whatever you want to meter light from? If so, I just wasn't aware that this was called metering.
I'm assuming that you are "jesting", when basing a persons knowledge of a subject on their overall post count.
If that is the case, you must be a genius.
I have heard people say that they will meter from the sun, meter from the subject.
Is this basically just half pressing the shutter whilst aiming at whatever you want to meter light from? If so, I just wasn't aware that this was called metering.
Last edited:
arclight
Oooh that burglar's a cutie
- Messages
- 11,638
- Name
- Doug
- Edit My Images
- Yes
Yes, that about sums it up. All you are doing is measuring the light reflected from what you point your camera (or separate light meter ) at, or in other cases measuring the light falling on your subject (called incident light measurement).
The skill comes in knowing when to simply point your camera at the subject and let it use the measured light to calculate the exposure (very bright or very dark subjects can confuse meters and in that case using an incident light measurement will be more accurate.
As you get familiar with exposure you'll look to measure (i.e. meter) from a light to mid grey, or equivalent, tone within your pic so as to get a reading that will let the camera make an accurate exposure (that will give an accurate reading like using incident light measurement.
When you get your head round exposure (and don't be reluctant to come back and ask anything else) have a think about shooting in fully manual then ask or read up on bracketing exposure (sort of scatter gun approach to ensure that you get at least one shot correct).
- Messages
- 766
- Name
- mark
- Edit My Images
- Yes
most of us (myself included) go out do our photography and go through the motions. and when we sit down and think about it. most of us probably dont understand half of what we do
i asked a question recently asking what a stop was. i sort of half knew , but didnt fully understand it. and im still asking questions that i should know the answers to
it does everyone (even pros) good to get back to basics from time to time,
and look at stuff that is for beginners .
i asked a question recently asking what a stop was. i sort of half knew , but didnt fully understand it. and im still asking questions that i should know the answers to
it does everyone (even pros) good to get back to basics from time to time,
and look at stuff that is for beginners .
- Messages
- 16,666
- Name
- Ade
- Edit My Images
- Yes
Simplistically and without getting too technical.
Not sure on Canons, but Nikons have three "auto metering " modes.
1.Spot meter, where it takes the light reading from a small area in the middle of the sensor.
2.Centre weighted, where it takes a reading from a larger part of the middle of the sensor.
3.Matrix metering, where it takes a value from the whole area of the sensor.
For example, a blackbird sat on a branch that is half filling the frame and your focused on its eye, spot will measure the eye, evaluative will measure the bird and matrix , the whole scene. If you are not shooting in manual and are not keen too, then you can take an image and have the screen set to show "blinkies", blown out white bits, if you have some, try dialling in some negative exposure compensation.
Again, I only use Nikon, your camera may be different, but hope that helps a tad anyway.
And yes, if your camera is set to do so, it will meter upon half depressing the shutter.
Last edited:
- Messages
- 15,790
- Name
- Rich
- Edit My Images
- Yes
Change of mind, too tired to try and get what's in my head into words
Last edited:
- Messages
- 23,200
- Name
- Richard
- Edit My Images
- No
Just for clarity, 'metering' is a rather general term that is often used to describe both exposure (light) measurement, and exposure setting (of shutter speed, lens aperture, ISO). Since the two operations are usually done simulataneously, they get mixed up together.
And on matrix (Nikon) or evaluative (Canon) metering, it is actually by far the most sophisticated and reliable method for most point and shoot situations. What is does is take dozens of readings from all over the image area. From this, it not only knows what the average scene brightness is, it also knows the difference between the brightest and darkest parts (dynamic range), where they are in the image and how much of the total picture area they occupy.
From this information, the camera can make deductions and moderate the final exposure according to a database of typical image situations. Simple example is if the meter detects a large bright area towards the top of the frame it will assume this is a landscape with bright sky and will downrate the sky area to prevent underexposure of the foreground. If the camera is also being held horizontally and lens also reports a long focusing distance, that will likely confirm it. BTW not all lenses report focusing distance but those that do can help here, and are especially helpful with flash exposure calculation which is very sensitive to distance.
Spot metering is only to be used with care and knowledge, or you'll get in a pickle. The spot facility in most cameras is not really spot in the true sense, which refers to a hand meter that reads just a tiny 1 degree angle. The spot mode in most cameras reads from the entire centre circle indicated in the viewfinder which, depending on the lens, is usually a heck of a lot more than one degree.
Final comment is that all metering is just guessing at what the correct exposure might be, and is subject to all manner of assumptions are varaibles that can sometimes throw it out by miles. But if you take a picture and check the LCD, that is an actual finished image - no guesswork - and with the help of the histogram and blinkies for analysis, as Ade mentioned, you can get very accurate exposure indeed.
And on matrix (Nikon) or evaluative (Canon) metering, it is actually by far the most sophisticated and reliable method for most point and shoot situations. What is does is take dozens of readings from all over the image area. From this, it not only knows what the average scene brightness is, it also knows the difference between the brightest and darkest parts (dynamic range), where they are in the image and how much of the total picture area they occupy.
From this information, the camera can make deductions and moderate the final exposure according to a database of typical image situations. Simple example is if the meter detects a large bright area towards the top of the frame it will assume this is a landscape with bright sky and will downrate the sky area to prevent underexposure of the foreground. If the camera is also being held horizontally and lens also reports a long focusing distance, that will likely confirm it. BTW not all lenses report focusing distance but those that do can help here, and are especially helpful with flash exposure calculation which is very sensitive to distance.
Spot metering is only to be used with care and knowledge, or you'll get in a pickle. The spot facility in most cameras is not really spot in the true sense, which refers to a hand meter that reads just a tiny 1 degree angle. The spot mode in most cameras reads from the entire centre circle indicated in the viewfinder which, depending on the lens, is usually a heck of a lot more than one degree.
Final comment is that all metering is just guessing at what the correct exposure might be, and is subject to all manner of assumptions are varaibles that can sometimes throw it out by miles. But if you take a picture and check the LCD, that is an actual finished image - no guesswork - and with the help of the histogram and blinkies for analysis, as Ade mentioned, you can get very accurate exposure indeed.
- Messages
- 16,666
- Name
- Ade
- Edit My Images
- Yes
