Mirror Lock-up...when to use it?

[cruz610]

I have read many posts suggesting using mirror lock-up, but there is no succinct answer as to what situation warrants it. Do most people use it all the time? What is the difference between mirror lock-up and not using it?

[Nick_C]

I tend to use mirror lockup if im on a tripod & my shutter speed is very slow, below 1/20th, combine that with a cable shutter release & its about as steady as it can get.

Nick :-)

[ghibli99]

I use it in situations where any slight camera movement (i.e., the mirror mechanism) might affect a shot. Used in conjunction w/ the timer or a remote trigger, you can pretty much guarantee that your shot won't be affected by vibrations from camera mechanicals or you pressing the shutter button. I always use this function for night shots or anything requiring a longer exposure.

-Mike

[Cathpah]

with long lenses or long exposure times. only on tripod and usually only if using a cable release. If I'm not using a cable release, my shutter press will make far more vibration than the mirror slap.

[Ephemeral]

with long lenses or long exposure times. only on tripod and usually only if using a cable release. If I'm not using a cable release, my shutter press will make far more vibration than the mirror slap.

Without a cable release you can still use the timer function. :)

[Uhland]

I use it for long exposures only.

[Jman13]

Mirror lock up is useful for shots between about 1/25s and 1 sec. Any shorter and the shutter speed cancels it out. Any longer, and the vibration is for such a small part of the exposure that it isn't going to make a difference. (Kind of like when a person walks in front of your camera during a 30 second exposure...as long as they don't stop you can't see them.) It's most needed around the 1/6-1/15sec ranges in my experience. I always use my cable release when using MLU (and I'll use my cable release for almost all long exposures)

[KCMO Al]

I use it in conjunction with the cable release for macro shots on a tripod.

[WGTB]

(Kind of like when a person walks in front of your camera during a 30 second exposure...as long as they don't stop you can't see them.) It's most needed around the 1/6-1/15sec ranges in my experience. I always use my cable release when using MLU (and I'll use my cable release for almost all long exposures)

I disagree with that, two differenct effects. If the camera moves during in exposure the whole photograph will suffer camera shake. If you kick your tripod and the camera moves for 1 sec, adding another 10 secs to the exposure isn't going to cure it. Similar if the camera moves because of mirror slap the camera moves (no matter how short the legth of time), and no extra length of exposure will compensate.
If someone moves in front of a time exposure, they will appear ghost like or disappear, but the background will be sharp.

[gjl711]

I disagree with that, two differenct effects. If the camera moves during in exposure the whole photograph will suffer camera shake. If you kick your tripod and the camera moves for 1 sec, adding another 10 secs to the exposure isn't going to cure it. Similar if the camera moves because of mirror slap the camera moves (no matter how short the legth of time), and no extra length of exposure will compensate.
If someone moves in front of a time exposure, they will appear ghost like or disappear, but the background will be sharp.
It all depends on the exposure time. The longer the exposure time, the less of an impact the mirror shake will have. For example say 1000 photons are needed to hit the sensor for the photo site to be perfectly exposed. It is dark so your exposure time is 30 seconds. That means every second 33 photons hit the receptor. If the mirror slap shakes the camera for 100 milliseconds you have missed 3 photons but you still have 997 perfect ones. It will have an impact but so small that it will be unnoticeable.

[WGTB]

It all depends on the exposure time. The longer the exposure time, the less of an impact the mirror shake will have. For example say 1000 photons are needed to hit the sensor for the photo site to be perfectly exposed. It is dark so your exposure time is 30 seconds. That means every second 33 photons hit the receptor. If the mirror slap shakes the camera for 100 milliseconds you have missed 3 photons but you still have 997 perfect ones. It will have an impact but so small that it will be unnoticeable.

I can't argue against that as I don't have the facts, but it seems logical.

To get back to the original posted question
Mirror Lock-up...when to use it?

It would seem, from the answer above, that mirror slap for long exposures is not a problem (and I have often done iso 100 f22 45secs). On this thread three people have said they use mirror lock up for long exposures.???
Yours confused.

[SimonG]

... On this thread three people have said they use mirror lock up for long exposures.??? ...
Well, it may not really be needed, but if one is already committed to dragging out the tripod for their long exposures, taking it one step farther by enabling mirror lock can't hurt, right?

As an aside, this whole mirror lock discussion would be far easier to follow if it were contained in a single thread. ;)

[WGTB]

Well, it may not really be needed, but if one is already committed to dragging out the tripod for their long exposures, taking it one step farther by enabling mirror lock can't hurt, right?

No it can't hurt, but can add to the confusion :lol:



As an aside, this whole mirror lock discussion would be far easier to follow if it were contained in a single thread. ;)

Yes, it would. I didn't start either, just throwing in my tuppence (two cents) worth on both ;) ;)

[Jman13]

WGTB - it may not be logical, but it's true....many photographers before me have experimented with this, and at around 1 second, the effects of mirror slap become about nil. I'll still use mirror lock up for long lenses and 5-10 second exposures, but not on short lenses (unless it's in the danger zone.)

[cruz610]

So would using mirror lockup be useful in conjunction with IS or would it not be necessary? Obviously if the camera is on a tripod IS becomes less useful but for handheld shots up to 1/4 to 1/2 second, would mirror lockup be useful?

[Wilt]

MLU has most benefit at slow, not long exposures. For example, maybe around 1/8 sec. the effects of mirror-induced vibration are present during a significant enough portion of the total exposure time to make a visible difference; for for longer exposures (a couple of seconds) the dampening period is a small part of the total exposure. Published tests have shown this to be true, not mere speculation.

[Atomic79]

Once again my favorite reference for this topic. About 75% down on the page is his info on Mirror Lock Up, but the whole site is worth reading.

http://www.cambridgeincolour.com/tutorials/night-photography.htm