Measuring Photo exposure without a meter
I have some bench marks I use like shorthand to jump to a certain exposure on my camera, where I don’t need to think about it too much. For the below photo I’ll take you through my thought process as I figured out the camera settings. For a more detailed look at the relationship between ISO, Shutter Speed and Aperture, click here.
Granda sitting in his favorite corner living room chair contemplating his next move.
Exposure Data for this photo |
||
|---|---|---|
| ISO | Shutter Speed | Aperture |
200 |
1/60 |
1.8 |
SOFT Indoor light
In this photo I am shooting with a relatively diffused floor lamp as my only light, indoors… at night. I was shooting on relatively slow Kodak Gold 200 film. Slow in relation to film means the film needs more light to properly expose the photo. And this is a situation where there is not a ton of light to begin with. So 200 ISO is locked in.
ISO: 200
I know I need as much light as possible, so I open up the iris all the way to f/1.8 or perhaps f/2 (to sharpen up the image a bit).
f/1.8
That leaves the shutter speed. When I know I need more light I change to the slowest shutter speed at which I can keep images sharp, which is 1/125 of a second. Occasionally I will go to 1/60 if both me and the subject are going to stay still, like for a portrait. I shot this at 1/60 I am almost certain.
1/60 second
Additionally, in my scanning and digitization I probably was able to bring back a stop or two of light which adds the grain you may be seeing (along with digital noise from squarespace’s compression).
In summary
Shoot pretty wide open with soft indoor light if your ISO is 200 or less. Even at 400 or 800 I would rarely have my iris more stopped down than f/4 or f/5.6. It just isn’t worth taking a chance on underexposed photos. And in many cases I would speed up the shutter if I got to a brighter section of the room. Freezing motion will be better for sharpness and most of what I want to get.
Reasons you may want to use other settings in lower light indoor settings:
One might slow the shutter speed in order to capture motion in the frame. For instance if you wanted to see the hair on a woman dancing or the movement of hands in a portrait. For this however YOU will need to be incredibly still and would greatly benefit from a tripod for this kind of shooting. Additionally, you may close down the iris to have more depth of field, but this only works for captuing items that don’t move.
Grand Bayou Casino inside a gas station in Grosse Tete, LA. An example of “Sunny 16”
“SUNNY 16” and certain exposures for set lighting conditions
Sunny 16 is one of the most straightforward shortcuts to use to calculate exposure without a meter. With Sunny 16, if you are shooting at roughly the peak of daytime brightness, then you can set the camera to an f/16 aperture and shoot at what is called “box speed.” Box speed is simply using the iso rating of your film as the denominator in your shutter speed. So, for example, 400 ISO film would be roughly 1/250 of a second or 1/500 on most cameras. That is precisely how I took the above photo. I set the aperture immediately to f/16, I knew the film was rated at 400, so I shot at 1/250 of a second, because I wanted to get some detail in the shadows. on the treeline.
You can eventually use this method with certain times of day or night where the light is relatively constant. For example, in the golden hour (generally the first and last hour of daylight”, you can shoot at anywhere between f/2.8 - f/5.6 at box speed as well, depending on what you want to expose for.
A more foolproof way to do this would be to use an exposure value chart to help you calculate your shutter speed. I will spare you by not sharing the full exposure value chart, which is eyewatering. Instead I will link to the Wikipedia article here where you can find it. I will below list the exposure value chart with some common light sources which roughly correlate with those values.
Exposure Values |
|
|---|---|
| Exposure Value | Type of Light |
-6 |
Moonless overcast night sky |
-5 |
Crescent Moon |
-4 |
Bright Crescent Moon |
-3 |
Quarter Moon |
-2 |
Full Moon |
-1 |
Bright Full Moon |
0 |
Shadows of soft indoor light |
1 |
Soft indoor light - not nearby |
2 |
Nighttime-distant lights |
3 |
Deep Twilight outdoors |
4 |
Near Christmas Lights |
5 |
Soft Incandesent |
6 |
Typical Indoor Lighting |
7 |
Night Street Scenes and Window Displays |
8 |
Bright Street Scenes |
9 |
Night Sporting Floodlights |
10 |
Indoor Galleries/Metros |
11 |
Next to a window on sunny day |
12 |
Overcast/Shadows on sunny day |
13 |
Cloudy with bright overcast skies |
14 |
Typical Sunlight (Soft Shadows) |
15 |
Sunny Sixteen (Full Sunlight) |
If you consult the chart you can see that if the scene you are shooting has a 9-12 Exposure Value, then your iso can make a great deal of difference in the kind of pictures you can take. Using a calculator I made below if you put in a film speed of 100 iso and an exposure value of 9, which is when the illuminating power of most streetlights equals the output of the sun, you need to be wide open aperture-wise on most lenses to freeze actions at 1/125 of a second or 1/250. If you are trying to capture a sunset and want to really get everthing in focus at this time of night with that film speed you would need to put the camera on a tripod, close down the aperture to f/8 or f/11 and snap a pick with a cable release or delayed shutter at 1/4 or 1/8 of a second.
Select your settings
Dial in your aperture, the ISO of your film and the rough lighting situation.
Aperture (f-stop)
Exposure Value
ISO