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 10/06/2005 11:11:42 AM · #1
While checking out the long end of my new lens, a Sigma 70-300mm DG, I got an important reminder on just how UNSTABLE a tripod can be.

I offer up the following example:



The image on the left was shot at 300mm @ f5.6 with my camera clamped down tight onto my triod. The shutter was tripped with a cable release.

Everything was the same with the image on the right, except that I used my camera's MLU or mirror lockup feaure, in addition to the cable release to trip the shutter.

Quite a difference. And I feel it really underscores how much vibration can get introduced by the camera itself. This is only an issue with DSLRs and SLRs--not digicams.

Depending on the length of the lens and the shutter speed you are using, the most stable tripod in world will not help you get sharper pictures when the effects of mirror vibration start rearing its ugly head.

Any telephoto lens, at virtually any shutter speed, can show these effects to some degree. The key is understanding how your equipment performs so that if need to use MLU you can. Providing, of course, that your DSLR has MLU--not all of them do.
10/06/2005 11:14:13 AM · #2
Very interesting - I would not have guessed that the difference would be this dramatic.. especially when a cable release was used on the first, eliminating user induced movement.
 10/06/2005 11:26:38 AM · #3
Good examples--do you know what your shutter speeds were for those two shots?
 10/06/2005 11:31:03 AM · #4
Originally posted by brianlh:
Very interesting - I would not have guessed that the difference would be this dramatic.. especially when a cable release was used on the first, eliminating user induced movement.


I like using my 2-sec timer as well.
 10/06/2005 11:32:04 AM · #5
what tripod?
 10/06/2005 11:32:50 AM · #6
Since this was taken outside, are you sure that wind wasn't a factor in the first shot, possibly buffeting the camera/lens enough to cause the bluriness?
 10/06/2005 11:33:07 AM · #7
I use mirror lock-up and timer delayed shutter release whenever I am using a tripod. However, another important consideration is to have a tripod of adequate strenght. As a general rule of thumb you should use a tripod that is rated to support two times the weight of the camera and lens combination.
For example: The SD9 weighs about 2 pounds with it's battery, add 1.3 pounds for 70-300 DG, say that's about three and a half pounds - so a tripod that is rated to support something in the range of 7-8 pounds will be needed to get the best results.

Message edited by author 2005-10-06 11:35:16.
 10/06/2005 11:35:00 AM · #8
Originally posted by Zal:
Good examples--do you know what your shutter speeds were for those two shots?


Oops, forgot to mention that the speeds were low, 1/8 of a sec in both examples. Slower speeds will show more movement, but in this case shutter speeds were the same.
 10/06/2005 11:38:00 AM · #9
Which tripod were you using?
 10/06/2005 11:40:14 AM · #10
To answer the tripod and wind issue questions.

The tripod is an old SLIK U212 Deluxe, it is quite hefty and sturdy. It's not fancy, but it is VERY stable. (Ought to be, it weighs a ton.) Wind was blowing outside, but I was actually inside a doorway several feet and wind was not an issue on the camera.

I took a whole series of shots at varying apertures and the effects were the same for all MLU vs. non-MLU shots.

Message edited by author 2005-10-06 11:41:14.
 10/06/2005 11:41:49 AM · #11
Originally posted by mcmurma:
Slower speeds will show more movement....


Up to a point that's true, but the effect should be minimal on a really long exposure because the shutter vibration would only last for a small percentage of the overall exposure.

Message edited by author 2005-10-06 11:42:02.
 10/06/2005 11:44:03 AM · #12
This Luminous Landscape article speaks about this as well.
 10/06/2005 11:47:48 AM · #13
this is exactly what I discovered with my Sigma 70-300. even though me tripod was stable and I used my remotecontroller, there was movement. I checked the camera when pressing the button and saw the shutter was moving to hard to keep the camera stable on the tripod.

my solution: don't use a tripod when you've got the 70-300 on your cam ;) right now I'm saving money for a new, more stable tripod!
 10/06/2005 11:52:53 AM · #14
Did you use manual focus?

On auto focus the focus may have been different on the two photos.
 10/06/2005 12:07:54 PM · #15
Yep, also forgot to mention, manual focus was used on both shots. In fact, I achieved focus on the non-mlu shot, and did not change it for the mlu shot.

Also, the results may look bad, but I'm sure they are very typical of most cameras used at 1/8 of sec with a 300mm focal length. Especially on a 1.6x crop factor sensor like the SD9, which gives you an effective focal length of about 500mm! Quite a long lens.

And one last thing. The SD9 has a very heavy mirror slap. Results on cameras with a lighter mirror slap (any Canon I have tried) would not be as bad, I do not think.
 10/06/2005 12:27:52 PM · #16
It's obvious from your photos that the wind was strong enough to shake the brick wall as well as the tree branch in the first photo, but it died down before you took the second shot.

Ha ha ha! I crack me up.
 10/06/2005 12:30:28 PM · #17
It's a very real phenomenon. Mirror lockup gives me significantly sharper results on the 20D, with all lenses. I use it as a matter of course.

