BetterPhoto Q&A
Category: New Answers

Filter to help reduce or eliminate green flare

I normally do these photos using two 45" photoflex umbrellas with two 430ex flash slaves. Normally it doesn't happen just every now and then, but it makes life painful having to photoshop a persons face to this degree.

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June 10, 2008

Range, lens distortion, light position, polarization.

Several more for a color cast to the flare.

Mixed lighting, secondary color bounce, tinted glasses etc...

Can you post a example so we might better analyze it?

Pete

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June 10, 2008

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June 11, 2008

Digital photography affords you the opportunity to proof every shot. If you are vigilant you can re-shoot spoiled images. Often a tilt of the head, either up or down, is all that is needed.

As to the flare color: Flares from glass is caused by a surface reflections and/or a secondary refection. Light is capable to transverse the glass and reflect back from the rear glass air junction. This secondary reflection travels twice through the glass thus it pick up the tint strengthen by a factor of two.

As to the polarizing filter: You stated that you always have a circular polarizer mounted. A polarizing screen is likely the most valuable filter in the arena of color photography. It darkens blue sky adding contrast and saturation without altering the over-all color balance. It subdues reflections from non-conductive surface like glass, water, polished wood etc. Therefore, if properly orientated it could mitigate, to some extent, reflections from eyeglasses. The trick will be rotating it to the proper angle. This will prove to be a most difficult task when using a flash. Likely, the proper ordination can only be discovered by trial and error and it will be different for each set-up. In other words, a polarizing screen for this application will likely be ineffective.

The polarizing screen acts as a natural density filter with a factor of 4. That translates to 2 f/stops compensation. When mounted, you or the camera automation must compensate, likely by opening up 2 f/stops. This act will reduce depth-of-field, a good thing if you are pursuing a classic portraiture. The alternative will be to slow the shutter speed and risk blurring due to camera or subject movement.

Flare from glasses is common, dealing with it is difficult.

Alan Marcus (marginal technical gobbledygook)
ammarcus@earthlink.net

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June 11, 2008