Metz 52 as control and slave not exposing properly


NeilP

Link Posted 06/11/2016 - 22:10
As many of you know I take photos of pond creatures in an aquarium set up and have been experimenting with using more than one flash, both Metz 52. One flash is held just above the (small) aquarium and is controlled from the hot shoe via a P-ttl cable and set to 'master', the 2nd is to one side (set as slave). Problem is most my shots came out like this



After adjusting exposure and flash power to increase the exposure level and adjusting the flash distance/diffusion amount, to little effect, it would then over expose for 1 or 2 frames



The odd frame came out ok though, when the slave fired and worked



When trying to photograph badgers in the dark (with no interfering infra light from the sun etc), with one flash to one side on the p-ttl cable set to master and the 2nd to the other side set to slave) it seems the slave does not affect the exposure at all. It seems to fire, but does not seem to provide any light to the image from its direction. The slave mode on Metz is p-ttl (not a 'dumb' slave') so I am unsure as to why it doesn't seem to work the majority of the time. Any ideas?
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McGregNi

Link Posted 07/11/2016 - 16:11
Neil, there's nothing obviously wrong from the settings descriptions you gave ....

..... the 'on-camera corded' flash set to 'Remote Master' (which adds its illumination as well as controlling the Slave flash)

.....The off-camera flash set to 'Remote Slave' / TTL

I'm assuming they're both on the same Channel as you said the slave was firing ....

You didn't mention what Camera exposure mode you were using. For this sort of thing I would suggest Manual mode, with a fixed ISO, will give the best control over things. Set the aperture to what is needed for DOF, and use the shutter to control the amount of ambient light you allow to record, if any .... if you don't want any then use 180th sec with ISO 100, which will wipe out most ambient light and give the best image quality.

You are probably better, for the aquarium shots anyway, to forget P-TTL and switch to manual flash exposure mode. The close proximity of the flashes to the frame, plus glass is likely to play havoc with the flash metering, and so is a possible cause of erratic exposures.

Just check carefully the working distances involved .... its all too easy to have the flashes too close for the various exposure settings. Step down the ISO and stop down the aperture progressively and try again after each step to be sure the flashes are at a suitable working distance.

It would be good to hear if any of this has an effect. Good luck finding a solution !
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Helpful

NeilP

Link Posted 11/11/2016 - 08:16
Thanks for your reply. Reassuring Im not doing anything wrong, but not so good that the flashes are not working as they should, I guess that's another limitation to add to my Pentax gear!

I tried using my cheap ebay manual triggers to great effect yesterday with the aquarium set up, its just a shame that using wireless pentax flash I cant photograph badgers.
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McGregNi

Link Posted 11/11/2016 - 15:50
I think both of your described situations would throw a high challenge to any automatic flash exposure system. The aquarium sort of subject is very much a candidate for manual flash control, and you can use manual mode on the Metz flashes and trigger optically using the Pentax wireless system still. You need to set the power levels directly on the flashes themselves though.

The other situation, badgers, and I presume with darkness all around, is more of a puzzle. Exposure wise it is a likely candidate for overexposure automatically, as large areas of blackness and a relatively small subject in the frame will trick any TTL exposure system into overexposure. So not seeing the flashes effect suggests more a communication/triggering issue, unless the distance involved is too great for the ISO and aperture. Have you tried to zoom the flash head in order to more tightly target the subject?
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
Last Edited by McGregNi on 11/11/2016 - 15:51
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