Digital camera technology has changed the way we take pictures. Not only can we now rattle off as many images as our memory card will allow, but thanks to the advent of digital displays and advancements made in viewfinder technology we can also choose how we want to compose our images and then instantly review them to see if they’re any good.
While many old film cameras indicated important shooting settings via a small monotone LCD display (usually on the shoulder of the camera), modern digital cameras almost universally come with a full-colour rear display that can provide a live feed of what the camera is looking at – a technological development that is generally referred to as live view. Depending on the type and price of the camera this may well be complemented by an eye-level viewfinder of either the optical or electronic variety.
While they might not generate the same marketing buzz that a fancy new sensor or exciting new technology does, viewfinders and rear displays are nonetheless hugely important components of your camera so it pays to be informed of the differences between the various types on offer and how they might affect your use and enjoyment. Here’s what you need to know…
Viewfinders vs Rear Displays
There are two types of built-in viewfinder that allow you to use a camera at eye-level: an optical viewfinder (OVF) and an electronic viewfinder (EVF).
Optical viewfinders can be split into pentamirror/pentaprism types that use mirrors to see directly through the lens, and tunnel types that use a separate optical arrangement that’s wholly independent of the lens. Many manufacturers also make standalone viewfinders of both the optical and electronic variety that can be attached to certain cameras via the flashgun hotshoe.
In contrast, most compacts and smaller Compact System Cameras don’t come with a built-in viewfinder at all and have no means to attach a standalone one either, relying instead on the LCD screen on the back of the camera, which presents a live feed of what the sensor can see.
Both approaches have their own distinct advantages and disadvantages; eye-level viewfinders help to block everything else out so that you can concentrate fully on what’s in the frame, however they do require the camera to be bigger in order to house the required mirrors and/or electronic circuitry. In addition, all but the very best optical viewfinders don’t give a completely 100% accurate representation of what the sensor will capture, with the presented image either slightly misaligned or cropped. While EVFs don’t suffer from this particular issue, cheaper versions will produce a noisy viewfinder image in poor light and can also struggle to keep up with fast-moving subjects.
Cameras that only come with a rear LCD display will offer 100% accuracy in terms of framing, and can also be made much smaller than their viewfinder-equipped rivals. Cheaper displays will generally lack sharpness though, and may also be hard to see in bright sunlight, or in extreme cases might even taint your images with an unrepresentative green or magenta hue colour cast.
Compact Cameras Tunnel Viewfinders
While the majority of cheap to mid-range compacts are equipped only with a rear display, a small number of compacts – for example the Canon G16 – do sport built-in optical viewfinders, usually of the tunnel type design. These aren’t nearly as popular as they once were though, with manufacturers increasingly switching to electronic viewfinders instead.
The main benefit of a tunnel type optical viewfinder is that it produces a clean, natural-looking image and relays it instantly without any of the stuttering or flickering issues that can sometimes plague cheaper EVFs in low light. The big downside to tunnel viewfinders, however, is that because the viewfinder is offset from the lens they aren’t particularly accurate. This is referred to as the parallax error and manifests itself more the closer you are to your subject. Shooting at wideangle settings you can also expect to see the lens protrude into the viewfinder window, which can be a little off-putting.
Thankfully most tunnel viewfinders offer superimposed guides around the edges or corners of the frame, which you can use to ensure you don’t accidentally cut anything out of the frame when composing an image. Another thing to be aware of is that tunnel viewfinders tend to produce a very small viewing window, which can reduce their overall usefulness. If you’re after a compact with a built-in optical viewfinder then be sure to try before you buy.
Our Essential Guide To Viewfinders And Rear Displays- Mirrors & Prisms
DSLR Viewfinders Pentamirror vs Pentaprism
Aside from Sony, which has its own unique system, DSLRs employ one of two distinct types of optical viewfinder designs: a pentaprism or a pentamirror. While there are differences in the construction and performance of each, both rely on a mirror positioned inside the camera body at a 45° angle to the lens that bounces light up into the roof of the camera where the viewfinder optics are housed. Indeed, this is the defining characteristic of a ‘single-lens reflex’ (SLR) camera as it’s what allows you to see directly through the lens.
The main difference between the two types is that pentaprism viewfinders are constructed from a single piece of glass, whereas pentamirror viewfinders use a series of individual mirrors. Pentaprism units are heavier and more costly to produce than their pentamirror counterparts, which in turn means they are generally only fitted to more expensive DSLRs, with pentamirrors more commonly found in entry-level models.
In terms of optical quality, pentaprism viewfinders are the superior design also as they retain more light than their pentamirror counterparts, making them brighter and clearer in everyday use.
Size, Coverage and Magnification
In addition to design type, three other important factors to consider when evaluating a DSLR’s optical viewfinder performance are window size, viewfinder coverage and magnification.
