How to buy a camera: what you want in a viewfinder
The viewfinder is your eye on the world, so the bigger, brighter and clearer its image, the better. This is essential not only for accurate photo composition, but also for greater precision when it comes to adjusting focus
Cheaper, entry-level DSLRs such as the Canon 1100D, and even some more expensive models including the Canon EOS 650D and Nikon D5200, use pentamirror viewfinders. These are cheaper to manufacture and lighter in weight than ‘proper’ pentaprism viewfinders, being constructed from a set of three separate mirrors.
The main disadvantages of pentamirror-based DSLRs are that the images they produce are a bit dark and gloomy, and can be a little lacking in contrast and outright sharpness. This doesn’t affect the recorded image, just the image you see through the viewfinder.
Based on time-honoured tradition, the best viewfinders, as fitted to upmarket cameras including the Canon EOS 60D and EOS 7D, and the Nikon D7000 and D300S, as well as all full-frame cameras like the new Nikon D600 or Canon EOS 6D, are of the pentaprism variety.
Constructed from a single, five-sided block of glass, the pentaprism reflects the image directed up from the reflex mirror twice, so that it appears the right way up and the right way around when viewed through the eyepiece. Pentaprism viewfinders are relatively heavy and expensive to make, when compared with pentamirror viewfinders, but produce better quality, brighter images.
For compact system cameras that lack a built-in optical or electronic viewfinder (EVF), there’s often an electronic device available as an optional extra, such as the Olympus EVF VF-3 viewfinder for the Olympus E-PL3.
Optional EVFs usually slot into the hotshoe mount at the top of the camera, but they are typically expensive at about £150 to £200. Other drawbacks are that you can’t use the viewfinder and a flashgun at the same time, and that electronic viewfinders lack the clarity of an optical viewfinder, being essentially mini-LCD screens. Sluggish refresh rates also tend to give the viewed image a smeared appearance when panning.
Field of view
Ideally, it’s good to be able to see the whole of the image that you’ll capture as you look through the viewfinder, but in fact, this often isn’t the case. Many viewfinders, especially cheaper pentamirror types, typically only give a 95% field of view, so you can’t quite see everything that will appear in the final picture.
In practice, this isn’t too much of a problem – it’s good to have a little spare to play with, because the edges of an image can be lost if you need to straighten it (eg, level the horizons) when editing. Good pentaprism viewfinders often creep up to around 98% coverage, and the best provide a full 100% view.
Bigger is always better when it comes to the viewfinder image, and again, this varies considerably between cameras. For example, the Canon EOS 550D only offers 0.87x magnification, while the Canon EOS 7D gives a direct 1.0x magnification.
PAGE 1: Overview of how to buy a camera
PAGE 2: Body design and new DSLR features
PAGE 3: How many megapixels do you need?
PAGE 4: DSLR video options
PAGE 5: What you want in a viewfinder
PAGE 6: How fast should your new DSLR be?