Hi all,
Intrigued by the thread on using a Wratten
filter to reduce noise in digital pix I decided to run a little test.
You can see the results here:
http://www.grovestreet.com/jsp/picview.jsp?album=79756
Click on the thumbnail to enlarge the pic.
Click on that to see the full size image.
Camera was Sony F707 – 5mp ASA 200
tripod mounted. The Wratten gelatin filter was a Kodak #80A – 3200K
Tungsten source filter for daylight type color film.
Pic 1 - Daylight balance 1/30th sec @ F2.1
- full image
Pic 2 - Daylight balance 1/30th sec @ F2.1
- actual size
Pic 3a - Daylight balance + Wratten filter
1/8th sec @ F2.1
Pic 3b - Pic 3a filtered by NoiseNinja
Pic 4a - In camera white balance 1/30th
sec @ F2.1
Pic 4b - Pic 4a filtered by NoiseNinja
Noise Ninja is a popular noise reduction
filter – I wanted to see what affect it would have.
If you download the image and cycle through
the channels you can see that the blue channel has a more uniform – less blotchy
noise profile in the Wratten balanced pic than in the in-camera white balanced
pic.
With the Wratten I lost 2 stops in
exposure.
Best, Gordon Pritchard