Metering Help please

[gnome33nz]

I have googled this subject - read the book Understanding Exposure, read heaps of articles and I just don't get it. I must be really dumb.

All the articles, books etc tell me the trick to get correct exposure is to take a 'meter reading' from my camera, but they don't tell me how to do it other than to point my camera at a subject and take a meter reading. What is a METER READING? - what should I be looking at on my camera? Do I have to put it in automatic or p mode to take a reading?

I'm so confused as to what taking a meter reading means.

Can anyone help a novice please?

[scootermcq]

My Nikon just has a bar style exposure display. When you point the camera and push the shutter release halfway, it will show where you sit. 0 is perfectly exposed, towards the negative is under exposed and towards the positive is over exposed. I can then adjust shutter speed, aperature, or iso and take another reading to see if it is near 0.

[RichardTaylor]

With most cameras nowdays the meter reading is done when you partially depress the shutter button. There will be a display, you may need to activate it (see your camera manual) , of the shutter speed and aperture and possibly the ISO either in the viewfinder or on the top of the camera or on the screen at the back.

[inkista]

Originally Posted by gnome33nz

What is a METER READING? - what should I be looking at on my camera?

a) What camera are you using?

b) What mode are you shooting in?

If you're in an Auto mode, such as the green-box full auto, P, A/Av, or S/Tv, you have no meter displayed in your camera. The camera's auto-exposure (AE) system is doing the metering and setting settings automatically to get what it thinks is the optimal exposure. You will have an exposure compensation scale, which (if you're not in full-green-box-Auto), you can slide around to fine tune/override what the AE system thinks is perfect exposure.

If, however, you are shooting in full Manual mode, THEN, what was your exposure compensation scale, has now become your light meter. As you adjust your settings, the meter reading will automatically compensate. The center of the scale (0) is where the AE system thinks you ought to be. If you're shooting Nikon, by default, if you're to the left of the zero on the + side of the scale, the AE system thinks you're overexposed and the image is too bright, if you're on the right side of the zero on the - side of the scale, the AE system thinks you're underexposed and the image is too dark.

If you shoot Canon, the scale is actually logical , and goes the other direction, with underexposure (-) on the left and overexposure (+) on the right, just like with a histogram.

What the books mean by taking a metering reading "off the sky", is that, if you are in, say, aperture-priority mode, you point the camera so that the frame is filled with the sky, and you half press the shutter button. The camera meters the sky, and sets your settings appropriate. You then set the AE-lock (usually the * button, it's configurable to do either AE-lock, or autofocus lock or both), and that locks the settings in. Then you recompose and take the shot, with the same exposure settings as you would have used if you'd just shot the sky.

[gnome33nz]

Inkista, that's incredible, you explained it so well. Answers to questions:

a, I am just a reasonably new person to photography and have only a Canon 450d.

b. I use all the modes depending on circumstances.

So making sure I have this correct....

I ONLY have a light meter in my camera when in full MANUAL mode?

All other options like auto, p, Av, Tv etc it's the exposure compensation I'm looking at?

If this is correct, no wonder I had so many problems trying to take meter readings... arrrghh! All the books assume you know what 'taking a meter reading' means.


And the other thing I try to aim for is the '0' in the middle of the meter... so either alter aperture or shutter, or ISO to get as close to the '0' as possible for correct exposure?

Oh, I feel so excited about nailing this hugely valuable tool - (if my assumptions here are correct).

[kencaleno]

First of all, you need to know how far off "0" (+or-) your camera's meter is, so you are sure of optimum exposure:

With camera on tripod, A/AV mode, Matrix/evaluative/multi-segment metering mode, exposure compensation at 0-0 and a scene with a good range of tones (a bright sunny day)

Set Exposure compensation (+/-) at +1 take a shot

Now in 1/3 (0.3) increments adjust exposure compensation and take a shot each time, all the way to -1, giving you seven images.

load these into imaging programme and select the image with best detail in shadows and highlights, without blowing highlights or clipping shadows-

This setting will be your standard, set this on your camera, and you will never need to do this again - your camera will be calibrated for optimum exposure.
This is baseline, so if shot looks too dark or light, in certain conditions, just adjust (+/-) to suit.

