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Infrared photography



 
 
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  #31  
Old September 27th 08, 12:28 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
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Default 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  
Old September 28th 08, 03:25 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
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Default 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.

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Updated Infrared Photography Gallery:
http://www.phred.org/~josh/photo/ir.html
  #34  
Old September 28th 08, 04:51 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
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Default 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?

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|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
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  #35  
Old September 28th 08, 06:11 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
carlislestamford
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Default Infrared photography

On 28 Sep 2008 03:51:18 GMT, wrote:

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?


When I was searching for IR-ready and UV-ready cameras (I had a penchant to
photograph all the hidden patterns in plants that insects and other animal
orders depend on) I found that the Sony "Super-HAD" CCD sensors had the most
sensitivity to the largest spectrum of IR frequencies, covering the widest
bandwidth with the most sensitivity (in consumer cameras). You can find the
spec-sheets on various CCD arrays online. This was (5?) years ago when I did my
initial research and I'm not about to recreate that for you by Googling it for
you again. The IR frequencies that you want to expose for on these sensors being
determined only by the bandpass filter used in front of the lens array. Their
"Super-HAD" CCDs are conveniently used in all their inexpensive "NightShot" and
"NightFraming" capable IR-ready consumer P&S cameras.

Now on the other hand, only one camera out there (no longer available, I don't
think, and I don't recall who manufactured it because it was prohibitively
expensive, I didn't even want to think about trying to purchase it) was designed
to do both IR and UV with the flick of a switch. It was an expensive specialty
camera manufactured by Canon, Panasonic, or some other popular company, designed
to sell to research and forensics investigation departments.

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.

  #36  
Old September 28th 08, 08:48 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
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Default 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.

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|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  
Old September 28th 08, 09:20 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
carlislestamford
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Default Infrared photography

On 28 Sep 2008 07:48:25 GMT, wrote:


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.


Some acrylics and specialty plastics are indeed exceptional in the visual
wavelengths. This is why they were so popular in the "almost disposable" 35mm
and 126-film cameras of the past. Quickly molded in mass numbers with the
perfect properties and curvatures needed. One or two plastic lens elements
taking the place of expensive and difficult to figure/assemble
multiple-component achromat glass arrays, the inexpensive and lightweight
acrylic lenses preventing nearly all chromatic aberration problems.

I have not researched how they might be used for IR and UV though. UV might be
difficult because the carbon-based materials are often fluorescent (or
absorbing) to particular UV wavelengths. Though I'm sure there must be some
plastics that would easily fit the bill. I've often thought that many of our
modern cameras today could benefit greatly from their (plastic lenses')
properties, especially with chromatic aberrations being a prevalent problem in
many digital cameras/lenses. Not to mention just the weight benefits and
cost-savings. I assume they don't incorporate them (on internal lens elements
only, to prevent abrasions) only because of the marketing aspect of advertising
"plastic lens components". The average consumer would not understand their vast
benefits over glass lenses and, as you say, scoff at them. Revealing only their
ignorance and stupidity.

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.

  #38  
Old September 29th 08, 01:29 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
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Default 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.

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|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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