How To Buy A CAMERA - Part 1

Ah, the billion dollar question, how should I choose a Camera?

I almost thought about my first camera for five minutes and ended up buying an Olympus point and shoot, long back. Thought for my dSLR for a month and bought a Nikon. Over time I have realized few deciding factor which play a major role in buying camera. Let’s get to them.

Mirrorless vs. Compact: 

A mirrorless ILC is almost always a better choice than an advanced compact. Most of them have larger sensors (all but those from Nikon and Pentax). Even with respect to price they tend to be a better deal; you can find a decent ILC kit with an APS-C sensor, but a good compact with a smaller 1-inch sensor will run you about the same. The only two disadvantages an ILC (Interchangeable Lens Camera) has relative to a compact are size (though the lenses are small, they never retract into the body the way they do on a compact) and price for a good lens. Decent advanced compacts in high range have fast lenses, while the kit lenses that ship with an ILC tend to be slow f3.5-5.6 versions. On the other hand, you can start with the kit lens and upgrade to a better one when you can afford it, something you can't do with a fixed-lens model.

Mirrorless or dSLR: 

This is a bit trickier, though one rule of thumb is if you need good battery life or fast startup, stick with a dSLR -- those are the two standout weaknesses of mirrorless models, since they have more electronics. Additionally, if you're on a tight budget, cheap dSLRs tend to be cheaper than cheap mirrorless cameras. And if you're looking at the higher end, midrange-to-high end dSLRs still tend to be faster than higher-end mirrorless options.

On the flip side, mirrorless models are frequently as good or better for video than dSLRs. The best ones can do all the same things as a dSLR, but you can also view through the viewfinder while shooting, they support power zoom lenses and they're much smaller. And the less expensive mirrorless models tend to be better than their cheap dSLR equivalents.

Specifications to look for when buying a Camera:

Resolution:

Generally referred to in megapixels. This number tells you how many pixels the camera uses to produce an image. Every modern camera has more than enough for any need. That's why it's not important as a spec. In fact, watch out for cheap cameras with high resolutions -- they usually lack the processing power to deal with the large images, which can slow them down.

Lens:
There are two important specs relating to all lenses: aperture and focal length(s). The lens' focal length, measured in millimeters, conveys the magnification of the image and the amount of scene covered by the lens (called the angle of view). As focal length increases, things look bigger and take up more of the frame. A lens that covers multiple focal lengths is a zoom lens, and the zoom spec is the ratio of the longest to the shortest focal length: a 20-100mm lens, therefore, has a 5x zoom. A lens of a single focal length is called a prime lens, and very flat ones are usually referred to as pancake primes. Note that the focal lengths as imprinted on the lenses of compact cameras will not be the same as the reported focal lengths; they frequently don't reflect a multiplier that normalizes the length based on a frame of 35mm film, a reference point that adjusts for the multitude of sensor sizes in cameras. Sometimes called the crop factor, you really only need to think about it when looking at lenses for interchangeable-lens cameras. Ultra-wide-angle (less than 18mm) is good for very large scenes where lens distortion adds rather than detracts from the appeal.

Wide-angle (around 18mm to 30mm) is good for group shots, landscapes and street photography, as well as selfies and group shots. Normal (about 30mm to 70mm) is good for portraits and snapshots.

Telephoto (about 70mm to 300mm) is good for portraits, sports and arena photography. Super telephoto (greater than 300mm) is good for sports, wildlife and perhaps private detectives and Batman.

