help with slave flash

[ib2loud]

I posted this in another thread, but I wasn't sure if it didn't fit in better in this one


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I am not trying to be a pro, but I would like to take better pictures of the babies (my wife's cats). I have a S3 right now and all of the pictures i took indoors had really bad eye glare from the flash, so I got a small slave flash. The pictures do look better, but they seem to come out really dark (opposite of what I would have thought). The eyes still have a glare, but it's nowhere near as bad as it was.

do i need to crank up the exposure when using the slave or is there a setting somewhere that i have wrong?

thanks for any help!


the attached photo is one of the better ones

[sonnyJ]

Hope you get the answer. I had same problem with S2 - whenever using the slave flash pictures came out dark. I tried variety of settings without success.

[Headcase650]

What kind of slave is it? If its the one made by canon for the powershots I think its compleatly automated. I have a sigma 500dg super and it works as a manual slave and is adjustable. The camera has to be set to manual mode as well as the flash on the camera to eliminate the cameras preflash. Then you just play with the manual settings and the slaves power until you get the proper exposure.

[strmrdr]

If the slave is triggering on the pre-flash they will come out dark.
Either need a slave that triggers on the second flash or set it in manual mode to not preflash.

[brantfordbandit]

i just bought a slave having a similar problem. i think the slave is firing a split second after the pop up flash. i'm going to try and put the slave on the same plane as the pop up flash.
To get rid of alot of that awful white flash look try putting a white envelope over your p[op up flash it works really well

[sonnyJ]

Someone told me he puts the translucent case from 35mm film ovetr the pop up flash and is works as a difusser

[Headcase650]

Try a ping-pong ball with a knotch cut out of it.

[MaxZoom]

OK just so no one gets confused.

Putting a diffuser over the camera flash addresses the hard light issue that caused the change to a slave flash in the first place. It does not address the 'dark' problem.

The slave flash is a problem due to the camera putting out a pre-flash so it can judge the correct energy to use in the main flash for proper exposure. You can...
#1 Use a digital slave which will ignore the preflash.
#2 Switch the camera flash mode to manual (not the same as manual exposure mode in many cameras) In manual flash mode you can typically specify one of three power settings and there will be no pre-flash.

With a slave you now have two hard sources of light, you probably want the diffuser on both flashes.:)

[ib2loud]

there is no pre-flash on this camera though, it has a green light that shines out to get the focus

the flashes fire at the same time, at least by my naked eye it appears to

thanks for the advice, i'll have to play around with it when i get time

[Jon]

It has a pre-flash to meter your flash exposure. With both the main flash and the slave firing for this pre-flash, the camera will overestimate how effective the main flash will be and give you an underexposure. The pre-flash will also have a "red-eye reduction" effect on your cat, as you can see from the photos (her pupils are contracted).

[GordonSBuck]

Try to include the slave flash in the full picture so you can tell if the slave has fired.

[MaxZoom]

there is no pre-flash on this camera though,
Don't confuse red eye reduction which is a series of flashes to which your eye is supposed to react to.
The green light is a focus assist light, nothing to do with flash or exposure metering.
You cannot perceive a pre-flash it is less than 20ms before the main flash so happens too quickly for the eye to notice. We used to attribute this to 'persistence of vision' but it is just a human limitation. I would not want want to try and sell TV to an alien. When the aliens finally do visit our planet they will be driven crazy by the flickering screens we all watch which flash red green and blue lights and from which the stupid humans tell them they can see colored pictures. :lol:

[ib2loud]

I guess it does have a pre flash, was just too fast for me to see. I put the slave to fire on the 2nd flash and now the images are very bright, so I can adjust everything accordingly

thanks for the help

[padylyn]

Hi everybody with S2 flash problems,
This works very well for me....
I have S2IS for about a year. I have been conscious of the shortcomings of the built-in flash. It's a bit weak if you are used to a stronger one.
I have a fairly old Unomat automatic flash which I had been using with a non-digital SLR, but could not use with S2 as it has no hot shoe.
I bought a cheap slave actuator (that sounds better than slave-driver) but had exactly the same problems. It just wouldn't work correctly with S2IS.
Just a couple of weeks ago, I read a post on this forum, suggesting that if it was used with the camera in Manual Mode it should work.
I tried that and I am now getting very good results.
I have made a bracket to fix the flash unit to the tripod mounting point on the camera.
I have also made a bracket to mount the flash to the tripod when necessary.
I'm very happy now!

Best Wishes
Padylyn

[ib2loud]

I'm pretty happy with how it's progressing. I shot with it last night in manual mode and this one was in pitch black almost

I know it's not perfect but it's definitely a start

http://ib2loud.redonblack.com/cats/IMG_0593-reszied.JPG

now i need to perfect the exposure and work on the shadows, but at least her eyes look more normal

[Jon]

For the shadow, try either bouncing the flash off the ceiling or even just raising it above the camera. The former will give a softer light, and make the on-camera flash carry more of the weight; the latter will help the shadow move down and behind your subject.

[Headcase650]

Point the flash up at the cieling and attack ABetterBounceCard on the flash to direct some of the light forward.
http://www.abetterbouncecard.com/