Zoom in photography is a term applied to lenses. We’re familiar with the affect of zoom lenses because we use the phrase “zoom in” in regular daily banter. Zoom in means get closer, but how does that work?
We have learned that lenses with longer focal lengths (telephoto lenses) are able to make the image larger to create the effect of getting closer, where as lenses with shorter focal lengths (wide angle lenses) make objects seem more distant.
What a zoom lens does is allow the focal length of a single lens to be changed allowing the photographer to choose how large the subject of the photo will be in the frame. This in turn allows the photographer a great deal of control on the composition of their final photograph.
Yellowing. Those old prints you’ve kept for all those years might look a little yellow now. I know from personal experience that the prints I made in my high school’s dark room have definitely yellowed.
The yellowing, at least with respect to my high school prints, is the result of being a little impatient during the printing process.
There are several steps to printing and developing photos.
Once the photographic paper is exposed to the negative there are four chemical steps to develop the image.
First, the DEVELOPER. The image appears on the paper as chemical reactions darken the emulsion that was exposed to light.
The developing will continue until it’s stopped with the STOP bath. Without stopping, the entire paper will go black.
Even after stopping, the paper continues to react, so the image needs to be fixed with the FIXER bath. I had plenty of photos I didn’t fix well enough that gradually faded to gray.
But the last step is the one that prevents yellowing in the long term. The WATER rinse. If the print isn’t washed well enough, the leftover fixer will cause yellowing on the print.
And thus I came up with a Y word related to photography. Whew!
X-rays are part of the electromagnetic spectrum, which includes light. X-rays are invisible, but behave like the light we’re familiar with. We use X-rays in medicine because X-rays can pass through soft tissues like skin and muscles, but are stopped by dense materials like bones.
We can use photosensitive films, therefore, to take pictures of bones in the body without needing to do surgery by shining X-rays through the body and seeing what part of the film gets exposed.
X-rays are dangerous, though, which is why we don’t have X-ray units in our homes. They are of even higher energy than UV light (which we already know can cause burns), and without care can result in cancers.
Wide angle is a term applied to lenses that can capture an image over a large area in a single shot.
A wide angle lens is essentially the opposite of the Telephoto lens. Telephoto lenses work by increasing the focal length (the distance between the front of the lens and the film) to capture objects far away. Wide angle lenses work by decreasing the focal length and bringing the lenses closer to the film.
An extreme example of a wide angle lens is the ‘fisheye’ lens.
Wide angle lenses are great for photographing landscapes and architecture, and can also be used for some fun effects.
The viewfinder is the window (or sometimes just a wire frame) attached to a camera that is used to frame the part of the scene that the photographer is trying to capture.
For most point-and-shoot cameras, the viewfinder is near the top of the camera close to the lens. The image seen in the viewfinder is not exactly the same as what will actually be captured on the film. Thus, it can be important to make sure the subject you’re interested in photographing is somewhere near the center of the viewfinder’s view.
With single-lens-reflex (SLR) cameras , the image that’s seen through the viewfinder is the exact same one that will be captured onto the film (or onto the CCD [the electronic ‘film’] in the case of digital SLR cameras) .
Many modern digital cameras including your phone lack a viewfinder, and instead show the image that’s being captured by the CCD on a digital screen.
UV stands for ultraviolet, which is part of the spectrum of light which is invisible to humans but will cause you a dandy sunburn. UV light is very high energy (hence the burns) and will cause film to be exposed even though we can’t see it.
The UV filter removes UV light from the light entering the camera, which provides more control over the exposure of the film and improves the focus.
UV filters are also a good idea to simply keep on your camera because they also protect the camera’s lens from dust and other things that can obscure the image or damage the lens. It is far cheaper to replace a UV filter than it is to replace a lens.
Telephoto… It’s a term that maybe you’ve heard before. If not, we can take it apart and figure out what it means.
The ‘tele’ part is the same root as telephone, television, and telescope. In all cases, it refers to accessing something far away: telephone, hearing something that’s far away; television, watching something that’s far away; telescope, seeing something that’s far away.
Telephoto means then, perhaps, taking a picture of something far away.
And that is pretty much what it is, for practical purposes.
Telephoto is often applied as an adjective to ‘lens.’ A telephoto lens lets you see and take a photo of something that is a great distance away.
For technical purposes, it’s a little more complex.
