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Author Topic: MLU again  (Read 13124 times)
AndyF2
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« Reply #20 on: November 26, 2007, 11:53:43 AM »
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Andy,
This is something worth looking into.
...
I've had my 100-400 on a tripod, attached by the collar, and seen quite obvious wobbling as a result of the mirror slap and shutter release. I recall on a number of occasions looking through the viewfinder as I pressed the shutter with remote cord and noticing pronounced image shimmer immediately afterwards.
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This tripod is very light, weighing just 2.2Lbs or about 1Kg and very compact. It is recommended for a maximum load of 5.5lbs and is described as being suitable for digicams. If mirror slap is going to have an effect, then this is the tripod that will reveal it, (or do you think my logic is flawed?)

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Interesting results Ray; I don't see any difference between the images.  The 50mm lens is too good though!  If this test would be standardized in any way, it would have to specify a 200 or 400mm lens and a reasonably long target distance that can still be set up indoors (for controlled lighting and "clear weather").   I saw your followup post with the 100-400 lens at 1/30.

At the moment I rent my longer lenses (Headshots, Ottawa and Toronto) so I don't have one at hand to experiment with, but will have to do my own experiments to see what vibration exists on the 400D/XTi.  

When you saw vibration using the 100-400 after the exposure, there are likely differences in mirror dampening in each direction; not much need to dampen the mirror when it descends so that may have caused the movement you saw afterwards.  OTOH, not much need to descend it rapidly, so it could be a softer impact.

The lightweight tripod should have poorer performance, implied by the poorer results in the PT article when the center column was extended.  For dampening effect, a sandbag is sometimes hung from the tripod - perhaps for maximum dampening, perhaps it should actually be gently draped over the top of the camera body and lens?!

Another way to measure the movement of the lens would be to tape a small mirror or  piece of aluminum foil to the end of the lens barrel, tape a laser pointer so it's always on, aim at the mirror so it reflects to the ceiling, and watch any deflection of the spot when the shutter is released.  I may set that up.

Andy
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Ray
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« Reply #21 on: November 26, 2007, 11:48:04 PM »
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I saw your followup post with the 100-400 lens at 1/30.
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Eh? I haven't mentioned anything about using the 100-400 specifically at 1/30th.

After testing my 20D with 50/1.8 on my lightweight Manfrotto, I repeated the experiment with the 5D and same lens. The 5D has a very pronounced mirror slap problem at 1/30th, unlike the 20D which is problem free at all exposures.

I used this tripod with centre column down and cameras vertical. I have an RSS L-bracket for both cameras, which contributes to stability.
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Wayne Fox
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« Reply #22 on: November 27, 2007, 12:21:45 AM »
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The 40D allows for disabling auto-power off. Only the LCD will be turned off after a periode of non-usage (I don't know, how long that is).
Been playing with this for a few minutes on a 40d.

The auto-power off setting has no effect on MLU functionality ... it will return after 30 seconds regardless of whether auto-power off is disabled.

The only way I can find to keep the mirror up before exposing it is to partially depress the shutter release ... doing this does seem to reset the timer.

As far as battery life, I believe I read on this site that Canon uses battery power to keep the mirror down, and not up?  Someone wrote about shooting star trails, and I believe it was mentioned the Canons are more able to do this because multi hour exposures are possible without wearing down the battery, some other cameras function opposite so they will drain the batteries after 30 minutes or so.

(My memory has been known to fail, couldn't find it with a quick search, will check more).
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Panopeeper
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« Reply #23 on: November 27, 2007, 12:55:08 AM »
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Been playing with this for a few minutes on a 40d.

The auto-power off setting has no effect on MLU functionality ... it will return after 30 seconds regardless of whether auto-power off is disabled

Not in Live View mode.

Btw, Live View has another great advantage: when shooting bracketed exposure, with a remote control, one click and shot shot shot without mirror, without time delay. I hope this will give a good basis for HDR (perfectly overlapping shots if not windy); very useful for panoramas as well.

It's a pitty that only three shots are possible in AE bracketing. With 8 and more GB cards I would not care for exposure any more, I would make six shots for each frame of the pano, with 1/3 EV steps.
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Gabor
Ray
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« Reply #24 on: November 27, 2007, 12:59:03 AM »
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The only way I can find to keep the mirror up before exposing it is to partially depress the shutter release ... doing this does seem to reset the timer.
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So there's really no problem here. I can't imagine why anyone should be using a remote that doesn't permit autofocussing.

