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Old Mar 12, 2005, 10:02 AM   #1
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I was at a elementary school concert the other night and thought I'd practice (just got the FZ-20), so I used flash and no flash. The pics without flash were way too dark, so I'm playing with PSP-8 on them (which is working nicely).

When using the pop up flash from about 25-30 feet away I got the illumination I needed, but I also got red eyes on every kid. The flash was set for red eye with an fstop of 2.8 and shutter of 1/60th, so why did I get it anyways? I have a Vivitar 3500 from my old Canon AE-1 days that I plan to use, will that be a better flash than the pop up?

thanks,
Ed
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Old Mar 12, 2005, 10:50 AM   #2
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The red-eye reduction mode on cameras isn't a guarantee that red eye wont be there. It just help reduce the chances. The Vivitar flash may work and it may not, I dont know anything about it or your camera, but it may be worth a shot. The only way to prevent red eye is to move the flash away from the lens, and using an external flash does exactly that.
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Old Mar 12, 2005, 11:12 AM   #3
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You will probably be able to use your old Vivitar. Give it a shot.

Keep in mind the "strength" of the flash. Check out the "guide number" of your old Vivitar.

Without getting too technical, the higher the guide number, the more powerful the flash.

If you want a flash with serious horsepower, buy a flash with a guide number of 120 or higher.

I bought my Sunpak super 383 (Guide No. 120) for $70 including shipping from B&H Photo Video.

The Sunpak will likely work on any digicam with a hotshoe.

-- Terry


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Old Mar 12, 2005, 1:13 PM   #4
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Rob & Terry, thanks for the replies.

Terry, how do I find out the guide number? I still have to check the voltage (battery is dead in my meter) before I'll try this flash. Back in my 35mm days this flash worked great, so I'm hoping to be able to utilize it on the FZ.

Ed
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Old Mar 12, 2005, 1:14 PM   #5
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Red-eye reduction on flashes works by firing a single or burst of flashes prior to the main flash causing pupils to shrink. It only works if people are looking directly at the pre-flash to begin with. Chances are from that distance the output is not enough to cause the pupils to shrink. From all the cameras I've owned I think I can remember only one - a film P&S by Olympus that had a red-eye reduction that worked well. Most of the time they only seem to work about 50% of the time.
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Old Mar 12, 2005, 1:20 PM   #6
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So Post Processing is the rule rather than the exception in regards to red eye?

Ed
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Old Mar 12, 2005, 3:17 PM   #7
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The root cause of red-eye is that the flash-eye-lens angle is small so you get reflections retina at the back of the eye. The solution is to increase that angle so the reflected light does not come back to the lens- typically by increasing the distance between the lens and the flash. If your shooting range is 25-30 ft, you need more lens-flash distance than the pop-up provides. At that range, even a camera mounted flash unit might not be far enough away from the lens.

All kinds of other things come into red-eye as well, the biggest other issue is likely to be abient light. If it is dark, pupils will be open more.
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Old Mar 12, 2005, 3:26 PM   #8
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Ed,

The guide number would be mentioned in the flash's documentation, under it's technical specification.

I looked your flash up on the web to try to figure out the guide number, but it's too old to have that level of detail on the web.

Usually the flash has a little scale on it (like a slide rule) that helps you to calculate how many feet (or meters) the flash is effective at a specific shutter speed, ISO and aperture. Guide 120 means the flash will be good for 40 feet at F2.8 aperature, assuming an ISO setting of 100 (40 x 2.8 = approx. guide 120).

So, if your flash is only good for 10 feet at F2.8, you have a guide no. 30 flash (pretty weak). Most flashes "built in" to a digicam run guide number20-40, which will light up about three friendsin a close formation at 10 feet in a dark room (lol).

Of course you can always "dial up" the ISO higher to get more coverage from your flash, but that will bring in more digital noise and strangeness,which becomesREALLY apparent in dark pictures.

The farther the flash is away from the lens, the more "reduced" the red eye will be.

Even with a flash sitting on a hot shoe, I still have to do red eye reduction with software.

Ahot shoe mounted external flash will result in less red eye than the built in flash but not eliminate it.

Some of those flashes that send out a "pre-flash" work okay. Most paparazzie use those flashes on a "handlebar" positionedwell off to the sideof the side of the camera.

-- Terry

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Old Mar 12, 2005, 4:10 PM   #9
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[email protected] wrote:
Quote:

Usually the flash has a little scale on it (like a slide rule) that helps you to calculate how many feet (or meters) the flash is effective at a specific shutter speed, ISO and aperture. Guide 120 means the flash will be good for 40 feet at F2.8 aperature, assuming an ISO setting of 100 (40 x 2.8 = approx. guide 120).

So, if your flash is only good for 10 feet at F2.8, you have a guide no. 30 flash (pretty weak). Most flashes "built in" to a digicam run guide number20-40, which will light up about three friendsin a close formation at 10 feet in a dark room (lol).

I've long since lost the manuals (bought the flash in 1982), so checking out my slide scale on the back, at ISO 100 and 2.8 my flash says 10ft. On eBay there is the exact same flash and the seller is claiming a guide #80 (which I was hoping for). I guess I'll play with it and if it doesn't fire bright enough, no harm no foul, I'll just get a newer flash.

Ed
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