Taking the picture – pinholes and f-stops

An excerpt from From pinhole to print – Inspiration, instructions and insights in less than an hour. What to consider when taking photographs with a pinhole camera.

Your camera is ready, loaded with photographic paper and you have found the perfect scene. You have got a light tight shutter, but how long do you open it?

The focal length of your pinhole camera is the distance between the pinhole and the paper or film you have loaded the camera with.

The focal length of your pinhole camera is the distance between the pinhole and the paper or film you have loaded the camera with.

There is a perfect exposure time and it depends on your camera, the film you are using, the size of your pinhole and the amount of light available. If you don’t expose it long enough your negative will be too light and if you leave it too long your negative will turn too dark.

There are two basic methods you can use to determine exposure – use a light meter and do a calculation, or test your way to good results. You will find that it is probably the latter or a combination of these two that will work for you.

Keep notes of your exposure times and the results you get. Learn from your experiences.

F-stops

If you know the size of the pinhole and the focal length you can work out the f-stop of your camera. The f-stop will help you work out the right exposure time.

Doing the maths

The formula for calculating the f-stop of your camera is the focal length divided by the size of diameter of the pinhole.

The focal lenght / diameter of the pinhole = the f-stop

F-stops have a ‘standard sequence’. If you have an ordinary camera, you can see the f-numbers on the lens.

The f-stop sequence
Ordinary lenses rarely go beyond f/22. The sequence is:
f/16
f/22
f/32
f/45
f/64
f/90
f/128
f/180
f/256
f/360
f/512
f/720
f/1024

Have fun!

Beginners guide to pinholing
From pinhole to print – Inspiration, instructions and insights in less than an hour
by Gary Fabbri, Malin Fabbri and Peter Wiklund
The quick and easy way to learn how to build a pinhole camera!
From pinhole to print will guide you from drilling your first pinhole to printing your first pinhole photograph. It is an easy to read, step-by-step guide to making a pinhole camera and creating images.
Strongly recommended for beginners

 


One Comment

  1. cornelius
    Posted March 8, 2014 at 5:48 am | Permalink

    What with the annual Worldwide Pinhole Photography Day coming up on April 27th, it’s time to start tinkering and fine-tuning. This article (and the book) will doubtless be coming in handy.

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