Program EOS 70D to hold exposure

[moonlight33]

On the Canon EOS 70D, there is a button one can press to hold the exposure and then reframe the shot. It is unbearably difficult, because often I need to hold the focal point as well and it is hard not to accidentally press the shutter, etc.  When I utilized a Canon film camera, I could use the focal point to hold the focus AND the exposure point together by simply pressing the shutter halfway, then re-framing.  Please can someone help me to find a way to program this camera to always sync the exposure with the focal point so I do not have to press the little button (which is hard to not mess up due to there being 2 other little buttons in the same area)? Thank you so much, this is how I shoot all of my shots, it is not possible to work quickly without a way to program this.

[Anonymous]

You want to go into custom controls in the menus and program the shutter button to Metering Start and AF Start.

 

[Waddizzle]

Using One Shot AF and Back Button Focus is what I would use.

One Shot AF locks metering when focus is locked.  The default metering, Evaluative Metering, allows the camera to meter a scene at the locked and active AF point.  It is crucial that both conditions must be met for the camera to meter from the AF point.  If not, then the camera will meter the scene in a manner similar to Center-Weighted Averge.

Using just the center AF point, [use] just the BBF button to lock focus on your subject.  Keeping the BBF button pressed, recompose the scene.  While still keeping BBF pressed, fully press the shutter button.

Done!

[Waddizzle]

BTW, there should not be any need to reprogram control buttons, either.  Using the instructions that I described above, use the [AF-ON] button whenever use “BBF button.”

[Anonymous]

If I am not mistaken, the OP has his camera programmed that way and wants to change it back to the default metering and AF start with the shutter button. He says he has a problem holding the BBF button while pressing the shutter half way. Maybe I am misunderstanding what he is looking for, but that is how I take it.

[jrhoffman75]

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@Anonymous wrote:

If I am not mistaken, the OP has his camera programmed that way and wants to change it back to the default metering and AF start with the shutter button. He says he has a problem holding the BBF button while pressing the shutter half way. Maybe I am misunderstanding what he is looking for, but that is how I take it.

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I think you are correct. He should restore factory setting and use focus-recompose by focusing using the center point and then holding shutter button halfway. 

The 1D series allows exposure to be assigned to the focus point being used, avoiding need to focus-recompose. 

[Waddizzle]

“ The 1D series allows exposure to be assigned to the focus point being used, avoiding need to focus-recompose. “

You may have Spot AF in mind.  Only 1D series bodies allowed any AF point to be used in Spot AF mode, as well as meter at any selected Spot AF point.

[Waddizzle]

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@Anonymous wrote:

If I am not mistaken, the OP has his camera programmed that way and wants to change it back to the default metering and AF start with the shutter button. He says he has a problem holding the BBF button while pressing the shutter half way. Maybe I am misunderstanding what he is looking for, but that is how I take it.

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After re-reading the original post, you are correct.  I guess I became confused when the OP said that recomposing is hard to do without firing the shutter.  

I’m not sure why the shutter would be fired, not unless your finger is already half-pressing the shutter, or something, as you recompose.  There should not be any need to touch the shutter until you are ready to take the shot.

I would think using only the shutter button would be a little more difficult to recompose without firing the shutter compared to using two buttons, one for focusing and the other for firing the shutter.

Now I wonder if there is an issue with how the camera is being held, too.  You have to keep your elbows close to your body.  No chicken wings.  When your elbows are sticking out to the side, that makes it easy for someone to bump you and cause you to drop the camera.

[Waddizzle]

“ This is frustrating for circumstances in which I would like to have a very black background and need spot metering and need to work quickly.  Is there any other way for me to link the partial metering with the focal point and hold that exposure when reframing? And if not, I've read that evaluative metering still concentrates on the focal point, but I wouldn't think it would be as accurate as the partial metering. Thank you for your help! “

It almost sounds like you are asking about a different shooting scenario now.  Achieving very white or very dark backgrounds is best achieved in post-processing, not in the camera.

I have thought that you wanted to meter the scene at the selected AF point.  This is very easy to do because this is the default behavior for the camera when you use One Shot AF combined with 1 pt aF.. Select any AF point you wish.  The center AF point is the most sensitive and accurate.  This only requires the use Shutter Button, a half-press to lock focus and exposure followed by a full press to take the shot.

If you wish to focus here while metering over there, then that is a different scenario that will likely necessitate the use of the [AE LOCK] button as John suggested.  This means that you could be returning to a dual control button shooting scenario.

Could you describe exactly which end result you are trying to achieve?  Are you looking to do both?

[Waddizzle]

There are three basic scenarios when it comes to recomposing shots.

1 - Focus, recompose, followed by metering and taking the shot.

2 - Metering, recompose, followed by focusing and taking the shot.

3 - Metering and focusing, recompose, followed by taking the shot.

This last scenario is what I have been describing and can be easily achieved using only the Shutter Button.  The first two scenarios are probably dual control button shooting scenarios.

Spot AF is more subtle and complex that many realize.  It does not help or allow the camera and lens to focus more accurately.  Spot AF allows you acquire your subject more accurately.  

Similarly, Spot Metering does not allow the camera to meter a scene more accurately.  Metering takes place over a significantly larger area than many may realize.  Unlike Evaluative Metering, Spot Metering completely ignores the rest of the scene.

The only scenarios when I may use Spot AF and Spot Metering is shooting from a tripod, 

[moonlight33]

I am in need of #3. I wish to use partial metering most often (and periodically spot metering). I choose the focal/metering point simultaneously and then reframe and shoot.  I do not re-focus.  I need one step only. Thanks!