Mini Flash Sensitivity

Derek Zoolander · Feb 5, 2009

So I bought two of these 690045 Smith Victor PG250S Wireless Mini Slave Flash, Guide Number of 70', ISO 100.

A pretty hasty buy considering I don't have an external flash. Do you guys think it will work with my built in flash if I deflect the light upwards? or does it have to be pointed in the exact direction of wherever that flash is sitting?

Big Mike · Feb 5, 2009

The effectiveness of optical slave triggers depends on a lot of factors. Ambient light, surfaces to bounce the light etc. Sure, direct line of sight is best but not necessary.

Will that work with your built-in flash? Probably...but you need to be aware that your built-in flash might fire a pre-flash. If it does, that preflash will trigger these slaves and they won't be able to fire again when the exposure is being made.
Two ways around this would be to have your built-in flash fire in manual flash mode (no preflash)...but many cameras don't have this option. The other option is to have a slave that is smart enough to ignore the preflash (I don't think these qualify)....so you might be SOL...but that is yet to be seen.

Derek Zoolander · Feb 5, 2009

bummer...wish i had my camera here to find out. by chance do you know if a Canon Rebel XS has this option?

Derek Zoolander · Feb 5, 2009

Doesn't look like it's possible. So since that's the case, what's the next alternative for me? Would this help? Gadget Infinity :: Digital Camera :: Flash Trigger :: 4-Channel Wireless Flash Trigger V2s

Big Mike · Feb 5, 2009

I don't know...but I'd be pretty sure that it does not. I don't think any of the Canon DSLR cameras can be set to have the built-in flash fire manually.

There is a way to get around this though (if your camera has FEL). Set up your shot and press/activate FEL (flash exposure lock). This fires the preflash early. Then all you have to do is wait for the flashes to recharge (I believe they quoted 4 to 6 seconds) then take the photos. The flash will only fire once this time.

There is a time limit as for how long the camera will remember the FEL...so make sure you don't take longer than that.

Big Mike · Feb 5, 2009

That radio trigger will get you on your way yes.

Check out these 'strobist kits' from MPE Strobist 1 light Kits

Derek Zoolander · Feb 5, 2009

So that radio trigger...tell me if this is right.

I would put the transmitter part of it on my hot shoe.
then i would slide the mini flash into receiver and flash stand.

Built in flash stays down, click to shoot and the flash would go off?

I appreciate all your help Big Mike. I'm really trying to get into lighting but want to take it slow and use as little money as possible.

Big Mike · Feb 5, 2009

I would put the transmitter part of it on my hot shoe.
then i would slide the mini flash into receiver and flash stand.

Built in flash stays down, click to shoot and the flash would go off?

Those mini flashes have a hot shoe right? If so, then yes, that's exactly what you would do.

Derek Zoolander · Feb 5, 2009

I'm assuming the left side with the silver nubbin deal is the hot shoe? I always thought the hot shoe was the part on my camera you slide it into...

Big Mike · Feb 5, 2009

I'm assuming the left side with the silver nubbin deal is the hot shoe?

Yes, that is what it looks like.

I always thought the hot shoe was the part on my camera you slide it into...

Yes, that is the hotshoe....I should have said the 'foot' of the flash goes into the 'shoe' on the receiver unit.

Derek Zoolander · Feb 5, 2009

haha you're rolling your eyes aren't you?

Big Mike · Feb 5, 2009

:roll:

Ron Evers · Feb 5, 2009

Derek Zoolander said:
haha you're rolling your eyes aren't you?

Big Mike, always helpful, never snarky, Canadian eh. :thumbup:

Derek Zoolander · Feb 12, 2009

I'm happy to report that I finally got my cactus V2s and my mini flashes and they work well together. Now onto figuring out how to use the lighting off camera. I took a few here at the office just to make sure they worked and it blew everything way out. ill play more when i get home.

Big Mike · Feb 12, 2009

I took a few here at the office just to make sure they worked and it blew everything way out. ill play more when i get home.

When using flash in manual control (without any auto flash metering), you pretty much need to have the camera in manual mode as well...because the camera gets its' exposure from how the scene looks before the shot. It can't measure for the flash because it doesn't fire until the shutter is already open....thus, the flash just adds to the exposure and you end up with overexposed images.

Try this; put the camera into manual mode and set the shutter speed to 1/125, the aperture to F8 and the ISO to 100. Try a test shot.

If the exposure from the flash is too much, then use a smaller aperture. If it's too little, then use a larger aperture or a higher ISO. The shutter speed only affects the ambient exposure, not the flash exposure.