Peter Hill


Peter Hill

Written by:

Peter Hill
October 16, 2009

Mirror Lock-up - what it is & when to use it

It sounds really iffy and risky, but it’s really quite simple.

Do you use an SLR?

When you look through the viewfinder, the image you see is courtesy of a mirror. When you press the shutter, the mirror has to firstly swivel up out of the way of the light path before the sensor captures the light coming through the lens – this action you see as a dark flash in the viewfinder immediately after pressing the shutter release.

When the mirror moves out of the way it slightly vibrates the camera. Not much, but more than the act of pressing the shutter release.

If you are taking a fast shot, this vibration, along with the vibration of pressing the shutter, doesn’t factor.

But for a long exposure it will reduce your clarity.

So, for the shutter release, we can use a remote release to avoid that vibration.

And for the mirror swivel vibration we can use mirror lock-up. How does it work?

When “enabled” – usually as a Custom Function, you take a photograph by pressing the remote shutter release twice.

First press and the camera goes “kerplunk!” as the mirror swivels out of the way. Second press and you hear a small “click” as the shutter opens, along with the red light appearing on the back of the camera indicating the shutter is open.

Not all digital SLRs have mirror lock-up as an option, and it is hard to do a search to create a list of the ones which do. However, as far as I can tell, the Canon EOS 20Da, released in 2005, was the first Canon digital SLR to offer it, and hence if you have a later model, eg 30D, 40D etc, they should all have it.

If you don’t have a remote shutter release, but rely on the self-timer, it seems the mirror lock-up will only work with a 2 second delay on some Canon digital SLRs, not 10 seconds. This is the case for certain at least with the Canon EOS 500D (aka Rebel T1i or Kiss Digital X3)

Further reading here and here.

Cheers

  • Charuhas Images

    Charuhas Images

    Very informative Peter. Thanks for sharing.

  • Peter Hill replied

    no worries, my pleasure, thanks

  • salsbells69

    salsbells69

    Fantastic info Peter, thankyou :))

  • Peter Hill replied

    no problemo Sal, thanks

  • jacqleen

    jacqleen

    Peter…I loveeeeeeeee these mini courses….YOU are such a GOOD Teacher…and I love any info that YOU share with us…thank YOU soooooooooo Sooooooooo MUCH :) xx

  • Peter Hill replied

    [blush blush]

    Most of my family will be pleased to learn of my [apparent] teaching skills. They’re the teaching crowd I did not join!

    Cheers and thanks!

  • Wendi Donaldson

    Wendi Donaldson

    You are SO.O.O.O.O. helpful!!!!!! THANK YOU!!!!

  • Peter Hill replied

    No worries Wendi!

  • Alex Marks

    Alex Marks

    Thanks Peter, very informative

  • Peter Hill replied

    Cool, thanks Alex.

  • Prasad

    Prasad

    Thanks for sharing, Peter

  • Peter Hill replied

    thanks my friend

  • Globalphotos

    Globalphotos

    Interesting info Peter :-))

  • Peter Hill replied

    Thanks Varinia

  • David Murphy

    David Murphy

    Gday Peter…...I’ve been using this function for some time now…...it makes a helluva difference for overall clarity. You wouldn’t credit how good it is till you do a comparison when you don’t enable it!! I use the canon 400D, for those who might not know that it has that ability.
    Cheers mate, great info!!

  • Peter Hill replied

    :)

    thanks David!

  • Richard Stanley

    Richard Stanley

    Thanks for this Peter – I’ve been thinking about using MLU for some time and now you have convinced me. I’d better get a remote.

  • Peter Hill replied

    Thanks Richard. Kicking myself for not doing sooner.

  • lizalady

    lizalady

    Thanks for sharing your wisdom.

  • Peter Hill replied

    thanks Liza

  • Jim Worrall

    Jim Worrall

    The use of the mirror lock up feature is actually more advantageous for exposures requiring a faster shutter speed rather than a long exposure.
    See Wikipedia – mirror lockup article

  • Peter Hill replied

    Thanks Jim. I hear you. That article was the first one I linked above. It mentions “shorter shutter speeds” as being more or a problem for MLU to fix – but doesn’t say shorter than what. It also blithely adds the rather (un)helpful advice that “Use of a tripod helps prevent movement of the camera during this operation” whereas I would proffer that unless you use a tripod it pretty much is pointless using MLU ie the article makes some bland statements.

