topic Program EOS 70D to hold exposure in EOS DSLR & Mirrorless Cameras

Program EOS 70D to hold exposure

moonlight33 — Sat, 30 Sep 2023 08:40:50 GMT

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.

Re: Program EOS 70D to hold exposure

jrhoffman75 — Sat, 30 Sep 2023 12:51:54 GMT

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.

Re: Program EOS 70D to hold exposure

Anonymous — Sat, 30 Sep 2023 14:50:05 GMT

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

Re: Program EOS 70D to hold exposure

Waddizzle — Sat, 30 Sep 2023 15:00:57 GMT

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!

Re: Program EOS 70D to hold exposure

Waddizzle — Sat, 30 Sep 2023 15:10:37 GMT

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.”

Re: Program EOS 70D to hold exposure

Anonymous — Sat, 30 Sep 2023 15:15:16 GMT

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.

Re: Program EOS 70D to hold exposure

jrhoffman75 — Sat, 30 Sep 2023 16:06:34 GMT

@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.

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.

Re: Program EOS 70D to hold exposure

Waddizzle — Sat, 30 Sep 2023 16:53:21 GMT

@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.

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.

Re: Program EOS 70D to hold exposure

Waddizzle — Sat, 30 Sep 2023 17:22:17 GMT

@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.

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.

Re: Program EOS 70D to hold exposure

moonlight33 — Sat, 30 Sep 2023 19:50:57 GMT

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.

Re: Program EOS 70D to hold exposure

Waddizzle — Sat, 30 Sep 2023 19:52:39 GMT

“ 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.

Re: Program EOS 70D to hold exposure

Anonymous — Sat, 30 Sep 2023 20:36:18 GMT

You want metering start and AF start for the shutter button. If you select the trash can while programing the buttons, it will reset all the buttons back to default.

Re: Program EOS 70D to hold exposure

jrhoffman75 — Sat, 30 Sep 2023 20:51:51 GMT

@moonlight33 wrote:
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.

Check your manual and read about the AE Lock (*) button. It has a 4 second timer (I believe) so you don't need multiple fingers.

Re: Program EOS 70D to hold exposure

moonlight33 — Sun, 01 Oct 2023 06:39:02 GMT

Hi, thank you for the response. I did go through the steps..in Operation/Others I proceeded to Custom Controls (#4), then moved to the Shutter butt. half-press Metering and AF start screen, then selected the icon on the upper left, then had the screen "Shutter butt. half-press" and selected the first one on the left with the "Metering and AF start", then hit "Set/OK. Then exited out of these menus by hitting the Menu option. I then tried to shoot, but the same thing occurs, that the camera will not hold my exposure along with the focal point, when I reframe the shot. Of course, I am still holding the shutter button down halfway. I'd be thankful for any further suggestions to solve this. Using the little button on the back is not possible with the type of photography I do. I'm not shooting nature scenes and need to work quickly. Thank you so much for the help.

Re: Program EOS 70D to hold exposure

Waddizzle — Sun, 01 Oct 2023 08:10:47 GMT

@moonlight33 wrote:
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.

Reset custom control programming to factory defaults. Use Evaluative Metering mode, which is the factory default and everything should fall into place.

Use just a single AF point. The center AF point is the most accurate. Binding exposure can work with any single AF point.

However, Spot AF only works with the center AF point. I only use Spot AF on a tripod. It meters an area that is much larger than AF point. Notice how the Spot AF circle shown in the above illustration touches at least 5 metering points. I almost never use Spot Metering because of this.

Use One Shot AF because when it locks focus it will also lock the exposure.

Re: Program EOS 70D to hold exposure

moonlight33 — Sun, 01 Oct 2023 08:43:24 GMT

Hello Waddizzle, thank you for the info. Re: evaluative, is this is my only option to avoid utilizing the exposure lock? I'm learning this camera system, but have been working with partial or spot metering in my attempts to recreate the way I used to work with my Canon film camera. I shoot mostly black & white backlit (natural light) with models/people as my subjects (or journalism) in AV mode. I want to control the way the light appears for the creative work. The only workaround I can come up with, is to use evaluative along with exposure compensation, to allow more light in (or less). 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!

Re: Program EOS 70D to hold exposure

Waddizzle — Sun, 01 Oct 2023 14:23:51 GMT

“ 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?

Re: Program EOS 70D to hold exposure

Waddizzle — Sun, 01 Oct 2023 14:38:45 GMT

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,

Re: Program EOS 70D to hold exposure

Anonymous — Sun, 01 Oct 2023 17:23:32 GMT

I would go back and check the shutter button programming again. Perhaps the change wasn't saved. You can also use the trash can button while in the custom button programming screen to reset all the buttons and controls back to default.

Re: Program EOS 70D to hold exposure

moonlight33 — Sun, 01 Oct 2023 19:14:40 GMT

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!