More on lens:

Aperture:
The aperture is the size of the opening that lets in light, alternatively referred to as an f-stop or f number. The lower the number the larger the aperture. The largest aperture usually varies over the zoom range; lens specs generally list the maximum aperture at the shortest and longest focal lengths. Thus, when the spec is listed as 18-55mm f3.5-5.6, that means the widest aperture is f3.5 at 18mm and f5.6 at 55mm. As aperture size increases, the area of sharpness in front of and behind the subject increases; area of sharpness is called depth of field. Since wider apertures let in more light and give you more control over depth of field, wider is better. A lens with a wide aperture is referred to as fast or bright and one with a narrow aperture is slow. Fast lenses are considered better than slow lenses; confusingly, "fast" and "slow" have nothing to do with focusing performance. Watch out for lenses that start wide but get narrow very quickly. For instance, with a 24-120mm f2-5.9 lens you don't want the maximum aperture to jump from f2 at 24mm to f5.9 at 28mm.

Sensor size and type:

Sensor size is the dimensions of the array of photoreceptors that create the pixels that become an image. Bigger sensors generally produce better photo quality, but the bigger the sensor the bigger the camera -- a larger sensor also requires a larger lens, more space for supporting electronics, and if the camera uses sensor-shift image stabilization, it requires an even larger footprint. Larger sensors are also more expensive to make, so the cameras are pricier.

Sensor sizes are usually indicated in one of two ways: actual dimensions in millimeters or with labels such as "1/1.7-inch." The latter is an old convention from the early days of digital video, and don't represent actual sizes; 1/1.7 inch isn't equal to 0.59 inch, for example. However, they are accurate in a relative sense -- in other words, 1/1.7-inch is smaller than 2/3-inch, for example.

There are a few primary sensor technologies. CMOS is the most popular. A variant, BSI (backside illuminated) CMOS, is popular for compact cameras because it allows greater low-light sensitivity on a relatively small sensor. There are some manufacturer-specific variations of these as well, usually with different arrangements of the on-chipcolor filter array (CFA), which separates the incoming light into red, green and blue primaries that later get recombined to form the colors in the image. The most common CFA is the Bayer array; some CFAs have extra green-capturing sites (because green carries the most detail information -- it's a human eye thing), such as Fujifilm's X-Trans, and Sigma's Foveon-based technology stacks the filters so that each pixel processes each color primary.

Cheaper point-and-shoots still use CCD (charge-coupled device) sensor technology. Inexpensive CCDs don't deliver photo quality as nice as pricier CMOS sensors, but conversely, expensive CCDs like those used in medium-format cameras produce better photos. In general, CCDs are slow and poor for video.

Light sensitivity:
A camera's sensitivity to light is dubbed ISO sensitivity; the higher the number, the better the camera is capable of shooting in low light. However, as sensitivity rises so does the amount of noise -- those colored speckles you see in night shots. Cameras perform noise suppression to try to eliminate it, but that can result in smeary-looking artifacts. As a result, few cameras perform usably at the top of their rated ISO sensitivity ranges, making an unreliable spec. If you take it with a big grain of salt you can usually guess at the maximum usable sensitivity; for instance, a camera rated up to ISO 6400 will probably produce decent images up to ISO 800.

Viewfinder:
While most consumer cameras these days have eliminated a viewfinder altogether, more advanced models still have them. They're useful when it's hard to read an LCD in sunlight, and holding the camera up to your eye forces you into a more stable body position for shooting. There are basically three types of viewfinders: the type that used to be found on film point-and-shoots which gives you a direct view of the scene rather than a through-the-lens (TTL) view called a reverse Galilean; an electronic viewfinder or EVF; and the TTL optical viewfinder found on dSLRs.

EVFs have an advantage when shooting video, as you can't simultaneously view and record video using an optical viewfinder, plus they can simulate what the photo will look like. On the other hand, optical viewfinders are better for shooting action, though they have a tiny blackout period between shots as the mirror flips up and down; an EVF can only show you the action once it's already happened, not while it's in progress. Some EVFs are better than others for this, however. Important viewfinder specs are percentage coverage, or how much of the scene they can display -- 100 percent is best, obviously -- and effective magnification, which tells you how big the image looks in the viewfinder. A good viewfinder will also have a diopter adjustment, to fine-tune the viewfinder focus for your vision or for glasses wearers.