artur5
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 Re: Pre-order: Sony A9 | |
Matt Grum wrote:
Bespoked wrote:
Has anyone had a chance to measure the sensor read rate?
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To my knowledge no-one has measured it but reviewers have reported being told a scan time of 1/160s. That would make it very close to the Canon 6D (1/180s), so given the absence of threads complaining about 6D banding issues it should be ok, of course people are going to go looking for banding problems with the electronic shutter so I'm sure they'll find some.
The "readout time" of mechanical shutters is not the flash sync speed. It has to be considerably shorter. Once the first curtain has reached the bottom of the frame, the second curtain shouldn't start for at least 1/300" or 1/400", because this is the lightning time of many big flashes at fullpower. For the Canon 6D, a a flash sync of 1/180" means that the curtains take aprox. 1/300" to travel from top to bottom (or viceversa). For cameras with a sync of 1/250" the curtains must travel in 1/500" or less. I suspect though that Sony and other manufacturers limit the lightning time of dedicated flashes in order to raise artificially the sync. Proof is that when using manual flashes the speed goes down from 1/250" to 1/160-1/200".
Anyway, back on topic, if it's true that the readout of the A9 is 1/160" then it's still slower by some margin than the speed of most mechanical shutters. Sony claimed in the press release that the A9 is 20 faster than their former models The slowest of the A7 series is the A7rII at 1/12". That would mean 1/240" for the A9 ?.
It's easy to test it with an analog oscilloscope. I did with my A7rII and it's certainly 1/12".
I also tested the speed of the mech.shutter and its around 1/300-1/320", so with manual flashes near at full output, you can't use 1/250". Even 1/200"·is quite tight.
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