• Ultraviolet Photography

UV-Pass Filter Test I: Baader-U, Precision-U(old), Hoya 340 + S8612, Hoya 360 + S8612

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#1 Andrea B.

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Posted 19 July 2013 - 02:39

With the D600-broadband and a Nikon 105mm f/4.5 UV-Nikkor, I photographed, in sunlight, a Color Checker Passport, a small Melampodium paludosum flower and three Labsphere Reflectance Standards (99, 75, 50) using four UV-Pass filter options.
  • Baader-U
  • Precision-U: the older version
  • Hoya 340 + S8612(1.75mm)
  • Hoya 360 + S8612(1.75mm)
The NEFs were converted in Photo Ninja.
White balance was set on the top white Labsphere 99 Standard.
For saturation and contrast, the Scenic option was chosen. This corresponds approximately to a Nikon Picture Control of Standard with perhaps a +1 for contrast and saturation.
For colour accuracy, a Photo Ninja D600 profile made with the Color Checker Passport was applied.
Minor tweaks were made for white point, black point and highlight control.
Some dust bunnies were removed in Capture NX2.

The standard curve applied during demosaicing was left untouched. Therefore the reflectance standards are not accurately reproduced with respect to brightness. If the curve were adjusted to reflect the actual brightness, then the photo would appear too dark.
The flower is out of focus.

The purpose of the experiment was to see what the differences are between the four photos made with the listed UV-Pass filters after the resulting photos have been both colour- and white-balanced.
Apparently, for these particular subjects, there is not much difference once colour and white are standardized.
However, for other subjects, you might see some variations in the presence of green or intensity of yellow. And the intensity of violet or blue shades might vary somewhat for any subjects.
I will try to repeat this test with some floral subjects to see if I can show more about these minor differences.

f/11 for 1/8" @ ISO 400
Attached Image: D600_UVBaaderU_Sun_070613wf_12932orig_ScenicCC.jpg

f/11 for 1/5" @ ISO 400
Attached Image: D600_UVPrecisionU_Sun_070613wf_12948_ScenicCC.jpg

Hoya 340 + S8612
f/11 for 1/6" @ ISO 400
Attached Image: D600_UVU340_S8612_Sun_070613wf_12980_ScenicCC.jpg

Hoya 360 + S8612
f/11 for 1/6" @ ISO 400
Attached Image: D600_UVU360_S8612_Sun_070613wf_12996_ScenicCC.jpg
Andrea G. Blum
Often found hanging out with flowers & bees.