Hi all,
Does anyone know if it is possible to use a DSLR in near Infra-red wave length to capture a picture of foliage, transform this pict in data and analyze the diseases. I was thinking in produce something in this direction. And then use a modified DSLR and Magic Lantern as a background to analyse the datas e categorize the leaves diseases. Anyone know something in this direction?
Cheers
Depends if you want to make a permanent modification to your camera.
As standard the cameras have a 'hard wired' IR filter which makes IR photography almost impossible without removing this. It's an expensive modification (I think) and also it's not reversible. It really depends on how much you really want to do IR photography.
I am not exactly an expert on this but that's my understanding of this from what I have read in the past.
There is a site that offers the mod here:
http://www.maxmax.com/canon_5d_mkii.htm (http://www.maxmax.com/canon_5d_mkii.htm)
Buy a cheap second hand camera, follow the relevant guide (http://www.lifepixel.com/tutorials/infrared-diy-tutorials).
Buy one of the cheap cameras you can put CHDK on.
Or find a 2nd hand 1100D or something.
You can remove the UV/IR blocking filter yourself, and there are some good guides online showing you how. You'll need to replace the filter with an infrared-transmitting filter too (quartz normally). There are a few companies that do this for you, and it's not all that expensive (£260 + VAT from ACS in the UK).
Next you'll probably need lens filters, e.g. ones that only let through >720nm etc... Your camera will be able to see up to around 900-1000nm, but peak sensitivity (and solar iradiance) peak around the human-visible range, which you'll need to block. These filters are pretty cheap (about £30 on ebay for a set). Then if you want your camera to take "normal" visible-spectrum photos again you'll need an IR/UV blocking filter on the lens, which is actually more expensive (around £90-100 for a decent hoya one).
Then you'll need post-processing to combine photos from different wavelengths (unless the plain >720nm show you what you need to know).