Do infrared filters work?

shaylou

shaylou

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Shayne
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I know very little about infrared photography so I'm not going to convert one of my camera's over to an infrared camera. That leaves the question if those front lens filters actually work and if so how well. Is there a particular filter to get? Just trying to get some basic knowledge. It seems it may be a good avenue to get very creative with.

Thanks for your help.:exit:


:canon:
 
They certainly do work Shayne but the downside is that they increase exposure time by between 2 and 4 stops whereas a modified camera doesn't.
Different cut-off values will give different effects as the amount of visible light becomes less and less......typically cut-off values are 595.690 or 720nm with 720nm blocking most of the visible spectrum.
I'd start with a 720nm filter (Hoya R72 is commonly used) and see if you like the effect.

Kolarivision have an excellent overview of IR methodology on their website http://kolarivision.com/filterchoices.html

Bob
 
shaylou said:
I know very little about infrared photography so I'm not going to convert one of my camera's over to an infrared camera. That leaves the question if those front lens filters actually work and if so how well. Is there a particular filter to get? Just trying to get some basic knowledge. It seems it may be a good avenue to get very creative with.
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Yes, they work. Without them the images you take will actually look quit normal, despite removing the IR filters from your camera.
 
some better than others. I found the Cokin IR filter pretty hopeless as it let in too much normal light wavelengths. A filter i got off ebay for a couple of quid was much better. One of these.... http://www.ebay.co.uk/itm/New-Infra...es_CameraLensesFilters_JN&hash=item2a389a4bfe

Also depending on the camera youre bolting it onto. My fuji x10 can still manage quite fast shutter speeds but the D800 has an IR blocker on the sensor so needs way longer exposures.
 
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It depends on the sensor as much as anything. Some cameras extend their sensitivity well into the infrared, others cut it well short.
Filters work with the first but not with the second type.
Some cameras are very easy to permanently convert to IR use. Others are best forgotten.

There are very many sample shots on the web.
 
Yes they work very well. Depending on your camera though they may not magically create IR pictures. (Briefly the internal IR filter cuts out nearly all the IR light. The front filters cut out everything but the IR light. So if your camera is IR sensitive and the internal filter isn't too strong you'll get nice pictures.)

Start with an R72 like @Canon Bob says.
 
Mr Perceptive said:
A lot of 'modern' lenses have IR hotspots at many aperture settings. Worth doing a bit of research on the web before buying any filters.
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They certainly do, and there is a dramatic loss of sharpness at the periphery of the image if you use full frame camera. APS-C body probably would be preferable, and pick the glass carefully. Of course £20 won't hurt if you just want to have a play. If you are more serious perhaps look if you can find a bargain converted 40D or something like that on ebay.
 
shaylou said:
What do you mean by IR hot spots?
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You'll get a bright spot in the centre of the image, which will vary at different apertures. Worst case it will look like the aperture blades. Different lenses have different characteristics, see here for an example list http://www.kolarivision.com/lenshotspot.html

094-800px_zps7347f877.jpg

Unprocessed Hoya R72, you can remove most of this in post processing

101-800px_zpsc79a4f6e.jpg

R72 converted to Mono

099-800px_zps5fc74eb1.jpg

Extreme!! Hotspot with flare!!
 
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Shayne you should be able to pick up a screw in IR filter for $30 or something. I've used one a little on my 5D. I can't see any particular softness at the edges, and contrary to conventional wisdom, my 5D will auto expose and auto focus with it fitted. I've only used it with 17-40 L I think.
 
Mr Perceptive said:
A lot of 'modern' lenses have IR hotspots at many aperture settings. Worth doing a bit of research on the web before buying any filters.
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i was going to mention this. I took some pictures a few years ago and they came out okay, but there was a centralised burn which seemed to be related to the aperture.
 
What is channel swap? I can't find it in LR, is it a Photoshop thing, what would I need to get these results?
 
The red and blue channels from the output image are swapped to render the skies blue again. LR doesn't have the facility but Irfanview (a good free program) can do it along with a host of others.

Bob
 
It's definitely worth the effort. My first few attempts with a Cokin filter on my Nikon D90 were absolutely hopeless, and didn't get better quickly! It took a year (of barely using it because I thought it was hopeless!) before I got usable results. These photo were taken with a Cokin filter, and though you can't see it, the bridge one does have a hotspot in the middle, which I corrected using a reversed centre filter in PS. (Handy hint for Cokin filters - you can reduce light leakage by sliding the filter into the extreme inside gap - it's not a slot, but it can take a filter if you sand off the bits that stick out at the top and bottom).

