Mirror Lock-Up

[barry_kleinberg]

Hi all,

 

I have installed the Russian Hack for my 300D and was just wondering

whether or not there are any disadvantages to always enabling mirror

lock-up. Whilst I will no doubt only need MLU for macro work it will

save changing the Custom Functions.

 

Thanks

 

Barry

[cfimages]

AFAIK, faster than about 1/30 or slower than 1 sec you won't need MLU.

[barry_kleinberg]

I understand that it will not be needed but is there any reason to disable it when I dont need it?

[mark u]

You can switch to continuous drive which will disable MLU even if it's set as a CF. But if you don't do that then MLU will lead to shutter lag, the need for double shutter presses if you aren't using the delayed timer and problems with maintaining accurate framing if you're not using a tripod. With continuous drive you might end up wasting some frames if you're too slow to release the shutter, and as with a follow through on a golf shot, it may affect your hand holding stability if you raise your finger too suddenly.

[always_wanderlust]

Could be wrong, but this is how I understood it. The MLU basically delays the shutter - it brings up the mirror, then depending on the time you set in the function, it fires the shutter (delays in 1/3 of second and so on) after the mirror is up. So if you want fast continous shots, its not a good idea to have MLU on. So, yes there's an advantage to disabling it when not in need. You'll notice this delay - try it with the MLU on and then without.

[charlie_vigue]

I have no idea what this hack is or does, but MLU is simply that the first shutter button press raises the mirror (and blacks out hte viewfinder, of course), the second shutter button press triggers the shutter. It is generally used to permit mirror induced vibrations to damp out before making the exposure. Generally anything that needs MLU can be well planned for, I use it a lot, but never leave it on.

[mormegil]

I've read somewhere that MLU might actually be detrimental to pics with the 300D.

 

The reason being, the 300D wasn't designed to use MLU. In fact, the mirror movement may be counteracted by the shutter curtain movement, yielding slightly less vibration (due to opposing motions yielding a lower net force).

 

Separation of the mirror motion from the 1st shutter curtain motion via MLU may yield more shake.

 

I wish I could find the link, but there were close crops that showed this effect.

 

 

I haven't done any tests yet, and my tripod sucks, and my camera is off for hotspot repair, so I can't test any of this myself. Personally, I'm a little skeptical that such a light curtain can counteract such a heavy mirror (but it does move faster, and KE=mv^2 - so velocity has a disproportionate effect on work/energy than mass).

[henry_minsky1]

The mirror lockup fires the shutter after a two second delay using the Russian firmware hack on the 300D. That kind of removes all the advantage of the DSLR low shutter lag. So I would find it annoying to keep it on all the time. If you've got the camera on a tripod, and you're framing a shot carefully, that's obviously more in line with what MLU is all about, and the delay won't bother you.

 

As someone pointed out, switching to multi-shot mode overrides this, so that's not a bad way to go, you can switch into it with one button push, it's that just you may get two shots fired now and then if you hold the button down.

[mcgarity]

The mirror and the shutter of a properly functioning camera do not move at the same time. Motion induced vibration of one can not cancel out vibration induced by the other.

 

I think its safe to say MLU is an advantage on any camera when using slow shutter speeds or long telephoto lenses. The 300D is no exception.

[fisher]

See <a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=008nrV">this</a> thread about 300D mirror lockup issue!