Are light meters still relevant in 2021?

Over the last few years there seems to be a lot of people talking about light meters and how they are no longer relevant in today’s photography.  I’d like to share an opposing point of view that says that light meters are still very much relevant and very useful.

But before we get into the guts of this, let’s start by covering off the basics.  What is a light meter?

 A light meter is a device used to measure light.  That light can be a strobe or it can be constant light such as the sun or a video light.  You are probably aware that most cameras have a light meter built into them.  This is what a camera uses to set the exposure when using any automated mode such as Aperture Priority, Shutter Priority, Automatic, etc.

 My trusted Sekonic L-358 Light meter. Click on image to find out more about it.

So if my camera already has a light meter, than why do I need a sperate light meter?  The reason for this is that the light meter built into your camera is measuring reflected light.  Reflected light is the light that is being reflected back off the subject.  Let’s take this example.

Let’s imaging you are taking a photo of a brown suitcase.  You measure the scene through your camera’s light meter and take the photo.  Now let’s cover that suitcase in aluminium foil.  The shape is still the same and let’s assume the lighting has not changed.  The only thing that has changed is the reflective surface of the suitcase.  It is more reflective so the light meter is going to give you a different reading.  This is what is meant by reflected light.  You are measuring the light being reflected by the subject not the source of the light.

A light meter measures incident light.  This means that it is measuring the light falling on the subject and not the light being reflected off the subject.  Because it is measuring the light from the source and not the light being reflected, it does not matter how reflective the subject is.  Assuming the lighting source has not changed, the reading on the light meter will always be the same.  Additionally, if you are trying to measure the light from a flash, you will need to use a light meter.  A flash’s duration is so short that it needs to be measured by a light meter.  A camera’s light meter is not able to measure flash.

Now that we’ve covered the difference between the light meter in your camera and a dedicated light meter we can move on with the rest of this article.  I should make it clear that I’m not suggesting that we should be using a light meter every single time.  What I’m saying is that there are still times where a light meter is useful to have and in some cases essential.

In my professional work I find light meters to be very useful when photographing products.  I have a client that sends me new products every few weeks to add to their website.  These products are somewhat styled and the look of the photograph must match all the other shots.  Because of this, I use a lighting diagram where I document the position and power of the lights as well as other information.  Because of the setup, having a light even 1 inch closer than it should be can result in a very different looking photograph.  This would not match the other shots and is not acceptable to the client.  This is where the light meter pays for itself.  A light meter allows you to measure the light falling on the subject very accurately.  By recording this information in your lighting diagram, I am able to place the light at the exact distance and power to match my original photo.  This gives me a way to accurately reproduce the lighting from a previous image.  Now, you could do this without a light meter, but it would take longer because you would need to shoot test images until you were able to reproduce the results.  It can be done but it takes longer.  A light meter just gets you there quicker.  Could you just use the LCD screen?  Maybe, but it’s not something I would trust.  LCD screens on the back of cameras tend to be brighter than the actual scenes.  It makes it easier to see the screen during daylight but can also throw you off a little.  You could use the histogram to help you get there but light meters work at 0.1 of a light stop and so they are more accurate.

Should you use a light meter when making artistic decisions on lighting?  You could.  I don’t actually do this because in those instances I would rather make the decision on the aesthetics of the image using the LCD on the back of the camera but I might still use a light meter to get me to a starting point if I wanted to.

So given all this information, do I still thing that light meters have a place in 2021 and beyond.  Absolutely!   Do you use a light meter?  Let me know in the comments if you do or don’t and the reasons why.