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03-21-2007, 04:32 PM   #1
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P-TTL on K10D w/540 question...

Ok, this may be completely dumb question, I've never own a dedicated flash, 540 arrived yesterday, I after reading the manual over and over again, and few test shots, very confused:

P-TTL, manual states "flash pre-fires" so more accurate reading via multisegment metering takes place" - I've read this question in this thread

https://www.pentaxforums.com/forums/pentax-camera-accessories/3256-p-ttl-pre-...n-visible.html

I'm in the fairly dark room, flash set on P-TTL, A-Zoom, leading curtain sync - I see no pre-flash, only the "red light" in the front sensor is being activated...

Camera set on Av... Am I doing something wrong? Shouldn't I see the pre-flash? Even tried holding the camera off to the side, not looking into the viewfidner...

Regards,
D

03-21-2007, 04:43 PM   #2
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Pre-flash and the main flash happen very quickly, it is not easy to detect two separate flashes. The easiest way to see it is through the viewfinder. If you saw any flash in the viewfinder - however brief, it was the pre-flash. The main flash cannot be seen in the viewfinder at all.

In the old 35mm days, you simply cannot see any flash through the viewfinder. The fact that you see a brief flash a fraction of the second before the mirror blackout is the preflash.

That's why I am surprised that some people get blinkies. I suppose some are very sensitive, but I do not see much blinkies at all.
03-21-2007, 04:51 PM   #3
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Does the pre-flash still works if the head is angled or lifted say for bouncing? And the exposure then automatically compensated immediately after pre-flash? Or based on this split second reading, the flash output adjusted and exposure remains unchanged?

Many thanks for putting up with this dumb questions, but honestly, after reading the manual from core to core, I still have these questions...

Regards,
D
03-21-2007, 09:01 PM   #4
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QuoteOriginally posted by Duh_Vinci Quote
Does the pre-flash still works if the head is angled or lifted say for bouncing? And the exposure then automatically compensated immediately after pre-flash? Or based on this split second reading, the flash output adjusted and exposure remains unchanged?
Yes, it should all work automatically in theory. But in real life, you may have to dial in some exposure compensation e.g. +1 EV for bounce flash in some situations.

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