This article is more of a PSA about rating and metering film methods than a tutorial. But it’s an issue I see lots of people fall victim to (including myself!), so it’s worth addressing and being wary of.
A Quick Overview of Rating and Metering
First, what is rating and metering?
Rating is the ISO you set your camera or light meter to for a particular film stock. If you set your light meter to ISO 400, you are rating the film at 400.
Metering is the entire process of reading the light before you take an image and choosing the appropriate aperture and shutter speed settings for your camera. This is done with a handheld light meter or the light meter inside your camera.
So, What’s the Issue?
Here’s the situation: Someone online will ask others how they rate their film for a given stock. (Meaning the ISO they set their camera to for a particular film). And because the film community is extremely helpful, within a few minutes you’ll get a dozen responses regarding how people do this.
“I always rate my Fuji 400h at 100.” or “Portras should be rated at box speed.” etc.
And, yet, when we talk like this, we’re missing a major piece of information… how the photographer meters for light.
It’s like asking someone what temperature to set the oven to for baking cookies without asking how long to bake them. One piece of information begs the answer to the other piece.
Ultimately, rating and metering work together as a means to an end. That “end” being your aperture and shutter speed settings. To get a full picture of how an image was captured on film, you need to know how the image was metered as well as how it was rated.
The Many Variables in Metering Film
Unfortunately, finding out how someone metered their film is not as simple as it sounds. There are so many different factors when it comes to metering.
You can meter with a handheld light meter or with an in-camera light meter. You can meter bulb-in, bulb-out, in the highlights, or in the shadows. You can use incident metering or reflective metering…this will all wildly affect your settings.
Metering is even more illusive in that even the angle you hold your meter will cause different results.
To see how different metering results there can be in a given situation, I wanted to test how adjusting a few variables can change the setting outputs.
The Shooting Setup
To gather some data, I took my son outside on what happened to be a cloudy day and got to work.
It was late afternoon and the clouds made the light look extremely flat. The difference between the light on the side of his face towards the sun and the side of his face away from the sun looked relatively minor, so I was curious what the readings would show.
I placed him on the sidewalk so he was facing north and the sun was in the southwest. The sun ended up being behind him and toward his left side, so I knew the left side of his face would be more illuminated than the right.
The Metering Test with a Handheld Light Meter
Using my Sekonic L-358 handheld light meter (find the L-358 at KEH Camera or on eBay), I set the ISO to 400 for one test and 200 for the next test and set the aperture to a constant f/2.2. The meter reading would give me the resulting shutter speed.
Since there are about infinite ways to meter, I chose to consistently place the bulb of my light meter about 45 degrees from the ground at his chin, and I metered the following ways:
Bulb-in (retracted) on the left side of his face (the brighter side / in the highlights)
Bulb-in on the right side of his face (the darker side / in the shadows)
Bulb-out (protracted) in the highlights
Bulb-out in the shadows
Here are the results with the shutter speed reading listed in red for metering in the shadows and green for metering in the highlights.
Comparing My Handheld Light Meter with My In-Camera Light meter
I also took one last step and metered with my in-camera light meter using reflective light off the grass. This is usually how I meter, so I was curious how it compared!.
I typically meter for grass or something else that is similarly mid-toned in a shadowy area. (It’s like metering off of a grey card, but using nature as your grey card).
Since we are coming out of winter, our grass is extremely browny-yellowy, so it’s lighter than normal. I accounted for that by overexposing up to a stop from the meter reading I got.
It was cloudy, but I found a spot that would be in the shadows if the sun was out (under a tree) and metered off that. At ISO 400, I got a shutter speed of 1600, and, at ISO 200, a shutter speed of 800.
And since grass is lighter than normal, I would most likely account for that by overexposing a stop by shooting at a shutter speed of 800 for ISO 400 and 400 for ISO 200.
As you can see in this particular instance, my in-camera meter reading was somewhere between bulb-in and bulb-out in the shadows, which made me happy because it felt like it validated why I love the ease of an in-camera meter for most situations.
Why This Makes the Rating Question so Tricky
I found it interesting that rating a film at 400 and metering bulb-out in the shadows would result in letting in a little more light than rating the film at 200 and metering bulb-in in the shadows.
So someone could insist that rating at 200 is the only way to go, but they could potentially be letting in LESS light than the person who rates their film at 400–depending on how the two people meter.
And all of this doesn’t even account for the different ways people hold their meter (45 degrees to the ground vs perpendicular to the ground). Or if the sun is out, resulting in greater discrepancies between highlights and shadows.
All this to say, when you discuss ways to rate your film, be sure you’re getting the full picture. And even more, this goes to show your shooting experience could be vastly different from someone else’s.
Video Demonstration for Metering Film
I ended up eliciting my husband to video me on a sunny day with the meter so you could see how I’m metering for these readings. (Trying to paint a full picture like I’m preaching, ya know?)
I was also curious how different the readings would be on a sunny day….and oh my goodness, the readings were extremely different.
The most marked difference was between bulb-in and bulb-out in the highlights. This goes to show you that merely talking about metering without describing HOW you meter is almost worthless.
I also metered in-camera and got 1/90th of a second for ISO 400. I realize this is a weird reading…blame my Nikon n80 for its funny numbers. But that is very similar to bulb-in in the shadows. I would even overexpose up to a stop from there to account for the difference in the grass this time of year compared to summer.
If you’re new to film, here’s my word of advice (you might not like it, but I’m going to say it anyway): shoot ALL the film ALL the ways.
The only way you’re going to know how you like to rate and meter your film will be to experiment and try different methods. It will depend on how YOU shoot (not how the famous photographer you follow shoots). It will depend on how much contrast with punchy colors or muted with pastel colors you want in your photos.
And once you dial in a look you like, don’t feel bad because you like to rate your Fuji 400h at 400 while your neighbor is telling you rating it at 100 is the ONLY way to go. Your own personal trial and error will lead you where you need to be.