advise on IR Filter

[ash243]

hi as a new comer to this forum and digital photography been one of the point and press keen amateur i have been around for a year reading up and looking at all the wonderfully images i hoping to do a HND in photography next year.
But in the mean time i have been inspired to try differing shots and techniques form the members on the forum
the next topic i have is IR and have some questions please help if you can.

1) As there are so many different IR filters I'm assuming the "numbers are a gradient of light that passes through the filter" do you guys use one filter for all shots or do you have a selection?

2) I am assuming in the shot you use a High ISO and wide aperture /or longer shutter speed but the higher ISO will give a Graining look to the picture. As well as the wider the aperture the focus will deteriorate.

3) will a red or orange filter be any better for a more moderate setting

sorry thanks and Hello

all the best ash

[Picture North Carolina]

Hi, Ash. Welcome to POTN.

I am sorry that I cannot help with filters because in using converted cameras, I am not current with how easy/hard it is to shoot IR with current unmodified hardware.

But I can give you one piece of advice that will save you grief and money. Do not buy a cheap or ebay IR filter. Over the years I have seen post after post here on POTN from people buying bargain filters that turned out to be simple red-colored filters.

Spend the extra money to buy a good quality, known name brand filter so you can be sure that when it says it's an IR filter, it's an IR filter.

[TedVitale]

Im new to the IR bug too, but i picked up a Hoya R72 77mm filter on here brand new for about 170. Their a costly lens but fun when you get the hang. The hardest part is getting the colors right, you know those great false colors you see in everybody else's photos. I found this site: http://thegistofit.org/custom-white-balance-using-lab/ and it was pretty helpful. But theres a plethora of info out there just google through the internet an youll have fun with it. As far as exposures and ISO and all, keep it low and long, otherwise you do end up with noisy shots. Also keep in mind theres tons of PP with filter IR photos. Good luck with it, and Ill look forward to seeing some of your stuff. Hopefully I have something decent to post soon too.

[sabianq]

i would be willing to bet that you can use red and blue optical or lighting filter gels stacked and build yourself a decent IR pass filter. for practically nothing i want to give it a try.

being a low level theater geek for the past 20 years, i know they have one cool secret.

Lighting gel cuts!. duh!
we all save the rest of the gel when we cut it. and any theater tech worth his weight will have a heap of red and blue gels.

i know from astronomy that the better deep red filters actually cut the upper frequencies in a measured way.

i bet that if you cut them to your filter size then stack red blue red and you will get a real Ir pass filter (although maybe not with a linear spectrum absorption line (which is what you are paying for anyway) like what you find on the real filters. but something usable for experimentation to see if ya want to spend the real money.

i would go about it this way,
close aperture to around 4 or 5 or 6
try a 300-1000 ISO as a start
then open the shutter up for 10 seconds.
in mid day full sun..
the filters are very dark.
see a blurry underexposed dark image..
use the red dot on the lens to focus to instead of that line (Ir focus different)
and try again until something recognizable came out.

[sabianq]

1) As there are so many different IR filters I'm assuming the "numbers are a gradient of light that passes through the filter" do you guys use one filter for all shots or do you have a selection?



yes, you are 100% correct!
er... sort of.. come to think of it, i think each manufacture may have a different label system.
but any high quality filter should come with a frequency response graph or "transmission graph" showing what the pass/cut slope looks like.

you would look at the frequency response or "Spectral Energy Distribution (S.E.D.) curve" to see what passes and what does not.


2) I am assuming in the shot you use a High ISO and wide aperture /or longer shutter speed but the higher ISO will give a Graining look to the picture. As well as the wider the aperture the focus will deteriorate.


that "grainyness" is noise and is caused by the sensor misfiring.
apature does affect DOF just like visible light but because of the longer frequency of IR light, the refraction the glass imparts to the ir-light is different than with visible light, this pushes back your focus so you have to compensate.
some lenses have a little dot on the focus window that indicate the focus distance in IR for that lens..


3) will a red or orange filter be any better for a more moderate setting

have no idea.. maybe someone should check it out and report back?
:)

cheers!

[sabianq]

here is a typical curve of some various Tiffen ND photography filters.

[PlayersZ28]

You can't just do IR with any old digital camera. Unlike film cameras the digi's have an IR blocking filter as the sensor will respond to the IR spectrum otherwise (in the film world you just modified the film base to accept/reject IR). Some cameras will allow more IR than others, some allow removal of the filter, some are useless. When I convert a digi camera for IR I remove the hot filter and replace it with an R72 so it is IR-only after that.

Some IR images are on my site www.highpointimages.ca (lame site, just click on the link on the left side).

[Clean Gene]

hi as a new comer to this forum and digital photography been one of the point and press keen amateur i have been around for a year reading up and looking at all the wonderfully images i hoping to do a HND in photography next year.
But in the mean time i have been inspired to try differing shots and techniques form the members on the forum
the next topic i have is IR and have some questions please help if you can.

