new Infrared filter question... - DPChallenge Forums

08/31/2006 11:19:29 AM · #26

depends on a number of factors
1) type of filter (cutoff freq. of normal light vs IR)
2) type of camera /Hotmirror in the camera

1)if it leaks in alot of 'normal visable light' you will see normal colors coming through
filters that are in the high 600nm and low 700nm range will do this

filters that have a sharp cutoff in the high 700 will tend produce only one color ...

2) if the camera hotmirror is very sharp (high fall off ) you will likly get one color - if it is a so-so filter it will leak colors into red & green & blue

My tiffen #87 will produce a very narrow red/pink (with a tinge of blue) range of colors on the d100
on the d200 the hot mirror is so good that i have to up the exposure 8-16x (3-4 stops) which makes it less fun ..
useing a 87 wratten gell i get ONLY red (with a 2stops extra) -

Message edited by author 2006-08-31 11:20:22.

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

08/31/2006 11:21:38 AM · #27

Originally posted by freakin_hilarious:

I have a question for you IR gurus out there, and I figured this was a good place to put it. I am wondering how to go about getting different colored trees (grass, etc.) in the final version of the image. Most IR shots seem to make green things totally white, but then there are others with bright pink or even yellowish trees (see examples from this thread below).

Any help would be greatly appreciated!

part of it is going to be the camera... some actually allow a bit of visible light through to color things... (or so i understand)

the other things that effect it are your preset white balance, how you convert in the channel mixer (i don't always shift the blue and red at 100%) and then there's also what you can do with hue/sat to bring those colors out...

for instance, my golf course shot (check my IR gallery), similar to marbo's shot above, i set the WB with the filter on, to a shaddy spot of grass... gave me a light blueish tint to the trees that became pink w/ the channel conversion and some mild hue/sat... the treeline pic above, i metered on some greenish weeds in the late afternoon sun, and it left the trees (which were very shaded from the sun) w/ a yellowish tint that i brought out w/ the hue/sat.

basically, it's all about experimentation...

freakin_hilarious

Canon EOS-550D Rebel T2i

08/31/2006 11:24:24 AM · #28

Very cool. Thanks for the info!

Bugzeye

Fisher Price Kid-Tough Digital

08/31/2006 11:31:04 AM · #29

wish I wouldnt have clicked on this thread. Now I have to make another trip back to the camera store to get one of these IR filters. just dropped a boat full of money in there 2 days ago. hopefully they will give me a fine deal....

cornettcag

Canon EOS-350D Rebel XT

Tamron AF 18-200mm f/3.5-6.3 XR Di II for Canon

08/31/2006 11:31:49 AM · #30

Originally posted by Raziel:

Originally posted by GeneralE:
IR light = heat.

Hot objects should expose as highlights, cool objects as shadows. When you look at a scene, you have to adapt to this interpretation to predict what you'll get.

IR occupies a fairly wide spectral band. Heat IR is emitted at wavelengths for which glass is opaque. The kind of IR that a digital camera sees is near infra-red. Hot objects emmit some near IR radiation, but not enough for thermal imaging. The brightness of objects depends on how much IR they reflected. The sky doesn't reflect much IR and is therefore black in IR photos. Trees reflect a lot of IR, that's why they show up white.

Living organisms are metabolically active so they should be emitting heat. I don't understand how or why they would reflect IR - could you explain it or share a reference with us?

08/31/2006 11:34:41 AM · #31

Originally posted by Bugzeye:

dosen't work well with the D200

08/31/2006 11:36:16 AM · #32

Originally posted by ralph:

Originally posted by Bugzeye:
wish I wouldnt have clicked on this thread. Now I have to make another trip back to the camera store to get one of these IR filters. just dropped a boat full of money in there 2 days ago. hopefully they will give me a fine deal....

dosen't work well with the D200

no, but he also has a d50, which works rather well...

08/31/2006 11:38:57 AM · #33

Originally posted by cornettcag:

Living organisms are metabolically active so they should be emitting heat. I don't understand how or why they would reflect IR - could you explain it or share a reference with us?

don't think of Near IR as heat -- it is just a bit longer wave length than red
were Heat IR is much longer wave lenght & can ONLY be picked up with very specialized equipment

standard ccd's (and thier ilk) can not see heat

what near IR is reflected Sun IR or if you have your camera modified (hot mirror removed) even lightblubs & flashes will produce IR to take pictures with

08/31/2006 11:42:36 AM · #34

Originally posted by kudzu:

no, but he also has a d50, which works rather well...

oops didn't look ...

