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.

[jrhoffman75]

I don't believe the 70D has the capability to set exposure to the selected focus point. That is a 1D series feature for DSLRs.

[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]

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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]

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@jrhoffman75 wrote:

I don't believe the 70D has the capability to set exposure to the selected focus point. That is a 1D series feature for DSLRs.

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I disagree.  Just about any Canon DSLR can bind exposure to a locked AF point.  That is how Evaluative Metering works.  

It is crucial for the AF point to be active and locked when the shutter is fired.  Having [Metering Start] part of the shutter button functionality guarantees this precondition is always met.  

It is when people use BBF that the potential to not bind AF and Exposure can occur.  This is one of the reasons I reprogrammed BBF to be [AF-OFF].  Also, I only need to press one button to fire a burst of shots, which makes doing so while panning much easier.

[EDIT] This is not my first choice of articles.  There is/was a better one at DPReview that included this same illustration.

https://digital-photography-school.com/understanding-evaluative-metering-on-your-eos-camera/ 

Every AF Point was paired with its own metering sensor element.  This basic design still applies today, even though cameras can tens of thousands of metering points.

[moonlight33]

Thank you so much to everyone for your responses. I am reviewing and testing out these suggestions and will be back for a follow-up.  Yes, I am trying to connect my auto focus spot (with one shot) to my metering, 100% of the time, without having to find that tiny little button on the back.  I already tried the Metering Start setting as suggested, but this stopped my ability to auto-focus.  Will be continuing to review all of the helpful links.