I have a silly question about using a canon DSLR

[kriskent]

hi guys, all canon dslr users.

when we take a picture, there's something on the view finder that moves. basically it's composed of short vertical dash and then there's the blicking sensor that moves from left to right. of course we all know that the value is determined by the combination of both shutter speed and aperture values. Is it always true that when you are in M mode, you always have to lock or keep that thing in the middle? coz if you adjust any of the shutter or aperture values to the right, the pic goes overexposed, if to the left, it's under. Can you please enlighten me and answer if it should always be in the middle?

Thanks

what are the different techniques you can share?

[n0d3]

Its the exposure meter. If you're in Av or Tv, the camera will then select the corresponding value of the shutter speed or aperture in order to maintain a "correct" exposure, meaning the centre of the bar you see in the photo. If you're using manual override, the meter is just that to tell you how the exposure is going to turn out, you don't have to keep it in the middle.

Sometimes using M might be troublesome so usually one would use Av or Tv, if you find the exposure determined by the camera to be too overexposed or underexposed for your liking, you can always use exposure compensation (read the manual).

Depending on which camera you use, its wise to turn on the safety shift for Av/Tv in your custom functions. In this way, the camera can override your value for the aperture/shutter speed in Av/Tv modes if theres no way the camera can get a correctly exposed photograph. E.g. Using f/1.4 in broad daylight and your shutter cannot keep up.

[Discreet]

to makes clearly, this is what the camera is trying to do.

First you choose a metering mode and the camera will use the mode to meter the scene. Evaluative, Average, Center Weight or Spot (5D 30D and 1 series only). Each mode is slightly different but in a nutshell, evaluative is "idiot proof" mode where the camera decides everything for you. Average is as implied, sometimes it gets fooled if you have bright areas in teh picture. Center Weight and Spot is the same thing excpet Spot is covers a smaller area. The idea is that you just consider the middle portion of the screen when you meter. This is helpful when average or evaulative fails. For example if you are shooting a wedding, where teh bride is wearing white and the groom is wearing black, the metering might be off. So you can switch to center weight and try to find something that is of moderate brightness. Good things to meter off is the skin. The idea is this, the camera will adjust the setting such that whatever you meter is dead center in the histogram and you have a plus minus of 2 3 stops of exposure to the left and right.

Going back to your situation. Switch your camera to center weight and manual and notice the meter in your camera.

Supposed you set the aperature/shutter/ISO such that the picture comes up with a correct nice exposure. When you move over a dark area, the meter will show underexposure (to the left) while over a bright area, it will show over exposure (to the right). So with your center weight mode, you can move around to see whether your highlights and blacks are within range.

So you can use this in a slightly different way. For example if you want shoot a person wearing black and you want to make sure the black is black. You can shoot in AV, set a -1 1/2 to -2 on the EV and meter on his black shirt. Or you could go to M mode, and when you meter off his shirt, make sure your settings is around there. This is called exposing for your blacks. Basically it will ensure that your black will come up as true black and hopefully the rest of the picture will be within your dyanmic range. You can do the opposite and expose for the highlights by metering on a white dress of bride.

Hope you get what i mean...

[kriskent]

nice inputs mr discreet and thanks.

I have been hearing the terms meter using the skin tones and shoot half or 1 stop over/under.

Can you guys explain what these meant? i mean, how do you meter the skin tone of the bride wearing a white gown and a guy in dark suite? do you specifically focus (the center focus of the view finder, the one where you partially press the shutter button and then you hear a click sound) on the skin and then re compose? sorry for my confusion.

thanks

[kriskent]

what and how is "exposure compensation" by the way? Please enlighten me.

Thanks

[Discreet]

Okay i did no clarify the use of the AE Lock button which is the * button.

In normal camera shooting (AV and TV not MANual), the camera will meter and choose the exposure right before you fire the shutter. With AE lock, you can force the camera to take a camera meter and use it for the next shot. So for example, if you want the skin tone of the bride to be nicely exposed, you have to meter off her face using center weighted. So set your camera to center weight, compose the picture such that her face fills the area of your center weight meter. You might want to zoom in a bit. Then press the * button. in your viewfinder, you should see the * light up. If you half press the camera to AF, the camera will not re-meter. if you are in AV mode, the camera will change the shutter speed, if you are in TV mode, the camer will not cahnge the aperture. Instead it will show you whether you are over or under exposing in the EV scale.

So for example... you want to a bride face to be slighly overexposed for a high key look. So you dial in a +2/3 EV in AV mode. You choose Center weight metering, zoom in on her face and press teh * to meter. The camera takes a meter. For example, it might choose a shutter of 1/200 to get the face to be slighly overexposed.

if you move the camera's center weighed area to a dark spot like the groom black suit. what happens?

The camera will not adjust the shutter speed. It will still be 1/200. However, if you look at the camera EV meter at the bottom of your viewfinder,you will see the meter blinking something like -2 or something. there should be a solid mark at the 2/3 EV still. This shows you the difference in exposure compared to the skin you meter off. Understand?

Right now, you can even readjust the EV value, and the whole thing will move left or right accordingly. With a 1 series camera, you can store up to 9 spot meter reading around the EV meter.

Again, after you meter the scene with * button, you will see the * button light up in the viewfinder and it will not change the shutter/aperture until you either re-meter with the * button, fire the shutter or press teh DOF button or turn off the camera (maybe got more).

In a manual mode, you dont really need the * button, because the camera is not going to calculate the shutter/aperature for you. It will just show you how much over/under exposure. So like if you meter off the skin as i mentioned, you have the freedom to adjust aperture or shutter to get whatever EV you want. If you want to overexpose the skin a bit, you can do it.

On the 20D, 10D, 300D, 350D, there is no spot meter, so you might have to zoom in a bit to meter correctly. The thing is after you meter the scene, you recompose the shot, half press to focus and fire.

If you do not use the * button, half pressing the shutter will both AF and take a meter reading (AE). Using the * button means you can first meter teh scene and then af. This is useful for tricky situation where the subject you want to be in focus might not be the right subject to take a meter.

[Discreet]

http://photonotes.org/articles/begin...recompensation

read this... and read every article on canon. It is hard to explain stuff when you are not clear with the nomenclature.