Red-eye and optical slaves

Slowpoke Rodriguez · 09-07-2008, 10:56 PM

I am going to begin experimenting with multiple flashes and such I have what is probably a very novice question. If I use optical slaves to triger my tripod or lightstand mounted flashes, and I trigger them with the built in flash on my K10D, is red-eye still a concern?

I should get no red-eye from the mounted flashes because I will be off-axis from them, but the pop-up flash on my camera is just inches from the lens and therefore red-eye might be a problem. If the predominant light sources are the mounted flashes, can the smaller amount of light that my camera will produce still trigger the red-eye effect?

Thank you to all who submit.

Russell-Evans · 09-08-2008, 01:06 AM

Originally Posted by Slowpoke Rodriguez

I am going to begin experimenting with multiple flashes and such I have what is probably a very novice question. If I use optical slaves to trigger my tripod or lightstand mounted flashes, and I trigger them with the built in flash on my K10D, is red-eye still a concern?

Before you get to red eye, you'll have to deal with the preflash of the onboard flash. If you don't have optical slaves that can deal with the preflash you'll probably find your remote flashes won't fire on the main flash. Have you considered how you will deal with this?

Thank you
Russell

Slowpoke Rodriguez · 09-08-2008, 09:27 AM

I understand what you are talking about, but I believe I have seen optical slave triggers that can be fired appropriately by digital cameras. How well they work, I don't know, but when I look for slave triggers I see several models that indicate they can be triggered by digital cameras.

My assumption was that these devices would work, which then gets me back to my original question of will I still get red-eye from the pop-up flash?

Thank you for your help.

Russell-Evans · 09-09-2008, 07:02 PM

When you have the red eye option set, you get the preflash happening with a distinct delay. I think you will need an optical slave that is very adjustable to be able to deal with that. I think most digital optical slave are expecting a much smaller gap between the pre and main flash.

With the remote flash and a diffuser on the camera flash, you might find you don't need to use the red eye flash mode. Dropping the on board flash's output, it just needs to trigger the remote, might work as well. Or do both.

You might think about using a radio trigger instead to get completely away from the problem. The range of an optical slave and the working environment aren't going to be any better than the working environment of an ebay radio trigger and the cost of a digital optical slave that can handle the pre flash might even be the same or more.

Sorry I can't be of any real help and specifically answer your questions.

Thank you
Russell

*Canada_Rockies* · 09-09-2008, 08:54 PM

There are optical slaves that can be set to trigger on the first, second, third, flash rather than the first. That would eliminate the main flash from the equation with the on board flash, which can be set to fire the strobes, but without adding to the exposure itself.

*janosh* · 09-12-2008, 10:26 AM

Wein's slaves now work with digital pre-flash, but you need to be careful about which model.

IMO optical slaves are secondary options for modern systems. My Skyport fires two Vivitar HD285 (cables from www.flashzebra.com are necessary)...they can be located places/distances where optical slaves wouldn't work. I also have a 25-yr-old Wein peanut slave mounted on an equally ancient Sunpak strobe, which works fine as a third light (eg behind a subject)...actually better than Pentax or Vivitar (just as powerful) for that purpose because of the way the head swivels.

You'll go wireless as soon as you understand how well it works. The systems on 'bay may not be 100% reliable but they're very cheap. I spent more and got Elincrom Skyports. AlienBee has something similar, but I prefer Skyport's far-lower on-camera profile.

For more about wireless and off-camera flash: Strobist ...which incidentally sells a SUPERB set of DVDs that teach off-camera lighting from soup to nuts :-) I think you can find all that DVD info somewhere on the site, but it's faster and more visually effective from the DVDs.

...as for red-eye and optical slave: no red eye if you aim the flash UP and perhaps gobo (baffle) it so it doesn't fire directly at the subject, the bounced and bouncing light will fire the slave IF it's not positioned too far away. "Too far" depends on all of the elements, including ceiling height.

It MAY be possible to gobo k10D's built-in flash to do this...or may not be.