Re: infrared photography questions
- From: "Neil Harrington" <neil@xxxxxxxxxxxxxxx>
- Date: Fri, 4 Apr 2008 20:27:14 -0400
Dave Busch wrote:
On Wed, 2 Apr 2008 11:19:18 -0400, "Neil Harrington"
<neil@xxxxxxxxxxxxxxx> wrote:
You'd still need an IR filter like the R72 to do infraredMaybe we're talking about something different, but the conversion I
photography. AFAIK, the professional conversions you're talking
consist mainly of removing the low-pass filter from inside the
camera that keeps the IR from reaching the sensor. They don't add
the necessary filtration to hold back visible light, and without
that you'll just be shooting visible light with considerable IR
corruption, probably causing problems with sharp focus -- the reason
for the camera having the low-pass filter in the first place.
had from Lifepixel removed the IR cutoff filter from my D70, and
replaced it with a visible light cutoff filter, roughly the equivalent
of an R72, so no filter is needed on the lens. Some conversion
companies do offer the option of a "hot rod" conversion that simply
removes the internal IR cutoff filter, so that conventional, albeit
weirdly colored (from IR pollution) pictures can be taken as-is, with
IR pictures with higher EV with a lens filter.
But maybe I misunderstood the question and/or your answer.
No, you're right and I was wrong, in that I wasn't aware of that method of
conversion. Alan Hoyle described it in this thread a couple of days ago, and
Frederick kindly supplied a link to LifePixel. It does look like a
near-perfect solution, and I'm thinking of having it done.
While I might have it done eventually on my D70s, which I don't use much
anymore now that I have a D40 and a D80, I'm thinking of first having a
Coolpix 5400 done -- the main reason being that that would seem to get
around any focus problems that a DSLR would have. I'd much prefer to use an
8400, which LifePixel says is the best compact for the conversion, but I
don't want to modify the one I have and I can't find one on eBay *at all* --
not a single one! If an 8400 does appear there I presume it will bring some
horrendously high price.
LifePixel explains that while they adjust focus for a DSLR, correcting
Nikons for the 18-70mm DX lens, which makes sense, they cannot correct for
all lenses or even all focal lengths on the same lens, since IR light
refracts quite differently from the visible wavelengths -- and DSLRs still
use visible light for AF, and for manual focus too for that matter.
A compact like the 5400 on the other hand uses the post-filter light, i.e.
at the sensor, for AF so should be at best focus with any focal length. And
the 28-116mm (equiv.) lens on the 5400 is all I'd expect to need for IR
work, at least for the time being.
Neil
.
- References:
- Re: infrared photography questions
- From: Neil Harrington
- Re: infrared photography questions
- From: Dave Busch
- Re: infrared photography questions
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