A Dedicated Setup for UV Photography
|© Bjørn Rørslett/NN|
Many approaches can yield good UV pictures, but the setup above constitutes an ideal solution for 35 mm photography. Nikon delivers the SB-140, a flash unit built specially for UV and IR photography. It is here depicted together with its mandatory battery pack SD-7, a UV bandpass unit SW5-UV (incorporating the FF filter) on the flash head, and a UV-Nikkor 105 mm f/4.5 mounted on an F4 camera. The UV lens has the "black" proprietary Nikon FF filter in front of it. The FF filter transmits slightly in the very deep purple and far red (see spectral transmittance curve). By the way, the photo above shows the full output from the flash (triggered with a slave flash unit) and as can be seen, it's not very strong visually. In fact, it's next to impossible to see the flash output under normal light conditions. The SB-140 unit is very similar to the standard SB-14 flash, but obvious lacks the internal, yellowish, flash head coating of the latter. I don't know whether it's possible to convert SB-14's into the more useful SB-140 type, so guess I have to stop banging my SB-140 around (it already has an alarming number of cracks and dents after 8 years of field use).
This is my normal setup for obtaining UV images using either an F4 or an F5 camera. The UV-Nikkor is a true Micro-Nikkor design with 6 quartz and fluorite elements in 5 groups. The front lens element is unusual in being concave shaped. There is a multicoating on this lens specifically computed for the UV band, which isn't highly effective in the visible light range. It focuses to 1:2 by itself and to 1:1 with the PN-11 extension tube. There is a nifty locking screw to secure focus when using the lens in an oblique position. According to factory specfications it transmits radiation from 200 to 900 nm (visible light is 400-700 nm). The UV-Nikkor is a superlative lens giving outstandingly sharp and contrasty images, unfortunately there is a steep price to be paid for it as this is a $3.000,- special-order item from Nikon. Rumours have it Nikon has discontinued this lens, which would be a pity indeed. Probably less than 2000 units were manufactured since 1984 so it isn't exactly qualifying for a "best-selling" item! I bought my UV Nikkor lens in 1992 and added the SB-140 flash a year later. With the appropriate cables (SC-12 for F3, SC-23 for FE2/F4/F5) it is possible to get TTL operation from the SB-140 and this extends into UV with F4 and F5 cameras. Also with F5, I can get rear-curtain sync with the SB-140.
The FF filter used in front of the UV-Nikkor is a rather thick glass filter being virtually non-transparent to visible light. It is mounted in an AF-1 filter holder so as to make it easy to flip away when I focus the scene. This is quite easy because there is no focus shift from visible to UV light with the UV-Nikkor.
Last Update 1 October, 2002