Okay, I have a digital camera converted to capture infrared light. I’m ready to go out and shoot pictures, right? My camera is ready–Is my lens?
Light is bent when it passes through transparent materials such as air, water, and glass. However, different colors (wavelengths of light) may not bend at the same degree so water droplets and prisms make rainbows by spreading out the mix of frequencies of light at different degrees. A lens bends this composite of colored light towards its focal plane, our camera sensor or film. It is shaped and coated with materials that eliminate the spreading out by different colors of light.
My subject is in focus–what’s the big deal about infrared light? Camera lenses focus the visible spectrum. Some lenses also bring infrared to the same focus as visible light. Others don’t do as well and may produce a hot spot on the image.
Compared to pro lenses, a kit lens may not be able to produce as sharp an image in the visible spectrum, but may focus infrared frequencies more accurately. Look here to read a list of some lenses which have been tested for infrared photography.
Yesterday, I put my old Polaroid SX-70 camera to use with a pack of Impossible Black and White instant film. The irony is that instant photography takes more time per capture than digital cameras do when I count shielding the film from light for a few minutes while it develops and the capacity of my digital camera to make bracketed shots with one click of the shutter realease button or bursts of several shots in sequence.
I feel differently working with analog media in photography. Shooting film feels more connected to mother earth. The tools are physical objects functioning in mechanical actions inside my camera: opening and closing shutters, advancing roll film, ejecting instant film. I have a wider selection of actions to perform as well: loading and unloading film, developing prints with chemistry (or waiting while instant film chemistry works its magic), pulling integral instant prints from a camera and shielding them from light, pulling, peeling, and waiting for Polaroid Land camera film to develop, etc.
Repeatedly, new inventions have provided quicker, less physically demanding tools and methods to get clean clothes, clean dishes, hot food, transportation for school, work, vacation, or family, and photographs! While it is easier to do more and more things, however, we’ve lost the down time that slower processes give us. In a way, every job is easier, but our lives are harder as we fit more and more tasks into our days.
Analog photography is one step back into the past that I can actually take. “You can’t turn back the clock,” the saying goes; but I can with my film cameras go back to a slower paced time, taking time to watch the seconds tick away while physical processes unfold into photographic images.
I’ve learned not to think when I run out with my camera to take some pictures. I may have a feeling about a place, a time of day, a sense of perfection or ruin in mind, but I am looking in my camera for something that just feels right. When I began as a photographer I had to think until I mastered operating my camera controls, which were all manual. Unfortunately, that habit of thinking about every shot really inhibited my shooting; and I took forever to expose a roll of film.
I was over my hesitancy when my enthusiasm for photography was reignited in 2000 or so when I accepted warm invitations from Randi Laak, then an instructor at the Worcester Center for Crafts, to enroll in his Friday evening photography class. I freely experimented with exposures, films, darkroom chemistry and processes as I had not when I started out.
Together with the freedom in the darkroom (And now in Photoshop), the history of photography of which I had learned as a beginning photographer and witnessed in publications and exhibitions as time passed, and my love of many paintings, prints, sculptures, etc. at the Worcester Art Museum and elsewhere, I am endowed with feelings associated with these beautiful or provocative objects that are evoked, I believe, as I walk through the world. I think those feelings and associations are part of my feeling of “rightness” when something captures my eye.
The universe seems to notice that I take the time to stop and see things then once in a while shouts at me to stop and look at this!
Here’s one example of a landscape photograph of a scene of light penetrating a shadowy wild place for which I felt similarly to when I look at an 18th century painting by Alessandro Magnasco:
Sensitivity is defined by the International Organization for Standards (ISO) in its abstract thus:
“ISO 12232:2006 specifies the method for assigning and reporting ISO speed ratings, ISO speed latitude ratings, standard output sensitivity values, and recommended exposure index values, for digital still cameras. ISO 12232:2006 is applicable to both monochrome and colour digital still cameras.”
Long ago we used to call this the ASA, which was the similar method for determining film sensitivity from the American Standards Association.
The lower the ISO number is set the longer it takes to record an image; and the less noise appears in the image files; higher ISO’s make faster recordings of images with more noise. Camera image processors have improved noise reduction so I may select higher ISO settings with little noise in my image with recent digital camera models.
