# AE-L / AF-L on D3100



## Big Mike (Jan 17, 2012)

OK Nikon minions...someone fill me in here.

I teach some photograph classes, one of which is Using your DSLR.  One part of the class is about using auto exposure lock as a way to get proper exposure while in auto/priority modes.

So looking at two Nikon cameras; the 3100 & the 5100.  They both have the same button for auto exposure lock *and* auto focus lock.  But what if you don't want to lock the focus?
On the D5100, there is a menu option to set the AE-L function to the shutter release button....thus allowing you to lock the exposure, but the camera still refocuses if for example, you go from a grey card to your subject.  (provided you're using AF-C).

But on the D3100, the menu option for assigning AE-L to the shutter button, seems to be absent.  So I couldn't find a way to lock exposure without also locking the focus.  (I guess you could use manual focus, but that's not ideal).

So am I just missing where to do this...or is it a limitation of the lower end camera?


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## MTVision (Jan 17, 2012)

Big Mike said:
			
		

> OK Nikon minions...someone fill me in here.
> 
> I teach some photograph classes, one of which is Using your DSLR.  One part of the class is about using auto exposure lock as a way to get proper exposure while in auto/priority modes.
> 
> ...



On the d5100 you also have the option to lock only exposure with the ae-l/af-l button.


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## MTVision (Jan 17, 2012)

The functions you can choose for ae-l/af-l button are:

Ae/af lock
Ae lock only
Af lock only
Ae lock (hold)
Af-on


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## Big Mike (Jan 17, 2012)

That's on the 5100? 

Do you know about the options on the 3100?


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## Rephargotohp (Jan 17, 2012)

Mike on page 146 of the D3100 manual, it shows you can set that button to AE-L or  AF-L


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## MTVision (Jan 17, 2012)

Big Mike said:
			
		

> That's on the 5100?
> 
> Do you know about the options on the 3100?



It's the same. I looked it up. I didn't find anything about the shutter but the ae-l/af-l function is the same.


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## Big Mike (Jan 17, 2012)

I'll try to look up the manual, I don't have the camera...but plenty of my students do.

I just ask because in the spot in the menu of the D5100 where you could set (enable) the shutter button to lock exposure....the D3100 didn't have that option at all.  

So it's somewhere else in the menu...and I couldn't find it.  And because of Nikon's absurd user manual layout (no index), I couldn't look it up quickly.


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## Big Mike (Jan 17, 2012)

MTVision said:


> Big Mike said:
> 
> 
> 
> ...


Yes, the button does the same thing on both cameras, but what I was seeing, was that it was easy to change it (AE-L moved to shutter release) on the 5100 but not on the 3100.


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## MTVision (Jan 17, 2012)

Ae lock - at default setting of off, exposure only locks when ae-l/af-l button is pressed if on is selected exposure will lock when shutter release button is pressed halfway. 

Looks like the ae lock is in the camera menu under the title buttons. That's what it shows in menu anyways


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## MTVision (Jan 17, 2012)

Go to menu button then setup menu and there should be a place to set up the Fn button, the ae-l/af-l button and the ae lock (which allows exposure lock by shutter).


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