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01-14-2012, 03:04 PM   #1
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Self timer and flash

If I use the K-5 self timer on 2s delay, or remote on 3s delay, combined with flash, the initial button press sets off the flash (seemingly at full strength), with a second less powerful flash when the actual pic is taken. This has sometimes caused me to lose the picture, as the flash is still charging after the first release when the pic is taken. The same does not happen with a 12s delay on self timer, so it seems to be connected to the mirror-up component of the shorter delays. Can this be prevented?

01-14-2012, 03:22 PM   #2
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I just tried to duplicate what you are experiencing and my flash ONLY goes off at the end of the timer sequence. Sorry, but that doesn't appear to be normal behavior for the camera.
01-14-2012, 03:42 PM   #3
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QuoteOriginally posted by bjdavey Quote
If I use the K-5 self timer on 2s delay, or remote on 3s delay, combined with flash, the initial button press sets off the flash (seemingly at full strength), with a second less powerful flash when the actual pic is taken. This has sometimes caused me to lose the picture, as the flash is still charging after the first release when the pic is taken. The same does not happen with a 12s delay on self timer, so it seems to be connected to the mirror-up component of the shorter delays. Can this be prevented?

I believe that the first flash when using 2sec delay is the P-TTL pre-flash and the flash at the end of the 2sec is the flash used to expose the shot.

I have used this in order to use a flash meter to figure out what flash ratios are used in various multi-flash set-ups. Not using the 2sec delay prevents me from separating the pre-flash from the main flash.


I wouldn't expect the pre-flash to be at full output though.


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01-14-2012, 08:39 PM   #4
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Thanks for taking the time to check, Robert. With my K5, the double flash is consistent every time with the short delay or remote release, only when combined with the concurrent mirror lock process. Dave seems to experience the same as me. Anyone else care to tell us what they see when using flash combined with 2s delay, or 3s remote release?

01-14-2012, 09:32 PM   #5
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Is the red eye reduction kicking in? Sorry for the dumb question.
01-15-2012, 08:04 AM   #6
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Hi Jim. No, it's not the red eye function. With red eye reduction alone set, there are the usual two flashes, one when the shutter release is pressed, and the other about 1/2 s later with the exposure. If I combine that with 2s delay, there are three flashes, the first on initial shutter release press, and then two more 2s later. In other words the same behavior as with no red eye reduction- the delay mode causes a strong flash at the initial shutter release press, followed by another flash when the shutter actually releases.
01-15-2012, 08:32 AM   #7
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Mine does the same thing at 2 second delay, but not with 12 second. Suspect it is because of the mirror lockup, but do not know why.
01-15-2012, 08:38 AM   #8
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QuoteOriginally posted by toooldtocare Quote
Mine does the same thing at 2 second delay, but not with 12 second. Suspect it is because of the mirror lockup, but do not know why.

It's because the pre-flash happens with the mirror down. The main flash is (obviously) with the mirror up and the shutter open.

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01-15-2012, 09:48 AM   #9
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It is indeed connected to the mirror lock-up process. I just tested using the mirror lock-up shooting mode with flash, and with no delays set. The first shutter release press (which usually just lifts the mirror) triggers the flash, with a second flash when the shutter is actually released. So it's got nothing to do with the delay function- its the mirror lock- up seemingly introducing a separation between the pre flash and the exposure flash.
01-15-2012, 10:15 AM   #10
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... and I've just confirmed that the two flashes (one before mirror lock up, and one at the time of actual exposure) are indeed the P-TTL pre flash and the exposure flash respectively. By using the mirror lock-up mode with flash, and moving the camera between mirror lock-up and shutter release, the exposure of the shot is altered by the exposure requirement of the initial position. If you trigger the mirror lock-up while pointing at a dark area, and then take the picture of a light area, the shot is overexposed, and vice versa. I guess this won't affect many people in real conditions, but interesting to note that you can actually see or measure the difference between the pre and exposure flashes when you use mirror lock-up mode (or any of the delay functions which also activate mirror lock-up). It would only be relevant if you are using flash+mirror lock-up together for some reason, and there is a possibility of a lighting change during the interval between mirror lock-up and exposure.

I should change the title of this thread to "mirror lock-up and P-TTL flash", but not sure how to do that. Thanks to those who helped me work out what is happening with my "double flash" problem.
01-15-2012, 10:46 AM   #11
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To take this further, if anyone is interested, I've now discovered that the mirror-lock / exposure link happens without flash as well, and its in the manual (pg 150 item 7). When using the mirror lock-up function, the exposure is set at the time of triggering mirror lock-up, and not at the time of the later exposure, no matter how long you wait before the actual exposure. So when you add flash to the equation, you get to see the metering process functioning via the separation of the pre and actual flash.
01-15-2012, 03:46 PM   #12
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Somewhat off-topic, but is there a way on recent cameras to "manually meter with flash", ie, trigger the preflash and have the meter reading set the exposure? Just the P-TTL flash, and without taking a photo?
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