Mirrorless cameras: The advantage of histogram displays.

Exposure is a key concept in photography.  It takes just the right balance of aperture, shutter speed, and ISO to produce a correct exposure.  Although RAW images and, to some point, JPEGs, do allow a certain amount of correction post-shot, it is always best to bring the best image you can into post-production.  

Getting the correct exposure is trickier than it sounds.  Cameras come with a light meter that interprets reflected light to generate an exposure setting based on selected criteria.  Those values aren't necessarily right though.  Harshly lit scenes, snow, sand, flash, and a host of other factors can cause the camera-generated exposure settings to be off.  Sometimes by as little as a third of a stop (± 1/3) up to or over five full stops (± 5).  So, how do you know when to alter the settings, and by how much?

There is a myriad of answers to that.  Bracketing, creating an HDR image, estimating exposure, using a gray card, using an incident light meter, exposure lock, exposure compensation, manual mode with the zone system, or simply relying on dynamic range and latitude all have their place and work.  I have used all these methods but have found that a live-histogram display is perhaps the most efficient and objective way to determine exposure.

As much as I love optical viewfinders (DSLRs), their one great disadvantage is that they cannot provide a live histogram display.  You can get around that by estimating the exposure, taking the shot, then pressing "play" and reviewing the image with the resulting histogram.  Make the necessary corrections and shoot again, repeating as necessary.  Some DSLR cameras (D750 for example) will allow you to display the histogram when using the "live view" function.  It is not a standard function though.

Mirrorless cameras provide the opportunity to see the histogram in the actual viewfinder.  I am a big advocate of shooting with my eye pressed against the eyepiece rather than seeing the virtual image from a foot away on the display screen.  Having the live histogram there helps me to observe the effect of altering exposure settings on the image.  I can pay attention to the changing shape of the graph while interpreting its rendering shape.

This entails another discussion as this post will get too long.  My next blog will address understanding what a good histogram should look like.  Until then.

Thanks for reading.   www.ericspix.com