The Difference Between Rating and Metering

We originally started this blog to be helpful (and also to show off the incredible works of some of our clients and friends) and today, in this post, we’re hoping to clear up the difference between two very important words in the film world: metering and rating. We’ve heard and read about the confusion between these two words and considering that they’re essential to understanding and using film well, we felt it was our duty to make clear what the difference was between these two concepts that are often misused.


Each film is given an ISO which stands for ‘International Organization for Standardization.’ The ISO indicates the speed rating on a film (for example, for Fuji 400H the ISO/film speed rating is 400). This rating on the film is used to indicate the relative amount of light necessary to give a proper exposure to that given film. Now there are films available that range in speeds from ISO 25 to ISO 3200. But what is the difference between all these available ISOs on films, you ask?


Some film stock with different ISO.


We’ll happily tell you 🙂 A typical normal film (let’s say Ektar) will be rated at ISO 100, this ISO 100 rating indicates that it needs A LOT of light. So shoot that sucker in the brightest environment you can. Now a film that is rated at ISO 200 (like Kodak Gold) will give a proper exposure with only half the amount of light as compared with the ISO 100 film, like Ektar.

Shooting Kodak Gold with an ISO of 200, instead of Ektar with an ISO of 100, will enable you to shoot in lower light or with a smaller aperture or faster shutter speed. The same goes for Fuji 400H or Portra 400, you can shoot those ISO 400 speed films in even lower light.

Most ISO 400 films (and films with higher ISOs) are referred to as ‘fast’ films because they require less light to produce an image. So basically, the higher the ISO number the darker the environment it can be shot in.



BUT, if you’ve been shooting film for a sufficient amount of time, you may have heard or read some sneaky individuals who take Fuji 400 film and instead of shooting it at the box speed, or at the ISO, which would be 400; you’ve seen them shoot it at ISO 200. GASP! What are they doing you may ask?! Well these individuals are “rating” the speed of film at a different number other than the ISO on the box or on the film canister. And guess what? You can totally do that! Some films perform even better when you rate it differently than what is prescribed or recommended by the manufacturer. So when you take a 400 ISO film (like Fuji 400 or Portra 400) and “rate” or tell your camera you’re shooting 200 ISO film, you’re telling that film to slow exposure down and overexpose the film in your camera. And vice versa, if you’re shooting a film with a 400 ISO, but rating it at 800, you’re essentially telling your camera to go expose faster and underexpose the film. Rating simply means you are telling your camera (or your handheld light meter) what ISO you want your film shot at, whether it be the box speed or another ISO other than what the manufacturer recommends. This is one of the (many!) great things about film: film is very flexible in what you can do with it and how you can experiment with it. You can get many surprising results by simply experimenting and having fun with it!


“We can indicate in the camera that we have a different ISO than the one on the film to change the way we expose”



So now that you understand rating a film and how you can change the rating of a film’s ISO, let’s talk about metering. Metering is super helpful when you want to exercise more control with your film. There are two ways to meter: in your camera or with a handheld light meter. When you meter in camera you set the aperture, the shutter speed, and the ISO you want for the film you’re shooting. Then you look inside your camera, at the scene you are about to shoot, and see what your internal meter says. Sometimes the dial or the internal display in the viewfinder will tell you that you’re going to really overexpose or really underexpose your film and you can adjust your settings accordingly to correct that. It depends on the camera that you’re using, but most cameras, especially with older models, are a little more fly-by-the-seat-of-your-pants in that they’re just a suggestion or they give you more of a ballpark idea as to what you can do to correct any mistakes before you take your shot.


“On the left, when facing the camera and bulb out we are not overexposing at all. On the right we are metering for the light that comes bouncing from the floor which will enable us to have well exposed shadows”


With a handheld light meter you have the most absolute control you can over the results you can get with your film. The downside being that on top of carrying around a camera you also have to carry around a handheld light meter. However, with a handheld light meter you can input your settings and see what exactly you need to shoot your film at to get the results you want. What you are able to do varies from light meter to light meter, and some have more bells and whistles on them than others, but most will allow you to set a particular variable (whether it be the ISO, or the aperture, or the exposure setting) and tell you what you need to tweak to shoot with the result you want. So for instance, let’s say we want to shoot Fuji 400, but we want to rate it at 200, and we want our aperture to be set at 2.0 (because we also love that dreamy bokeh). So we can input those two settings on our handheld light meter (the desired ISO and the desired aperture) and then test the light to see what our exposure setting should be. If it’s in a very bright setting your exposure setting may be 500, or if it’s in an area with a little less light it might be 60. Alternatively, if we want to shoot the scene with a particular exposure setting we can set the variables (that being the desired exposure) and test the light to see what aperture and ISO we should shoot under the lighting conditions we are in. This is essentially metering: you are testing the light with the settings you have inputted into your camera or handheld light meter to see what are the best settings for the lighting conditions you are in.

Super simple right?! You can even change up what light you test for. As an example, if you are facing a scene you want to photograph, you can measure the light in the shadows of that scene or in the highlights of that scene. Measuring the different kinds of light in one scene will give you different results for the settings on your meter (whether it be in camera or on your handheld light meter). There are some photographers who shoot to expose for the shadows in their images, so they typically meter for the shadows. And on the flip side there are also some photographers who shoot to expose for the highlights in their images, so they meter for the brightest parts in the scenes they are about to photograph. And then there are some photographers who meter for the light somewhere in the middle to achieve a more balanced image. If you’re not sure what light you want to meter for, all you have to do is experiment! You’ll see what style suits you best and what reflects your vision best by metering the light in various ways.


“On the left we are metering at box speed of the film (EV 0), on the right we are overexposing about +1,5 stops (or EV 1,5). We take in count that we set up the meter at the same ISO that the film has.”


If it wasn’t clear before, film is flexible and loves to be rated in different ways and loves to be played with in different kinds of light. You can do so many things with film, all you have to do is shoot it, have fun with it, and see what results you love best!  

Have a question about rating or metering? Or maybe you just want to tell us how much you love us? Drop us a line at! We are here to help 🙂

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply