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Paul R Mar 25, 2003 8:04 AM

Flash Help
 
Hi all,

I was hoping I could get a little help with a flash problem that has been plauging me. I am in the Aerospace Materials field and I do a lot of corrosion testing with brushed aluminum and steel panels. We recently have been asked to document the results with digital pictures and purchased a Nikon Coolpix 5700 for this task.

The problem I have encountered is a large amount of glare on the panels which is masking the results. I have been told by one person that I need an external speedlight or a polarized filter.

Could anyone offer any guidance on this ? Any help would be greatly appreciated.

Thanks
Paul

voxmagna Mar 25, 2003 10:32 AM

Just a suggestion, In-built flash will throw back light along the lens axis - Bad news. Have you tried an external unit on a long lead at an angle to the panels, or bouncing off a light ceiling if there is one? Don't pro's use those umbrella diffusers with the remote flash firing in from the focus?

I've never tried this straight off my head, but I wondered whether a polariser on the flash and a circular adjustable polariser on the lens might help. Although these lenses aren't always clear, experiment with a couple of lenses from sunglasses before comitting to photo quality polarisers.

steve6 Mar 25, 2003 12:03 PM

Try taking the pictures at an angle to avoid bounce-back.

I recently took some pictures at work looking at the effects of certain chemicals on certain paints. The flash ones were hopeless. In the end I got good results using ambient light, small apertures (DOF) and slow shutter speeds of about 10th sec on a tripod.

Halogen lamps are a useful indoor light source.

Binji7 Mar 25, 2003 2:19 PM

Get a hot shoe flash with bounce capability will do the trick. I am in the electronics industry and have often had to take pictures of circuit board components. I use my Minolta D7i and Sigma DG-500 Super flash. I mount my flash on a tripod and use wireless bounce flash. That lets me get in close (even macro) without all the glare. I can e-mail u samples if u like.

You can also try a clip on diffuser with your camera for a cheap fix.

Nikon sells a good hot shoe flash, but I don't know the cost.

A ND (Neutral Density) Filter will help a lot too.

A real cheap fix is to use a tripod and the built in timer. This keeps the camera still so you can use a long exposure and ambient light so no flash is needed.

Look at the circuit boards on this page, all taken with ambient light and a tripod. Shutter speed is around 1/3 - 1/10 of a sec.

http://home.neo.rr.com/keystar/rfremote.htm

rritter Mar 25, 2003 4:15 PM

If itís a still image use a tripod and let the cameraís auto feature set the shutter speed and aperture. Give it a try. No Flash Required :D

R. Ritter

Paul R Mar 26, 2003 9:29 AM

Thanks for all the tips.

Voxmagna,

I tried the polarizer trick with a spare from another camera and it did not work , but it was a good idea....Thanks. At least it answers part of my original question and I probably don't need a polarizer.

Steve6,

I tried taking them at an angle and I still get some glare. I will try the other recommendations. Thanks

Binji7,

Is a hot shoe flash similar to what Nikon calls a Speedlight ?


rritter,

I will try the tripod and see what it does without the flash



Thanks again
Paul

Binji7 Mar 28, 2003 10:25 AM

Yes,

I own a Minolta so I'm not sure which speedlight is compatible with the 5700 but i know one is. Note that if you use the speedlight and shoot straight on you will still have the same problem, you have to use bounce with a diffuser for the best results.

The Doctor Mar 30, 2003 2:34 PM

Try setting up two compact flourescent lamps at 45 degree angles to the item. They have the same temperature rating as sunlight and they don't get hot. Get some stretcher bars and a sheet of vellum from an art store. Tape the vellum to the stretcher bars and use that as a diffuser on one of the compact flourescent lamps. You can get two 100w compact flourescent bulbs for about $10.00 at a discount store and the stretcher bars and vellum should run about $5.00. Adjust your camera's white balance. If you want more, use the T.V. output on the camera to see what the picture will look like before you shoot.


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