Measuring Light for Pinhole Photography

Bob St. Cyr was granted the Canadian Association of Photographic Arts Maple Leaf and Associate Fellowship Awards for photographic achievement, service and exceptional contributions to photography. Bob has also won national and international awards for his photography. Although Bob is familiar with digital photography and employs it from time-to-time, he primarily prefers to work with medium and large film format lens and pinhole cameras. He also enjoys the challenge of constantly working to better himself not only as a photographer but as a darkroom craftsman from processing his film to black and white printing. His work has appeared in Canadian Camera Magazine, Pinhole Photography, and Photo Life Magazine, among other publications. What follows are his thoughts on measuring light for pinhole photography.

©Bob St. Cyr

©Bob St. Cyr

Even before I added pinhole imaging to my fine-art photographic practice, I saw the value in having a handheld light meter. My first light meter was the Sekonic L-408, which is a great meter with a fixed 5° spot as well as the incident dome. Some of the things I like about this meter aside from its technical offerings is the fact that it operates with a simple AA battery, is light-weight and of modest size. Eventually, I traded up to the L-508 and finally to the L-608.

Because I work with medium and large format lens and pinhole cameras, I purchased the L-408 again, so I have two meters to work with, depending upon which gear I am working with. However, I tend to keep the L-608 primarily with my Toyo large format gear because of the 1° spot option. Both meters cover most of my exposure needs and do so quite readily and easily.

In my case, using a light meter, has becomes a common part of making images.  It is a normal part of my workflow, just like toning prints for D-Max and optimum permanence completes my silver-gelatin fibre printing process. I try not to look at using a light meter or toning fibre prints as a time burden because they are important steps to finishing a print and correctly interpreting light for exposures that help translate my inner visualisation.

Now when working with pinhole cameras, of course, “There is an app for that,” and you can purchase or print off exposure calculators from the Internet. Occasionally I have used these instruments, but over time, I find my meters are what I rely upon to help interpret the light necessary to capture pinhole images upon film and paper. Nevertheless, pinhole photography requires f-stops exposures beyond the Sekonic’s range, so what can I do? Here is where some understanding of how f/stops and exposure times relate to photography, lens and pinhole comes in handy.

©Bob St. Cyr

©Bob St. Cyr

Typically, I will take readings at the maximum f/stop of the meter, i.e., f/90 or f/128. From here, I consider the f/stop of the particular pinhole camera I am working with and extrapolate the exposure and add a little more time for reciprocity failure. Or, I can take the meter reading for a given ISO and line up the corresponding exposure on a pinhole exposure calculator. For instance, Let us assume the following:

  • Using the Sekonic L-408
  • ISO three, direct-positive fibre paper from Ilford
  • Pinhole camera with an focal length of 100mm and an f/stop of 250
  • Early evening overcast at the ocean

I take a meter reading at f/90. I know that the next f/stop is f/128, then f/180 … f/250 … f/360 …. The correct exposure for f/250 is plus three stops from f/90.

At f/90, the meter suggests an exposure for, say, for four minutes. I know I need three stops above the meter, therefore f/90 @ four minutes = f/128 @ eight minutes = f/180 @ 16 minutes and finally it equals f/250 and 32 minutes plus a few more minutes to compensate for any reciprocity failure and the darkening of the sky at dusk. Remember that in photographic exposure calculations as the f/stop doubles so does the exposure time. I usually just make a quick calculation in my head, but you can also match f/90 @ four minutes with a corresponding exposure time for f/250 on a pinhole exposure scale. One other important step (which I don’t always do), is to keep notes in a small notebook or audio with a recording device for later reference when looking at prints or film. In the case of a difficult lighting situation, thankfully both of my meters allow for multiple spot readings which can then be averaged.

When working with black & white papers and films, I have some exposure latitude, but when photographing with transparency film, I have little room for exposure variation and thus, the Sekonic becomes even more valuable because the cost of purchasing and processing transparency film is very high. Even with metering, pinhole photography is not an exact process, which makes it somewhat artistically unique, challenging but enjoyable.  I believe there is something significant to be said for the immediate unknown … for patience … for critical thinking … for anticipation when waiting for paper or film to be processed.

The light meter is a tool that provides a good starting point from which to extrapolate an exposure. I do not always get this right, but when I do, the results are very satisfying. And by reviewing my notes, and the lighting conditions, I can somewhat fine tune my lighting protocols for given scenes under a particular type of lighting. Clear sunny days are probably the easiest to meter, since the exposures are generally consistent. I think light interpretations with the assistance of my Sekonic meters helps me as an artist relate what I see to others through images people can hold in their hands.

I also use a Mamiya C330f, a lens camera for which a hand-held light meter is very important since the camera has no meter itself.

©Bob St. Cyr

©Bob St. Cyr

This image was made on Ilford’s direct positive 4×5 fibre paper. The exposure took 37 minutes f/250 with the camera’s focal length was 100mm.

See more of Bob St. Cyr’s work on his sitePhotoBob’s Atelier, and RedBubble. Follow him on Twitter and Flickr.

The meters Bob still relies on are discontinued. The latest version of Sekonic’s spot-reflected and incident meter is the L-758DR.


All images and quotes in this post are used with permission and ©Bob St. Cyr, all rights reserved; story is ©Sekonic. Please respect and support photographers’ rights. Feel free to link to this blog post, but please do not replicate or repost elsewhere without written permission

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2 Responses to Measuring Light for Pinhole Photography

  1. Pingback: Article: Measuring Light for Pinhole Photography | pinholisticallyyours

  2. Dana Angela Williams says:

    Very Informative blog! Good that this blog explains the measuring light for pinhole and really appreciate the efforts of being not only as a photographer but also a darkroom craftsman.
    I just came across customizable, flat-pack design on Kickstarter, the Original Pin offers a user-friendly and intuitive method of changing your camera’s “personality.” By mixing and matching the wooden parts, you are able to create something that is both durable and unique.

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