I suppose there's always a possibility that one could forget or be unaware that 30 seconds has elapsed. However, there are always camera settings that can present a trap for the unalert. I sometimes have my camera on a particular manual setting and forget to return it to my usual mode of aperture priority. Next time I use it, assuming it's in Av mode, I take a wrong exposure. Can't blame Canon for that!

Oh! And I sometimes, after using MLU, forget to disable it afterwards and ruin the next shot   .
« Last Edit: November 27, 2007, 01:05:27 AM by Ray » Logged
Eric Myrvaagnes
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« Reply #25 on: November 27, 2007, 09:51:02 AM »
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Oh! And I sometimes, after using MLU, forget to disable it afterwards and ruin the next shot   .
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Ray,

I think you and I may both need brain transplants from someone much younger than us.    

-Eric
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-Eric Myrvaagnes

http://myrvaagnes.com  Visit my website. New images each season.
mahleu
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« Reply #26 on: November 27, 2007, 10:05:48 AM »
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Ray,

I think you and I may both need brain transplants from someone much younger than us.   

-Eric
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Don't worry, I frequently change my camera from single shot to self-timer (with my nose). People (including me) don't appreciate it when a light starts flashing from your camera in a theatre...
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AndyF2
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« Reply #27 on: November 27, 2007, 08:21:34 PM »
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Eh? I haven't mentioned anything about using the 100-400 specifically at 1/30th.

After testing my 20D with 50/1.8 on my lightweight Manfrotto, I repeated the experiment with the 5D and same lens. The 5D has a very pronounced mirror slap problem at 1/30th, unlike the 20D which is problem free at all exposures.

I used this tripod with centre column down and cameras vertical. I have an RSS L-bracket for both cameras, which contributes to stability.
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Ray - I mistakenly picked the combination of 400mm, 1/30th from two of your earlier statements:
"
Although I'm carrying my 100-400 zoom with me on this trip, I wouldn't waste my time using it on this ultra-lightweight 714SHB. However, I did run through the same test on this tripod with my 5D using the same 50/1.8 lens; same target from the same distance.

Surprise! Surprise! The 5D shows a mirror slap problem around 1/30th second exposure, but only around 1/30th. At 1/15th it's gone and at 1/60th it's gone. It's also not evident at any shutter speed slower than 1/15th.

"
Andy
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dobson
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« Reply #28 on: November 28, 2007, 02:56:29 PM »
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Since Canon seems to not want to put an MLU button on their camera bodies, why not compromise. Put a lock-up button on the remote cable-release.

I almost always use a cable in conjunction with mirror lock up so it wouldn't be an inconvenience to me. And the button wouldn't take up real-estate on the body itself.
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Wayne Fox
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« Reply #29 on: November 28, 2007, 03:16:21 PM »
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Not in Live View mode.


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Live View mode is not MLU.  If you are using Live View as an alternative to MLU, it is just that, an alternative.

On the surface it appears a decent one (I have been playing with it), with a couple of possible "gotchas" that I don't believe have been tested.

1)  Providing power to the sensor to enable live view may generate heat, and thus create some additional noise.  Until I've seen some "hard" tests proving it otherwise (which my company is currently doing) , I have to assume it does.  If it does at what point does it become a problem(10 seconds 30 seconds several minutes?), does ambient air temperature affect it .. lots of questions, no answers right now other than canon claiming it doesn't.  Their standard of "acceptable" may be different than mine, which is basically no additional noise is acceptable.  If using it simply to substitute for MLU, so we're talking only a few seconds each time, I would guess that there is no difference unless doing numerous exposures.

2)  from a mechanical and vibration perspective, Live View is not "exactly" like MLU.  When the shutter is released with live view, the 1st curtain must return then open again.  In MLU, that curtain is closed.  The 1st curtain is now electronic, is very quiet and most likely causes virtually no vibration.  However, since the entire goal of MLU is to enable the most vibration free stability of the camera, even this slight movement may have some impact.  At this point I can see none, but that doesn't mean that micro detail on a very large print might be compromised using Live View instead of standard MLU. I plan on testing it, but probably on the 1DsMarkIII, since that will be my primary DSLR body.

(Yes I know .. I'm quibbling here.  Just rambling thoughts going through too idle of a mind right now)
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