[Seiford]

I'm having a puzzling issue with inconsistent flash.

Canon Digital Rebel (old 300D). Taking 4 photo booth shots 4 seconds apart (ends up being 9 seconds due to transfer delay). The 2nd or sometimes the 3rd shot are brighter than the others. I set the camera to manual (1/100, 4.5), built in flash, AC adapter.

Any ideas what's going on? Could the internal flash not be re-charging quickly enough?

This forum sure is a great resource.

[Qapla]

Try setting the camera for 1/60th - this is the standard flash-sync. See if that makes any difference.

[photoboothier]

I also have the 300D. I don't think it's a problem with the flash recharge time. It's probably the camera's flash exposure compensation improperly exposing the flash. Setting the camera at 1/60 shutter speed will only get more ambient light, which you may want. I am setting my camera at 1/125 or even faster just so I can be sure to freeze the action and not get motion blur.

Hope that helps.

[rikiboy]

me too, we also use 1/125 shutter speed, f8 or f11 aperture but my friend told me that 5.6 to 7.1 would be fine, then adjust iso for proper exposure.

[MrFunBooth]

I'm having the same thing happen. First photo is brighter by a stop than the others. Has anyone figured this out.

[Chris Breeze]

It could be a flash sync issue. Please try the using a slower shutter speed by following the instructions in FAQ 12 on this page:
http://www.breezesys.com/articles/photobooth8.htm

[Eljae]

I'm having a puzzling issue with inconsistent flash.

Canon Digital Rebel (old 300D). Taking 4 photo booth shots 4 seconds apart (ends up being 9 seconds due to transfer delay). The 2nd or sometimes the 3rd shot are brighter than the others. I set the camera to manual (1/100, 4.5), built in flash, AC adapter.

Any ideas what's going on? Could the internal flash not be re-charging quickly enough?

This forum sure is a great resource.

Hi,

I made my first question post today so hopefully I can give back to the forum and help. There could be several reasons why this problem is happening.
As Chris mentioned, this could be a sync issue.

Additionally, the pro of using higher f-stops means that you will have a larger area in focus, but the con is that higher f-stops require more powerful flashes.

Using f4.5 makes your lens moderately fast, and 1/100 is a nice shutter speed for stopping motion when up close to get a sharp picture, but your trade off is that you have a limited depth of focus. Your flash therefore is not working overly hard in this case. Having a camera set to "Bracketing Mode" will produce different exposures, and it will do this in a very consistent way. Because the 2nd or 3rd frame is brighter this could be the case. Check the camera settings to see if this is the case.

On the flip side, when shots become progressively darker, this problem can occur with short time intervals between flashes. Both on camera flash and using a speedlight can produce different exposures if there is not enough time in between flashes for the flash to fully charge up. This will produce results in a much less consistent way because it is dependent on the battery power level. 4 seconds between flashes is relatively demanding for most on camera flashes, and many speedlights too if they are not fully charged. Increasing the time interval between flashes or using an external power source will help, but you will still need to test your system to find the correct interval between flashes.

Hope this helps!
Eljae