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K10D+ 16-50 - underexposure with Slave Flash

Ravi
Posted 06/08/2009 - 11:04 Link
Hi!
I bought a slave flash, & have tried it, but it gives very underexposed results...
I have seen the video on how to use it, should be straightforward, but haven't been able to get it right

Also, at a wedding, I used the 16-50 with K10D's built in flash, & got some very underexposed results...
I emailed the results to SRS, they were helpful & have offered to look at the camera's metering, but back at home, I got no problems! Must've been the strobe lighting at the wedding that "threw" the metering
OR,
I was too quick on the button!!

Anybody with slave flash experience, please help!

Thanks a lot- Ravi.
Pentax K10D, 18-55+ Digital King 0.7x, 50mm, 16-50mm DA*
Mannesty
Posted 06/08/2009 - 11:23 Link
It would help us to help you if you told us the make and model of the slave flash.
Peter E Smith - flickr Photostream
Edited by Mannesty: 06/08/2009 - 11:24
Ravi
Posted 06/08/2009 - 11:25 Link
Its a Pentax!
Pentax K10D, 18-55+ Digital King 0.7x, 50mm, 16-50mm DA*
Mannesty
Posted 06/08/2009 - 11:40 Link
Ravi wrote:
Its a Pentax!

That's a good start. Now we know the make, what's the model?
Peter E Smith - flickr Photostream
George Lazarette
Posted 06/08/2009 - 11:40 Link
Make AND MODEL!

G
Keywords: Charming, polite, and generally agreeable.
George Lazarette
Posted 06/08/2009 - 11:40 Link
Snap!

G
Keywords: Charming, polite, and generally agreeable.
Ravi
Posted 06/08/2009 - 12:34 Link
Dear Peter, George,
Thanks a lot for the quick replies!
Its zis one:
link
Its called the Pentax XTra Flash...
Pentax K10D, 18-55+ Digital King 0.7x, 50mm, 16-50mm DA*
gartmore
Posted 06/08/2009 - 12:50 Link
I'm sorry to say you've bought a little fill in flash that is manual and uncontrollable. All but useless in your situation, I'm afraid.

In the wedding situation it may well be that the flash hadn't fully re-charged before you took the next picture
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -
ChrisA
Posted 06/08/2009 - 13:01 - Helpful Comment Link
If you're triggering the Xtra flash from the pop-up, it'll be the pre-flash that triggers it.

So by the time the shutter opens, the Xtra flash is all over and done with, and will contribute nothing to the exposure.

It may be even worse than this - if the camera's metering sees any of the light from the Xtra flash, it may, in addition, think the scene is brighter than it is.

Underexposure is pretty much guaranteed, without there being anything wrong with the equipment.
.
Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
.
Ravi
Posted 06/08/2009 - 13:13 Link
Yes Ken, thanks possible that the flash hadn't re-charged fully before I took the next picture- I will check the setting where it blocks taking a picture if flash not re-charged.

About the Xtra Flash, I had read:
"With digital cameras you have to be careful that it fires at the same time as some have a preflash system that fools the slave to fire out of sync. "

Chris, could I ask if there is a way around the pre flash, or as Ken has said, the Xtra Flash will not work with the K10D?
Pentax K10D, 18-55+ Digital King 0.7x, 50mm, 16-50mm DA*
ChrisA
Posted 06/08/2009 - 13:25 - Helpful Comment Link
Ravi wrote:
Chris, could I ask if there is a way around the pre flash, or as Ken has said, the Xtra Flash will not work with the K10D?

There are two ways that I know of.

One is to use a pre-A series lens, or an A-series lens (or FA series) not set to A. The pop-up then doesn't emit a pre-flash, and triggers the Xtra flash just fine.

However, you'll have to do all the exposure manually, and ensure "Use Aperture ring" is set to permitted in the Custom functions.

The other is to use an old non-PTTL flash gun in the hot shoe to do the triggering.

Edit: or a PTTL gun in A or M mode. I've just tried it with the Samsung version of the AF 540, and it works fine. Again, you'll have to get the exposure sorted out by trial and error, I expect.
.
Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
.
Edited by ChrisA: 06/08/2009 - 13:33
gartmore
Posted 06/08/2009 - 13:34 Link
ChrisA wrote:
[quote:3496ace15f="Ravi"]The other is to use an old non-PTTL flash gun in the hot shoe to do the triggering.

which, ironically, probably cost less than the one you bought. You must be disappointed but at least it didn't cost a fortune and you might still find a use for it.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -
Edited by gartmore: 06/08/2009 - 13:35
Ravi
Posted 06/08/2009 - 23:39 Link
OK! I will surely give it a try: it may be cheap, that wil make it all the more fun- if it works!
That's the fun of digital!
Thanks for your help, and comments.
Rgds
Pentax K10D, 18-55+ Digital King 0.7x, 50mm, 16-50mm DA*
adwb
Posted 03/09/2009 - 00:53 Link
Hi bought one of these Xtraflash units that Ephotozine was offering on sale and it functions correctly ok,
the problem is all I get is black photos.
using pentax k 10 set to f5.6 100 iso, flash on, take photo all is ok.
as a above and as per Xtra flash instructions place xtra flash at 2 meter from the subject , take picture camera flash and xtra flash both go off and the result is a nearly black image.
I am obviously missing the point somewhere can some explain what I am doing wrong?
I have tried setting the speed to 1/125 but get the same result.
tried x [=1/180] flash setting same result
why does the image look as if it is vastly underexposed? I thought to much light will look washed out / horribly overexposed is that not correct?
I am not using red eye reduction which would cause early slave flash or in place so dark the pre-flash goes off to set auto focus. I have tried on manual focus as well, but unless the slave is a long way away , further than the supplied chart suggests then I get these very underexposed image.
Alistair
Assorted Pentax bodies and lenses as well as Sony and Olympus kit
Clarky
Posted 03/09/2009 - 05:57 Link
If I understand you correctly and as ChrisA explained in his post, its the pre flash on the pop up flash that is triggering your Xtra flash, so The Xtra flash is not contributing to the exposure as the flash has already gone off before the picture is taken.

Get yourself a little Pentax AF 160 flash and use that as the trigger for your Xtra flash.
Camera:|K-7|
Pentax Lenses:|DA12-24/f4 ED AL|DA35Ltd Macro|FA31Ltd|FA77Ltd|FA50/1.4|F70-210|FA20-35 f4/AL|A*200/f4 Macro ED|A50/1.7|A50 Macro f2.8|1.7xAF adapter|
Voigtlander|125/f2.5SL Macro APO Lanthar|
Sigma Lenses:|EX DG 100-300 f4|2X & 1.4X TC|
Flashes:|AF540FGZx2|RingFlash AF160FC|

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