Photography Equipment/What should I get?

=It depends.=

If you're seriously interested in photography and just starting out, you are generally best served with a DSLR.

Other classes of camera are also worth considering, and may suit your desires better.

In more detail:

 * Compact Digitals: These are for casual photographers: "point & shoot"
 * If you don't want to dedicate much time or money, want a camera that fits in a pocket or purse, and just want to easily take photos to view on computers or small prints, compact digitals are ideal, and the choice of 100 million people per year. Conversely, they are generally of lower quality than more advanced cameras, and their automatic operation takes control of the image away from the photographer.


 * DSLRs: These are for serious photographers.
 * DSLRs are suitable for almost all purposes, can provide excellent quality (properly used), and are reasonably portable and affordable. Systems start from below $500 and they can be easily carried around. Over 5 million bodies are sold per year.


 * Medium Format or Large Format, (film): top quality, bulky and slow, film workflow
 * Medium Format, and especially Large Format cameras are capable of superb image quality. They have some severe limitations though, notably bulk and speed: the largest systems require a car or fit person to carry. Further, only the most expensive top-of-the line models have digital sensors. Most large cameras still use film, and hence the film process, which is both more technically demanding of the photographer and more expensive in production, due to the cost of film and processing.. If you are interested in photographing subjects suitable for such cameras, and don't mind or would enjoy working with film, you should definitely consider such a camera, though perhaps not as your first system.

Sensor size


The key reason that compact digitals are disdained by serious photographers is that the sensors are small. All else equal, a bigger sensor is better – the typical compact digital sensor size is 25 mm2, while the smallest DSLR sensors are 9 times bigger, more typically 13–15 times bigger, with the biggest DSLR sensors being over 34 times bigger. This results in a major difference in quality, but an increase in cost and size – bigger sensors are harder to make, and require bigger (and heavier) lenses.

The larger sensors in DSLRs provide very significant advantages in low-light sensitivity, dynamic range, and image noise.

With a few exceptions (discussed below), until recently large sensors were found only in DSLR cameras. Today, the professional market is diverging towards professional mirrorless cameras, which offer reduced bulk and weight at the price of an optical viewfinder. As with other features, whether this is a good bargain depends on individual preference.

Compact digitals
Compact digitals vary greatly in appearance, interface, and features, and substantially in price, but rather little in image quality. Specific models are hard to recommend because of the rapid replacement cycle in this category.

Biggest issues (beyond price) are generally portability (does it fit where you want to carry it?) and usability: does the interface work for you?

Auxiliary camera. Compact cameras are widely used and recommended as auxiliary cameras – a camera is no good if it's at home – and thus many photographers will carry around a pocket or purse-sized camera when not on a specifically photographic expedition.

Ignore pixel count. At these sensor sizes, higher pixels yield higher noise which swamp the higher resolution and instead yield worse image quality, not better.


 * The Best Digital Cameras, by Philip Greenspun

Recently a few compact cameras with large sensors have been released – these allow a camera that can fit in a pocket but can take DSLR-quality images, though compared to DSLRs they generally lack features and make other trade-offs. These include the Sigma DP1 and Sigma DP2, which featured a fixed lens, and an announced camera by Olympus in the Micro Fourth Thirds system, which features interchangeable lenses and a retro design.

These have caused some measure of excitement, as they allow high quality images in a camera that can easily be carried around, and thus are suited as an auxiliary camera for when one does not wish to carry around a DSLR.

Bridge cameras
Bridge cameras—cameras between compact digitals and DSLRs—form an amorphous category.

Usual meaning
They generally mean "a small sensor with a big lens" – thus a style similar to a DSLR, but with a small sensor and hence relatively poor image quality. By comparison with compact digitals, they have bigger and faster lenses, hence can take photographs in lower light and of moving objects, while by comparison with DSLRs the lenses are much easier to make, and hence are generally super-zoom.

These fill a niche which is increasingly small as the price of DSLRs has come down, and one is almost always better served by an entry level DSLR such as the Canon Rebel XTi/XSi or Nikon D40. Currently in the US entry DSLRs (with kit lens) retail for $375 (Nikon D40) to $600 (Canon Digital Rebel XSi), while bridge cameras are in the $250 to $400 range.

If quality is a concern, get an entry-level DSLR or large sensor non-DSLR (see below); if budget is a concern, get a compact digital and play to its strengths.