Robt.
 10/06/2005 12:48:47 PM · #18
With the 1DII and a 70-200 F4, I can see the vibration, just looking at the lens.

I tend to use MLU all of the time when on a tripod, unless I'm trying to compose with dynamic elements. Even then, when using a lens longer than about 100mm, I'll still use MLU, just because of the vibration introduced by the mirror.
 10/06/2005 12:59:26 PM · #19
check out Tip #8 on the mirror vibration "1/15 Valley of Death" from Photographic Magazine. You can see what shutter speeds that are most impacted by mirror slap, and gives you an idea when MLU will be more of a factor.

Photographic Mag Article

P
 10/06/2005 01:01:31 PM · #20
I have used Mirror lockup but haven't really been able to see a difference. I assume it matters less with wide angle shots.

But this is the first camera I've been able to use it on (dRebel XT). I don't think my old spotmatic or spotmatic ES had it, nor my dRebel, and the twin lens cameras I used in high school didn't have mirrors ;)

I do find it weird (but makes sense based on electronics) that mirror lockup is limited in "time". I assumed I could just lock the mirror up and keep it that way. But you have to do two shutter presses each time--one for the lockup, one for the shot. That makes sense for varied subject shots but less so for studio setup. And if you don't shoot for a while after the lockup, it times out.

Or am I missing something on how it works?


10/06/2005 01:06:04 PM · #21
Originally posted by nshapiro:
I have used Mirror lockup but haven't really been able to see a difference. I assume it matters less with wide angle shots.

But this is the first camera I've been able to use it on (dRebel XT). I don't think my old spotmatic or spotmatic ES had it, nor my dRebel, and the twin lens cameras I used in high school didn't have mirrors ;)

I do find it weird (but makes sense based on electronics) that mirror lockup is limited in "time". I assumed I could just lock the mirror up and keep it that way. But you have to do two shutter presses each time--one for the lockup, one for the shot. That makes sense for varied subject shots but less so for studio setup. And if you don't shoot for a while after the lockup, it times out.

Or am I missing something on how it works?


There's a power draw when the mirror's locked up. That's why they time it and drop it if it's ignored. The power draw is substantial enough that they warn you to use a fully-charged battery when you do sensor cleaning, lest the mirror drop on your implement when power runs out I assume.

I don't see the drop-after-shot as a problem, since if you're doing multiple frames of the same setup it's just a double-click away anyhow.

Robt.
 10/06/2005 01:06:58 PM · #22
Originally posted by nshapiro:
I have used Mirror lockup but haven't really been able to see a difference. I assume it matters less with wide angle shots.

But this is the first camera I've been able to use it on (dRebel XT). I don't think my old spotmatic or spotmatic ES had it, nor my dRebel, and the twin lens cameras I used in high school didn't have mirrors ;)

I do find it weird (but makes sense based on electronics) that mirror lockup is limited in "time". I assumed I could just lock the mirror up and keep it that way. But you have to do two shutter presses each time--one for the lockup, one for the shot. That makes sense for varied subject shots but less so for studio setup. And if you don't shoot for a while after the lockup, it times out.

Or am I missing something on how it works?


If you don't want to do the 2 press shooting route, you can switch on MLU and use a 2 second timer - press the shutter and the mirror locks up, then 2 seconds later takes the picture - reduced vibration and still only one press.

The two step shutter press has the advantage of allowing you to decide when to take the shot, when certain elements are in the right place for example - models facial expression, light, whatever.

10/06/2005 01:35:26 PM · #23
Originally posted by nshapiro:
I have used Mirror lockup but haven't really been able to see a difference. I assume it matters less with wide angle shots.

But this is the first camera I've been able to use it on (dRebel XT). I don't think my old spotmatic or spotmatic ES had it, nor my dRebel, and the twin lens cameras I used in high school didn't have mirrors ;)

I do find it weird (but makes sense based on electronics) that mirror lockup is limited in "time". I assumed I could just lock the mirror up and keep it that way. But you have to do two shutter presses each time--one for the lockup, one for the shot. That makes sense for varied subject shots but less so for studio setup. And if you don't shoot for a while after the lockup, it times out.

Or am I missing something on how it works?


I was never able to see any noticable difference using mirror lockup on my 10D either, and I used it quite often too. I still use it once in a while, if I have the time and remember to change the camera setting, but only with long telephoto shots

Perhaps the type of camera has something to do with it. The Sigma SD9 may simply induce more vibration when the mirror moves than the 10D or 350XT.

10/06/2005 01:57:49 PM · #24
A number of mechanical factors come into play that can enhance or decrease the effects of mirror slap.

Camera variety is certainly among them. But also to be considered is how the camera and lens are mounted to the tripod--is the lens hanging from the camera or the camera hanging from the lens? And where is the center of balance for the camera/lens combo?

I've never done a proper test, but results with and without MLU using my 400mm lens, which has its own tripod mount, are not as profound as they are for this 300mm. I imagine the fact that the tripod mount is closer to the balance point of the camera/lens combo has somthing to do with why it performs better, even though the lens is quite a bit longer.
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