Canon G9 & Suntec-IR Filter Test#2 (HDR)

Copyright © 2008 John Powell.

All Rights Reserved.

 

I’m in the process, weather permitting, of conducting a series of tests involving the Canon G9 and a new Infrared Filter. In the past I have always preferred the Hoya R72, but wanted a filter that would block out more visible then the 720nm of the R72 type.

 

The G9 is quite sensitive to IR, which was another good reason to go for a deeper coloured filter.

 

There are many infrared filters of different brands and different "cut-off wavelengths" in the market.

 

Which one is the best filter?

 

Actually, there is no one best filter! The best filter depends on the lighting conditions, the camera, its sensitivity to IR and object being photographed.

The IR filter I used in this shot was a Suntec IR-750, an infrared filter with cut-off wavelength 750nm, which is exactly similar as a Kodak Wratten 88A.

 

Cut-off wavelength is a technical term in infrared photography. Simply, the larger the Cut-off wavelength the filter features, the less visible light entering the camera. So, a filter with a 750nm Cut-off will/should produce a more pure infrared image than does a 720nm one.

 

For this shot I decided to try an HDR shot. Therefore I put the G9 into AEB, set the EV to -2/+2, selected aperture priority mode and an aperture of f2.8. The ISO was set 100 and I used Evaluated Metering.

 

The resulting three exposures had their W/B set manually, using the exact same point for each exposure. Photomatix was used to generate the HDR file, which was subsequently toned mapped before saving.

 

In Photoshop I de-saturated the Blue Channel to give a more monochrome look.

 

More tests and better subject matter will trail soon.

 

Done