Digital pinhole photography

Digital pinhole photography is something I've not tried my hand at for some time so I thought I would refresh my mind, go back over some old notes and give it a try with my current gear. I wanted to answer two questions; would it be better/different with a newer higher spec camera and would it look different processing through Capture One rather than Lightroom. Below are some old notes reposted along with updates to address my two new questions.


My pinhole set-up

I have a simple low cost pinhole adapter based on a modified body-cap type design which fits my Canon EF mount DSLRs. These adapters are readily available for most popular camera mounts.



Pinhole adapter

DSLR with pinhole adapter fitted instead of lens


The focal length was quoted as 42mm (NB almost the same as the Canon EF flange distance which is 44mm) with an aperture of 0.25mm (not easy to confirm). These two parameters give a relative aperture of f168 (by dividing 42 by 0.25).

With the long exposure times required I place the camera on a tripod. Instead of a cable release I typically just set the drive mode to give a 2 second delay (and not worry about mirror lock-up).


Previous Lessons Learned


From my previous attempts at pinhole I discovered that the camera's stop down metering didn't work well, giving distinctly underexposed images so manual settings are required. When I had tried taking a light reading with my hand held light meter (a Sekonic L-758DR DigitalMaster) I found it has a minimum aperture of f161 (never previously an issue). It is possible to take the light meter reading at f161 (incident reading) and then allow another couple of stops or so. Alternatively just start with the exposure about double the camera's stop down metered time, then refine from there (for example on an average bright day try something like ISO 200 and 10 seconds as a quick ballpark starting point). Where exposures become excessively long increase the ISO.


Results this time


When I last tried pinhole I was using a Canon 5D mkII, with this looking through the viewfinder revealed nothing and live-view only showed a faint ghost of an image, making composition a guess. I found this a major headache, so got myself an external viewfinder.

Helios external viewfinder


This small hotshoe mounted device is the type of thing that might have traditionally been used with rangefinder type cameras. My finder is a Helios (found on eBay at just £22 in almost mint condition back in 2014) and marked with viewing guides for 35mm, 85mm and 135mm. The Helios is very straightforward and improves accuracy in lining up pinhole shots (can also be useful when using a 10 stop ND filter as this also blocks the camera's viewfinder completely).
NB If using the viewfinder close up then some allowance needs to be made for parallax.

However this time I was using a Canon 5D mkIV, which has much better low light capability, I found that in live-view (which allows it to work very much like a mirrorless camera) I was able to see my composition quite well and this made for quicker and more accurate composition.

Pagoda, Scottish Korean War Memorial

Torphichen Preceptory

Processing with Capture One was, not surprisingly, somewhat similar to Lightroom. I found a boost to saturation and some selective colour adjustment beneficial. I also made a small adjustment to reduce light falloff (vignetting). A heal layer allowed me to hide a few sensor dust spots (suggests I may be due a sensor clean, another topic for a blog post).


Pinhole Pros & Cons


The positives for a pinhole adapter are:

  • Very low cost or diy
  • Simple to use (no zoom, focus or aperture adjustments)
  • Small and light adapter, easy to carry
  • Encourages a slow and considered approach
  • Gives a unique style of image, very soft


The negatives for a pinhole adapter are:

  • It's a hole not a lens, dust may enter if not covered
  • Long exposures need a tripod, hand held needs very high ISO
  • Needs some experience in judging manual exposure
  • No DSLR viewfinder image can make composition challenging
  • Dust spots on the sensor have a tendency to be revealed
  • Lens EXIF missing or incorrect (I see focal length 50mm and aperture unknown)



Reflections


  • Having a better low-light camera so that I could use live-view made composition quicker and easier. I imagine the same benefit would be realised with many of the newer mirrorless cameras.
  • This pinhole adapter claims to be 0.25mm but I have seen claims that 0.30mm is optimum. I could consider permutations such as other hole sizes (may need to then make my own) and other sensor sizes etc to experiment with.
  • I had intended to try a zone plate and still might if I can find one.
  • It could be easier using lenses and then mimicking a pinhole effect in post processing (e.g. with NIK Analog Efex etc) though the results would not be the same as the real thing.
  • Images are very soft, this typically improves by going larger, i.e. medium format digital sensor (expensive) or medium/large format film (can be somewhat involved).

Comments

  1. Interesting. I've never tried it myself but might give it a go.

    ReplyDelete

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