Does "no mirror" really = sharper negs?

[David A. Goldfarb]

The laser pointer and penny tests don't really tell you if the vibration is affecting the image. There could be a lot of vibration when the mirror returns and the shutter closes, and that wouldn't make any difference.

[olwick]

Think of the Pentax 67. It's mirror is larger and heavier, with greater inertia and momentum, but it illustrates the concept of image degrading mirror induced vibration.

The Pentax 67's problems are also due to the shutter curtain. See the illustration, even with the mirror locked up, here:
http://www.luminous-landscape.com/re...ntax67ii.shtml

[frank]

The Pentax 67's problems are also due to the shutter curtain. See the illustration, even with the mirror locked up, here:
http://www.luminous-landscape.com/re...ntax67ii.shtml

Thanks for that link. Here's a quote from that site:

The problem I experienced requires some further explanation. The Pentax has a large rapid-return mirror. At slow shutter speeds (below 1/125 second) and especially with long lenses, it should be locked up. This is SOP (Standard Operating Procedure) for all medium format cameras, and should be even for 35mm cameras. Mirror shock is a real sharpness thief for critical work.

[Jedidiah Smith]

Wow, this is interesting. I wonder how an old slr, say a Minolta XD-11, would compare to a modern one, like the Minolta Maxxum 7 or a Nikon F100. Does anyone know if they made any serious technological in-roads regarding mirrors and vibration over the years?

It's interesting to note that Minolta stopped putting MLU on their SLRs after the SRT 102, all the way until the Maxxum 7. That's nearly 30 years until they felt they needed it, I guess?

On the rangefinder lenses - is the wide angle lens advantage really obvious in a print, or have the lens makers been able to overcome the problems with SLR wide angle designs with computer aided drafting and such?
Thanks,
Jed

[2F/2F]

The laser pointer and penny tests don't really tell you if the vibration is affecting the image. There could be a lot of vibration when the mirror returns and the shutter closes, and that wouldn't make any difference.

In my understanding, however, the laser pointer test involves actually photographing the laser point on the wall, not just viewing it with your eyes. Therefore, the test should work just fine to tell you if the slap is affecting the camera during exposure.

As for the penny test, it is just silly, IMO.

[Rol_Lei Nut]

The laser pointer and penny tests don't really tell you if the vibration is affecting the image. There could be a lot of vibration when the mirror returns and the shutter closes, and that wouldn't make any difference.

I actually did a laser pointer test on my 6x7 with & without MLU and using slow speeds and B in order to differentiate between mirror rising, shutter opening and shutter+mirror closing (unable to differentiate between those two).

True, the worst vibrations were with the mirror/shutter closing. The shutter opening was fairly weak (but visble) and the mirror raising stronger still, but a long way from being a major part of the jolt you feel when you shoot the beast.

[Rol_Lei Nut]

There are big differences between 35mm SLRs in the degree of mirror (and shutter) dampening present.
Some SLRs I can hand hold at speeds practically as low as a rangefinder.
Others notoriously have no dampening at all (the otherwise lovely Nikon F & F2, for example).

[David A. Goldfarb]

In my understanding, however, the laser pointer test involves actually photographing the laser point on the wall, not just viewing it with your eyes. Therefore, the test should work just fine to tell you if the slap is affecting the camera during exposure.

As for the penny test, it is just silly, IMO.

I've usually heard the laser test as attaching the pointer to the camera and watching the spot dance. I think photographing the spot might tell you something, but a photograph of a projected laser spot wouldn't be as informative as a photograph of a resolution target with and without mirror lock up, if one were trying to determine the effect of mirror slap.

[df cardwell]

The thing about a rangefinder is that you MUST learn to see the world as it will see it.
You can't get lost inside the SLR kaleidoscope.

The reason a Rangefinder is good in the street is that the photographer learns to SEE what it will see.

Its like learning to play a violin. Following the SLRs are better argument, guitars must be better than fiddles because they have frets and you know where all the notes are.

So, it isn't so much whether a RFDR is sharper without the mirror, it is that WE become sharper when our eyes can see.

[John Koehrer]

The Pentax 67's problems are also due to the shutter curtain. See the illustration, even with the mirror locked up, here:
http://www.luminous-landscape.com/re...ntax67ii.shtml

That's an interesting photo with a double image in the detail.
But, if the shutter bounced that far it would have gone more than 1/2 way back across the negative.
In any case camera movement doesn't give a double image, it gives a blurred image.