Is the human eye capable of seing infrared?

[nanook s]

Infrared filter is not a binary device like our mathematic abstraction would make it out to be: 100% pass-through for photons with wave length at 721nm or longer, 0% pass-through for photons at 720nm or shorter.

In reality, a typical infrared filter more likely has a transfer curve of, say, 50% of pass-through at 720nm, 85% at 750nm, 96% at 800nm or longer (surface multicoating decides whether the max pass-thru gets beyond 96% or so), 25% at 700nm, 10% at 650nm, 1% or less for wavelength shorter than 600nm (green color). 1% of a the brightest broad daylight is still noticeabe amount of light, about 8 stops below, 1/2000 shutter vs. 1/20 shutter speed. In other words, no worse than typical evening indoor lighting.

Jim

ps.

My wife says I have a talent for explaining things in the most complex way possible ("scientificly precise" is what I say). Since she is a science teacher and I'm an electrical engineer by training who sees infrared filter as a low-pass filter, I will give you her version: an infrared filter is just like a tinted sunglass; the filter drasticly reduces the amount of visible light that can pass through in the visible spectrum, but does less to infrared.

I did a little test today and I was surprised of the result. I took
my Hoya R72 filter and put it in front of my eye, covered the
visible light as much as possible so no light will go to my eye
from the ambiant light and I was surprised to see that the foliage
looked white!

Now can the human see IR light? Am I the only one seing infrared
light with my own eyes?

I know I am not allucinating or imagining things because I can see
the wall is light and the vegetation is dark green without the
filter and if I put the filter in front of my eye, I can see the
vegetation sudendly is lighter than the wall and if I stare a bit,
I can really see that the vegetation is white with a red tint. I
can see the dark grass patches become very light when I look at
them through the IR filter.

Of course it is not as well defined as when I capture the actual
image with my camera CCD, but I still can see that the ratio
light/dark for the vegetation changes.

Is the human eye capable of seing IR light but we don't realize it
because it is hiden by the stronger visible light?

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

 

[Parker North]

Wow 40 posts and you are the first one to use the word coating.

Great stuff, thanks for breaking this one down, I really enjoyed the info.

Parker

 

[Daniella68313]

I think in the case of plant is because they are reflecting the IR light and not because they are warm. Then on other end, they are rather white in IR maybe because they emit a little bit of warm IR?

I do not think that the plants are whiter because they produce eat though...more a matter of refection and since this effect can be seen with the human eye, I am starting to suspect that cutting off the green light alone is enough to brighten the foliage.

Confused,

Pete

Depending on the sensitivity range of the red pixels on a CCD, you
could probably take an infrared photo in pitch darkness, although
it might be a very long exposure - maybe you could run that
experiment and let us know?

I'm also guessing that that is one reason why there is more noise
on a CCD when it is hot....

"Our eyes only see the tiny fraction of energy emitted by the sun
in the form of visible light. However, if we could see the infrared
rays emitted by all bodies--organic and inorganic--we could
effectively see in the dark."

we cannot see infrared light unless there is some source of IR
light first...in the dark, there is no source of IR so how can this
statement be true?

http://www.omega.com/literature/transactions/volume1/historical1.html

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com

c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND, Hoya-red-Intensifier, Hoya R72.

 

[Daniella68313]

Dr. Waston, explain why I can see the effect of the whitening foliage with my R72 filter with my own eyes?

not nuff said I still have the same question.

If you have a R72 filter, try it yourself..you will be surprised

Humans are not capable of seeing infrared light. Nuff said. But I
would pay
$ to watch Daniella walk around holding a filter in front of her
face!!!

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com

c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND, Hoya-red-Intensifier, Hoya R72.

 

[Daniella68313]

that's good but why the human eye can see the effect of the vegetation getting lighter when one look through the R72 filter? What is dark green vegetation become much lighter, almost white.

Here you are talking about the filter and that's fine, but since the human eye cannot see the IR light..then what is making the foliage lighter?

In reality, a typical infrared filter more likely has a transfer
curve of, say, 50% of pass-through at 720nm, 85% at 750nm, 96% at
800nm or longer (surface multicoating decides whether the max
pass-thru gets beyond 96% or so), 25% at 700nm, 10% at 650nm, 1% or
less for wavelength shorter than 600nm (green color). 1% of a the
brightest broad daylight is still noticeabe amount of light, about
8 stops below, 1/2000 shutter vs. 1/20 shutter speed. In other
words, no worse than typical evening indoor lighting.