08/31/2006 12:06:52 PM · #35

hows the 30d with IR filters? i always wanted to try this and i gigure i should do it right if im gonna do it :/

-Dan

08/31/2006 10:49:10 PM · #36

Originally posted by I Enjoy Ham:

hows the 30d with IR filters? i always wanted to try this and i gigure i should do it right if im gonna do it :/

i don't know about the 30d specifically, but it has been said that the nikon's (mainly the d50 and d70) do much better than the canons because the canons have a more restrictive high pass filter.

case in point:

marbo is a canon user who purchased a d50 to do IR...

not to say that it can't be done, mind you... it just may take longer shutter speeds...

08/31/2006 10:59:51 PM · #37

hmm thanks... another question,

when using film, does one have to use infrared film, or will a filter work with film aswell?

-Dan

08/31/2006 11:00:43 PM · #38

Originally posted by I Enjoy Ham:

hmm thanks... another question,

when using film, does one have to use infrared film, or will a filter work with film aswell?

-Dan

must use IR film (with or without the filter .)

08/31/2006 11:01:33 PM · #39

ah ok... any idea why?

crayon

Samsung Galaxy S24 Ultra

08/31/2006 11:02:36 PM · #40

Originally posted by Nikonian Ninja:

marbo's pic is only 1/80 but a superwide aperture. This is one of the pics that inspired me to get the filter.

that is one of the pic that got me buying my IR filter as well.
and now that pic is a sad reminder that I can never be as good.

08/31/2006 11:08:58 PM · #41

Originally posted by I Enjoy Ham:

ah ok... any idea why?

IR emultion is only sensitve to IR
normal film is more restrictive than Digital camera sensors
a ccd/cmos sensor is sensitve to the visable & IR/UV so it needs the hotmirror in formt of the sensor to cut the unwanted stuff

Nikon AF Nikkor 50mm f/1.8D

08/31/2006 11:12:18 PM · #42

Originally posted by ralph:

Originally posted by I Enjoy Ham:
ah ok... any idea why?

IR emultion is only sensitve to IR
normal film is more restrictive than Digital camera sensors
a ccd/cmos sensor is sensitve to the visable & IR/UV so it needs the hotmirror in formt of the sensor to cut the unwanted stuff

ah ok, so the film is unable to "see" the IR rays even if you put the filter infront of the lens. Thanks for you help guys :)

FireBird

08/31/2006 11:14:08 PM · #43

I saw in one of the forums last week someone with a scratched sensor cover on a D70 wanting to sell it for 200 bucks. Assuming he's not kidding there is a company that will remove the filter/cover and replace it with one that is transparent to IR. Cost about 200-250, so for about 500 bucks an IR camera that you compose normally and have normal shutter speeds. They'll do most of the Nikon line but who has the money to emasculate a D200 or D2X? heheh

Off to eBay to search for a 2020.

Message edited by author 2006-08-31 23:14:59.

wavelength

Nikon D300

08/31/2006 11:21:56 PM · #44

you could get a Fuji S3 PRO UVIR it's like ~~$1600~~$1800, but uber cool. Also has live video mode to preview the effects of other filters you may want to use too.

Message edited by author 2006-08-31 23:23:28.

freakin_hilarious

Canon EOS-550D Rebel T2i

Tamron SP AF 28-75mm f/2.8 XR Di for Canon

09/01/2006 11:04:20 AM · #45

I finally got my filter and took a few shots. This one turned out the best.

I do have another question, though. It appears to have a lighter area toward the center. All of the shots I took have a similar light area. Any ideas what that could be?

Nikonian Ninja

Nikon D50

Tamron AF 28-80mm f/3.5-5.6 Aspherical for Nikon

09/01/2006 11:29:04 AM · #46

I have just taken a few shots with mine now but unfortunately it has been nothing but cloudy and rainy here so far. I just took one yesterday while it was cloudy and the sky turned yellowish like marbo's Hogwarts picture. it actually looks pretty cool :)

DrAchoo

Panasonic Lumix DMC-LX5

Canon EF 24-105mm f/4.0L IS

09/01/2006 11:36:49 AM · #47

Originally posted by freakin_hilarious:

I finally got my filter and took a few shots. This one turned out the best.

I do have another question, though. It appears to have a lighter area toward the center. All of the shots I took have a similar light area. Any ideas what that could be?

That's the internal reflection of your lens. Some are better and some are worse at this.