Photography 101 - A Primer on the TLAs and Terms
The CameraSLR - Single Lens Reflex camera. Throw a small "d" in front of that to make it digital. Yes, I know, bucking the "i" trend, but the digital camera was first. At any rate, an SLR is generally defined to be a camera that has interchangeable lenses, a mirror (the reflex in the camera), and usually an optical viewfinder. As you might guess, if there's a need to specify the quantity of lenses, there are twin lens cameras, from the dusty past, but that's where they remain.
P&S - Point and Shoot. Basically, these are your typical digi-cams. The camera does not have interchangeable parts, it's basic idea is you point and then press the button and the camera does much of the work. Various P&S camera offer varying degrees of manual control, but by and large they don't offer what the SLR offers in this realm.
EVIL - Electronic Viewfinder, Interchangeable Lens. Now, this is not an official acronym, but you will see it a lot out there. An EVIL camera is v ery close to being an SLR, but as a result of the electronic viewfinder, it does not need to have a mirror. You'll often see them referred to as mirrorless as well.
There are more, but these are the consumer oriented options out there. I'll venture into the pros and cons of these options in a later posting, but suffice to say that terms like "better" are really situational when it comes to these options.
The SensorThe sensor in modern cameras replaces the film we traditionally used, so it really is the true heart of the system. The sensor comes in a variety of sizes and some of them carry some letters to indicate what size they are. For many P&S cameras, the sensor sizes are quite small and generally only the dimensions are given.
APS-C - You may also see APS-H, but in any event, the APS stands for "Advanced Photo System" and the following letter designates the type which, generally, means the size. In fact, the letter designations map to the classic film sizes, roughly, of the APS system from Kodak. So for you old film types that know these sizes, it's basically the same.
MFT - Micro Four Thirds. This is a small sensor, often found in EVIL cameras, with an aspect ratio of 4:3. Traditional 35mm film is a 3:2 aspect ratio.
FF - Full frame. This means that the sensor is the same size as traditional 35mm film. Cameras with this sensor format are usually quite expensive and primarily aimed at the professional market.
MF - Medium format. Any sensor size larger than 35mm. There are a lot of variations in size, but they all share a mighty big price tag! Anyways, these big beasts are often found in professional studios or in the hands of professional landscape photographers.
File Formats and Their PartsRAW - Okay, this isn't really an acronym, it's just a big bucket for all of the various camera formats for capturing the actual raw data from the sensor, unprocessed. Pentax, for example, offers a couple of formats for raw and other camera makers usually have their own proprietary formats as well.
JPEG - Joint Photographic Experts Group. Basically, a standardized, compressible (data is lost on compression, hence the term "lossy" you may see) image format. This is, far and away, the most common format to view images. Even if you shoot in raw, you'll very likely convert the end result to JPEG at some point if you intend to share it with family or post online.
DNG - Digital Negative. This is an Adobe promoted standard for raw image storage that isn't camera specific. Most cameras don't save to this format, Pentax is a rare exception, but many will convert to it in post-processing using various software tools.
EXIF - EXchangeable Image File is a standard for embedding informational data in photographic images. For example, your camera will record the shutter speed, the aperture, the ISO setting, etc. in the image amongst other things. More importantly, it will record the date/time of the image, so turn off the function that puts that value into your visible shot!
The LensesSome cameras support different lenses, some have the lens integrated into the camera. Regardless of that, they share some common terms:
Zoom - These are lenses that have a range for their focal length. For example, a common lens for new SLR buyers is an 18-50mm zoom lens. Most P&S cameras have an integrated zoom lens, but be careful when looking at the marketing noise on the box because they often give the zoom range as a multiplier rather than as a range. For example, a P&S camera may be listed with a 10x optical zoom, but that can me 10-100mm or 50-500mm, that multiplier is just the ratio between the widest and longest focal length on the lens and tells you almost nothing.
Prime - These are lenses with a fixed focal length. For example, a 50mm prime lens was once very commonly sold as a standard lens for an SLR as the focal length approximated the same field of view as human eyes. At any rate, why buy a prime lens? After all, isn't a zoom more flexible? Well, the biggest reason is usually quality and "speed" of the lens. Prime lenses, by virtue of being fixed, have simpler optics in them which reduces light loss and abberations. Bear in mind that the material (which is not really glass anymore) does not transmit 100% of the light, so the more glass in the lens, the less light you get. Also, because they're simpler, they often have wider apertures which allow them to perform better in low light. Now, there are professional grade zoom lenses that approach prime lenses in quality, but you will pay serious money for them.
Stabilization - Many camera/lens makers offer stabilization on the lens. Not all do, Pentax has stabilization in the camera body, but Nikon and Canon have it in the lens. As a general rule, stabilization can give you the ability to push down the shutter speed in low light or give you extra support for very long telephoto. As a general rule of thumb, if your shutter speed is slower than 1/f, where f is the focal length of the lens, you should use a tripod, but you can extend that by up to 4 times with stabilization. So, which is better: on lens or in body? Neither, both have their advantages. For on the lens it means that your image is stabilized in the viewfinder, a real plus when shooting wildlife with a long lens, but you pay for it with each lens purchased. For in the body, it means that every lens you own is stabilized, including old manual lenses, but you don't see it in an optical viewfinder.