Jim

ps.
My wife says I have a talent for explaining things in the most
complex way possible ("scientificly precise" is what I say). Since
she is a science teacher and I'm an electrical engineer by training
who sees infrared filter as a low-pass filter, I will give you her
version: an infrared filter is just like a tinted sunglass; the
filter drasticly reduces the amount of visible light that can pass
through in the visible spectrum, but does less to infrared.

I did a little test today and I was surprised of the result. I took
my Hoya R72 filter and put it in front of my eye, covered the
visible light as much as possible so no light will go to my eye
from the ambiant light and I was surprised to see that the foliage
looked white!

Now can the human see IR light? Am I the only one seing infrared
light with my own eyes?

I know I am not allucinating or imagining things because I can see
the wall is light and the vegetation is dark green without the
filter and if I put the filter in front of my eye, I can see the
vegetation sudendly is lighter than the wall and if I stare a bit,
I can really see that the vegetation is white with a red tint. I
can see the dark grass patches become very light when I look at
them through the IR filter.

Of course it is not as well defined as when I capture the actual
image with my camera CCD, but I still can see that the ratio
light/dark for the vegetation changes.

Is the human eye capable of seing IR light but we don't realize it
because it is hiden by the stronger visible light?

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com

c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND, Hoya-red-Intensifier, Hoya R72.

 

[Parker North]

Dr. Waston, explain why I can see the effect of the whitening
foliage with my R72 filter with my own eyes?

not nuff said I still have the same question.

If you have a R72 filter, try it yourself..you will be surprised

Why does Sherlock always make one liners without reading the thread or participating in the subject? I wanted to tell him the same thing, but I was polite and waited for you. Why is this good Dr.?

Or maybe you know Daniella, nuff said.

Parker

 

[Parker North]

Oh yeah, the primary colors combined make white, correct??

Parker

That's right for sure. However, remember that digital image
sensors are really just luminance (light intensity) sensors.
Filters over the individual sensor sites determine the color. With
the Bayer algorithm and the exposure cranked up, I suspect that it
would be fooled into thinking the image was white. Also, I don't
know how the green and blue filters over the sensors work. Do they
pass any infrared light? If so, then that explains why the image
is white wherever the infrared is bright (if I can call it bright).

Hmm, not quite sure on either, oh well this has beem a fun thread, I think add/sub color is all that is happening really, when she peers through the filter with the naked eye, no? Seems I remember a demo on this sort of thing before, not relating directly to photography.

Parker

Dewdrop

 

[nufferkay]

Plants do have a metabolism - they produce more heat than something that isn't burning energy (plants do burn energy). That's not a lot of heat, but it could be it's more than you get from the parts of the sky where the sun is not. I don't really know, I'm just throwing around ideas.

And no, I never tried to imply that plants emit light. Light and heat are different wavelengths of the same sort of energy.

I'm not sure why cutting off green would make plants relatively brighter - after all, green is the part of the spectrum that they reflect most. They absorb a heck of a lot of the red spectrum because it's the most efficiently used for photosynthesis.

Daniella, it would be really interesting to see an infrared photo of a bunch of objects of different colors and temperatures.....

I do not think that the plants are whiter because they produce eat
though...more a matter of refection and since this effect can be
seen with the human eye, I am starting to suspect that cutting off
the green light alone is enough to brighten the foliage.

Confused,

Pete

Depending on the sensitivity range of the red pixels on a CCD, you
could probably take an infrared photo in pitch darkness, although
it might be a very long exposure - maybe you could run that
experiment and let us know?

I'm also guessing that that is one reason why there is more noise
on a CCD when it is hot....

"Our eyes only see the tiny fraction of energy emitted by the sun
in the form of visible light. However, if we could see the infrared
rays emitted by all bodies--organic and inorganic--we could
effectively see in the dark."

we cannot see infrared light unless there is some source of IR
light first...in the dark, there is no source of IR so how can this
statement be true?

http://www.omega.com/literature/transactions/volume1/historical1.html

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

 

[nanook s]

Lets have some numbers, say, the vegetation gives off 100 units of light at 600nm (green) and 10 units of light at 720nm (red), the vegetation would be very green, and a full stop less bright than something else cooler giving off 200 units of light at 600nm but 2 unit of light at 720nm. Behind the IR filter however, the vegetation would be perceived by your eye as giving off 1 unit of light at 600nm, 5 units at 720nm, total 6 units of light; whereas that something else would be perceived by your eye as 2 units of light at 600nm, 1 unit at 720nm, for a total of 2.5 units of light. In other words, the vegetation would be more than a full stop brighter than that something else behind the filter, compared to a full stop dimmer previously. After your eye acclimatize to the dimness and reddish hue (and retina rod cells that are more sensitive to luminosity under dim light not being as sensitive to color to color as the cone cells are), all your eye see would be the more than a full stop difference in luminosity/brightness in favor of the previously dimmer vegetation.

