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Author Topic: Mirror LockUp  (Read 3679 times)

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Mirror LockUp
« on: August 19, 2004, 08:52:42 pm »

[font color=\'#000000\']It's called vibration. If you're shooting with a long lens at slow shutter speeds it's quite real.

Here's the way to test it. Put a long heavy lens in a tripod mounted camera and then place a small glass of water on top of the camera. Release the shutter. Look at the shimmer in the water.

Better yet, take some photographs with and without mirror lock-up under appropriate conditions. You'll be surpirsed.

Michael[/font]
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Pete

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Mirror LockUp
« Reply #1 on: August 19, 2004, 11:01:45 pm »

[font color=\'#000000\']Hi All,

It's been a while since I last posted, but here's a tip that Nikon School instructors suggested about mirror lock-up, for what it's worth.

Simply cover the front of the lens with a piece of cardboard or paper for an extra second or two (or as long as you think the vibration lasts).  

It's a simple solution for cameras without mirror-lockup.

I myself, don't find any trouble using the menus on my 10D to set mirror lockup, so I'm not sure what all the fuss is about.  When I need it, it's there and easy to set for a night out photographing those subjects that need long exposures.[/font]
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Mirror LockUp
« Reply #2 on: August 20, 2004, 04:45:57 am »

[font color=\'#000000\']I thikk that Nikon instructor needs to go back to school. What he's suggesting (or what you're reporting) is ridiculous.

The technique that you mention is good for night photography with Bulb exposure, but will do nothing to eliminate mirror vibration in the 1/30th sec to 1 sec range, where it is potentially most harmful.

Michael[/font]
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dimitris

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Mirror LockUp
« Reply #3 on: August 20, 2004, 09:21:17 am »

[font color=\'#000000\']The problem with the MLU function being buried in the menu is forgetting to turn it off...  
At least in "the good old days" there was a lever or switch for MLU and it was obvious if the function was on or off - not so with our DSLRs.[/font]
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Lin Evans

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Mirror LockUp
« Reply #4 on: August 24, 2004, 02:30:50 am »

[font color=\'#000000\']
Quote
And more pragmatically: does anyone actually have a sample image that shows artifacts that can truly be attributed to the lack of mirror lockup?

Of course, but the "artifacts" are simply motion blur. Need for mirror lockup increases proportional to focal length and diminishing light.

I frequently use my digicams and dSLR's to do digiscoping (shooting with a telescope as a lens) and often shoot at focal lengths of up to 6000mm. With an effective focal length of 6000mm and an F13.8 (typical spotting telescope aperture) even with excellent lighting and using relatively high ISO's it's necessary to shoot at some reasonably long shutter speeds. I rarely can use more than 1/200th or so and get good results. As you know the typical "rule of thumb" for full frame sensors and hand holding (35mm film, Canon 1DS, Kodak 14n, etc.) is 1/focal length = shutter speed. This would mean that ignoring the "crop factor" one would need a shutter speed of 1/6000th to avoid camera shake from causing motion blur. Obviously, one doesn't hand hold at 6000mm but just mirror slap and pressing the shutter will cause so much vibration that getting a sharp image at 6000mm on a good rock-solid tripod at 1/200th or so is impossible. To get good results it's necessary to first focus, then lock up the mirror, wait for the vibrations to dampen (around three seconds) then use an electronic remote release to prevent any movement other than the shutter itself. Even the very slight vibration caused by the shutter can affect the outcome.

This is, of course, an extreme example, but the identical forces are at work when you shoot with conventional lenses at extreme focal lengths such as 800mm to 1200mm and mirror lockup is of great value in these cases.

Best regards,

Lin[/font]
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Lin

boku

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Mirror LockUp
« Reply #5 on: August 24, 2004, 08:27:54 am »

[font color=\'#000000\']Lack of using MLU can be somewhat offset by using a massive, rigid tripod/head/attachment setup. Things get ugly in a hurry though.

Unless you're shooting on a $2000 Mother-of-all studio camera stand - in which case you're probably using strobes and MLU isn't an issue - you need MLU at the shutter speeds already discussed. And you need it accessible without the hassle that modern DSLRs put us through.[/font]
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Bob Kulon

Oh, one more thing...[b

32BT

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« Reply #6 on: August 19, 2004, 07:00:50 pm »

[font color=\'#000000\']Just wondering out loud:
A digital SLR camera can simply open the mirror a fraction before actually engaging the chip, and close it a fraction after disengaging! I don't know whether it actually works that way, but doesn't that irredicate the need for mirror lockup?

