Megapixels don’t matter

Thinking of buying a new camera? Do yourself a favor and stop thinking that megapixels matter.

Think I’m being hasty? Just ask yourself what’s the largest you’re ever going to actually print a photograph.

5 x 7? …8 x 10? …11 x 14? …Even a massive 30 x 40????

For those purposes, literally any camera now on the market (even the very cheapest!) will do just fine. See, 6 or 7 megapixels, the industry standard of fully half a decade ago, are all one really needs to print beautifully at this size. Naturally, of course, more megapixels are cheap and easy to cram onto sensors, and are therefore the favored marketing tool for selling cameras — more megapixels = better photos!!!!

Except that isn’t really the case. Unless you’ve just been asked by city hall to create a building-sized photographic mural that can be seen from outer space, or unless you’re making ridiculously deep crops, those extra megapixels aren’t doing you one iota of good. Speaking simply, the technical issues that make a bad photograph look bad, and a good photograph look good, have NOTHING to do with megapixels.

Want to know what actually matters? Look for these things first:

(1) Sensor size

The sensor inside most point-and-shoot cameras, the thing responsible for capturing the actual image, is shockingly small, little bigger than the nail on your little finger. Photos with these cameras might look okay taken outdoors on a bright, sunny day, but come dusk (or shooting indoors) your camera has to turn up the sensitivity of its sensor to get a proper exposure (akin to turning up the ‘gain’ on a guitar amplifier). This increases the signal-to-noise ratio in your image, with the upshot being a grainy, speckled photograph full of sensor “noise“.

Noise is the number-one technical consideration that impels people to lug around big, bulky DSLRs. It’s precisely those cameras’ larger sensors that are responsible for the creamy smoothness of DSLR images, including those taken in low light conditions at higher ISO values (like ISO 1600 or 3200, where images from most compacts will look truly awful at any size).

Don’t think that because a camera is bulkier that it will necessarily have a larger sensor — lots of DSLR-shaped “megazoom” cameras have sensors the same size as the smallest compacts.  If you plan on shooting in anything other than full daylight outdoors, forget the megapixel count and look for the sensor size.

Common sensors in ascending order of size:

  • 1/2.3″ (used in most compacts)
  • 1/1.7″ (used in ‘large sensor’ compacts like the Canon G-series and Nikon P7700/7800)
  • 1″ (used in Nikon 1 mirrorless system and a couple of newer high-end compacts like the Sony RX100)
  • 4/3rds and micro 4/3rds (now used mostly in Panasonic and Olympus mirrorless cameras)
  • APS-C (used in most entry-level and mid-range DSLRs, though Canon’s version is slightly smaller than other manufacturers)
  • Full-frame (used in top-end DSLRs and the new mirrorless Sony A7, with the  same effective sensor size as 35mm film)

(2) Look at the lens.

Know what else matters more than megapixels? Your lens. No matter how swish the sensor in your rig is, generally speaking it won’t make as big a difference to your photos as the quality of the lens. Qualities like ‘sharpness’ are to some extent particular to specific lenses, but general things to look for in a lens, whether attached to your compact or interchangeable on a DSLR or mirrorless, are as follows:

  • Max aperture: This F-number shows your how ‘fast’ a lens is, i.e. the largest possible hole in your lens,to let light in and decrease the time the shutter needs to be open to make a proper exposure. Many pros swear by lenses with a large maximum aperture, in order to freeze action or shoot in low light. ‘Fast’ lenses generally have a max aperture of F2.8 or below, though cheaper lenses will generally have a max of F3.5 or F4 (keep in mind that smaller numbers = larger apertures).
  • Constant or variable aperture?: Lenses either feature a constant maximum aperture across the entire focal length, or else a variable maximum aperture that narrows as you zoom. For example, a lens such as a 24-70mm F2.8 will do F2.8 at both ends of the zoom. An 18-200mm F3.5 – 5.6, however, is a variable aperture lens — at 18mm the aperture can be as wide as F3.5, whereas zoomed to 200mm, it will narrow to a maximum of F5.6
  • Zoom range: While many pros and enthusiastic amateurs swear by fixed-focal-length ‘prime’ lenses for their sharpness and light weight, the ability to ‘zoom’ — covering multiple focal lengths with the same lens — is a huge luxury and help. Most DSLRs these days come with an 18-55mm ‘kit’ zoom covering a roughly 28-83mm range (this owing to the 1.5x sensor crop factor — compact cameras come with a sensor crop factor many times more massive than this), but there are zoom lenses covering everything from ultrawide to pure telephoto and everything in between. In general, it’s often worth looking for a lens that’s a few millimetres wider on the wide end, rather than a few mm longer on telephoto — the difference between 16 and 18mm when you’re trying to get everything into the frame is significant, but the difference between 135 and 140mm on the long end is much less so. Many pros, again, swear by prime lenses with large maximum apertures; but the value of a go-anywhere lens with a useful broad zoom range is also hard to deny.
  • Image stabilisation: Whether it’s called Vibration Reduction (VR), Optical Image Stabilisation (OIS) or any of a host of other equivalent acronyms, this form of shake-correcting lens wizardry will allow you to shoot more things, handheld, at longer focal lengths, in lower light than you would ever have been able to before. Try shooting a distant object at 300mm handheld at dusk WITHOUT image stabilisation, and you will immediately see what I mean. Image stabilisation is your friend, and for those of us who like to be able to shoot without lugging a heavy tripod around, it’s a friend well worth having.

(3) Performance.

The other thing that people pay for when they get lux-ier, pricier gear is performance. What is ‘performance’? Simply put, it means that when you push the shutter, the picture gets taken, immediately and without any discernible shutter lag (the cause of many a missed shot). It means that when you turn the camera on, rather than waiting around while it ‘boots up’, it’s immediately ready to shoot (the cause of many a great shot captured). It means that in low light, it doesn’t hunt around for autofocus, but finds focus quickly and reliably, and that it can capture a ‘burst’ of images at a high frame rate at full resolution when you want to shoot fast-moving subjects like sports, kids or pets. You might be able to find the burst rate of a camera quite easily on a manufacturer’s website, but to really know how a camera performs in the nitty-gritty of daily use, you’ll have to read some reviews. and both offer admirable in-depth reviews of a broad range of camera gear.


One thought on “Megapixels don’t matter

  1. I LOVE your first sentence, I always say the same to everybody!!! The other day I was having dinner with my family when they saw a commercial of the new Nokia phone that has 41 megapixels. The second they heard that they all went “Woooo what a phone!”. Why everybody thinks pixels is what matters?

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