Here you are talking about the filter and that's fine, but since
the human eye cannot see the IR light..then what is making the
foliage lighter?

In reality, a typical infrared filter more likely has a transfer
curve of, say, 50% of pass-through at 720nm, 85% at 750nm, 96% at
800nm or longer (surface multicoating decides whether the max
pass-thru gets beyond 96% or so), 25% at 700nm, 10% at 650nm, 1% or
less for wavelength shorter than 600nm (green color). 1% of a the
brightest broad daylight is still noticeabe amount of light, about
8 stops below, 1/2000 shutter vs. 1/20 shutter speed. In other
words, no worse than typical evening indoor lighting.

Jim

ps.
My wife says I have a talent for explaining things in the most
complex way possible ("scientificly precise" is what I say). Since
she is a science teacher and I'm an electrical engineer by training
who sees infrared filter as a low-pass filter, I will give you her
version: an infrared filter is just like a tinted sunglass; the
filter drasticly reduces the amount of visible light that can pass
through in the visible spectrum, but does less to infrared.

I did a little test today and I was surprised of the result. I took
my Hoya R72 filter and put it in front of my eye, covered the
visible light as much as possible so no light will go to my eye
from the ambiant light and I was surprised to see that the foliage
looked white!

Now can the human see IR light? Am I the only one seing infrared
light with my own eyes?

I know I am not allucinating or imagining things because I can see
the wall is light and the vegetation is dark green without the
filter and if I put the filter in front of my eye, I can see the
vegetation sudendly is lighter than the wall and if I stare a bit,
I can really see that the vegetation is white with a red tint. I
can see the dark grass patches become very light when I look at
them through the IR filter.

Of course it is not as well defined as when I capture the actual
image with my camera CCD, but I still can see that the ratio
light/dark for the vegetation changes.

Is the human eye capable of seing IR light but we don't realize it
because it is hiden by the stronger visible light?

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

 

[nanook s]

6 units of light vs. 3, not 2.5, after filter.

Here you are talking about the filter and that's fine, but since
the human eye cannot see the IR light..then what is making the
foliage lighter?

In reality, a typical infrared filter more likely has a transfer
curve of, say, 50% of pass-through at 720nm, 85% at 750nm, 96% at
800nm or longer (surface multicoating decides whether the max
pass-thru gets beyond 96% or so), 25% at 700nm, 10% at 650nm, 1% or
less for wavelength shorter than 600nm (green color). 1% of a the
brightest broad daylight is still noticeabe amount of light, about
8 stops below, 1/2000 shutter vs. 1/20 shutter speed. In other
words, no worse than typical evening indoor lighting.

Jim

ps.
My wife says I have a talent for explaining things in the most
complex way possible ("scientificly precise" is what I say). Since
she is a science teacher and I'm an electrical engineer by training
who sees infrared filter as a low-pass filter, I will give you her
version: an infrared filter is just like a tinted sunglass; the
filter drasticly reduces the amount of visible light that can pass
through in the visible spectrum, but does less to infrared.

I did a little test today and I was surprised of the result. I took
my Hoya R72 filter and put it in front of my eye, covered the
visible light as much as possible so no light will go to my eye
from the ambiant light and I was surprised to see that the foliage
looked white!

Now can the human see IR light? Am I the only one seing infrared
light with my own eyes?

I know I am not allucinating or imagining things because I can see
the wall is light and the vegetation is dark green without the
filter and if I put the filter in front of my eye, I can see the
vegetation sudendly is lighter than the wall and if I stare a bit,
I can really see that the vegetation is white with a red tint. I
can see the dark grass patches become very light when I look at
them through the IR filter.

Of course it is not as well defined as when I capture the actual
image with my camera CCD, but I still can see that the ratio
light/dark for the vegetation changes.