Window size refers to how big the viewfinder window appears when you hold the camera at eye level. As might be expected, professional-grade DSLRs offer much larger windows than entry-level models. That said, you can expect even the most basic pentamirror-equipped DSLR to have a significantly larger, brighter and clearer window than any tunnel viewfinder-equipped compact.
While single-reflex optical viewfinders provide flawless directional accuracy, they don’t always cover the entire frame. Again, more expensive DSLRs will generally offer better coverage, with pro-spec DSLRs usually offering 100% viewfinder coverage. For entry-level and mid-range models this usually drops to around 95-96%. Viewfinder coverage is important to bear in mind, because at 96% your camera’s sensor will actually capture slightly more than what you can see through the viewfinder.
Viewfinder magnification, meanwhile, refers to the size an object appears to be in the viewfinder image in relation to the size it appears when viewed with the naked eye. Most mid-range APS-C DSLRs offer about .8x magnification, which translates to 80% of the actual size, whereas cameras with larger full frame sensors tend to hover around .7x, which translates to 70%. Ideally, you want magnification to be as high as possible so that you get a truer representation of things when peering through the viewfinder.
This shouldn’t be confused with dioptre adjustment, as this refers to the small correction tool – usually a small dial on the side of the viewfinder – that’s used to adjust the perceived sharpness of the viewfinder image for long- or short-sighted users. It does this by moving a small lens at the front of the viewfinder and has no bearing on the camera’s AF system.
Our Essential Guide To Viewfinders And Rear Displays- Electronic Viewfinders
Electronic viewfinders have really come of age in the past few years. Whereas they used to be largely derided for producing small, low-resolution images with washed-out colour, modern EVFs are perfectly capable of delivering a big, vibrant and impressively sharp view.
The primary benefits of using an EVF rather than an optical viewfinder include 100% frame coverage, an enlarged viewfinder window, amplified viewfinder brightness in poor light, viewfinder-displayed shooting information, and faster continuous shooting speeds. Disadvantages include a distinct lack of sharpness on cheaper models, along with the propensity to flicker in poor light. Slower refresh rates on cheaper models can also make it tricky to capture fast-moving subjects, while they can also be a major drain of battery life.
Many superzoom cameras come equipped with an EVF, although quality can often be an issue on cheaper models. If you’re specifically after a DSLR but would prefer to use an EVF, then Sony’s innovative SLT (Single Lens Translucent) range is well worth a look. Strictly speaking Sony SLT cameras aren’t technically DSLRs at all because they use a semi-translucent mirror that’s fixed in place rather than a hinged silver-backed mirror, however to all other intents and purposes they look, feel and operate in exactly the same way regular DSLRs do. The EVFs used in the SLT range are also some of the very best around too, with impressively sharp 2.36m-dot displays in some models.
Our Essential Guide To Viewfinders And Rear Displays- LCD Displays
Rear LCD Displays
Rear LCD displays are common to all digital cameras these days, although their size and quality does, of course, differ wildly between the various manufacturers and models.
When comparing models the first thing to take note of is screen size, which is measured as a diagonal line from one corner to the other. The very cheapest compacts tend to come with a 2.7in screen, however spend a little more and you can expect a 3in screen. This has pretty much become a standard display size, not only for compacts but also for Compact System Cameras and DSLRs. That said, some manufacturers have recently begun to introduce larger 3.2in screens into their DSLR ranges – it’ll be interesting to see if other manufacturers follow suit.
While a bigger display is certainly desirable, resolution is arguably much more important. Rear LCD displays usually offer one of three common resolutions: 230k dots, 460k dots, and 921k dots or more. Cheap budget compacts tend to come with 230k-dot displays and while this is fine for day-to-day use, captured images won’t look particularly sharp or detailed when you view them on your camera.
Making the step up to a 460k-dot resolution results in a much clearer, sharper image. At this resolution you should have little problem reviewing your images, or indeed showing them off to others. Likewise, at 921k dots and higher, images will look impressively sharp with lots of fine detail clearly visible – especially if you zoom in a little on the images. As a general rule though, the jump in quality from 230k dots to 460k dots is more noticeable than the step up from 460k dots to 921k dots or more.
All digital camera displays presently use LCD technology as this provides the most accurate colour reproduction. Manufacturers have invented plenty of fancy names for their various display technologies with many offering their own noticeable traits. Sony’s TruBlack display technology, for example, ramps up contrast levels while Canon’s PureColour displays are noticeably vibrant.
AMOLED displays are all but non-existent for the simple reason that they oversaturate colour and produce undesirable green and purple hues. Be sure to read our individual camera reviews closely as it’s not unknown for some displays – usually those fitted to cheaper cameras – to have white balance issues, or to produce undesirable colour hues, though this is thankfully increasingly rare.