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01-29-2011, 04:31 PM   #1
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K7 pre-flash (P-TTL)

Does anyone know how to disable the pre-flash from the pop up flash when shooting in full manual mode???

I suspect that it probably can't be done, but I'm not sure.

01-29-2011, 07:22 PM   #2
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Never tried but I'd bet taking the lens out of A would work if the lens has an aperture
01-29-2011, 07:38 PM   #3
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QuoteOriginally posted by Lowell Goudge Quote
Never tried but I'd bet taking the lens out of A would work if the lens has an aperture
Thanks, I'll try that and let you know.

The Lens that I use most in the studio have aperture rings.
01-29-2011, 07:55 PM   #4
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Disable red-eye?

01-29-2011, 09:38 PM   #5
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QuoteOriginally posted by wlachan Quote
Disable red-eye?
Red-eye just adds some bursts prior to the metering pre-flash.

The only solutions are:
- Using the lens out of its A position (as Lowell said), but it will fire at full power.
- using a manual flash in the hotshoe (so you'll be able to dial the power down).
01-29-2011, 10:00 PM   #6
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QuoteOriginally posted by dlacouture Quote
Red-eye just adds some bursts prior to the metering pre-flash.

The only solutions are:
- Using the lens out of its A position (as Lowell said), but it will fire at full power.
- using a manual flash in the hotshoe (so you'll be able to dial the power down).
It's the metering pre-flash that I want to disable. I use radio triggers to fire my monolights. If I disable the metering pre-flash, I can fire them optically with the pop up.

It's not that I want to do this all of the time. I had a radio trigger failure and have to use a PC cord. I just think it would be a lot easier if I could use the pop up. but, with the metering pre-flash, the monolights have already fired before the shutter opens.

I'll try shooting out of the "A" position and see what happens.
01-30-2011, 02:15 AM   #7
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The problem is that with the built-in firing at full power, it may register in your photo...
That's why an inexpensive manual flash could be a good idea. Or maybe a Nikon SG-3IR flash screen, if you want to keep equipment to a minimum (and it is useful when you want to use P-TTL wireless in controller mode, as the K7/K5 has a pretty strong minimal power)...
01-31-2011, 07:50 PM   #8
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More....

The metering pre-flash is eliminated when shooting out of "A". The K7 indicates that the flash output can be reduced by a factor of -2.0 when the body is in manual mode. I didn't have the proper equipment with me to do and accurate measurement to see if it actually does lower the output..

I did put my hand a few inches in front of the pop up to block the flash from hitting the scene directly. My monolights did fire optically with my blocking.

Of course, this is nothing I intend to do on a regular basis but use as a method if I have a radio trigger failure again.

More later once I accurately measure the pop up flash intensity.

02-01-2011, 12:00 AM   #9
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QuoteOriginally posted by Ed n Georgia Quote
The K7 indicates that the flash output can be reduced by a factor of -2.0 when the body is in manual mode. I didn't have the proper equipment with me to do and accurate measurement to see if it actually does lower the output..
It doesn't. The flash power reduction setting has no effect when the lens's aperture ring is out of the A setting.

I tested with a K7, a Tamron 90mm macro (aperture ring at F/2.8), and a Minolta Auto Meter IV F.
02-01-2011, 08:04 AM   #10
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QuoteOriginally posted by SOldBear Quote
It doesn't. The flash power reduction setting has no effect when the lens's aperture ring is out of the A setting.

I tested with a K7, a Tamron 90mm macro (aperture ring at F/2.8), and a Minolta Auto Meter IV F.
Thanks, Good info.

I was going to run a similar test, and may still do it, with my FA 77 and Sekonic L358.
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