wpo - infra-red digital photography

moonlight scenes     Minolta D7 review    Steve's digicam reviews  astro-images >Terry Platt    Maurice Gavin   James Weightman

St Mary's Church - Cuddington - Worcester Park - Aug 17 AM
These midsummer images were taken in infra-red light via Minolta D7 digital still camera on auto and IR transmitting filter - rendering foliage white like snow and blue sky dark or even black.  A variety of filters were used...

1] dedicated BDB IR photo filter
2] pair of Polaroid filters crossed for max light extinction
3] homemade filter from stack of red, green+ blue gels - this combo seems to work best !

When held to the eye all IR transmitting filters appear essentially opaque to visible light.  On no account look through the filter towards the sun as eye damage may result!

Digital cameras use CCD detectors which [unlike their astro-CCD brethren] incorporate an IR blocking filter for good colour reproduction.

However some IR is still recordable via an IR filter by increasing exposures 500-fold ie 1000 ISO becomes 2 ISO rating! 22/8=138
 
 
 
 
 
 
 
 

IR best taken in full sunlight + flat fielded to remove corner vignetting as Bourne Hall -Ewell Surrey image below.  More IR pics #1¦#2¦#3¦#4¦#5


 


IR can be used to demonstrate the reflectivity of metal surfaces used for astronomical domes etc [here stainless steel seems a poor reflector that remains hot] whilst chlorophyll in plants is the near perfect IR reflector [i.e white] as a shade material.



text & images copyright - Maurice Gavin 2002  visitors