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#31
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Infrared photography
In article ,
Whiskers wrote: It isn't clear from the user manual; the specification only says 'through the lens autofocus' that's the key. it's off the sensor, not something separate. but there is also an 'autofocus lamp' on the camera body. Perhaps that is only there to ensure sufficient illumination for the TTL 'contrast detection' system to work? yep. |
#32
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Infrared photography
If you want to make simple, you could just buy a camera designed for IR.
Personally, I use the Fuji IS-1. By design, it is sensitive to both visible and IR light; you select the spectrum you want and just put on an appropriate filter. It will work pretty well up to 1000nm IR filter or any of the 87 series, or you can do false-color IR using near-IR or visible red or orange filters. -- is Joshua Putnam http://www.phred.org/~josh/ Updated Infrared Photography Gallery: http://www.phred.org/~josh/photo/ir.html |
#34
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Infrared photography
In rec.photo.digital DaveC wrote:
| I want to photograph and video in infrared mode. I'd like to know the spectral range possibilities of various sensors, both in how long they can go for IR, and how short they can go for UV (assuming the filter on the sensor is removed or replaced). I have heard figures of 1000nm and 1200nm for IR, but no figures for UV. Are there cameras with special sensors that go well beyond what normal cameras intended for the visible spectrum can do? -- |WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance | | by the abuse department, bellsouth.net is blocked. If you post to | | Usenet from these places, find another Usenet provider ASAP. | | Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) | |
#35
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Infrared photography
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#36
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Infrared photography
In rec.photo.digital carlislestamford wrote:
| UV is a whole other beast to contend with. Most optical glass in nearly all | camera lenses is a good absorption filter for many UV wavelengths. Even the | micro-lens array and Bayer-filter on the sensor is a UV blocking filter to some | extent. Imaging most of the UV bandwidths requires special and EXPENSIVE lenses | that will allow transmission of UV to any electronic sensor. Short-wave UV | transmission is totally obliterated by nothing more than a layer of flint or | crown-glass as thin as the material in a drinking-glass or standard | daylight-filter. In high-resolution UV photomicroscopy, for example, it requires | specialty lens elements made of hard pure-quartz and soft fluorite, throughout | the whole light-path, from subject to recording medium. Due to the high melting | point of pure quartz and the difficulty in figuring soft (and easily | moisture-destroyed) fluorite into the right curves (the reason L-Glass lenses | are so expensive) you aren't going to easily obtain camera lenses that can | transmit a wide bandwidth of UV with most consumer's bank-accounts. Most CCD | cameras will be somewhat sensitive to the long-wave UV spectrum, but only some | of it. Limited by the very optics that are a part of all white-light-imaging | lens assemblies. Long-wave UV, yes, you can reach into that bandwidth somewhat | successfully with standard lenses and common CCD sensors, but don't even think | about imaging in the short-wave UV spectrum with any of the standard glass lens | elements available on the market. Even L-Glass lenses are incapable for this use | because they are a mixture of more-common glasses elements plus fluorite | elements. The standard flint and crown glass components (as archaic examples | only, there are hundreds, if not thousands of modern glass recipes) will quickly | filter-out any short-wave UV that the L-Glass lenses' few fluorite elements | might pass. What about plastic lenses we ordinarily would scoff at? There are some better quality plastic materials these days. Maybe it could be a semi-useful, even if not the best quality, lens specific for shorter UV that you could ever hope to get out of glass, without having to mess with quartz. -- |WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance | | by the abuse department, bellsouth.net is blocked. If you post to | | Usenet from these places, find another Usenet provider ASAP. | | Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) | |
#37
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Infrared photography
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#38
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Infrared photography
In rec.photo.digital carlislestamford wrote:
| There is not a large outcry for UV and IR capable cameras. I would be first in | line to buy an inexpensive tri-bandwidth (IR, Vis, UV) performer, but I'm the | exception rather than the rule. I wish my camera to be able to image in all the | frequencies that could be captured by a CCD array. As well as record audio from | sub-sonic to ultra-sonic frequencies. Your average person has no concern over | what they can't see nor sense, out of sight -- out of mind. They have no | curiosity about something that is beyond their crippled perception of reality. Many years ago I was actually thinking about a design for "an antenna camera" to produce some rough imaging of RF frequencies. It would, of course, have to be a huge array to get anything approaching a "picture" below the microwave frequencies. It might be interesting to do this from a distance "looking" at the downtown area of a major city, and merge the 124000000nm to 120000000nm view with the 700nm to 400nm view to see all the wifi radiation spots. -- |WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance | | by the abuse department, bellsouth.net is blocked. If you post to | | Usenet from these places, find another Usenet provider ASAP. | | Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) | |
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