Click on images to view at full size for better comparison of noise levels in the two images.
Methods of noise reduction include blurring or smearing small artifacts, subtracting pixels based on another exposure, and so on. Perhaps some small details get lost in the process. Although, details may be recovered using the algorithms used in the camera image processor or post processing. Some pixels in the resulting image thus may be made by firmware or editing software rather than light.
In summary, I can apply three basic camera settings: aperture, time, and sensitivity to make creative choices such as sharpness, and blurred or frozen motion. I can compensate for the lighting; I can select high sensitivity for low light exposures, and low ISO settings for cleaner, more detailed images.
Making choices with these settings lets me capture how I see a thing and share it in a photograph.
Today, I want to talk about time. The duration of an exposure can be very short, very long or anywhere in-between. Cameras can be set for exposures of one thousandth of a second or less, or of many seconds or minutes.
Time, how long the shutter is open, or how long the sensor is recording can be set for a capture that is shorter, which will freeze action, and is handy for sports and fast moving subjects like children and race cars.
I can choose a longer exposure to blur objects as they move across the frame for an impression of speed, or to smooth moving surfaces like river rapids in which the water is a smooth clear or milky flowing substance over rocks.
With very long exposure times, electronic noise can get recorded in my image file as the camera circuitry builds up heat, and, especially if it had been low at the start, the battery could run out of charge.
There may be technical consequences to very short and very long shutter speeds that I want to bear in mind. Higher sensitivity (which I’ll write about in my next post) may be required to capture an image completely when I wish or need to make a very fast exposure.
Sometimes I understand the way one person says things better than others. So here in my words are a few comments about camera settings that may help us know our cameras better. Photo editing software may allow me to compensate for less than ideal exposures, but better results come with good initial captures.
Loosely defined, these settings are:
Aperture: The size of the lens opening relative to the distance from the sensor.
Time: How long the lens is open for light to pass, how long the sensor is recording.
Sensitivity: How long it will take for the sensor to record enough data for an image.
Today, I’ll discuss number one, the aperture. Aperture, the diameter of the opening for light, is expressed as an f-stop. The higher the f-number is; the smaller the opening. The f-number is equal to the distance from the aperture opening to the sensor divided by the diameter of the opening. If I had a gigantic camera with a one mile diameter opening that was sixteen miles from my gigantic sensor, my aperture would be f/16. Sixteen miles distance divided by one mile diameter is f/16. Fortunately, my camera is smaller, but because f-stops are ratios they work at any scale.
One impact of my choice of aperture is how much of my photo is sharply in focus. The smaller the aperture (higher f-stop), the greater percentage of the distance in my capture from foreground to background is sharply in focus. The larger the light opening (lower f-stop), the less depth of field is in focus. High f-stops are ideal for lots of sharp detail in my image, maybe for a landscape or architectural shot. Low f-stops allow for selective focus, so I can, for instance, take a portrait shot of someone where they are in focus, but the background is softly focussed.
Next time, I’ll take a look at time and sensitivity.
Bankruptcy and the ceasing of production of instant films by Polaroid could have left only Fujifilm as a producer of peal apart instant film for Land Cameras, but no integral instant films for classic Polaroid cameras. However, in 2008 The Impossible Project was conceived and funding was found to purchase the last Polaroid film manufacturing plant in the world.
Ten of the best former Polaroid employees were recruited to join in the effort to recreate film chemistry for SX-70, 600, and Spectra/Image cameras.By 2010 Impossible released its first black and white instant film, recreating instant film for Polaroid format cameras.
Today, it produces black & white and color integral films, 8×10 black & white film, and the Instant Lab, which works with black & white or color SX-70 or 600 films to make instant prints from smartphones and tablets; and it refurbishes classic Polaroid SX-70, 600, and Spectra/Image cameras.
The naming scheme for digital camera sensors is derived from old television camera sizes expressed as the diameter of the tube through which light enters to strike the sensor at the end of the tube. The sensor’s diagonal measurement is about one third less than that of the tv camera tube so camera sensor diagonal measurements are smaller than you might expect from their names.
Here are a few film and sensor dimensions, and their relative sizes compared to 35mm film and full frame digital sensors.
