Fiona said:
...I have just got myself a flash gun a Centron F G 30...
...I have just started doing cave photography with my canon A 80 dig but the buit in flash is causing problems with steem...
Can anyone tell me will this flash gun go with any slave unit ? and will I any cables to connect it ?
any tips advice would be good
Thanks Fiona.
A couple of people in our club use the 'jessops' flash slave, but they do have the disadvantage that they need a pretty clear line-of-sight to the flash that's triggering them. I much prefer
David Gibson's flash slave, not really suitable if you're not into soldering together gadgets, so the next best would be the
Firefly slave.
The largest cause of mist is your own breath being illuminated by the flash positioned right next to the lens. The best way to avoid it is to move the source of light (ie. flash) away from the lens.... not possible with a flash on the camera! The two options available are to hold your breath for two or three seconds before pressing the shutter, this will let the mist clear a bit. (Digital gives a clue whether it's misted up or not at the time - but can look clear on the camera but still misty when you look later on a PC... so I've been told)
The alternative is to hold the camera in one hand and a flash slave in the other, to stop the light from the camera you cover it with a piece of unexposed (but developed) slide film, this is black and will block visible light, but allows infra-red light through to trigger (a D. Gibson/Firefly) slave flash. Most people these days have access to negative film rather than transparency/slide film, this seems to work as well - only in this case you want to use a frame that's overexposed (might find a bit right at the beginning/end of the film where it hung out of the canister).
A combination of techniques can produce some good photos, ie. hold a flash slave in one hand but don't cover the camera flash - you still have to hold your breath before taking the picture (else risk mist) but if the slave is more powerful than the camera's flash (not usually difficult to achieve) then the subject gets some modelling from the light to one side, but you don't get inky black shadows because the less powerful flash on the camera acts as a fill.
If you've got a spare slave then it can really lift a photograph to use a bit of 'backlighting'. Position the flash behind your subject looking back at the camera - make sure the flash is hidden behind your subject or around a corner though (ie. no direct line of sight between flash and camera lens). This technique will put highlights on the edges of rocks/water etc. and gives the feeling of depth in a photograph, it can prevent the illumination just fading into muddy darkness. For the sake of a couple of slaves it's a trick worth trying.
If all of the above seems double-dutch, then just go underground and keep taking photos and experimenting. Change how you do things and make a note (mental or paper) on what works and what doesn't. Most important of all, have fun!
Mine X.
PS: Yes, the flash slaves usually connect to the flash gun using the 'hot-shoe', the slide in connector usually found on cameras. If you build a David Gibson one you have to make your own connections - or purchase a suitable hot-shoe adapter and cut the other plug off.
