have my studio flashes gone bad - i'm dumbfounded by these results

[brh986]

First the setup...

Two novatron 500 ws monolights using shoot thru white photoflex umbrellas. We're trying to do product photography and the subject is a medium sized jar of jam. The tips of the umbrellas are no more than a meter away from the jar. The jar is on a white paper background. I know this isn't the optimal setup for product photography so please hold your critiques - working with limited equipment and this isn't the problem.

The camera is a Nikon D5000 set to manual mode 1/125 F5.6 18-55 nikon lens at ~55mm. White balance daylight, ISO 200 - 3200 (explained further below). I tried shutter speeds between 1/25 - 1/200 to see if there was a sync problem but there didn't seem to be. The flashes are being triggered by the on camera flash set at minimum power. The studio flashes are both set at slave. The studio flashes are definitely firing every time.

The flashes are set to high range and full power.

The photos are coming out unbelievably dark. I can't imagine why. Even at 3200 ISO and F5.6 they are not total whiteout. They are maybe 1 stop overexposed max. Does this camera have some kind of setting that overrides manual mode and does some crazy nonsense? I shoot with these same studio flashes with a Nikon D70 and at full power with just one light i could totally overexpose a human model at F9 - F11. This was years ago. Do flashes go bad?

To thicken the plot I got a simple point and shoot camera (Nikon S220) and triggered the flashes with slave again using the on camera flash and I got total white out. Checking the exif data I see that the point and shoot used 400 iso, F3.1 and 1/30 sec. As a control the same scene from the point and shoot at F3.1 ISO 800 and 1/30 looked quite underexposed so ambient light is not playing a roll here.

What in the world is going on? Factoring in the point and shoot would make me tend to blame the D5000 but I can't understand how.

 

[Derrel]

I wonder...is the D5000's flash "pre-flash" off? Have you set the D5000's flash mode to MANUAL, in the menu system? I suspsect that perhaps a pre-flash from the D5000's flash is triggering the Novatron flashes, and thus they are firing, but the shutter is a few milliseconds AFTER the flash burst, thus giving these unbelievably dark results you mentioned. A cross-check with another body would be a good way to check.

Also, if the light output from the two Novatron flashes looks "bright" to your eyes, then the flashes are still strong and good. I mean, an f/9-f/11 flash pop for ISO 100 to 200 looks "bright" when the flashes fire. If the Novatron flashes look "bright" when they fire, then the problem area is synchronization.

Honestly, studio flash tubes are either GOOD, or DEAD. SO, there's not any middle ground. I suspect the issue is one of pre-flash (which is basically almost invisible to the human eye many times) messing things up.

 

[ghache]

Ive had the same problem when i first started playing with my strobes,

couldnt figure out why my strobe was not taking part of the exposure of my pictures.

my oncamera flash was set to TTL and the preflash was fireing my strobe a little bit too soon.

like derel said, make sure its in manual or -- and your flash should sync with your camera,

 

[Big Mike]

I agree. It sounds like your problem is that the camera's pre-flash is triggering the strobes early (before the exposure).

If you can set the camera's flash to manual mode, that should eliminate the pre-flash. If you can't, then find a way to trigger a strobe without flash.
Something like this...Gadget Infinity :: Digital Camera :: Flash Trigger :: Wireless Trigger :: Cactus Wireless Flash Trigger Set V4

Or even just this FlashZebra.com: Multipurpose Hotshoe Adapter (Item #0064) and a cord.

 

[brh986]

You guys were exactly right thanks so much. Why i didn't post here before smashing my head against a brick wall for 6 hours...

Thanks!!!!