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-   -   Need help estimation exposure w/external + cam flash (

DGehman Mar 27, 2005 5:54 AM

My Kodak DX7630 can use external flash with a simple slave trigger - it has a single flash (except for red-eye flash mode). It doesn't have a flash connector or hot shoe.

With the external,I'm not getting anywhere close with manual settings. I get pix at least 4 stops overexposed. I use the exposure calculator on the flash, an old Vivitar 283 (guide # 100). I often find I can't stop down the camera sufficiently at the lowest ISO (100).

How do people handle this?

Any good Web hints/tips for using external flash on point-and-shoot cameras?


marokero Mar 28, 2005 2:25 AM

I'm not familiar with the flash, but can't you dial down the power output on it? Your Kodak may not have a small enough aperture to control the ammount of light coming in.

DGehman Mar 28, 2005 6:20 AM

marokero wrote:

can't you dial down the power output on it?
Yes, but not enough. In fact, the on-flash sensing circuit may be wonky.

Meanwhile, I've found a couple of pages on the Web that show how to cut down on the 283's output using a variable resistor (potentiometer).

(The 283 has to be the most popular flash ever made. It's been in production for 30 years or so, and Vivitar still sells it. I have one of the old units with very high voltage across the hot shoe adapter, so even if I had a hot shoe on the Kodak, I couldn't use it. The latest 283s are low voltage.)


marokero Mar 28, 2005 9:42 AM

How about a neutral density filter? That ought to reduce the ammount of light coming in. As for the high voltage sync, in case you could attach it, Wein makes a hot-shoe accessory that curtails the high voltage and allows for a safe <6V sync:

Idle Apr 1, 2005 6:25 AM

You might also try a diffuser -- many external flash units are supplied with one.

You could even experiment with white paper or pieces of semi-opaque plastic -- here in Australia we get milk in plastic bottles that are almost the colour of the contents.

It would be simple to cut several pieces the right size and stack them for different effects.

That's the beauty of digital, you can experiment free!

DGehman Apr 1, 2005 6:56 AM

Thanks all!

I've rigged a 100K Ohm variable resistor in place of the original plug-in thyristor sensor and that gives me virtually infinite control over flash output.

I have to hunt down my old slide collection to find out for myself if an underexposed bit of E6 taped over the camera's flash will block visible light, yet pass enough IR to trigger the remote slave.

The ND filter and milk bottle ideas sound like excellent alternatives... milk bottle first...I've learned to move from least expensive to most.


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