And more pragmatically: does anyone actually have a sample image that shows artifacts that can truly be attributed to the lack of mirror lockup?[/font]
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~ O ~
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boku

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« Reply #7 on: August 19, 2004, 08:57:54 pm »

[font color=\'#000000\']When you need mirror lockup, you better have it.

And, it better be easy to turn on. But it is a royal pain on the 10D.[/font]
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Bob Kulon

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Digi-T

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« Reply #8 on: August 19, 2004, 11:55:38 pm »

Quote
[font color=\'#000000\']Hi All,

It's been a while since I last posted, but here's a tip that Nikon School instructors suggested about mirror lock-up, for what it's worth.

Simply cover the front of the lens with a piece of cardboard or paper for an extra second or two (or as long as you think the vibration lasts).  [/font]
[font color=\'#000000\']huh? I don't understand what you mean.

T[/font]
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boku

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« Reply #9 on: August 20, 2004, 08:19:32 am »

Quote
[font color=\'#000000\']I thikk that Nikon instructor needs to go back to school. What he's suggesting (or what you're reporting) is ridiculous.

The technique that you mention is good for night photography with Bulb exposure, but will do nothing to eliminate mirror vibration in the 1/30th sec to 1 sec range, where it is potentially most harmful.

Michael[/font]
[font color=\'#000000\']Indeed. MLU is needed most at shutter speeds between 1/4 sec - 1/125 sec.[/font]
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Bob Kulon

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Pete

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Mirror LockUp
« Reply #10 on: August 20, 2004, 12:03:44 pm »

[font color=\'#000000\']sorry for the confusion--I was referring to night photography and longer exposures than the 1 sec range.

Hey, I'm only paraphrasing what the instructor suggested.[/font]
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61Dynamic

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« Reply #11 on: August 20, 2004, 12:33:57 pm »

[font color=\'#000000\']
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But it is a royal pain on the 10D.

If you think it's a pain on that camera, try using it on a Russian Hacked 300D.[/font]
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61Dynamic

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« Reply #12 on: August 24, 2004, 02:58:38 am »

[font color=\'#000000\']The longest focal length I have is 85mm so I can only speak from experience at that length or less. Even though the 300D has more mirror slap, the hacked firmware lets me set it to a delay of up to 6 sec. from when I hit the release to when the shutter opens. On a stable tripod with a remote release, this should be more than enough time for all vibration to be dampened.

I have not encountered any noticeable difference using MLU in my testing.[/font]
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didger

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« Reply #13 on: August 24, 2004, 08:43:31 am »

[font color=\'#000000\']I used to be annoyed by the hassle of MLU lockup activation and de-activation, according to whether I was doing a tripod or manual shot.  Now I leave MLU on all the time period.  For landscape work having to trigger the shutter release with the viewfinder dark is no problem.  You just have to anticipate the fact that you need to hold the camera as still as possible so there's no framing change between the lockup phase and when you hit the button the second time for the exposure.  I think this extra little bit of concentration for each hand held shot is actually helping me be steadier for the exposure.  In any case, I haven't had a single case where the framing wasn't what I was going for because of the little delay.

Of course, for any kind of hand held live action shooting this wouldn't work, but for landscape shooting leaving MLU activated all the time sure beats fumbling around in the menu to activate and de-activate MLU all the time.

I think for any modern digital SLR you really need to figure out just what you need and learn to do that in a streamlined way.  It's nearly impossible to learn to do every conceivable operation that something like a 1ds is capable of in the field quickly.  I've occasionally done shooting in slot canyons (back in my 35mm film days) and watched people with expensive complicated cameras (still film back then) sitting on a tripod while they were paging through their manual as the light was deteriorating.  This complexity has gotten even more overwhelming with digital cameras and we also have this complexity with our constantly changing computers and software, phones, fax machines, etc.  Even setting a watch is complicated.  We can't learn it all.  We have to prioritize and streamline to mitigate CAS (complexity anxiety syndrome).[/font]
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