COVERING OUR TRACKS January 2007
by John
Mantzefield
Copyright 2007
Prior
to buying my Nikon 990 digital camera a few years ago
all of my photographs were shot on 120 roll film and
35mm. During those days of chemical based photography I
also shot a few roles of 35mm infrared film. To shoot
that type of film you had to place a very dark red
Kodak Wratten Gel filter (now sold by Tiffen.com) on
the lens. It blocks visible light and allow only
infrared light to expose the ASA/ISO 50 film.
CAMERAS
AND FILTERS
This months cover was shot with a Nikon 8400 8Mp digital camera with a BW brand 093 (87C) infrared filter attached as illustrated in the picture to the left. This brand of grass filters and the step-up rings are available at bhphotovideo.com. The 8400 has a fixed lens, but auxiliary lens (wide angle & telephoto) can be used by attaching them with Nikon’s metal lens mounting tubes as shown in the picture at “A”. The tube screws onto the camera body at “D”, and to mount the filter I needed to add a 52MM to 58mm step-up ring (at “B”) which supports the IR filter at “C”. Cameras of this type have telescoping lens that move out of the camera body and usually can not have filters attached directly onto the lens. If filters can be used, as in the case of the 8400, they will be limited to the type that Nikon offered like their skylight filter. To overcome this problem I ordered the lens mounting tube hoping that it’s thread size would be close enough to allow a standard step-up ring to be attached. Nikon didn’t give specifications about the tubes size, but fortunately the threaded end measured about 51.75 millimeters, which allowed me to attach any 52 millimeter filter or adapter ring.
SHOOTING/EDITING INFRARED
To shoot the cover photo the camera was mounted on a tripod because long exposure times of several seconds are required. The dark red infrared filter is so dense that it blocks almost all visible light and so the long exposure times are necessary to shoot a picture even in a bright sunlit scene. When long exposures like this are taken with a digital camera it produces significant amounts of noise in the image. Noise in a digital image looks somewhat like grain in a photographic negative. The digital noise was filtered out of the upper half of the cover photo by using a Photoshop Plug-in called Noise Ninja 2.1.3 from Picturecode.com. After copying the cover image onto an additional Layer, Layer Masks were painted across the center of both Layers in the scene where the tree line meets the sky - this allowed me to make separate Levels (Image>Adjustments>Levels) adjustments and to run Noise Ninja on the top half of the image.
This months cover was shot with a Nikon 8400 8Mp digital camera with a BW brand 093 (87C) infrared filter attached as illustrated in the picture to the left. This brand of grass filters and the step-up rings are available at bhphotovideo.com. The 8400 has a fixed lens, but auxiliary lens (wide angle & telephoto) can be used by attaching them with Nikon’s metal lens mounting tubes as shown in the picture at “A”. The tube screws onto the camera body at “D”, and to mount the filter I needed to add a 52MM to 58mm step-up ring (at “B”) which supports the IR filter at “C”. Cameras of this type have telescoping lens that move out of the camera body and usually can not have filters attached directly onto the lens. If filters can be used, as in the case of the 8400, they will be limited to the type that Nikon offered like their skylight filter. To overcome this problem I ordered the lens mounting tube hoping that it’s thread size would be close enough to allow a standard step-up ring to be attached. Nikon didn’t give specifications about the tubes size, but fortunately the threaded end measured about 51.75 millimeters, which allowed me to attach any 52 millimeter filter or adapter ring.
SHOOTING/EDITING INFRARED
To shoot the cover photo the camera was mounted on a tripod because long exposure times of several seconds are required. The dark red infrared filter is so dense that it blocks almost all visible light and so the long exposure times are necessary to shoot a picture even in a bright sunlit scene. When long exposures like this are taken with a digital camera it produces significant amounts of noise in the image. Noise in a digital image looks somewhat like grain in a photographic negative. The digital noise was filtered out of the upper half of the cover photo by using a Photoshop Plug-in called Noise Ninja 2.1.3 from Picturecode.com. After copying the cover image onto an additional Layer, Layer Masks were painted across the center of both Layers in the scene where the tree line meets the sky - this allowed me to make separate Levels (Image>Adjustments>Levels) adjustments and to run Noise Ninja on the top half of the image.
