RE: Nikon Data Backs

[Theo Benson <TBenson@xxxxxxxxxxxxx>]

Rolland: I had trouble with my MF-26 on both my N90 and N90s. The data back
does not use LED's (light emitting diodes) to imprint the film. Instead, it
uses a reflective LCD (liquid crystal display) which uses less battery
current. It works as a "selective mirror." When it is turned on, it forms
characters on the film by selectively REFLECTING some of the light that
passes through the film BACK onto the film from behind. The characters
appear as red on normal color film because, in effect, it's becoming very
overexposed where the characters are. Apparently, even when the back is
turned-off, it reflects infrared back onto the film. When it's turned on, so
much IR is reflected back that a small rectangle is blasted onto the film,
as you observed. It's fainter when it's turned off, but it's still there.
You didn't mention what filter you used, if any, but I suspect that this
only becomes a problem with the 87C filter, and the longer exposures it
necessitates. Without the filter, more visible light is present, and this,
along with shorter exposure times, probably obscures the rectangle you might
otherwise see. It IS faint in any case, but noticeable in some scenes.

- -- Theo Benson

> -----Original Message-----
> From:	Rolland Elliott [SMTP:rolland_elliott@xxxxxxxxx]
> Sent:	Tuesday, July 14, 1998 8:41 AM
> To:	infrared@xxxxx
> Subject:	Re: Nikon Data Backs
> 
> Theo Benson wrote:
> >One last note for Nikon users: do NOT shoot IR with >any of the data
> backs on your camera body. Even when >they are "turned off," ........
> 
> I use a Nikon N90s camera with a MF-26 back and it does not cause any
> problems when using Kodak's HIE or EIR film, as long as you have the
> data imprinting feature turned off.  What Nikon Camera back are you
> using?
> 
> The data imprinting feature on the MF-26 (if turned on) is useless
> with IR films though, because the light intensity from the LED's is
> too strong and just makes a big white spot on the film. You could
> probably filter it through a small piece of IR gel, but then I've
> never really liked having numbers on the corner of my negs anyways.
> Peace Roland Elliott
> 
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