Is the human eye capable of seing IR light but we don't realize it
because it is hiden by the stronger visible light?

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

 

[Parker North]

Maybe I can find a used one of these to play with. I want to get 2 flashes and one of those 2200 printers or something like that first. Work before play. Or do you know what to a bank first. Can't do that.

 

[Daniella68313]

Plants do have a metabolism - they produce more heat than something
that isn't burning energy (plants do burn energy). That's not a
lot of heat, but it could be it's more than you get from the parts
of the sky where the sun is not. I don't really know, I'm just
throwing around ideas.

They probably generate heat, but I don,t think that's the type of IR that the camera is seing. Or maybe there is both refected IR and heat. not sure.

And no, I never tried to imply that plants emit light.

I got you ok

Light and

heat are different wavelengths of the same sort of energy.

I'm not sure why cutting off green would make plants relatively
brighter - after all, green is the part of the spectrum that they
reflect most. They absorb a heck of a lot of the red spectrum
because it's the most efficiently used for photosynthesis.

so if they reflect green light and so what we see from them is mostly the green spectrum...then if we filter that out, what's left for them to reflect? IR and not much else. Could it be that it is the green color it reflect that is making the vegetation dark? Of course I am just guessing but that's the only logical explenation to why I can see the effect with my eye and the filter, even though the eyes cannot see IR.

That is what I am curious to know, because I already read about how IR and visible light works etc...all this does not explain what I have experienced.

I could even see that one branche of a tree was whiter than other. Confirmed that by taking the photo with the camera.

Daniella, it would be really interesting to see an infrared photo
of a bunch of objects of different colors and temperatures.....

that's an interesting test, but that is largly dependant on the white balance. When you totaly filter out the visible light and let only IR through, objects like rocks, stone and ciment, cars etc. tend to stay the same as if taken in black and white. Only few things change their value...sky, water and vegetation are most noticeable. animals can looks ghosty and humans too.

Most unanimate objects look about the same as in black and white.

I do not think that the plants are whiter because they produce eat
though...more a matter of refection and since this effect can be
seen with the human eye, I am starting to suspect that cutting off
the green light alone is enough to brighten the foliage.

Confused,

Pete

Depending on the sensitivity range of the red pixels on a CCD, you
could probably take an infrared photo in pitch darkness, although
it might be a very long exposure - maybe you could run that
experiment and let us know?

I'm also guessing that that is one reason why there is more noise
on a CCD when it is hot....

"Our eyes only see the tiny fraction of energy emitted by the sun
in the form of visible light. However, if we could see the infrared
rays emitted by all bodies--organic and inorganic--we could
effectively see in the dark."

we cannot see infrared light unless there is some source of IR
light first...in the dark, there is no source of IR so how can this
statement be true?

http://www.omega.com/literature/transactions/volume1/historical1.html

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com

c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND, Hoya-red-Intensifier, Hoya R72.

 

[Daniella68313]

Maybe I can find a used one of these to play with. I want to get 2
flashes and one of those 2200 printers or something like that
first. Work before play. Or do you know what to a bank first.
Can't do that.

Hmm I am sorry but I do not understand your question. what to a bank first? do you mean get a loan?

Here is a c2020 for 189$ not a bad price. It is refurbished but still a good deal.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2922814097&category=30003

Nikon 800 for 160$:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2922968476&category=11070

the Mikon 800 gives really nice shade with the R72 filters.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com

c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND, Hoya-red-Intensifier, Hoya R72.

 

[Parker North]

Thanks Nanook, I was not thinking of this stuff, but you have made it clear for me to understand this effect better.

Parker

Here you are talking about the filter and that's fine, but since
the human eye cannot see the IR light..then what is making the
foliage lighter?

In reality, a typical infrared filter more likely has a transfer
curve of, say, 50% of pass-through at 720nm, 85% at 750nm, 96% at
800nm or longer (surface multicoating decides whether the max
pass-thru gets beyond 96% or so), 25% at 700nm, 10% at 650nm, 1% or
less for wavelength shorter than 600nm (green color). 1% of a the
brightest broad daylight is still noticeabe amount of light, about
8 stops below, 1/2000 shutter vs. 1/20 shutter speed. In other
words, no worse than typical evening indoor lighting.

Jim

ps.
My wife says I have a talent for explaining things in the most
complex way possible ("scientificly precise" is what I say). Since
she is a science teacher and I'm an electrical engineer by training
who sees infrared filter as a low-pass filter, I will give you her
version: an infrared filter is just like a tinted sunglass; the
filter drasticly reduces the amount of visible light that can pass
through in the visible spectrum, but does less to infrared.

