IR filters

[timmyquest]

I'm not too crazy, they do exsist dont they?

I'd like to get them for my digital, but also for my 35mm if they work because i cant use IR film aparently unless i put it in my AE-1. Which is fine, but i dont have all that much as far as glass for that camera.

[thomascanty]

I've been shooting digital IR with my Olympus cameras for several years now using a Hoya R72 infrared filter. I'm just now branching out into shooting IR on film, using a Pentax K1000, and so far most people seem to be saying that for film, a #25 red filter is best.

I've never shot digital IR with a Canon dSLR though. I don't know how well they do. Digital cameras can be fickle about whether they work or not. Olympus just happens to be very good in this regard, which was fortunate for me because my first digital camera with manual controls was an Oly.

Also, be warned, Hoya R72 filters in the size you'd most likely need for a dSLR can be very expensive! They're much more reasonable in smaller sizes, which was another good thing for me using an Olympus.

[Longwatcher]

I have a Hoya R72 IR filter I bought from BH. They have them along with some others.

It works on my 10D and 1DsMKII
It does NOT work on my D60.
I have been told it works on rebel, but have not heard about 1D, 1Ds, 1DM2 or 20D yet.

It has a cutoff of 720nm (0.72um)
The Wratten #25 has a cutoff of 600nm which lets in a lot of red
The reason you want I higher cutoff for digital is the sensor is essentially set for the same range as regular film, however the sensor itself does have some sensitivity beyond the visual which has been cutoff by a low-pass filter. What this means is that if you use a #25 filter, too much red light will pass through to the digital and you will blow out your highlights long before you get enough IR energy to the sensor to be noticeable as IR.

Although I have not tried a filter with a higher cutoff (mainly because of cost), I suspect it would not work anyway as the Hoya R72 is already pressing the limits of at least the 10D. I have some suspicisions that the low-pass filter on the 1DsMkII may actually have a band rather then a cutoff and it might let some IR light above 720 get to the sensor.

The best size filter to get is a 58mm filter ($47.95 at BH) which will allow you to use it on the 50/1.4 or with a step-up ring use it on a 50/1.8 one of which everyone should have for their SLR. That size is reasonably low cost compared to the next most common size of 77mm ($283.50). The RM90 the next cutoff up is $308.95 for the 58mm which is a bit high just to see if it works. I could blow $50 for the RM72 to try, but not $300.

The advantage to the Hoya R72 filter is we know it works with most digital cameras and it is the lowest cost IR filter. There are some B+W and Tiffen filters that I have read work on some DSLR cameras, but have not read of anybody trying them on Canon's DSLR.

Hope that helps,

[timmyquest]

Thanks, great info. Sadly i'd want it for my 17-40 more then anything else so i'd have to dish out some cash. I'd much rather have it for film right now though, i presume that it works fine for film?

[Longwatcher]

If you get the Hoya R72 make sure you get the correct film to work with it (don't ask which that is). Each IR film has it's own sensitivity, Some can even do LWIR, but those films and filters are really expensive. I suspect the standard IR film is designed with the Wratten #25 in mind. The Hoya R72 may work, but it will take some practice. And the setting for film and digital will not be the same.

[thomascanty]

Timmy, check out the thread I started the other day for more info:

http://www.photography-on-the.net/forum/showthread.php?t=53559

[timmyquest]

If you get the Hoya R72 make sure you get the correct film to work with it (don't ask which that is). Each IR film has it's own sensitivity, Some can even do LWIR, but those films and filters are really expensive. I suspect the standard IR film is designed with the Wratten #25 in mind. The Hoya R72 may work, but it will take some practice. And the setting for film and digital will not be the same.

The only reason i'm interested in the filter is so i dont have to use IR film so i can use it in my rebel 2000 and my newer, better lenses.

It's looking like there is no real solution then pulling out the 'ol AE-1, which could be fun :-)

[Jon]

An IR filter won't work without IR film. Most film has a low sensitivity to IR; what makes IR film special is that it is sensitive in the IR range. It's like trying to shoot IR with the D60, which has an aggressive anti-IR filter over the sensor.

[Alan Neilson]

I use the cokin IR filter, from a article in a uk photo mag, I think it has the same IR wave lenght as the Hoya, or very similar. I have used it on my 10D and did not get very good results, I have also used it on my G2 and the results were a lot better. Think there must be some filter on the chip in the 10D that blocks out that wave lenght, as I have heard of others using IR filters on there 10D's.

The one advantage with the cokin is that you can use it on different lens, although with you saying you want to use it on your 17-40 unless you are using the size above P then you will likely get vanetting at wide angle, at least I did on my film camera, haven't tried it on digital yet, with the change in propective with the smaller chip you might be alright on film on my 19-35 I had I couldn't go past 28mm.

Like Jon said you do need to use IR film if you are using film normal film won't work. Not sure about the Rebel 2000 or the UK equvilent is, but you might have a problem with foging on the rebate and edge of film as the newer EOS camers use an IR sensor to check the film as moved on the right amount. On older cameras such as the 600 you are ok. The all you need to do is make sure about the focusing as IR wave lenght means you have to make a slight adjustment. Due to the filter being nearly opaque you need to use it on a tripod so if you stop down enough you will have enough DoF any way. I set the camera on the tripod compose the shot then slide the flitter in the holder.

Hope this helps.

[Steven M. Anthony]

There is a simple way to test if your digicam will pick up IR. Get a IR remote control unit--like the one for your TV. Aim it at the camera and press any of the buttons on the remote. Take a picture while doing this. If you see a bright light coming out of the remote, you can capture IR light.

[Agaric]

I'm not too crazy, they do exsist dont they?

I'd like to get them for my digital, but also for my 35mm if they work because i cant use IR film aparently unless i put it in my AE-1. Which is fine, but i dont have all that much as far as glass for that camera. Timmy, I have the Hoya R72 filter and have used it on my DRebel. I believe the DRebel has a lowpass filter in it to block IR but with some extended exposure times and a tripod you can get some decent shots. I took this one just a month or two back.

http://webpages.charter.net/alanamend/IR_1867.jpg

It takes a bit of post processing to get the red out of the pictures without desaturating but they will turn out decent.

I got my hoya R72 off of Ebay for a very good price, brand new $30 for a 58mm.

Good luck and hope to see some shots of yours later.