Greg Beetham wrote:Tom it’s the hoary old chestnut that the SLT defenders trot out at every occasion, that mirror slap in the SLR design degrades the image. Something that only occurs at high magnification in actuality, whether the high magnification is macro or telephoto the high magnification magnifies the tremor caused by the mirror flipping up, it’s never been seen as an issue in general photography. They conveniently forget that good SLR’s have a mirror up ability that the SLT’s don’t have. Just like they also forget about the EVF lag/smearing, and the flash shutter delay caused by the double shutter movements in the SLT’s, things that don’t exist in a conventional OVF-SLR design.
Greg
Greg,
Thanks, I thought it might be that. I've run tests and have never seen mirror slap as an issue in handheld photography; I wish I vibrated as little as the mirror. Maybe it might be an issue handheld in the "danger range" of shutter speeds now that we can handhold at slower shutter speeds because of stabilization, but I doubt it based on my experience and macro tests.
In my tests I have seen it as an issue in tripod mounted macro photography although on a tripod it is not as bad as trying to shoot by directly releasing the shutter without a cable or wireless remote.
Back when there was all the "Sony is evil because they won't put MLU in the 5 series and lower cameras" (i.e. pre A580) postings along with the "MLU is not needed" responses I ran some controlled tests to see the effect of MLU with my A700.
The way I ran my tests was to use flash and set up the exposure compensations (ambient and flash) so that you could see both the contribution from the flash part and from the ambient lighting. Shutter speed was in the danger zone (1 sec). Subject was a printed circuit board that had very fine parallel traces in a "|/\_" pattern so there were horizontal, diagonal, and vertical groups of traces (to show motion in any direction). The flash was set to rear flash so any initial shake would be picked up by the ambient exposure. I used the Minolta 100 f/2.8 at f/5.6 and almost 1:1, with manual focus using a magnifier.
When there was any shake, the image (blown up about 6x) would show sharp traces from the flash with ghost ambient images.
My results showed:
(all on tripod)
No remote, no MLU, no 10second delay: obvious ghosts
No remote, no MLU, 10 second delay: small ghosts
No remote - poke the shutter button, MLU (2 sec): small ghosts
No remote - very carefully press the shutter button, MLU (2 sec): No ghost
remote - MLU (2 sec): no ghost
One of these days, I'll do another series handheld using that method and another on tripod all with remote. I'm still trying to come up with a good subject for running the flash/ambient method at about 5 to 10 feet with a longer lens.
I used to check out all my lenses using the newspaper test both with my old manual focus cameras as well as my AF and DSLRs and would examine the results with an 8x loupe as well as blown up on a monitor, I never saw any mirror slap issues outside the 1/20 to 2 sec shutter speed range. And within that range, I would use MLU.
Today with IBIS I very rarely use a tripod (primarily for set up macro), and with the ISOs available to us don't often shoot in the danger zone. So I'd say the SLT's fixed mirror would relieve me of a non-issue.
tom