Ken

[inkista]

Originally Posted by gnome33nz

So making sure I have this correct....

I ONLY have a light meter in my camera when in full MANUAL mode?

All other options like auto, p, Av, Tv etc it's the exposure compensation I'm looking at?

Well, you have a meter in the camera working all the time. It's just that the scale in your viewfinder only acts like a light meter, rather than a compensation scale when you're in full Manual mode (M). In Av/Tv/P/green-box modes, the camera automatically messes with your settings to put your "needle" in the middle at 0. So you never see it look any differently, unless you dial in exposure compensation.

And the other thing I try to aim for is the '0' in the middle of the meter... so either alter aperture or shutter, or ISO to get as close to the '0' as possible for correct exposure?p

Kinda/sorta, but not really. If you want to duplicate exactly what the auto-exposure in your camera will do, then yes, 0 is always right. But sometimes the AE system is wrong, which is why we like having Manual mode and exposure compensation.

A simplistic view of how metering works is that the AE system looks at all the values of every pixel, and then averages them. Then, it sets that average value to the middle of the exposure scale (aka "middle grey"). This works really well for most scenes. But say, for example, you're shooting a snow scene. The majority of your values are going to be white, or at the light end of the scale. So, your average value is going to be very light. But the AE system will stupidly think that's supposed to be middle grey, and your picture will be underexposed. Or you're taking a night scene, where your values are mostly black. And the resulting average is going to be very dark. Dark gets set to middle grey, and your scene will be overexposed.

The AE system is a stupid mechanical thing. You're smarter than it is. You know if it's a snow scene, or a water scene with extra reflected light, or a night scene, so you can choose how to move the exposure accordingly.

You also know, say, if someone's standing in front of the window, whether you want them to be properly exposed and the scene in the window behind them to be blown to white, or a silhouette of the person, against the properly exposed sunny scene in the window behind them. In this case, you can tell the AE system which bits of the scene are more important. You can use center-weighted metering (where the values in the center of the frame count more towards that average), or spot metering (where values from only a certain portion of the frame are used). Or you can turn on the flash to light the person so they match the brightness of the scene outside.

[TerryMC]

Originally Posted by gnome33nz

All the articles, books etc tell me the trick to get correct exposure is to take a 'meter reading' from my camera, but they don't tell me how to do it other than to point my camera at a subject and take a meter reading. What is a METER READING? - what should I be looking at on my camera?

Point your camera at a subject and half pressed the shutter to activate the meter. Then read the aperture, shutter speed and ISO values. Assuming the metering is within range (scale at 0 maker) then that's your meter reading.



Note that it may not be the proper setting for that particular image. You may have to use a different metering mode or adjust the exposure compensation.

Another way to describe a meter reading is by Exposure Value (EV). In this example, the metering reading is EV 16.9. That's why your camera has EV +/- (exposure compensation).

Originally Posted by gnome33nz

I ONLY have a light meter in my camera when in full MANUAL mode?

All other options like auto, p, Av, Tv etc it's the exposure compensation I'm looking at?

The aperture, shutter speed and ISO are interlocked in semi-auto modes (i.e., maintaining the same EV value). So you use the exposure compensation (EV +/-) to override the camera setting (EV).

[gnome33nz]

Thankyou so much everyone for explaining that in english.

I so 'get' that now. I feel so enlightened - it was a huge missing piece that I just couldn't understand and now I can re-read those books knowing what a 'meter reading' is.

Really appreciate your help

[KiwiClare]

I would just like to thank the above people for the input here as i am a novice too and have found this infomation so valuable. Just to go a step further tho, what about hand held meters?? Which type of metering system would you use if say you were out doors trying to photograph the school sports day and its sunny and fine, aposed to inside in a church??/ I do understand about iso /shutter speed etc but have read articles on spot metering, reflective and incident and have a very basic understanding of the grey card . Could some kind person take pity on me and explain the best system for different envirnments or have i missed the point completley!!!!!!!!

Clare.