Teach me who to use Mirror-Lock-Up to shoot very long exposures.

Wail

Wail

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Wail
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2nd post on “teach me” in the same days.

I am not a big fan of very long exposures and have no idea how to use the mirror lock-up to reduce camera shake.

My understanding is, when the mirror is up the picture is being “captured”; as such once I press the shutter button this causes the mirror to move up and sensor starts to absorb light to register the image. I then press the shutter release button for the second time to bring down the mirror.

So, how does this reduce camera shake, since there are two pressing of the shutter release button? How do I time the duration for the exposure, should I use a stopwatch?

I know these questions may sound trivial for many, but please bear with me as I’ve never used these functions and I figured today is a good day to learn.

Thanks for any feedback.
 
when the mirror lock up is on. the first release of the shutter moves the mirror out of the way, the second actually opens the shutter curtains (then closes them and drops the mirror back into place after the exposure time) this way the vibrations the mirror causes going from down to the up position don't affect the actual capture process.
 
Someone with more knowledge can correct me if I'm wrong, but I think the purpose of the mirror is only to reflect light coming through the lens up to the eye piece. It serves no function in blocking the light in terms of taking a photo. This is taken care of by the shutter which opens to let the light through.

By locking the mirror up you will not be able to use the viewfinder, but the exposure will not start till you push the button and the shutters move. By using a combination of tripod, remote release & mirror lock-up you remove all possible sources of vibration.

I would assume there would be no benefit to locking up the mirror if you aren't using a tripod or remote release (or the timer).

If you are using the bulb function, then yes a stopwatch or the timer on your camera if it has one.

Mike
 
OK, so the it's the second pressing of the shutter release button that opens the curtain .. but then how do I keep the exposure long? Since as soon as I press the shuter release button for the second time the mirror comes down!
 
How do I keep the shutter open, say for a whole 2 minutes, while the mirror is locked up?
 
Use the bulb setting. Put the camera either in manual or shutter priority and increase the shutter speed till the camera says "bulb". then you have to press the button for as long as you want the exposure, that's why a shutter release that can lock down is useful, otherwise you will be shaking the camera like mad!

I'm now "Quite Chatty"!:D
 
Oh that's great ... I just gave that a try and worked very well. Of course, I was only hand holding the camera to try out the concept to see if I got it right ... :)

Thank you all for the replies and for helping me out on this subject.
 
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