CAN YOUR CAMERA SHOOT IR
Many digital cameras can be used to shoot infrared photos and here’s an easy way to test yours to see if it will see this portion of the light spectrum. You’ll need an infrared type TV or other home entertainment center remote control. Set your camera to shot in it’s black and white mode and then in a dark room hold the remote about a foot or two away from the camera lens and press any button on the remote. You should see a small white spot (the remote’s growing infrared bulb) on the cameras LCD screen. Most digital cameras will capture infrared images, although some have lens coatings (or an IR blocking filter over the CCD/CMOS sensor) that will block some or all infrared light. My Nikon 990 has this type of lens coating, and so it could not be used for full spectrum infrared photography. The filter I use on that camera is a BW brand 092 which is much less dense then the 093 noted above. Even with it’s limited infrared sensitivity the 990 still shoots really nice infrared shots, but the sky isn’t quite as dark and the clouds are not quite as bright.
WORKING
WITH IR PHOTOS
Properly exposed infrared shots taken with a digital camera look very dark on the cameras LCD screen and in Photoshop as you can see in the image to the left. This occurs because infrared photos (film or digital) are very low in contrast, and must be enhanced and manipulated in Photoshop to create an image like you see on this months cover. The histogram graph below the “Camera Original” in the image was copied from Photoshop’s Levels dialog box and show how all of the pixels in the image are in the black to dark gray region. The “Levels Adjusted” histogram to the left shows how the images tonal range has been expanded by clicking the “Auto” button in Image>Adjustments>Levels and then dragging the center gray colored Middle Tones slider (below the histogram) until I got an image with a full tonal range.
FINAL NOTES
One of the beautiful elements of infrared landscape photographs is the elevated contrast levels you get in light colored foliage and clouds. Trees with dark green foliage like Fir trees don’t reflect enough infrared light to appear any different than you would see them in a standard photo. Grass or other light colored ground foliage, and anything else that reflects IR like light colored skin tones, cloths or animal fir will yield this contrasty IR effect. Keeping these factors in mind will help you to predict what type of scenes will be suitable for IR photography.
Many digital cameras can be used to shoot infrared photos and here’s an easy way to test yours to see if it will see this portion of the light spectrum. You’ll need an infrared type TV or other home entertainment center remote control. Set your camera to shot in it’s black and white mode and then in a dark room hold the remote about a foot or two away from the camera lens and press any button on the remote. You should see a small white spot (the remote’s growing infrared bulb) on the cameras LCD screen. Most digital cameras will capture infrared images, although some have lens coatings (or an IR blocking filter over the CCD/CMOS sensor) that will block some or all infrared light. My Nikon 990 has this type of lens coating, and so it could not be used for full spectrum infrared photography. The filter I use on that camera is a BW brand 092 which is much less dense then the 093 noted above. Even with it’s limited infrared sensitivity the 990 still shoots really nice infrared shots, but the sky isn’t quite as dark and the clouds are not quite as bright.
Properly exposed infrared shots taken with a digital camera look very dark on the cameras LCD screen and in Photoshop as you can see in the image to the left. This occurs because infrared photos (film or digital) are very low in contrast, and must be enhanced and manipulated in Photoshop to create an image like you see on this months cover. The histogram graph below the “Camera Original” in the image was copied from Photoshop’s Levels dialog box and show how all of the pixels in the image are in the black to dark gray region. The “Levels Adjusted” histogram to the left shows how the images tonal range has been expanded by clicking the “Auto” button in Image>Adjustments>Levels and then dragging the center gray colored Middle Tones slider (below the histogram) until I got an image with a full tonal range.
FINAL NOTES
One of the beautiful elements of infrared landscape photographs is the elevated contrast levels you get in light colored foliage and clouds. Trees with dark green foliage like Fir trees don’t reflect enough infrared light to appear any different than you would see them in a standard photo. Grass or other light colored ground foliage, and anything else that reflects IR like light colored skin tones, cloths or animal fir will yield this contrasty IR effect. Keeping these factors in mind will help you to predict what type of scenes will be suitable for IR photography.
