Because the viewfinder is electronic, driven from data gathered by the sensor, what you see in the viewfinder is exactly what the camera is going to record. There’s no more uncertainty about exposure, no more guessing depth-of-field or White Balance. Every change you make to the main camera settings, you instantly see the effect in the viewfinder. What’s more, there’s a live histogram and highlights alert, so you can make adjustments before you take the picture, for greater accuracy.

Have you ever wondered why AF sensors in a DSLR are always positioned around the centre of the viewfinder? The answer is, because of the mirror. And what do you do if the subject you want to focus on sits closer to the edge or corner of the frame? In mirrorless cameras AF is driven by the sensor, which means you get AF points across the whole image space, corner-to-corner, so wherever your subject is in the frame, there’s a convenient AF point.

In a DSLR camera, auto-focus (AF) is managed by a dedicated unit that sits beneath the mirror. In order to work, this unit needs sufficient light and because most of the light entering the lens is passed from the mirror to the viewfinder, the AF unit struggles to work effectively in low light. In a mirrorless camera, the sensor deals with AF, which means all the light entering the lens is available for focussing. When you shoot in the kinds of conditions I do (under dense jungle/forest canopies, at dawn and dusk, etc.) these small advantages make a big difference between getting the shot and the shot that got away.

Photographing wildlife, sometimes the slap of a mirror and the click of a shutter is enough to frighten off skittish animals. No more. Switching from the manual shutter to the electronic one, which is a quick My Menu selection, means I can work in total silence. Better for the subject and better for me. And it’s not just wildlife photographers who can benefit from silent shooting. Anyone who operates in noise-conscious environments will be rewarded.

A reflex mirror has to be accommodated, which means DSLR cameras have to be bigger than is necessary. The mirror, along with the mechanism to drive it, and the pentaprism needed to turn the image the right way up and around, all add weight on top of the already increased body size. All this means the average DSLR is around 30% heavier than a mirrorless camera, with top-level DSLR’s being around twice as heavy. The footprint of mirrorless cameras is also far smaller than equivalent DSLR’s. As a guide, I can fit two mirrorless cameras in the space I need for one DSLR. All this means a lighter, smaller bag, which, when you get to my age, is no small blessing, especially when I’m cutting my way through a tropical jungle or hiking at 4,500m in the Himalayas.

Assertions that mirrorless cameras lack the performance of high-end DSLR’s are generally way off mark. The top shutter speed on some mirrorless cameras is 1/30,000 (yes, 1/30,000 – that’s not a typo), frame rates are pushing 14-15 fps (although I rarely need to shoot above 5-fps), ISO/Noise performance is on a par with any competing camera, and AF tracking is accurate enough to keep pace with a hungry cheetah in hot pursuit of a gazelle. My one gripe is that battery life is generally lower due to the demands of powering the electronic viewfinder. Even so, carrying a couple of spares, I’ve yet to run out in a single day’s shooting.