Large sensor non-DSLR
The "large sensor non-DSLR" class is an emerging class, consisting of cameras with large sensor (like entry-level DSLRs), but a smaller format. Several of these are in the Micro Four Thirds System, by Panasonic and Olympus, which features a Four Thirds size sensor and interchangeable lenses. There are currently two types:
 * High-quality compact
 * These are pocket-size (compact) cameras with a large sensor
 * Sigma DP1 & Sigma DP2 are available, and have a fixed (non-interchangeable) lens with a fixed focal length.
 * Olympus has also announced a camera in this class with interchangeable lenses and a retro design.
 * DSLR-style without viewfinder
 * These are similar in design and size to bridge cameras, but with large sensors: smaller bodies than DSLRs, and an electronic viewfinder (EVF)
 * Panasonic Lumix DMC-G1 & Panasonic Lumix DMC-GH1

High-quality compact cameras have generated some measure of excitement, as they finally provide a camera that takes quality photographs but fits in the pocket. These are limited in many ways compared to DSLRs (the Sigma DP1 & DP2 have fixed lenses with fixed focal length), but can function within their limits, and as auxiliary cameras.

Large sensor non-DSLRs fill a similar role to entry-level DSLRs, and are worth considering as alternatives – the lack of a pentaprism and mirror makes them significantly smaller and lighter, at the cost of not having an optical viewfinder. Further, there are very few cameras in this class.

DSLRs
As discussed at DSLRs, you are first buying a system, not a camera or body. Unless you find an other brand particularly compelling – and there are reasons to do so – you should get a Canon or Nikon body and some lenses.


 * Building a DSLR system, by Philip Greenspun

System
See Canon and Nikon for comparison between the systems; they are both excellent and high in quality. Try them both out to see if either particularly delights you, and consider how you expect to use your camera, and whether either brand has particular strengths or weaknesses. If you have trouble deciding, price up what you expect to buy on either system and choose one if it's substantially cheaper than the other. Otherwise, flip a coin: they're both good.

Body
Which body is mostly determined by budget: the more you spend, the higher quality and more features. Some issues:
 * weight: The largest DSLRs (like the 1Ds Mark III) are very heavy and bulky, which may bother you.
 * full-frame: Several top-end DSLRs (currently Canon 1Ds, 5D, and Nikon D3, D3X, D770 and Sony α 900) are full-frame. This is a substantially larger sensor and consequently yields much higher quality pictures; for some this is a sine qua non. However, this is more demanding on the lenses.
 * high-speed: If you wish to do professional sports photography, the Canon 1D and the Nikon D3 have much higher speeds than the others.

Lenses
In general, one begins with a standard lens, and subsequently buys lenses as necessary for particular subjects. See lenses for details.

As a standard lens, most commonly people use the zoom lens that is included with the DSLR body (called the kit lens). Indeed, many people use no other lenses, and thus reap relatively little of the flexibility benefits that a DSLR affords. Others decry this practice and suggest instead that one use a (prime) normal lens.

Kit lenses are not the highest quality zoom lenses, having low Image Quality and being slow (hence needed lots of light and not being capable of Depth of Field effects); they may be a good value though.

For a prime normal lens on a small sensor DSLR, the appropriate focal length is 50mm divided by the crop factor. For APS-C Canons (EF-S: Rebel, 20D/30D/40D), this is 1.6x, so a normal lens is 31.25mm, or about 30mm. For APS-C Nikons (DX), this is 1.5x, so a normal lens is 33 1/3mm.

Some common recommendations follow.
 * Canon Lenses Overview by Bob Atkins, especially for APS-C (Rebel, 20D/30D/40D)
 * General Purpose Canon Lenses (from The-Digital-Picture)

Sample professional collections:
 * Canon lenses
 * Nikon lenses

Canon
Photography Equipment/Lenses/Canon standard

Standard Zoom

 * kit lenses: Canon EF-S 18-55mm: considered very soft
 * Canon EF-S 17-55mm ($1,300) excellent general-purpose lens

Standard Prime

 * Sigma 30mm f/1.4 for Canon ($400)

Nikon
Photography Equipment/Lenses/Nikon standard

Standard Zoom

 * Kit
 * Nikkor 18-55mm (various versions)
 * Nikon 18-70mm f/3.5-4.5
 * Nikkor 28-105mm f/3.5-4.5, ~$325
 * Comparison of popular Nikon zoom lenses
 * Nikkor 28-115mm

Standard Prime

 * Sigma 30mm f/1.4 for Nikon ($400)

Medium Format and Large Format
Medium Format (MF) and Large Format (LF) are largely film cameras. Digital backs (bodies/sensors) exist, but are quite expensive and limited.

Film

 * Choosing a Medium Format Camera, by Philip Greenspun
 * Choosing a Large Format Camera, by Philip Greenspun

Digital
MF backs exist that are similar to DSLR sensors: a full sensor. These are extremely expensive, but can be rented.

LF backs are scanning backs: a sensor the size of a LF image would be prohibitively expensive, so instead one uses a row of sensors which scans across the image, with exposures measured in minutes. They are thus only suited for photography of static objects.