The Game Called ISO
Taking Advantage of the EV System for Better Results
All photos by the author except where explicitly stated.
As long as I’ve been shooting film, I’ve faced a nagging problem: the desire to shoot in the dark. My Dad — who gave me my first and his only camera Zorkiy with 3.5/50 mm Industar-22 — taught me not to even bother shooting at 1/30 sec or slower as the pictures would come out blurry. Given that the only film available to me was b/w Svema’s Foto 65 (ISO 50), this meant that by around 5–6 pm, our outings would continue without the camera, as it was too dark for a decent exposure.
A few years later, I would struggle with the same film to take pictures at the parties, concerts and dark alleys. I was trying to push film 3–4–5 stops, but that rendered even beautiful faces to look like those of white-faced mimes. The pictures were horrible, and more than once they would be torn into shreds after being given to the subject.
Fast forward to the year 2000. A friend of mine gifted me an Olympus Stylus Epic Zoom 80 for my birthday — I have dozens of cameras but I will never refuse another one. I thanked him profoundly, but inside, I was laughing. I graduated to SLRs something like 25 years prior and felt that shooting with a P&S was certainly beneath my dignity. Anyway, I loaded some color film and started poking around. I discovered a completely different world in which the camera makes all the decisions short of my pressing the shutter button. The size of the camera and the fact it did not need any protective case made it a favorite with my wife. I was satisfied with the results when it was casually shooting on the street, on a subway or anywhere else where I would not carry any of my SLR’s to.
But the old problem persisted: the issue of light and its sufficiency. Then I asked myself a simple question: what film should I use given my shooting style? Given that I did not have enlarger or lab space anymore, I was sentenced to use C-41 film and develop it at a pharmacy store. The first question was: How fast should my film be? I did not care about grain or anything, but just how nimble my film would be about the light.
I began my calculations with the goal that my camera’s shutter speed should not exceed 1/20 to 1/30 sec. That would give me some chance to capture the action where ever I went. Certainly, I did not have any control over the automatic program that camera uses, but playing with the camera I could see that it would open aperture wider rather than risking longer shutter speed.
Okay, with that set, I knew my Olympus have the max aperture around f/4. What would be the brightness of the scene in a reasonably well-lit space — such as a subway car, a restaurant, or a city at dusk? From all my practical experience I knew that with ISO 100 film I need to go for 1/4–1/2 sec shutter speed and use a tripod or hoist the camera somewhere and use a cable release. I did not want any of that so I needed extra 3 stops of sensitivity. That brought me to ISO 800. I wasn’t concerned about shooting in bright light; I knew the camera would handle that. Even in the worst-case scenario, overexposing by a couple of stops on any negative film would still produce acceptable negatives.
This is how I independently discovered what has been known for decades as the Exposure Value System. For this particular camera, equipped with a slow lens and before the era of image stabilization, and considering the highest ISO film I could afford, the scene had to possess a certain level of luminance for me to capture a sharp picture on the go and ensure proper film exposure. Certainly, I wasn’t the first to recognize the simple correlation between scene luminance and film speed on one hand, and shutter speed and aperture on the other. What I came to understand, given my shooting habits and the gear available to me, was that I was destined to use film with a minimum speed of ISO 800.
The Value of “Exposure Value”
Regardless of the vast variety of possible lighting conditions, the ‘Exposure Value for Light’ chart offers decent estimates for many common scenarios. This can be quite useful for anyone needing at least a rough idea of what kind of film stock to carry, given the specific capabilities of the camera they have in their backpack. By the way, one well-known example from this chart is the ‘Sunny 16’ rule.
Here’s my favorite part from the chart, and let’s examine its usefulness. The EV value provided is for ISO 100 film and for now just make a note of it.
Imagine taking a nighttime stroll around Piazza Navona in Rome.
This scenario would likely combine ‘Night street scenes and window displays’ with an EV of 7–8 and ‘Floodlit buildings, monuments, and fountains’ with an EV of 3–5.
So let’s plan our shoot for light at EV 6 level. Lets calculate camera’s best EV per Wikipedia article:
The conclusion: my Olympus Stylus Epic camera, loaded with ISO 100 film and equipped with an f/4 lens at a shutter speed of 1/30 sec, achieves a maximum EV of approximately 9 — three steps short of the necessary EV 6.
As it stands, my camera won’t handle the walk without adjustments, but bridging the gap is straightforward. All I need is to load film that is three stops more sensitive than ISO 100. This means using ISO 800 film, which will effectively allow my camera to handle light at EV 6. Problem solved!
The Film
And indeed, there was inexpensive Fujifilm CZ 135–36 Fujicolor 800 Color Negative Film (ISO-800) which was retailed at something like US$3 at the time. So that was the film I would routinely load in my Olympus when I was going out and making of “true art” was not in the calendar for the day. That’s how I preserved many sweet memories shot without any pretense and without torturing my dear ones with the setups the SLR would call for.
2001 — blast from the past
All images in this post are taken from the same roll of film Fuji ISO 800 shot in December 2001-January 2002 with Olympus Stylus Epic. The shots are provided as-is : as they came from ofoto.com which processed and scanned film at hoping (1024×1536) — 1.5 MP. The greenish tint was apparently given by a scanning software. I did not want to fix any of that to preserve the look and feel of the shots.
Streetscape at snowy night. Shot hand-held at available light.
Kid is enjoying the snow. Scene is illuminated with the street light only. Shot hand-held at available light. Theoretically one can asses the camera-set shutter speed by analyzing the length of strokes left by snow flakes. Let’s keep it as a homework.
They did read books once. Shot on the NY subway while car was running above ground using available light. I suspect now that having aperture about f/4 on point&shoot cameras was not only the matter of the lens cost, but also the easy way to have some rather deep depth of field (DoF) , so even in the absence of the precise focusing the shots would come sharp enough.
That how streets looked for a few months after September 11. Disaster cards ruled newsstands across Manhattan. Shot on the go with the available light.
Another newsstand in Manhattan shot apparently at 4–5 pm in January, 2002. Note how warm colors at news stand give scene a pop-up against the background lit with vanning daylight. Note the pitch-black darks — the hallmark of the film.
Suppose you do want to shoot film with a traditional vintage camera, but you’re unsure what exactly you’ll be shooting — only that it, say, will be indoors. Given that most cameras have shutter speeds between 1/20 to 1/30 sec, it’s the lens aperture and lighting conditions that will dictate the necessary film speed. If you happen to have a fast lens, like an f/1.4 or f/2, you might manage with a finer-grained ISO 200 film.
By the way, these principles are not unique to film cameras; they also apply to consumer-grade point-and-shoot digital cameras. The same challenges exist because the lenses on these cameras are generally not very fast. Often, their sensors produce noticeably grainy images at ISO 800. The only solutions manufacturers seem to employ are implementing image stabilization and other techniques to gather more light and prevent image blurring, sometimes at the expense of megapixel count.
I hope this article has provided you with insight into basic photography principles. My intention was to sidestep discussions on film latitude and the techniques of pushing and pulling during development, as those are completely separate topics. In my view, you should only resort to these techniques when you’re truly desperate and unable to obtain the necessary film stock.
A word of caution: avoid applying these straightforward approaches when shooting reversible/slide film. Without meticulous light measurements, shooting reversible film can result in significant waste of both film and effort.
Understanding Exposure Value teaches you how to select the appropriate film ISO for your lens and camera and shooting scenario. In essence, I firmly believe that choosing the right sensitivity film for the job is the most important technical decision you make as a photographer.