1) As there are so many different IR filters I'm assuming the "numbers are a gradient of light that passes through the filter" do you guys use one filter for all shots or do you have a selection?

2) I am assuming in the shot you use a High ISO and wide aperture /or longer shutter speed but the higher ISO will give a Graining look to the picture. As well as the wider the aperture the focus will deteriorate.

3) will a red or orange filter be any better for a more moderate setting

sorry thanks and Hello

all the best ash


A red or orange filter will not do anything, as far as infrared photography is concerned. Both filters allow a SIGNIFICANT amount of visible light to pass through (which you can tell by looking at them...if you hold them up to your eye, it is very easy to see through them).

Combine that with the infrared-blocking filter in your camera, and this still means that most of the electromagnetic radiation reaching the camera's image sensor is still well within the visible spectrum. That's going to work against your pictures having that distinctive "infrared look."

If you want to do infrared, you REALLY need to use a deep red filter that's nearly opaque. Your standard red or orange filter won't get the job done. The filter will still be allowing so much visible light to reach the sensor that you won't get a good infrared effect.

It's also worth pointing out another thing...many people look up infrared pictures online, and many of those pictures were probably not made with digital cameras. Before everyone started doing digital, people were doing infrared photography on film. The most popular infrared film for a long time was the Kodak HIE film, which is now discontinued. This film was attractive for another reason aside from just being sensitive to infrared...the film lacked an anti-halation backing. This allowed light to travel through the film, then bounce back and expose the film again, leaving "halos" of light. That's generally undesirable, which is why most films have a component preventing that from occurring. However, with infrared, that sometimes or often left a desirable effect. Just be aware that you won't get that same effect by doing infrared photography in digital. Because you're not working with film, and halation is a non-issue. You can still get the dark skies and the bright foliage, simply because those are a function of certain objects' reflatance/transmission in the near-infrared part of th spectrum. But you will NOT get the halation effect, simply because you're using a digital sensor to record the image, instead of using film. That specific halation effect that many people like so much isn't a property of infrared photography, it is a property of certain kinds of film.

But as far as flters are concerned...you DEFINITELY want to stick to a filter that is heavily restrictive to visible light. A standard red or orange filter isn't good enough. Ideally, you want to go with a filter that is so red that it is nearly opaque. A "black" filter that only looks red when you put it right up against your eeye and then look at a strong light source (but NOT the sun...do NOT look at the sun through an infrared filter).

[tessa safadi]

Hi I am also interested in IR photography and have a Canon 500D EOS
I am looking at getting the Hoya R72 filter but have been told that it does not work with all Canon lenses, some leave bright spots. I have a Canon macro EF-s 60mm 1:2.8 USM lens and a Canon zoom lens EF 70-300mm 1:4-5.6 IS USM

Does any one know if I can use an R filter with either of these lenses.?

[Clean Gene]

Hi I am also interested in IR photography and have a Canon 500D EOS
I am looking at getting the Hoya R72 filter but have been told that it does not work with all Canon lenses, some leave bright spots. I have a Canon macro EF-s 60mm 1:2.8 USM lens and a Canon zoom lens EF 70-300mm 1:4-5.6 IS USM

Does any one know if I can use an R filter with either of these lenses.?

Not familiar with those lenses, but maybe you could find someone who has a filter and see if he/she'll let you take a few shots with your camera and lens. Just because it's documented that a lens causes hot spots doesn't mean that you can't use it. You might still be able to use it in certain situations.

For example, my lenses all leave hot spots, but it's usually only really a problem at f/8. In certain cases I can get away with f/8, and even try f/11. My lenses are still problem lenses, but the results are plenty acceptable as long as I shoot no higher than f/8 (which is usually what I do anyway).

Same way with film. I started trying out infrared film, and some of them are supposed to not work in my camera. I tried them out anyway. And while fogging did occur, it was very mild. The results were still more than acceptable, even though the film was DEFINITELY getting fogged by my camera.

I personally wouldn't BUY the filter without knowing for sure that it'll work for you. Not unless you've just got money to blow and are comfortable with buying the filter and then finding out that it's worthless to you. But if you can find a way to do so, I'd recommend actually getting your hands on a filter if possible, and then just trying it out to see if it's to your liking. Presence of hot spots can be affected by aperture value, focal length (so I've heard, though I've never noticed a difference on my lenses), and lighting conditions. There are a lot of variables that play into this. Hell...the lenses that I use and can't stop down lower than f/8 without getting hot spots? Well, I can slap that EXACT SAME LENS onto a film SLR, and be able to stop down to f/22 and smaller without getting any hint of a hot spot whatsoever. That's using the exact same lens, the exact same filter. I'd say that there are enough variables that even if someone says that those lenses will or will not work, it'd probably be a good idea to try it out yourself (provided that you manage to do so for free).

[LearnMyShot]

R72 is a good choice:
you might be interested in looking at this IR filter / infrared tutorial:
http://www.learnmyshot.com/Color-Infrared-Photography-Technique-Step-By-Step