You see, a lens with a long focal length (a common one is 500mm) allows the lens to greatly enlarge the image before it. But the lens then has to be 500mm long, or half a meter (and for those of us most comfortable with Imperial units, that’s like a foot and a half). That would be unwieldy, though such lenses do exist and called long-focus lenses. This would be essentially sticking a telescope onto the front of your camera (which can be done and is a lot of fun).
A proper and true ‘telephoto’ lens is one that has two sets of lenses inside that permits the lens to effectively have a long (like 500mm) focal length, but be practically much much shorter.
Such a lens may be used for sporting events, where cameras must be tucked at the edges of a stadium but need to be able to fill the screen with one or two players. Or a telephoto may be used for wildlife photography, when getting close enough to take a photo with a regular lens would either frighten off an animal or put the photographer in grave danger.
The downside to the telephoto lens versus a long-focus lens is that the two sets of lenses results in a loss of light entering the camera. This means that telephoto lenses can perform poorly under low-light conditions and is something important to think about when trying to find the ‘perfect’ telephoto lens.
This is one of the most handy things you can keep in mind if you have an old, fully manual camera.
Sunny 16 means that on a sunny day, if you set your aperture to f/16 and your shutter speed to 1/ISO, you’re likely to have the perfect exposure.
So if you’ve put ISO 200 film into your camera and you go outside to photograph flowers on a sunny day, you can set your shutter to 1/200 and your f-stop to 16, you will get good pictures.
What if you don’t want to use that shutter speed? Say you want to use 1/100 or 1/400 instead of 1/200. In this case, you adjust the f-stop one step in the opposite direction for each step in shutter speed change. So if sunny 16 says f/16 at 1/200, you can also use f/11 at 1/100, or f/22 at 1/400
What if it’s cloudy? Well, you’ll need more light. You can adjust the aperture or the shutter speed accordingly. You can open the aperture one or two stops (making the f-number smaller) or you can reduce the shutter speed.
Sunny 16 is a quick way to figure your exposure settings when your camera does not have automatic adjustments.
The shutter is the part of the camera the allows light in to expose the film. In early cameras, the film was not terribly sensitive to light, so the shutter could be as simple as removing the lens cap for a few seconds and then returning it.
Today, films are so sensitive to light that common shutter speeds are in fractions of a second, far too short for a person to time manually.
Standard shutter speeds found on modern cameras are typically in the following fractions of a second: 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000. Usually, the fraction is dropped, and they’re listed as 15, 30, 60, 125, 250, 500, and 1000 on a shutter speed selection dial.
Faster shutter speeds mean being able to freeze a moving object. With slower shutters, a moving object may be blurred. However, faster shutter speeds also mean less light getting to the film. This could be compensated for by opening the aperture wider. However, wider apertures (smaller f-stop) have reduced depth of field.
Thus, there is always a balance between shutter speed and aperture when the photographer wishes to capture fast motion or if they want a broad depth of field.
Another way to compensate for the reduced light of a fast shutter is to use film that is more sensitive to light (of higher ISO). However, more sensitive films often show more grain, so details of the object may be lost.
Understanding and utilizing these differences is among the many things that differentiate the amateur pleasure photographer and the professional photographer.
For a camera to take a clear photograph, the image must be focused. The way a camera is focused is by moving the lens (or components of the lens) forward and back. The final position of the lens that results in a focused image is dependent upon the distance that the subject is away from the camera.
With single-lens reflex cameras, it is possible to look through the lens and watch the image come into focus. But for older cameras it is necessary to know how far the subject is from the camera some other way and then adjust the lens accordingly.
One way to do this is with a rangefinder.
A rangefinder is a device with two windows at the front separated by an inch or more and one viewfinder at the back. The user looks through the viewfinder and sees images from both front windows superimposed upon each other, but typically not aligned.
The user then turns a dial until the two images line up correctly.
The dial adjusts the angle between the image, much as your two eyes will start to cross as you observe an object getting closer to your face. This angle is calibrated on the rangefinder to a specific distance away, and this distance can be read right off a dial on the rangefinder. Your brain also does this kind of calculation which is why you can tell about how far away something is when you look at it.
Once the distance is known, then the focus on the camera can be adjusted and the image will be clear.
Some rangefinders are built into the camera, so adjusting the rangefinder automatically adjusts the focus. Other times the rangefinder is an accessory that may attach to the camera by way of a shoe.