David Kilpatrick wrote:Disaster! The Alpha 900 at 1/40th, with a 250 mm lens, was incapable of taking a single sharp picture on the tripod. The mirror jolt blurred every shot.
Huh!? "Incapable"? What do you think mirror lock-up and mirror pre-fire are for? Hint: The A900 has both. So has the A700. And it actually works. I have taken hundreds of tripod shots with the A900 and haven't lost a single one to mirror slap.
David Kilpatrick wrote:The sharpest results by far came from the A380 with its tiny, light body and very quiet mirror/shutter action. They were still not as needed.
So if I understand correctly, the A380's mirror jolt is substantially less than the A900's but still not completely absent. But it has neither mirror lock-up nor mirror pre-fire. So unlike the A900/A700, the A380 really
is incapable of taking sharp pictures from atop a tripod at moderately slow shutter speeds.
As I keep saying: a toy.
David Kilpatrick wrote:... I can now see that the A900 has a really serious problem around 1/30 - 1/60th ... which probably affects handheld pix as well. The mirror jolt creates a double image, not a smooth blur.
The A900 has a problem!?
You're screwing up the facts. Actually it's the A200 - A380 series bodies which are having a problem, as they don't feature mirror pre-fire at all. And yes indeed, it does look like a double image rather than a smooth blur. For example, the Minolta SR-T 303b with a 600 mm lens on a big tripod at 1/15 s or 1/30 s did exactly the same. As a matter of fact, basically all 35-mm single-lens reflex cameras of the last four or five decades do that, to varying degrees (depending on the camera's weight, the lens' focal length, and the tripod's sturdiness). By the way, try it in portrait orientation---then it will come out even worse. That's why mirror lock-up is an essential feature for any SLR camera ... even at entry-level.
You don't want to tell us you never came across this phenomenon before!?