Thyristor Flash with Slave(s)

Hi Dee Ho, One and All!

While they don't let me have sherpas to schlep my gear around, my Vivitar 2500 flash gets a little Optex VLF3 slave to play with (it's really cute - so far they've just been winking at each other from across a crowded room.)

The output of the little Optex is quite tiny compared to the Vivitar main unit, and I only plan to use it as a side lite to take away some of the frontal harshness.

My question is, will the slave flash fool the auto reading of the thyristor in the Vivitar causing it to underexpose? ie: should I go fully manual and work with guide numbers, flash to subject measurements and calculate f stops - yuk.

Cheers

I think it will depend a great deal on how the flashguns are positioned. If the Optex is pointing at the Vivitar, it probably will cause under-exposure, and if the Vivitar is not close to the axis of the camera there is also likely to be a problem,

Get a little digi to try out the lighting with!

G

Oh George, you're a sly one! You never stop tempting me with up-to-date gear.

I agree a digital is a great way to try this stuff out - and I just realized something - my daughter has a sexy little point and shoot that I wouldn't be caught dead with (it's fushia or something), but I'm not beyond hiring HER to press the shutter.

Thanks!

Hi Mac.
If your two lights are not aimed in such a way as to cause the light from your small light to hit the sensor on your vivitar, (ie- 45 degree angles on iether side of camera, ) then the vivitar will cut out at the fstop indicated on the scale. It will in fact read the light reflecting back to it. The combined light of both units. Therefore you must check the guide numbers of the smaller unit and ensure it is at least one stop less than the thyristors setting. You can control contrast by moving the smaller light closer or farther from your subject, ( or taping paper or difuser to unit) and underexposure should not happen, however it would be easy to overexpose if the flash output of the smaller unit is higher than the vivitars setting.

ps my preferred method of using a two light setup like that would be to put the smaller manual unit on camera with a tissue and rubberband for a diffuser and the vivitar bouned off the white cieling, my camera set to match the thyristor setting on the vivitar.

Good stuff, Don.

I've loaded a roll of expired 100 ASA (stuff I use for testing new set-ups (and often get my best shots with)) into the trusty old SP F, and will write down every and all attempts 'till I figger dis out.

I'm pretty sure I'll have to use the manual setting on my main flash as the little slave has no auto setting and blasts away at full power when triggered.

Anyhoo, fun times ahead.

On a related subject, I've pretty much given up trying to locate 5000 kelvin photoflood bulbs and use an 80A blue filter with incandescent spots.
Easy, and the results are amazing. I have an 80B on order as well.

Ciao

Hi Mac,
A bit OT but did you get your bellows/macro question sorted out?

Kim

Kim,

Yup - by you!

Thank's so much!

Cheers