5D Mark IV - Set Shutter Lock to only AF not AE in Evaluative Metering

[manatee4mation]

I Canon 5D Mark IV. In evaluative mode, I am trying to half press the shutter to lock the AF but not the AE. By default it locks the AE and AF. I have been through all the settings (custom) and I do not see that option.

And yes I have reviewed the manual and googled this before posting.

I know this had to be a setting. Help!

[RobertTheFat]

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@manatee4mation wrote:

I Canon 5D Mark IV. In evaluative mode, I am trying to half press the shutter to lock the AF but not the AE. By default it locks the AE and AF. I have been through all the settings (custom) and I do not see that option.

And yes I have reviewed the manual and googled this before posting.

I know this had to be a setting. Help!

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If your objective is to deprive the shutter button of the ability to control metering while leaving its AF function intact, you should be able to do that with any of several configurations of the "AE lock" (*) button. See page 505 of your manual, also the table on pages 496-499..

I think the key to understanding this is that someone has to establish the metering. It doesn't have to be the shutter button, but the shutter button has to be able to do it if no one else does.

[Waddizzle]

I don't have any of the 5D bodies, but I do have a 6D, 7D Mark II, and a 1D Mark IV.  In all of them, I have noticed subtle differences in how and when exposure locks, depending upon your shooting settings.  The cameras do seem able to continuously and dynamically update the exposure settings.

First and foremost, I only see these behaviors in AI Servo mode, never in One Shot mode.  Another requirement is that you need to let the camera control at least one leg of the exposure triangle, which, of course, becomes the exposure setting that gets dynamically updated.  

I mostly use AI Servo only when I'm pretending that I am shooting for NatGeo.  I'l typically shoot in manual mode, but with ISO set to AUTO.  I also use BBF, too.  If I hold the BBF button pressed, I can see the ISO change as I pan the camera from a dark scene to a light one.

Whether that would work with aperture and shutter speed in Av and Tv modes remains to be seen.  I would suspect that they would update themselves on the fly, too.

[TCampbell]

You can set AF on the back button and metering on the front button, but I don't think you can set the reverse (AF only on the front button).  

You can, of course, disable AF via the switch on the lens ... but then you're manually focusing.  Possibly not what you want.

You can also lock metering so that pressing the front button will not attempt to re-meter when the camera auto-focuses.  You have two options here... 

The traditional option is the use of the "AE Lock" feature.  Point the camera at the subject you want to use as your metering source and press the asterisk button (*) and the camera will meter and then "lock" that meter reading in.  But it is only locked in as long as the metering system is awake -- if you wait too long before taking the shot, it will self-cancel.  It also self-cancels within 2 seconds of taking a shot.

But you can configure it to do "AE Lock + Hold".  If you enable that feature, the AE Lock will be held until you power off the camera (or until it goes to sleep from inactivity).  You can also manually cancel but pressing the AE Lock (*) button again.

This would let you meter on one thing... then re-compose, auto-focus, and shoot another thing -- without the exposure settings changing on you.

See:  http://learn.usa.canon.com/resources/blogs/2013/20131203_winston_aelock_blog.shtml

[manatee4mation]

All those options are ones I know about and not what I want to do.

What I want to do is keep AF locked with half-shutter but let the exposure continue to work. Obviously in TV or AV modes. Nikon does this. Sony does this. Why not Canon? You can have ISO continure to float. So we know there is nothing inherintly impossible about this for the camera. Furstrating for a $3500 camera.

[Waddizzle]

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@manatee4mation wrote:

All those options are ones I know about and not what I want to do.

What I want to do is keep AF locked with half-shutter but let the exposure continue to work. Obviously in TV or AV modes. Nikon does this. Sony does this. Why not Canon? You can have ISO continure to float. So we know there is nothing inherintly impossible about this for the camera. Furstrating for a $3500 camera.

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It's called "One Shot" focusing mode.  

[RobertTheFat]

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@manatee4mation wrote:

All those options are ones I know about and not what I want to do.

What I want to do is keep AF locked with half-shutter but let the exposure continue to work. Obviously in TV or AV modes. Nikon does this. Sony does this. Why not Canon? You can have ISO continure to float. So we know there is nothing inherintly impossible about this for the camera. Furstrating for a $3500 camera.

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Isn't that pretty much what it does by default? I think there's a timeout on the metering, but by that time the camera should have a pretty good idea of what the exposure should be. If it's not long enough for you, you could use the back button to lock focus and push the shutter button halfway again.

[Waddizzle]

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@RobertTheFat wrote:

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@manatee4mation wrote:

All those options are ones I know about and not what I want to do.

What I want to do is keep AF locked with half-shutter but let the exposure continue to work. Obviously in TV or AV modes. Nikon does this. Sony does this. Why not Canon? You can have ISO continure to float. So we know there is nothing inherintly impossible about this for the camera. Furstrating for a $3500 camera.

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Isn't that pretty much what it does by default? I think there's a timeout on the metering, but by that time the camera should have a pretty good idea of what the exposure should be. If it's not long enough for you, you could use the back button to lock focus and push the shutter button halfway again.

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Good point.  I was using BBF when i tested it.

[manatee4mation]

I spoke to Canon. They said it was a design choice. My point is simple. This should be an option. We can reasonably surmise that some people want this because Nikon and Sony offer the option.

BBF and BBE are terrific buttons. They do not solve for what I want; just offers an awkward work around.

[RobertTheFat]

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@manatee4mation wrote:

I spoke to Canon. They said it was a design choice. My point is simple. This should be an option. We can reasonably surmise that some people want this because Nikon and Sony offer the option.

BBF and BBE are terrific buttons. They do not solve for what I want; just offers an awkward work around.

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I don't quarrel with your right to be annoyed that an option you'd like to have isn't there. But I'm having a hard time seeing what that particular option is good for. If you had it, when would you use it and why?