Question on Mirror lock and cable release

[Doktaduck]

This is a question on the workings more than anything, for a Canon 650D.

I was attempting to do some night photography over the Easter weekend, and set up my 650D on the tripod. I set mirror lock to enable and attached the cabled shutter release.

using live view mode to focus, and zoom focus in manual..

when I press the shutter release I notice the actual composition change in the live view...

As I press the shutter button (on the cable release) the camera view actually seems to move up and left.

I presume this is while the mirror is being locked in place, but I wanted to know if this is normal?

Is there something wrong with my camera?

Thanks in advance

[William]

Hi ya Doc, Wont be much help but I've used Mirror Lockup and this does'nt happen , That I've noticed

[Granville]

Is there a VR on that could be doing this? I don't know Canon that well.

[Doktaduck]

hmmm, there is definitely image stabilisation on that lens. Thanks for the point. I'll have to investigate further...

[Mark L]

Firstly, turn IS off when using a tripod, though can imagine that's the problem here.

As I press the shutter button (on the cable release) the camera view actually seems to move up and left.

I presume this is while the mirror is being locked in place, but I wanted to know if this is normal?

The mirror should already be locked up when you press the button. That's why you use it, so nothing moves.
How did the photos turn out when downloaded? How you framed them, or how they looked on the camera screen as you described?
I'm with William, never come across this, thus the questions.

[William W]

I don't beleive the question / issue, has anything to do with 'Mirror Lock Up'.

I understand that the Custom Function ‘Mirror Lock Up’ is automatically disabled on all Canon DSLR’s, when ‘Live View’ is activated.

WW

[dodgyexposure]

As I understand it, it's not so much that mirror lock up is disabled in liveview as it is unnecessary. When you switch to liveview, the mirror is raised, and triggering the shutter occurs on the first press of the shutter button/remote.

I agree that a shift in composition is not a product of using mirror lock up. I can't think of any reason why framing would shift in teh situation described, absent some mechanical issue with the tripod (bumping, ball creep . . . ).

[Steve Axford]

Mmm, I agree with dodgy - it sound like the camera moved on the tripod. Hard to see any other option.

[William W]

As I understand it, it's not so much that mirror lock up is disabled in liveview as it is unnecessary. When you switch to liveview, the mirror is raised, and triggering the shutter occurs on the first press of the shutter button/remote.

Yes. Mirror lock up is not required because as you stated activating “Live view” raises the mirror.
But technically, I do believe that Mirror Lock Up Custom Function is indeed “disabled”.
If that Mirror Lock Up CF were ENabled, then the operation to make the image would require TWO presses of the Shutter Release, because that is part of that CF – and as you correctly stated that does not happen.
I am pretty sure that the User Manual Reference will confirm that that CF is actually “disabled”.
In any case the outcome is the same for the purposes of the OP’s question, but there might be other scenarios or relevance, which are not apparent at this time.

WW

[Doktaduck]

Well thanks folks, you have help eleviate one concern, and that is why I didn't have to press the shutter twice (like I had previously done using ML)..
I missed the bit about it not being used in live view (which I used so that I could zoom focus).
I'm pretty sure (almost 100%) that the tripod was not moving.

The 'motion' occurs while pressing the shutter release button (Cabled) and I watched in live the image move from centre to top left as I pressed (but not enough to take the photo) and then back to centre as I released.

The final image was as if I lined up the moon in the top left corner of the shot.

Of note, I am talking about a very minor movement, as this was while at +10 zoom. The final images are...ok... but not great. It was more a concern as the 'motion' was unexpected.

I have not had much chance to test it again, I'll endeavour to do so this week.

Thanks again for the ideas.