I did a little test today and I was surprised of the result. I took
my Hoya R72 filter and put it in front of my eye, covered the
visible light as much as possible so no light will go to my eye
from the ambiant light and I was surprised to see that the foliage
looked white!

Now can the human see IR light? Am I the only one seing infrared
light with my own eyes?

I know I am not allucinating or imagining things because I can see
the wall is light and the vegetation is dark green without the
filter and if I put the filter in front of my eye, I can see the
vegetation sudendly is lighter than the wall and if I stare a bit,
I can really see that the vegetation is white with a red tint. I
can see the dark grass patches become very light when I look at
them through the IR filter.

Of course it is not as well defined as when I capture the actual
image with my camera CCD, but I still can see that the ratio
light/dark for the vegetation changes.

Is the human eye capable of seing IR light but we don't realize it
because it is hiden by the stronger visible light?

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

 

[Daniella68313]

That's right for sure. However, remember that digital image
sensors are really just luminance (light intensity) sensors.
Filters over the individual sensor sites determine the color. With
the Bayer algorithm and the exposure cranked up, I suspect that it
would be fooled into thinking the image was white. Also, I don't
know how the green and blue filters over the sensors work. Do they
pass any infrared light?

They surely pass IR light if there is not a strong hot mirror. The simple prove of this is that a CCD can see the infrared light beam from a TV or VCR infrared remote control.

If so, then that explains why the image

is white wherever the infrared is bright (if I can call it bright).

Yes that is why the foliage is capture white with the IR filter. Actutaly is it more in term of value than in color I think. More in term of brightness and darkness, as a true IR image without any visible light is black and white.

Still, that does not explain why I can see the vegetation is much lighter with my own eye when looking through the filter. Since I cannot see IR light then there must be some other explanation why the vegetation is turning light or a combinaison of factors.

Dewdrop

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com

c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND, Hoya-red-Intensifier, Hoya R72.

 

[Parker North]

Maybe I can find a used one of these to play with. I want to get 2
flashes and one of those 2200 printers or something like that
first. Work before play. Or do you know what to a bank first.
Can't do that.

Hmm I am sorry but I do not understand your question. what to a
bank first? do you mean get a loan?

Exactly I just meant I need to buy the printer and flashes first, if I had unlimited cash, I would just buy everything, inclding a 10D. Then I would not have to worry about it.

Here is a c2020 for 189$ not a bad price. It is refurbished but
still a good deal.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2922814097&category=30003

Nikon 800 for 160$:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2922968476&category=11070

the Mikon 800 gives really nice shade with the R72 filters.

Can I make 8x10 or 7 1/2 x 22 prints with these models, at real nice quality level?? If I cannot make at least nice 8x10 I can't use it. I may need to crop large percentages with smalll lens if I try on my fish. Probably no chance then. I have not looked at these two yet, I am taking a look now.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

 

[nanook s]

I can be quite nerdy, sometimes ;-)

Jim

Parker

Here you are talking about the filter and that's fine, but since
the human eye cannot see the IR light..then what is making the
foliage lighter?

In reality, a typical infrared filter more likely has a transfer
curve of, say, 50% of pass-through at 720nm, 85% at 750nm, 96% at
800nm or longer (surface multicoating decides whether the max
pass-thru gets beyond 96% or so), 25% at 700nm, 10% at 650nm, 1% or
less for wavelength shorter than 600nm (green color). 1% of a the
brightest broad daylight is still noticeabe amount of light, about
8 stops below, 1/2000 shutter vs. 1/20 shutter speed. In other
words, no worse than typical evening indoor lighting.

Jim

ps.
My wife says I have a talent for explaining things in the most
complex way possible ("scientificly precise" is what I say). Since
she is a science teacher and I'm an electrical engineer by training
who sees infrared filter as a low-pass filter, I will give you her
version: an infrared filter is just like a tinted sunglass; the
filter drasticly reduces the amount of visible light that can pass
through in the visible spectrum, but does less to infrared.

I did a little test today and I was surprised of the result. I took
my Hoya R72 filter and put it in front of my eye, covered the
visible light as much as possible so no light will go to my eye
from the ambiant light and I was surprised to see that the foliage
looked white!

