Mirror Up or Down?

[dancqu]

I've done some UP and Down tests. Differences are
anything but obvious. Using an ETRSi, RB67, and RZ67,
what ranges of shutter speed would most likely, on
occasion, show Up to be the better choice? Dan

 

[Photo Engineer]

Dan;

In my experience, from about 1/60th down, when the tripod is not secure or suchlike, there can be camera vibration from the mirror which gives a tiny amount of 'blur' to the image which increases with lower shutter speed, and which is lower with heavier cameras or better tripods.

With very heavy duty tight tripods, you may never see a problem.

PE

 

[Christopher Walrath]

I'm with Ron on this one but I might up the ante a bit. (1/focal length) shutter speed on down, mirror up when it's an option.

 

[Toffle]

Depends if you are shooting eye-level or with a WLF, (wait a minute, what am I talking about... you're not shooting hand-held... how dumb am I? Even I've never flipped the mirror handheld. ) but I would tend to agree with Ron, or perhaps be even a little more conservative than that. I tend to lock my mirror at anything below 1/125. I don't have any of the cameras you mention, but my GS-1 kicks like a shotgun. With the mirror up, it has that nice, quiet "snick" of a smooth shutter.

 

[Marc Akemann]

I used an RB for years and have been using a Bronica EC-TL for the past 5 years or so and use the mlu (mirror lock up) when ever I can. I'm just extra cautious. Christopher's suggestion of using mlu at (1/focal length) shutter speed on down is probably the answer you're looking for. But then again, as PE says, the weight of your camera/lens and the quality of your tripod/head plays into the equation, too. Again, I simply lock up the mirror when I can.

Marc

 

[keithwms]

If you have a choice then the mirror is up, of course. If you have no choice... well then you have no choice and the mirror is down.

I believed the 1/60th rule for 35mm slrs until I tried an F100 and found that I could reproducibly go much longer with it, it has excellent damping. Surprising because it's quite light, but it is so. Likewise some of the more recent Nikons.

 

[23mjm]

On my 645's (Mamiya 1000s & e) I have shot down to 1/8 while on a tripod and have had great pictures, very sharp, without ML. On my RB67ProS I normally lock the mirror when ever on a tripod.

 

[edtbjon]

As other have said, if you have the option to prerelease the mirror, do so. I've also noticed the difference between cameras. I used to own a Nikon F100 which had very good mirror damping. My current F80 seems very good in that aspect, at least it's very quiet.
But this question was about MF cameras. My Hasselblads is a very different story from my Nikon (which is used as a "notepad" as opposed to the more "serious" shooting with the Hasselblads or the Sinar). Please note the quotation marks around "serious". The 'blad is quite noisy and it really "slams" the mirror up. Whenever possible I prerelease the mirror, regardless of shutterspeed. Of course, a good tripod does help to absorb or dampen the vibrations. I guess that an underdimensioned tripod could actually worsen the situation, but I don't think that anyone here would really use a $20 tripod for a 'blad, Mamaya, Pentax 67 or similar anyhow.

//Björn

 

[Photo Engineer]

I'm with Ron on this one but I might up the ante a bit. (1/focal length) shutter speed on down, mirror up when it's an option.

Chris;

Thanks for the addition here. You are totally correct about focal length being important. I should have had that in my post if I was thinking.

PE

 

[panastasia]

I do as Marc does - mlu when ever I can - unless I'm looking for that "decisive moment" while viewing/framing through the finder. Shots hand held @ fast shutter speeds (1/125+, faster for long telephoto lenses) makes mlu irrelevant, of course.

I'm using an RB most of the time and enjoy using all the controls offered by the machine.

Consider mirror induced vibration added to wind induced vibration on a tripod, and who knows what harmonics are present beyond what appears to be rock solid?

Paul

 

[keithwms]

Consider mirror induced vibration added to wind induced vibration on a tripod, and who knows what harmonics are present beyond what appears to be rock solid?

Paul

Yes, and without doing an actual detailed analysis on aparticular camera and lens combo (the damping has to do with the total mass and how rigidly it is all coupled to the mirror box etc.), one couldn't really say to what extend MLU is needed to get X degree of stability. Hence... I'd just say always use MLU if you have the option.

As far as I know, 1/FL and so forth have no obvious theoretical basis, they are just common sense ways of saying that the higher angular resolution /stability you need, the better off you are using MLU.

 

[dancqu]

Camera manufacturers might have dropped MLU years ago had
they adopted some other proviso for shutter delay, ie a full second
or even a variable delay. Essentially that is what MLU provides, shutter
delay; lift the mirror then fire. I'd think an easy to implement feature
for electronic cameras.

Just dawned: My Oly OM2000 has just that, a variable time MLU feature.
With the self timer set for so many seconds then the shutter released,
the mirror instantly LU. BTW, OLY does not mention MLU at all in their
literature of the OM2000. An undocumented extra. Dan