Exposure Lock

[Lucinda Luvaas]

The Canon XL2 manual doesn't say much about the exposure lock function. I want to be able to use it in AV mode or Manual mode to lock in my settings in order to avoid shifting light values which of course is the problem I had with my less expensive Canon. I assume that I should press the Exposure Lock after getting my setting and is that all there is to it? as I said, there's not much info in the manual. Any more information would be greatly appreciated!
Lucinda

[Chris Hurd]

Hi Lucinda,

Exposure Lock is not available in Manual mode. It would have no purpose in Manual mode because there is no automatic exposure to be locked. The purpose of Exposure Lock is to kill the auto exposure (AE) function within the auto or semi-auto program modes, "locking" it to whatever setting it had when you activated Exp. Lock.

Exposure Lock is available in the A (automatic), Av (aperture priority) and Tv (shutter priority) program modes. When activated, Exp. Lock converts each of these program modes into full Manual control. There is no difference between the M (manual) mode and A, Av or Tv modes when Exp. Lock is activated.

When shooting in A (automatic) mode, whatever f/stop and shutter speed the camera automatically finds at any particular moment is locked in when you press Exp. Lock. The camera ceases its automatic image control. Those settings remain fixed in place even under changing lighting conditions until you change them manually using the iris control dial or shutter speed buttons, or until you de-activate Exp. Lock.

When shooting in Av mode, you set the f/stop manually and the camera varies the shutter speed automatically. Press Exp. Lock for full manual control of iris and shutter. When you de-activate Exp. Lock, the camera goes back to automatic shutter speed but the f/stop remains fixed to what you set it to in the first place.

I'm not a big fan of the A or Av modes, because both of these programs involve the potential for the camera to automatically change the shutter speed. To my eye, watching a shift in the shutter speed is a jarring experience, not as visually smooth as shift in the f/stop.

That's why I greatly prefer the Tv mode, where you can dial in whatever shutter speed you want and the camera will not change it no matter what. This mode lets the camera find the right f/stop automatically. If you want full manual control, press Exp. Lock. Go back to AE (auto exposure) instantly by de-activating Exposure Lock.

My own personal preference for XL2 program modes:

1. The best is Tv + Exp. Lock. This is better than the M (manual mode) because it does everything Manual offers plus it gives you AE on demand (without affecting shutter speed). Use the AE shift dial to tweak the auto exposure to your liking.

2. In unfamiliar shooting situations where you've never been before, A + Exp. Lock. This is full Manual plus AE plus auto shutter. AE together with auto shutter is fine for quick shooting and totally unfamiliar environments that I haven't encountered before. The camera does a fine job in A (automatic) for those times when you've got to concentrate on what's happening in the frame. Use the AE shift dial to tweak the auto exposure to your liking.

3. I'll put M (manual) in a distant third place because there's no option for AE.

4. I usually avoid Av altogether. I don't want the shutter speed to change all the time as it constantly tries to compensate for a pre-determined f/stop that it's not allowed to adjust. Although Av + Exp. Lock equals M (manual), which is fine by itself, there's no provision at all for AE this way and I certainly don't want auto shutter all by itself.

5. Green Box (easy recording) -- the mother-in-law mode. Locks the human out of the equation entirely, so that even a civillian can get a decent image out of it. No way to override anything though.

Hope this helps,

[Lucinda Luvaas]

Thanks Chris! that about explains exposure lock which is what I thought I needed to do.

As far as TV over AV, etc...what about depth of field? Isn't AV mode best for that?

Lucinda

[Chris Hurd]

Hi Lucinda,

I wrote that from the point of view involving event videography, which is my background... concerning shoots that are unrehearsed, uncontrolled and unrepeatable. If you have the time while you're shooting to worry about depth of field, then I would call that a controlled situation. In that case the M mode or Tv + Exp. Lock mode might be your best bet. Just remember that if you dial in a specific f/stop for depth of field control, then you're forcing the camera to automatically find an appropriate shutter speed to match. Now that particular shot is going to look out of place in between other shots that are using different shutter speeds... unless all of your shots have similar shutter speeds... in which case you're back to M or Tv + Exp. Lock again. Hope this helps,