Archived posting to the Leica Users Group, 2004/09/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>I would be interested to know what the full spectral response might be as >the IR effect of shooting and keeping only the red information works pretty >well. >I did try shooting through a Leitz IR filter (looked about the equivaent of >an 87C- very deep red- and of course got zip, zilch, nada for my effort. :o( Most newer digicams have a filter over the sensor to eliminate IR and UV. Shooting in UV has other problems I've outlined below. Some of the older Nikon Coolpix cameras made fantastic IR images with an 87 series filter - obviously the filter was absent or cut in at a higher wavelength on the older cameras. >If the future is digital, think of the possibilities of shooting in the UV >and Near UV spectrum This is unlikely to be the case, unless some manufacturer decided to make a dedicated UV digicam. The main problem with `normal` cameras designed for picture taking in daylight is that modern multi-coating and to a lesser extent, some modern optical glasses, block UV effectively (yes, your UV filter really is redundant ;-) >I am pretty sure that folks like astronomers already do this with the CCD devices >they use- The Three College Observatory near here has published some really >neat timed exposures (5 minutes!- sharp with no camera shake!) of deep space >objects outside the visible spectrum. I guess they are 'false' color, but >they are simply beautiful. I can see why amateur astronomy is so popular! Many fields of science requite IR and UV photography. Archaeologists routinely use IR photography to show detail in stone work and other artefacts that cannot be seen under regular light. Botanists and biologists have realised in recent years that plants and animals often communicate and use as recognition systems patterns of UV reflection. Many insects and birds can see into this region of the spectrum. The lenses and filters used for this work are expensive and not very useful for anything else. UV lenses, in particular, need to be made of quartz rather than glass and are not coated. The Nikkor UV 105mm macro that was available briefly was a very good lens for UV work, although the $5K pricetag meant that the vast majority ended up in labs, rather than in the hands of photographers. There is some work done with this lens by Bjorn Rorslett here: http://www.naturfotograf.com/index2.html The best news of all is that an uncoated lens using old glass (like a 50mm Elmar!) and film can make acceptable near UV images: http://medfmt.8k.com/mf/uv.html in fact some of these special uses may keep film alive (it's going to be hard to get a digicam to do what Kodak HIE can - and it's already very expensive). Marty