The design of mirrorless cameras means they need to use electronic viewfinders. These have improved hugely in a very short space of time, but they still polarise opinion! In the early days their resolution was too low to display a scene with anything like the clarity and detail of an optical viewfinder, and they had so much ‘lag’ when you moved the camera quickly that it was difficult to follow moving subjects.
Early EVFs might have been pretty poor, but the latest and best electronic viewfinders available today have such high resolution that you can hardly see the ‘dots’ and they have a clarity that genuinely approaches optical viewfinders. The new Panasonic Lumix S cameras have the highest EVF resolution yet at over 5 million dots.
Viewfinder lag is less of an issue than it used to be thanks to faster refresh rates, and the most recent area of focus for manufacturers has been in the blackout effect you would typically see when shooting continuous bursts of images. Sony has successfully managed to eliminate this on its A9 model, and Panasonic is now claiming the same for its G9 model .
On top of all this, electronic viewfinders let you view the image with any changes to exposure, white balance, colour settings and so on applied instantly, something optical viewfinder cannot do.
Most electronic viewfinders can also be successfully used to show a more clearly visible view of the scene in low light – very much an underappreciated benefit – and the best examples are clear and largely free from noise in even these conditions.
What's good about optical viewfinders
It’s true that an optical viewfinder does not show a digital rendition of the captured image, but you’ll get to see that on the screen on the back of the camera as soon as you’ve taken the picture anyway.
What’s more, many photographers prefer the ‘naked eye’ view of an optical viewfinder over a digital rendition. It’s a mistake to assume electronic viewfinders are inherently more ‘accurate’ because the display depends not only on the camera settings (which you may change later if you shoot RAW images) but on the quality, contrast ratio and calibration of the viewfinder panel itself. These often display more contrast than the captured image, for example, and can mislead you into correcting exposure settings that don’t need correcting.
Optical viewfinders have themselves become more intelligent. Illuminated LED panels overlaid on the main frame, for example, allow for more information to be visible within them than ever before. This is the principle behind Canon’s Intelligent Viewfinder technology.
Optical viewfinders have another key advantage that’s particularly relevant for sports and action photographers. There is unavoidable screen blackout in the camera’s burst shooting mode as the mirror flips up and down between exposures, but this is rarely an issue – the key point is that there is no lag, and it’s much easier to follow a fast-moving subject with a high-speed DSLR like the Nikon D500, for example, than it is with the average mirrorless camera.