Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "yaakovsinclair" <sinclair@...> wrote:
>
> I'm considering getting my Canon adapted by Lifepixel to be infrared
> sensitive.
> They remove the factory filter in front of the sensor which stops IR
> getting through.
>   This allows the full spectrum of to be read by the sensor.

As Paul mentioned in an earlier post Lifepixel (and others) will add an IR Pass filter in place of the one that is removed.  You can choose the pass level from one that renders very close to IR films up to ones that allow some color to pass through as well.

>   My question is -  could I do the filtering in photoshop afterwards to
> achieve the effect of an opaque IR filter or would I need to use an
> opaque IR filter in the field. (This would make shooting much easier as
> I wouldn't have to use a tripod and shoot 'blind')

That is the purpose of adding the IR Pass filter.  However, all sensors and lenses will respond differently to IR so there is wide variance in response.  I personally use a Lifepixel converted Nikon D50.  With that camera there are a couple of caveats.  Since the meter is measuring visible light the IR images can be off anywhere from a half to two and a half stops in exposure.  It will take some time to get a feel for this but fortunately DSLRs have histograms to work with.  The other caveat is IR focal length.  Each lens will respond differently and you will either need to stop down a lot or work out manual corrections.  Unfotunately I found that the correction factor built in by Lifepixel did not correspond to the IR marks on my Nikkors so I had to calibrate them individually.  The Canon sensors and lens will I'm sure respond differently but along the same lines.
 
> This is probably not the best forum to ask this question, but it's
> certainly a black and white question -- ( even if the answer may not be
> b and w...)
> BTW -- is there another forum that would suit this question better?

I personally am comfortable with it as I shoot IR for b&w output.  I'm not a fan of altered foilage and most of my IR images are simply seen as b&w.  My favorite image from this past winter was immediately after a heavy snowfall had just stopped and there was a glow coming through the still heavily overcast sky that I was able to get with IR that I just don't think I could get with visible.  There is no other telltale IR qualities in the image and it just views as a b&w.

I saw that aspect of your images some time back when you announced your recent book.  There is a Digital IR group in Yahoo but it seems to focus on the false color type images that are popular with the sensors that allow some colors to pass as well.

Just to get it out there.  Noise with digital IR is quite ugly, nothing like IR film.  I find myself still using a tripod and often a monopod especially when I want to keep the ISO down and I need two or more stops of exposure correction and I need to shoot around F8-11 for focus.  If you have an extra body the conversion is great, no more fumbling in the dark trying to load IR film!