Canon Users – Don’t use Mirror Lockup!
If you are shooting on a Tripod and using exposure bracketing, for purposes such as HDR, I recommend you do not turn on mirror lockup, even for medium to long exposures. This may seem like a crazy recommendation and may go against everything you have heard but here is why. When using a Canon DSLR body with mirror lockup off, bracketing on, and when using the self-timer function to trigger the exposure, the camera will automatically expose all the frames in the bracketed sequence without further intervention. What this means is that even if you are using a cable release, turning on the self-timer function when bracketing, will allow you to press the button once and sit back while the camera exposes all of the bracketed frames.
If you were not using the self-timer, you would have to press the button once for each of the bracketed frames. That could be as many as seven button activation on a EOS 1D or 1Ds camera body (these bodies allow for 3, 5 or 7 bracketed frames) in order to expose all the frames in the bracketed sequence. And if you add mirror lockup to the mix, then you would have to press the button twice for each exposure (once to lock up the mirror and once to expose the frame).
And here is the catch. If you turn on mirror lockup, and still try using the self-timer, the whole process of the camera automatically exposing all of the frames is defeated. In this configuration, you would press the button, wait for the timer count down, have the camera lock up the mirror, pause, expose the frame and then nothing. You have to repeat the process for each frame of the bracketed sequence. Stupid, I know!
So how do you get the camera to lock up the mirror but still be able to use the self-timer and have the camera expose all the frames in the bracketed sequence automatically without further intervention? Is it possible? Yes. The key is Live View. In fact, I think the Live View method beats mirror lockup hands down.
When you activate Live View, the mirror is locked up so that the shutter can open, the sensor can be exposed and the image can be presented on the rear LCD display. If you have bracketing enable and you have the self-timer enabled, pressing the shutter in Live View will expose the entire bracketed sequence without the mirror moving at all. The process is so quiet, you know you are not adding any possibility of mechanical vibration. The only thing moving is the shutter. And after the exposure, you are returned to Live View and the mirror has still not moved. So even if you don’t need to use Live View for focus/composition, activating it prior to the exposure provides the best of both worlds. You effectively get mirror lock up but you also get to sit back and let the camera make all of the exposures in the sequence. Cool huh?
I use my Tilt Shift lenses for all my landscape work, so I use Live View most of the time to fine tune the focus. When doing HDR work, I normally use Manual mode with bracketing on and the self-timer set of just 2 seconds (not all Canon bodies offer the 2 seconds option but the 1Ds MIII and 5D MII that I use do). I activate Live View, adjust my exposure, focus and compose and just press the button and let everything else happen automatically. I don’t even bother with the remote release. I get enough time (the self-timer amount) for any camera movement to subside from having pressed the shutter button on the camera and I get all of my bracketed frames exposed with effective mirror lockup. In fact, during the long bracketing sequences that can take several minutes to expose, I use this time to think about alternate compositions or my next subject, instead of counting frames and repeatedly pressing the button.
Try it, you will like it!