K7 and flash synchro-speed


patrick

Link Posted 16/01/2010 - 15:23
good afternoon ! re K7 and flash synchro-speed: does the fact that anti-shake is on or not has an influence on the flash synchro-speed ? i ask that, because it happens on some other brands, like the sony alpha 700: 1/200 with, and 1/250 without. so, as on some docs, K7 flash synchro-speed had been mentioned at 1/250 , and in fact is announced at 1/180, i wondered ? ... patrick
Pentax - what else ?

bretti_kivi

Link Posted 16/01/2010 - 15:52
SR should be off when using flash?!

You should also be able to sync at 1/4000 with a compatible flash.

Bret
my pics: link
my kit: K3, K5, K-01, DA 18-55, D-FA50 macro, Siggy 30/1.4, 100-300/f4, 70-200/2.8, Samsung 12-24/f4, Tamron 17-50, and lots of other bits.

Anvh

Link Posted 16/01/2010 - 15:54
Patrick the flash sync of the k7 is 1/180.
1/250 was mentioned was just a rumour going around.
With HSS (high shutter speed/sync) you can however sync past 1/180 but the flash need to support that since it's a special feature.
It come close to strobing the flash during the whole duration of the shutter movement.

SR can be left on, I never found it a problem with the K10D and never heard something about the other cameras. So it's safe to assume it's no problem with the K7 either.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Last Edited by Anvh on 16/01/2010 - 15:55

patrick

Link Posted 16/01/2010 - 16:02
ok - my fault, i wasn't clear. i know all of what you all said; about alpha 700, notwithstanding all above mentioned functionalities, it is said that if you disconnect SR, synchro speed goes from 1/200 to 1/250; so, i was wondering if same happened with K7 - am i clearer ?
Pentax - what else ?

Anvh

Link Posted 16/01/2010 - 16:08
Yes, you're but no SR doesn't have influence on flash sync.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

patrick

Link Posted 16/01/2010 - 16:11
that's not what is written about alpha 700 - cf P. BUrian book ? - hence my question. ok, so end of post ?
Pentax - what else ?

Anvh

Link Posted 16/01/2010 - 16:33
Flash sync is only influenced by the shutter cutains.
It could be that sony calibrated it very critical to get the higher sync numbers, probably they took the number on which they knew the curtains aren't infront of the sensor.
Because the SR move the sensor it needs to have a bit more room so a less critical number must be chosen.
I think Pentax took the less critical one and took the time the shutter is open fully, so no relative to sensor size or placement so SR does not influence the sync speed.

I'm not a photocamera engineer but it does make for a logical explanation.

ps. in my previous post I was talking about the K7 explicitly, sorry that I wasn't clear about that.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
Last Edited by Anvh on 16/01/2010 - 16:35

patrick

Link Posted 16/01/2010 - 16:43
no problem - have a nice w/e !
Pentax - what else ?

Anvh

Link Posted 16/01/2010 - 16:46
You too Patrick
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
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