Re: Sony's Alpha..I saw it, nice "try" better luck next time...
- From: David Kilpatrick <iconmags3@xxxxxxxxxxxxx>
- Date: Sat, 05 Aug 2006 10:43:18 +0100
RichA wrote:
r opinion, the camera looks fine to me.
This reskinned D5 Minolta NEEDS the IS inside it to
cope with the shutter/mirror slap, this is no joke!
But it's just your opinion... not fact.
Actually, it's not. Tests have already shown that some DSLRs around
the
1/10-1/30 second mark do suffer from image blur caused by excessive
mirror
slap. Some have mechanisms that will raise the mirror, then release
the shutter
a couple to a few seconds later to avoid image blur. The Sony has the
worst
mirror slap I've felt in a DSLR. The Canon Rebel XT is the second
worst I've felt.
The Sony does not have bad mirror slap. You are talking about sound. Put plugs in your ears, FEEL the cameras, and you'll find that more damped actions usually transmit the energy as vibration into the body at a fairly low frequency. Noisy actions like the Sony transmit the energy externally as sound which typically has frequencies above the 70Hz maximum response of the anti-shake gyros. A relatively high pitched sound from the mirror/shutter action transmits no damaging vibration to the camera; a soft low-pitched muffled sound transmits potential shake.
Anyone who worked in the past with cameras such as the Miranda T used on microscope assemblies will be aware of this - clang like a bell when fired, no vibration sustained in the mechanism.
The KM Sony mirror/shutter mechanism was designed to run using low energy (relatively slow action) and mass, to avoid triggering the in-body gyros. I have interviewed two KM design team staff about this, it was one of the first questions which arose when discussion the 7D at photokina - why is the shutter so slow, why is the action so noisy? The question was immediately understoof and a full explanation given, including references to the frequencies, and the absorption of energy into the body by quieter SLRs. A side benefit is that the shutter has an expected cycle before failure of 140,000 shots. This also applies to other cameras, like the Nikon D70, Pentax *1st series, using the same low mass, low energy assemblies by KM/Sony has the slowest transit time and lowest energy requirement of all. The shutter is calibrated for flash at 1/180th in the factory (a speed not available via camera controls) and syncs at 1/160th officially. In practice it works up to 1/200th with normal flashguns.
SSS or AS is improved on the KM and Sony models by using the 2 second mirror pre-lift (tested and proved) but it's a bit of a strange thing to do without a tripod, and AS/SSS should be disabled when using a pod. So the mirror and shutter actions definitely do affect AS/SSS despite all attempts to prevent this. No doubt the same applies to in-lens IS systems, depending on where the gyros are located.
David
.
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