    But the point it tries to make (I think) is that if the length of time it takes the mirror to move out of the way is, say, X seconds, then an +-X.005 second exposure will suffer more from MLU than, say, an X +120 second exposure. to which I would add that if your exposure time is a fraction of X seconds, eg 1/8000th of a second, the impact of MLU is way way less.

    I’m interested to know if there are downsides to delaying the 2 releases, eg waiting for that right wave to hit that rock.

    I should also add that if you are using the remote shutter release and shooting Bulb, eg longer than 30 seconds, you should connect the remote shutter cable to the camera AFTER pressing the shutter the first time. that’s assuming you are using a tripod!

  • Tatiana R

    Tatiana R

    Cool! Does it work with noise reduction enabled at the same time? I don’t see why not…

  • Peter Hill replied

    No reason why not as far as I can think, which admittedly, being Friday afternoon, isn’t much.

  • drec

    drec

    Why do you connect the cable after pressing the shutter? Couldn’t that introduce camera shake?

  • Peter Hill replied

    No, the first time you press the shutter it merely locks up the mirror. then you connect, then use the remote shutter release to take the shot.

    If your exposure time is 30 seconds or less, just set the camera to manual, connect the remote, then use it to press twice. (You should pause anyway, not like a machine gun.) the point about waiting until the second shot only applies if you want a longer than 30 second exposure and need to go to Bulb.

  • dinghysailor1

    dinghysailor1

    cheers peter! thanks so much for sharing!
    :))

  • KathyT

    KathyT

    The original 20D (mine bought in 2004) also has mirror lock up. I use it for all my sunrise and sunset shots – usually in conjunction with the timer – therefore only having to press the shutter (or cable release) once.

    Great info Peter.

  • OldBirch

    OldBirch

    Thanks, Peter. When I got my Nikon D90, I had assumed that it came with mirror lock up and was dissapointed to find that it did not. But thanks to your article, I looked into it in more depth and found that the d90 has Exposure Delay mode, where the mirror is up for 1 second before the shutter is released. Is this one second long enough to have the same effect as mirror lock up? Thank you again!

  • Peter Hill replied

    Hmmm, 1 second … yes, I believe so [thinking aloud here about my own speed at the second shot]. Thanks for your comment too btw!

  • Brock Hunter

    Brock Hunter

    I often use the lockup feature on my Olympus E-30. My only caution is to remember to turn it off when done. It always seems the next time I use my camera it is for something I want to capture in a hurry and end up cursing myself when I figure out why the delay…

  • Peter Hill replied

    I hear you on that one!!

  • Glenn Stephenson

    Glenn Stephenson

    Yeah, thanks a heap Pete. I’ve just bought my first SLR and am lapping up any info my eyes and ears can get hold of. Very valuable info.

  • Peter Hill replied

    No worries Glenn – have fun!

  • Rob Toombs

    Rob Toombs

    This is what THE PHOTOGRAPHERS VAULT is all about… Great info for everyone to experience… Thank you and brilliant info…..

  • Peter Hill replied

    thanks Rob, no worries!

  • PaulBradley

    PaulBradley

    And you can assign the MLU custom function to one of the “My Menu” functions in Canon 40D bodies and above to make the process even easier.

    Incidentally, have you ever rested your fingers on the body when the shutter fires? Even tripping the shutter causes vibration.

  • Phineous Cassidy

    Phineous Cas...

    excellent i used to use mlu then forgot all about it after not shooting for a while thx for the refresh

  • Travis Easton

    Travis Easton

    I used to use mirror lock up as a matter of course with my old EOS30 film camera but when I got my 5DmkII and tried it to my frustration you could auto bracket 3 shots or do mirror lock up but not both together and it drove me crazy having to manually take each bracket so I haven’t used it since. Although with my 70-200mm f/2.8L IS the mirror swing shake is pretty noticeable on my hot shoe mounted spirit level so your article has reminded me again that maybe I should use it sometime. If you have worked out a way to mirror lock and autobracket I’d e most interested.

    Cheers

    trav

  • Linda Bianic

    Linda Bianic 10 days ago

    I hadno idea that mirror lock up even exisxted or how it worked, thanks so much!!

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