[url=https://flic.kr/p/ebheZv]Viaduct IR by Scotty Rae, on Flickr[/URL]

Neidpath Castle by Scotty Rae, on Flickr

Neidpath Castle by Scotty Rae, on Flickr


I moved on to a Hoya R72, which had it's own learning curve but gave far more predictable and cleaner results and was worth the investment!

[url=https://flic.kr/p/dUjZSH]Peebles 2012 033 by Scotty Rae, on Flickr[/URL]

and a rubbish false colour conversion with a corrected hotspot again
Devon landscape by Scotty Rae, on Flickr

Taking a photo on an unconverted camera requires patience and a workflow. You won't be able to see through the viewfinder, so you'll have to compose (and possibly set focus to manual once focused as AF might not work, although it always did for me), 30 second exposure at F9 would give a good exposure on a D90 in most weathers. Obviously that long an exposure will blur any moving object - great for clouds, rivers and getting rid of people! I really should have, but never set a custom white balance, and chose to do that in post processing. The problem is that Photoshop can't set a low enough white balance for IR, hence the fact I tend to convert to B&W rather than do false colour, however there are software tools (Nikon Capture for example) that will give you a low enough white balance, but it's then tricky to channel swap!) I always used to forget to cover the viewfinder - not a massive issue on the D90, but on the D7100 it will destroy a picture!

Hotspots are definitely lens dependent and probably aperture dependent - the Nikon 18-105 was pretty bad, the Sigma 10-20 is hopeless, the Nikon 18-200 is awesome, as is the 70-300, etc.

Last year I decided that IR was my "thing" so converted my D90 to IR 720nm permanently, and upgraded to a D7100 for my normal work. Again, what a difference! No setup, no long exposures, being able to compose using the viewfinder, instant results, white balanced camera (although I still can't use Photoshop to do false colour as it doesn't recognise the custom WB as it's too low! but then I'm happy with B&W)

[url=https://flic.kr/p/g9v4F7]Coniston Sunset in Infrared by Scotty Rae, on Flickr[/URL]

[url=https://flic.kr/p/f4HynH]Edinburgh Castle by Scotty Rae, on Flickr[/URL]

More on my Flickr stream.
 
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Canon Bob said:
The red and blue channels from the output image are swapped to render the skies blue again. LR doesn't have the facility but Irfanview (a good free program) can do it along with a host of others.

Bob
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Thanks for the info but I'm wary of downloads after thae last one I tried installed some annoying toolbars and search engines so I think I'll take a rain check on that. Thanks anyway. :)
 
James Blonde said:
Taking a photo on an unconverted camera requires patience and a workflow. You won't be able to see through the viewfinder, so you'll have to compose (and possibly set focus to manual once focused as AF might not work, although it always did for me), 30 second exposure at F9 would give a good exposure on a D90 in most weathers.
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Not true on a Fuji CSC, with the EVF or rear LCD you can see/preview a picture (and more importantly histogram), even with long exposures.
 
I'm jealous! Well, I would have been if I hadn't converted! ;) Is it dark, or are you getting a decent image to work from? Sounds like an ideal IR camera straight out the box!

The D90 wasn't a great camera for filtered IR as it had a strong IR filter on it. The D70 seems to be the legendary IR SLR
 
Wow, that's more than usable! I really like shooting handheld I have to say, although all the patience I'd learned through having to shoot long exposures seems to have vanished, and I miss the long exposure effects a bit. Alas my other half has no patience at all, so won't wait for me to set up for long exposures any more!
 
Scott, who did your IR conversion on your DSLR? I have an old D70 which I could get converted if it's cheap enough!

Mr Perceptive, which Fuji is/are those image(s) from? And what filter did you use?
 
There are / were only 2 places in the UK that did / do conversion - I had mines converted at Protech. It was sent and back within the week and service was excellent! I can't talk for ACS, but I seem to recall the prices were much of a muchness, so it was 6 and half a dozen as to where I sent it.

http://www.protechrepairs.co.uk/infrared_conversion.html

Nikon D70 conversion is £210 which is ripe for conversion, or £250 for anything other than full frame.

If you're brave, there is a D70 conversion tutorial online somewhere! Do it all for the price of a filter! (or a ruined camera...! :P)
 
I'm not that brave (or foolish! I know my limits). I might just keep my eyes open for a converted one. Thanks for the info and link, will file for future reference.
 
Thanks for that. Might have to get hold of an R72...
 
Since James mentioned ACS, I'll speak up for them doing the conversion - they modded my EOS600D and did a cracking job. Speaking of filters I tend to find my R72 softens the image. My B+W 093 (which is longer wavelength so you lose the colour response) is sharper. ACS put a 665nm filter in to replace the IR blocker they took out and I generally just rely on that now if I want "colour" infrared.
 
I've got two Protech converted 5DMkII's and can confirm that their service is excellent.

Bob
 
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