Infrared Digital Photography with an R72 Filter

Botanic Gardens in IR
Originally uploaded by jezza323

This shot is from me playing around with an IR 720nm filter. This type of filter blocks all light below the 720nm wavelength. This means some reds, and infrared are the only light which can pass through. By using 1 of these filters on your camera, you will get some interesting results.

Unfortunately most modern cameras have an IR reduction filter mounted to the front of the sensor, which means that blocking visible light will result in very long exposures being required. This particular shot was taken in broad daylight, at f11.0, ISO 200 and required a 30 second shutter speed! 30 secs in broad daylight is quite a lot. A typical exposure in this situation would be around about 1/400 sec!

The main features of IR photography are black skies, and white leaves on trees and grass. This results in cool contrasty shots where things are just a little different to the norm.

My Photography Gear

This is a full list of all my photography gear, I will try my best to keep it up to date as I buy and sell various things

Camera Body

• Pentax K200D
• Canon Powershot A590 IS (running CHDK software)

Pentax Lenses

• Pentax SMC DA 18-55mm AL II f3.5-5.6
• Pentax SMC A 50mm f1.7
• Pentax SMC M 50mm f1.7 (has fungus)
• Pentax SMC M 28mm f2.8
• Pentax SMC FA 100-300mm f4.7-5.8

Russian Lenses

• Mir 1 37mm f2.8 M42 - SOLD
• Helios 44-2 58mm f2.0 M42 - SOLD
• Jupiter 9 85mm f2.0 M42
• Tair 11-A 135mm f2.8 M42

Others

• Sigma 10-20mm f4.0-5.6 (enroute from ebay!)
• Tamron 17-50mm f2.8
• Hanimar 135mm f2.8 M42 (for sale)
• Soligor 135mm f3.5 M42 (for sale)
• Vivitar 135mm f3.5 M42 (for sale)
• Pentacon 30mm f3.5 M42 (for sale)
• Vivitar 35mm f3.5 M42 (loose rear elements, its my paper weight)

Lens Accessories

• Quantaray 2x AF Teleconverter (with Powerzoon contacts, may work with SDM - yet to be tested!)
• Vivitar Auto Teleconverter 2x-22 (allows wide open focusing but has no contacts and no autofocus) (for sale)
• Vivitar Auto Extension Tubes AT-22 (allows wide open focusing but has no contacts and no autofocus)
• 49mm Hoya 3 position rubber hood
• 58mm black metal hood - bought from ebay (for FA 100-300)
• Lens cleaning brush
• Lens Cleaning tissues
• Lens cleaning cloths (lots of these) - 3 packs are available from DealExtreme
• Giottos Rocket Blower Medium
• 67mm -> 77mm filter step up ring (allows 77mm filter on a 67mm threaded lens)

Lens Filters

• 49mm Cokin CPL
• 49mm UV x3 (came with various lenses)
• 49mm Blue
• 49mm Hoya Star Six
• 49mm Hoya Centre Spot (blurs out the edges, leaving only the centre of the image clear)
• 52mm Kenko MC CPL
• 52mm Hoya R72 Infrared
• 52mm Hoya NDX400 (9 stop ND filter)
• 52mm IR720 as mentioned here
• 52mm ND400 as mentioned here
• 62mm Kenko MC CPL (for sale)
• 62mm Kenko MC UV (for sale)
• 67mm Kenko PRO1 Digital Protector
• 67mm Kenko PRO1 Digital CPL (enroute)
• 77mm IR720 (enroute)
• 77mm Kenko MC CPL (enroute)

Cokin P Filters and Accessories

• Chinese copy 3 slot Cokin P holder
• 52mm adapter
• 49mm adapter
• TianYa ND8 filter
• TianYa ND8 grad filter (soft graduation)
• TianYa Sunset (orange grad) filter

Flashes and Accessories

• Sunpak Auto 200 flash (part of Dad's gear, unsafe for DSLR hot shoe mounting)
• Optical Trigger
• Hand made diffuser using cardboard, alfoil and plain white paper

Other Accessories

• Cable Release Remote - bought from DealExtreme
• IR Push Button Remote - bought from DealExtreme
• 3 axis hotshoe mounted bubble level - bought from DealExtreme
• Pentax D-BG3 battery grip for K200D

Tripod

• Slik 500 Pro DX w Head

Cheap ND400 filters Pt 2

Here we go, finally have a shot I can post from my cheap Ebay ND400 filter.

This shot was very underexposed. I allowed for about 9.5 stops of extra exposure (I use the PhotoBuddy app for the iPhone to work out exposures) but I would say this particular filter needs more like 11-12 stops extra. A Hoya ND400 filter is specified as a 9 stop filter. This shot has +4 stops of exposure in PP (Lightroom) and the colour cast is mostly corrected (but not totally) by adjusting the white balance. Here are the settings from lightroom and the shot. Its nothing special but it does display the problems with the colour, and obviously incorrect number of light stops filtered. As you can see I am at the limit of adjustment for white balance, but the photo still shows a slight purple cast. This means you will not get true colours from this filter.

IR72 Filter exposure issues

Along with my cheap ND400 I bought a cheap IR72 filter, again just to play with the effect more so than anything else. Again the filter is for my DA 18-55 AL II lens which I would like to replace in the future.

As some people may know, DSLRs have a filter in front of the sensor which blocks most of the IR wavelengths of light at upto 95% effectiveness. This means that when you go and place a filter in front which blocks all visible light below 720nm (like an IR72 filter) your required shutter speeds get VERY long.

Upon receiving my filter I went about taking some shots at ISO1600, 0.5sec, f4.5 handheld (got to love that Pentax Shake Reduction). What I found was that the images just came out like I had a red filter in front, not very IR at all. Today I finally got my tripod out and did some testing, I found to get a proper IR like image I needed to shoot at around ISO400, 30sec, f11 in broad daylight. The effect that you want from an IR filter is tree leaves and grass coming out white, while everything else is more like a black and white image (probably with a very red cast to it from the camera though!)

So here are some key points for shooting IR with a modern DSLR which has the sensor IR block filter still in place.

1. Shoot RAW - you will need to play with the white balance quite a lot to get a decent image. RAW also allows some give in exposure which means you dont have to get it exact (I am finding it hard to find the sweet spot).
2. Shoot in Manual mode - you will need to play with aperture, ISO and shutter speed to get a good exposure. The camera won't really know whats going on.
3. Go for LONG exposures - If the shots are not coming out how you expect (looking for grass and trees to have white leaves) don't be afraid to up the exposure some more, and then some more again! Remember I needed to go to 30 secs at ISO 400 to get the proper effect with my camera. Different cameras will have different filters on the sensors though, so play with your camera to find out what works for you.
4. Check your focus - AF should still work fine, however, it may shift slightly from what is the correct focus distance (due to light wavelengths). So make sure you check that the things you want in focus are actually in focus.
   

Cheap ND400 filters

I recently bought a cheap (very cheap) ND400 filter on Ebay for my DA 18-55 AL II lens. I picked the cheap option because I just wanted to play with the effect, but didnt want to spend lots on a filter for a lens I hope to replace soon.

Anyway, back to the point. Colour cast. This is where the quality difference really becomes apparent. The cheap filter produces a very pronounced purple cast. I havent tried to process any of the images yet, it is possible that setting the white balance can overcome the colour cast, but it should not be necessary.

Just another case of getting what you paid for I suppose! I will post some samples of pre and post processing soon.

UPDATE: Shots and details now available.