Tag Archives: Long exposure

Reciprocity failure

Recently I have been doing a lot of pinhole photography, and due to that I have had to explain to a number of people (unfamiliar with the more technical parts of photography) what reciprocity failure is.

Reciprocity is the relationship between shutter speeds and apertures, which means that as you reduce exposure with a change in, lets say the shutter speed by one stop, then increase the exposure by one stop with the aperture, you will have exactly the same exposure. Each one-stop adjustment of the shutter speed, is equivalent to a one-stop adjustment of the aperture. This holds true throughout the normal use of the camera in most lighting situations.

This linked relationship begins to slip away with exposures longer than one second, and the longer the indicated exposure, the more of a difference there is between the indicated exposure and what is actually needed. Many years ago I included in my book on night photography, a chart for working out the amount of exposure correction you might need in situations where exposures were between 1 second and 17 minutes. I have been referring to this chart for my extended pinhole exposures, and I include a link to a word document here which shows the full chart:

https://dl.dropboxusercontent.com/u/88621650/Reciprocity%20chart.doc

Walker Titan Pinhole 5×4

Using the Walker Titan pinhole 5×4.

I have been using the Walker pinhole camera for a few months now, though not exclusively because I’ve been busy with a lot of paper negative stuff. Having shot with it in a few different locations, I have really grown to love it.

When I’ve shot pinhole stuff before, I’ve always enjoyed making the cameras, -and for me this has been an important part of the satisfaction at the end result. I thought at first that using an ‘off the shelf’ camera would be less likely to satisfy and wouldn’t have the quirks of a home made one. I have been surprised to find that this simple plastic box is actually one of my favourite pinhole cameras of all time, -and I’ve been making them since 1978!

Angle of view. I prefer wide and super wide pinhole cameras over ones that mimic a standard lens, mainly because I enjoy the distortions that occur when objects are placed close to the camera. The Walker has an equivalent angle of view to a 70mm lens on a 5×4 camera and considering that 90mm is a pretty wide lens on this format, it would seem that this was in the realm of super wide. It is roughly equivalent to an 18mm lens on a 35mm camera, so that gives you some idea. Previous to using this, I had been using a home made 10×8 pinhole camera which had an angle of view equivalent to an 11mm lens on 35mm. This really did distort and had quite dark vignetting in the corners. Mike seems to have got the angle of view exactly right with this camera, as there is sufficient distortion (yes, I know it’s rectilinear, -no pedantry please), but virtually no vignetting.

Using it is simplicity itself. A standard 5×4 dark slide fits in with a pleasing click and you are ready to expose by removing the tethered plastic cap. With home made pinholes, especially if made from tins or cardboard boxes, there is always the problem of positioning and stability. Unless you go to the trouble of gluing a threaded nut to the base of your tin (no point doing it with cardboard), you are limited to shooting from the ground or any place you can rest it, -this severely limits your compositional options. With a properly made camera you are provided with a tripod bush -two in fact on the Walker Titan, so shooting from a tripod becomes the normal method and opens up all sorts of image making possibilities.

All of the shots I have shown here, were done on Ilford Ortho film. It is great for this kind of thing because long exposures give nicer results (Ortho is 25 ISO -or less, if you want more tonality out of it). I like long exposures for pinhole, because things happen during the exposure which you hadn’t planned for, and provide unexpected and interesting results.

All exposures were all 90 seconds, and during that time people have stood in the scene for a while and then wandered off, leaving a ghost (beach scene) and the boats sitting in the corner of the harbour were bobbing about violently, as the sea was quite rough and have become very indistinct on the pinhole shot.

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Night photography

First posted 16 November 2009

Although the weather is turning much colder now here in the UK, I really want to get out and do some more night photography. I’ve not done any serious night stuff for a while now and keep seeing shots while I’m driving or at other inconvenient times. I try to make a mental note of the location with the intent of going back with camera and tripod, but you know how it is, it doesn’t always happen. So I’ve decided I’m definitely going out this week.

prospect road, nottingham

I prefer cool, slightly misty Autumn nights for shooting. This is because it gets darker earlier, giving me longer to work and the misty air separates the tones as they recede into the distance (known as aerial perspective). This gives a better sense of depth and drama to a scene and suppresses the bright highlights of distant lights.

10 night back lane

Autumn also brings a colour change and the orange brown leaves reflect the street lighting better. This year I have missed the best of the Autumn colours as we have had some really windy weather, which has stripped many of the trees bare.

Coming back to night photography after shooting other subjects and styles for a while, I was thinking about approaching it in a different way this time. Previously I had shot mainly on 35mm and medium format. Now I think I would like to shoot on 10×8 using a 300mm 5.6 lens. This would be used at it’s widest aperture to give a very shallow area of focus which I think will accentuate the theatricality of the lighting, making each shot look like a stage set. I’ll post some images when I’ve done them.

copleys bakery

If you are thinking of doing any night photography and the lights where you intend to shoot are the common sodium type, then you might find chart 1 useful. These are the starting point exposures for Ilford HP5 under ordinary sodium lighting (orange lights).

The much brighter high pressure sodium lamps which are seen along motorways and in many city centres are paler in colour and twice as bright.

Use chart number 2 for exposures with such lighting.

As can be seen from the charts, the exposures increase dramatically as you use smaller and smaller apertures, this is down to reciprocity failure. This is a problem with exposures longer than one second, where extra exposure has to be added.

For anyone interested in taking night photography further, I wrote a book on the subject which has now sold out, but you should be able to find used copies on Amazon.

Chart 1

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Chart 2

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star trails

old railway station

night mist

5 Comments

  1. Posted 16/11/2009 at 5:56 pm | Permalink

    Firstly I can recommend Andrew’s book on Night Photography – mine came via ebay and I am sure a little patience would pay off there.

    Andrew have you ever used any of the Fuji films where reciprocity failure is said to be negligible and it may be possible to use 100ASA film and still get shorter exposures than HP5+?

  2. Posted 16/11/2009 at 6:06 pm | Permalink
  3. Posted 18/11/2009 at 5:51 pm | Permalink

    Amazing as always :)