Now can the human see IR light? Am I the only one seing infrared
light with my own eyes?

I know I am not allucinating or imagining things because I can see
the wall is light and the vegetation is dark green without the
filter and if I put the filter in front of my eye, I can see the
vegetation sudendly is lighter than the wall and if I stare a bit,
I can really see that the vegetation is white with a red tint. I
can see the dark grass patches become very light when I look at
them through the IR filter.

Of course it is not as well defined as when I capture the actual
image with my camera CCD, but I still can see that the ratio
light/dark for the vegetation changes.

Is the human eye capable of seing IR light but we don't realize it
because it is hiden by the stronger visible light?

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

 

[Daniella68313]

that is an interesting explanation. Do you speak with facts or are you speculating that something with a cooler color will appear lighter?

Here you are talking about the filter and that's fine, but since
the human eye cannot see the IR light..then what is making the
foliage lighter?

In reality, a typical infrared filter more likely has a transfer
curve of, say, 50% of pass-through at 720nm, 85% at 750nm, 96% at
800nm or longer (surface multicoating decides whether the max
pass-thru gets beyond 96% or so), 25% at 700nm, 10% at 650nm, 1% or
less for wavelength shorter than 600nm (green color). 1% of a the
brightest broad daylight is still noticeabe amount of light, about
8 stops below, 1/2000 shutter vs. 1/20 shutter speed. In other
words, no worse than typical evening indoor lighting.

Jim

ps.
My wife says I have a talent for explaining things in the most
complex way possible ("scientificly precise" is what I say). Since
she is a science teacher and I'm an electrical engineer by training
who sees infrared filter as a low-pass filter, I will give you her
version: an infrared filter is just like a tinted sunglass; the
filter drasticly reduces the amount of visible light that can pass
through in the visible spectrum, but does less to infrared.

I did a little test today and I was surprised of the result. I took
my Hoya R72 filter and put it in front of my eye, covered the
visible light as much as possible so no light will go to my eye
from the ambiant light and I was surprised to see that the foliage
looked white!

Now can the human see IR light? Am I the only one seing infrared
light with my own eyes?

I know I am not allucinating or imagining things because I can see
the wall is light and the vegetation is dark green without the
filter and if I put the filter in front of my eye, I can see the
vegetation sudendly is lighter than the wall and if I stare a bit,
I can really see that the vegetation is white with a red tint. I
can see the dark grass patches become very light when I look at
them through the IR filter.

Of course it is not as well defined as when I capture the actual
image with my camera CCD, but I still can see that the ratio
light/dark for the vegetation changes.

Is the human eye capable of seing IR light but we don't realize it
because it is hiden by the stronger visible light?

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com

c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND, Hoya-red-Intensifier, Hoya R72.

 

[Daniella68313]

I think 8 x 10 is really the biggest format you can print with a 2mp camera. 17 inch will not look so good at 2mp.

If you want to buy a 10D, then probably the 10D will be able to do IR with long exposure, better than the D7i or 7hi. I think the D30 or D60 was decent with exposure of 1 or 2 seconds.

Maybe I can find a used one of these to play with. I want to get 2
flashes and one of those 2200 printers or something like that
first. Work before play. Or do you know what to a bank first.
Can't do that.

Hmm I am sorry but I do not understand your question. what to a
bank first? do you mean get a loan?

Exactly I just meant I need to buy the printer and flashes
first, if I had unlimited cash, I would just buy everything,
inclding a 10D. Then I would not have to worry about it.

Here is a c2020 for 189$ not a bad price. It is refurbished but
still a good deal.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2922814097&category=30003

Nikon 800 for 160$:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2922968476&category=11070

the Mikon 800 gives really nice shade with the R72 filters.

Can I make 8x10 or 7 1/2 x 22 prints with these models, at real
nice quality level?? If I cannot make at least nice 8x10 I can't
use it. I may need to crop large percentages with smalll lens if I
try on my fish. Probably no chance then. I have not looked at these
two yet, I am taking a look now.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com
c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND,
Hoya-red-Intensifier, Hoya R72.

--
Daniella
http://www.photosig.com/viewuser.php?id=26918
http://www.pbase.com/zylen
C7OO FORUM: http://www.c700uz.com

c7OOuz, Dimage-7, Tcon14tele, C210tele, Cokin-173, Grad-ND, Hoya-red-Intensifier, Hoya R72.

 

[Parker North]

...a bit more of a nerd...sometimes...