# How to LOCK Exposure with only the Shutter-button MarkIII?



## ZoeEnPhos (Nov 2, 2012)

About the basic using of the Canon EOS 5D Mark III ( I have just made an order for Canon EOS 5D MarkIII and I am bit novice in how to make the right options for my future photography)

Firstly how can I understand the main and functional difference between manual selections of:

*1 - Single-point-Spot-AF*


2 - Single-point-AF

*3 - Single-point Expansion AF*

4 - AF Point Expansion

and with the AI Servo AF-function - which selection is the best when for example tracking BIF (Birds In Flight)?
And is the Case number five (5) or six (6) best choice to tracking a flying bird? What are you Bird Photographers using together with your Mark III DSLRs if I may ask your valued advice?

I have lenses in these Groups of A, B, C and group E.

Another importance would be - *how can I choose and LOCK the right exposure value, by only using the shutter-button* and *NOT using the AE-Lock button* in back of the camera, so it remains as I wish if I use SPOT-METERING with Single-point-Spot-AF? Is this possible? I feel that I can not really find the answer from the English manual (I am Swedish speaking natively)

Why I am asking this is, that I have noticed on my MKII when there is this option to choosing the Evaluating Exposure Measure - option, and I do "lock" the focus with the chosen center-focus-point (that I only use with my MKII) the MarkII also keeps that EXPOSURE VALUE which was in the focus-area-center and my single center-point-focus-area kind of is guiding and "locking" and keep the EV "locked" as long as I keep the shutter-button half-way pressed down and I do not release it - have you the same experience with using your MarkII and can this same option work with Mark III?

(By the way, this is not the case with my 7D that will re-estimate the exposure-value, if I change the framed selection from where I have locked-the-focus in lens, by keeping the shutter-button pressed down half-way!)
I just wonder how this using-shutter-button half-way pressed-down, will work on my not yet received 5D Mark III?
Or is this working only together with the 1DX (namely the Single-point-Spot-AF with "locked" spot-exposure value)?
Sorry if I am a bit vague here - I do not have the Mark III DSLR in my hands yet today but wish to start the learning curve in advance!

If anyone could give me some guidance - because I really wish to know HOW to make this working and NOT using the AE-Lock Button in the back of the camera!

Wishing you all All the Best!
Charl


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## neuroanatomist (Nov 2, 2012)

Using Custom Controls, you can assign AE Lock to the shutter half-press (you can do that on the 7D, as well).


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## TriGGy (Nov 2, 2012)

neuroanatomist said:


> Using Custom Controls, you can assign AE Lock to the shutter half-press (you can do that on the 7D, as well).



I dont have my camera with me, but try to see also if you can do an AE lock and Hold (*H) on the shutter button. AE will be locked unless the camera is turned off or you depress the button again to release the lock.


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## K-amps (Nov 2, 2012)

neuroanatomist said:


> Using Custom Controls, you can assign AE Lock to the shutter half-press (you can do that on the 7D, as well).



Didnt know this.... 

Why is this not the default setting? 

So doe sthis mean, if I choose spot metering and center AF and lock AE the way you have described, that I essentially have a 1 D series exposure lock synced with the AF, albeit only center point?


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## neuroanatomist (Nov 2, 2012)

K-amps said:


> neuroanatomist said:
> 
> 
> > Using Custom Controls, you can assign AE Lock to the shutter half-press (you can do that on the 7D, as well).
> ...



If it were the default setting, you'd have to take the shot - your metering would be locked until you took the shot or it timed out. You may not want AE Lock with anything but spot metering, anyway, I suspect.

Don't have my 1D X or 7D with me, but in the custom controls for the shutter button, I think the options are metering + AF start, metering only, or AE Lock. I think if you assign AE Lock to the shutter, you need to assign another button (AF-ON or AE Lock) to AF start. Not sure, though - I'd have to check.

But on my 7D, I'd often set spot metering, and I use back-button AF, so I'd center the subject, hit those two buttons (which are conviently close) to lock focus and exposure on the subject, then recompose and shoot.

Where the 1-series with AF point-linked spot metering has a big advantage is that you can take a burst with spot metering on an off-center subject, instead of just one shot.


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## ZoeEnPhos (Nov 2, 2012)

neuroanatomist said:


> K-amps said:
> 
> 
> > neuroanatomist said:
> ...



A really BIG THANK to you Neuroanatomist for this very good answer!
These facts I found very valued to me sir now quoting you about how to make this functional that I did not know about:
"But on my 7D, I'd often set spot metering, and I use back-button AF, so I'd center the subject, hit those two buttons (which are conviently close) to lock focus and exposure on the subject, then recompose and shoot.

Where the 1-series with AF point-linked spot metering has a big advantage is that you can take a burst with spot metering on an off-center subject, instead of just one shot."

Wishing you sir All the Best and very nice week-end!

Carl


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## traveller (Nov 3, 2012)

Here's another question, if you use the default AE lock (i.e. * button), is there any way to disable it without turning the camera off and the back on? Maybe I'm being stupid, but I've never found a way! (Personally, I generally use back button AF, with AF disabled on the shutter button and AE lock on half press).


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## Mt Spokane Photography (Nov 3, 2012)

traveller said:


> Here's another question, if you use the default AE lock (i.e. * button), is there any way to disable it without turning the camera off and the back on? Maybe I'm being stupid, but I've never found a way! (Personally, I generally use back button AF, with AF disabled on the shutter button and AE lock on half press).


Just let go of the button and its unlocked. You might have changed the default setting to AE Lock (Hold), which holds the AE Setting until you press the button again. Read page 321-326 of the manual to see how to re-assign the function to default.


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## neuroanatomist (Nov 3, 2012)

traveller said:


> Here's another question, if you use the default AE lock (i.e. * button), is there any way to disable it without turning the camera off and the back on? Maybe I'm being stupid, but I've never found a way! (Personally, I generally use back button AF, with AF disabled on the shutter button and AE lock on half press).



You have to set the shutter to AE lock while pressed, then the * button will do the same.


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