As I said in an earlier post, several years ago I resumed shooting and printing a lot. With some review at the Worcester Craft Center I went back out with my cameras and into the darkroom with less pain and more joy than ever. I changed formats from 35mm to 645 medium format when I bought a used Bronica ETRS.
There are parallels in digital photography. Point and shoots in general make nice images fairly automatically; that’s a big selling point for them. However, trying to edit nice looking images for fine art prints is not always successful.
A combination of factors may account for this. if we say a pixel on a camera sensor and a grain of silver on a negative are equivalent, 20MP or more is approximately equivalent to the resolution of a 35mm film negative. The size of a small camera sensor in a low price camera might be 1/2.5″ or smaller; that is about 2 percent as big as a 35mm negative. The electronic noise that leaks from all those pixels on a small surface area can be thought to be equivalent to grainy film.
Film as a rule records a wider dynamic range of tones than a camera sensor. More contrasty imagery with detail and texture in both shadow and bright zones was possible in a single click of the shutter with film. Electronic noise has been suppressed or reduced in successive generations of digital cameras; and dynamic range has improved–greatly improved in HDR captures which combine multiple exposures for dark and bright regions in the frame.
Another consideration is the file format in which a digital camera saves its image capture. Many point and shoot and fixed lens cameras save in a lossy compressed format called JPEG. In simplified terms, the file is saved in a smaller space by first applying all the optional and automatic camera settings, and then tossing out other data that the sensor recorded but is not required for the picture. It’s like we made a print, and threw out the negative. We can still make some editing choices, but not as many.
The situation may be remedied in the digital world with the right choices. Get a larger format camera. Cameras have been manufactured to utilize many sizes and formats of film from 8mm x 10.5mm frames on disc camera film to 8″ x 10″ large format cameras and even bigger ultra-large formats. In the digital market, point and shoot and fixed lens camera sensor sizes range from say 2 percent to 100 percent the size of one frame on a roll of 35mm film. Their prices range around $80 to $2700 roughly in parallel with sensor size. Lower priced, higher sales volume cameras benefit from economies of scale; higher priced, lower sales volume cameras benefit from better build quality, more durable components, and superior optics.
We get the equivalent to a film negative in cameras that are capable of saving images in camera raw format. Everything the camera sensor recorded gets saved in raw. Some fixed lens cameras have this feature, but many only save in a compressed format such as JPEG. I’ll work up a selected list of camera sensor sizes and post it next time; and another list of selected fixed lens cameras that feature raw capability after that.
When I was a kid, somewhere in high school, I probably thought sixty-somethings were from prehistoric times; I also bought my first serious camera, a Mamiya-Sekor DTL 2000(?) 35mm SLR (Mamiya only makes medium format nowadays)–on lay-away from Denholm & McKay. Before recorded history cities mostly had local department stores; and Macy’s was in New York–you had to go there to go to Macy’s. My best friend got a Nikkormat. That was Nikon’s economy brand–a solid, quality SLR none the less. I usually tell people I have been a photographer since about 1973, the year I began learning to work in the darkroom, but that’s just a convenient time to label as my beginning.
It was a step up from a long growing interest. I enrolled in a continuing ed course in black & white photography at the Worcester Art Museum (worcesterart.org) for two semesters. Dennis Wixted was a patient, encouraging, and thorough teacher who, in addition to technique, taught photography’s history and the contempory scene. At his wake I was just one of many who shared their appreciation of his teaching and friendship with members of his family. I labored with the camera to do assignments and take personal shots, thinking about the camera settings, the light, the film… I think I thought more than I shot. It was a job for me to expose all the frames on a roll of film. Eventually, I started buying 24 exposure rolls of 35mm film, 36 exposures being the other common packaging, a little less challenging to finish.
For most of my later film photography before I changed to primarily digital cameras I used a Bronica ETRS. Here’s one of my images from that camera. The maple trees in the background were at the height of their blazing orange autumn foliage. I used an orange filter on the front of my lens to brighten the leaves that were in full sun to nearly white in my print.
Next time I go over to the dark side and start using digital cameras. Eveything is the same if you think about it.
Imagery, and Information and Opinion About Photography