David S gave a full length presentation on Digital photography: the free software perspective which is too big to upload but which can be supplied on request.
He started by pointing out that:
images are data: the marginal cost of an image is zero
optical physics is maths: post-processing is open to anyone with a computer
information wants to be free: there has been a net-powered explosion of both ‘customers’ and ‘publishers’.
It has become a democratised art where the only limit is your imagination. For example, Panoramio can compute control points on ’photos to create a panorama around several people’s personal ’photos. This conflicts with the old publishers approach.
Now you can take a ’photo with your ’phone which makes them spontaneous and ephemeral, especially when your ’phone gets stolen and save it
to another ‘phone
to a memory card and print it at the supermarket
via a cable from the camera to the printer (with Pictbridge)
via a cable from USB mass storage to the PC — Xcept Canon/Nikon which needs gphoto2
which turns a computer into a media hub unaffected by developments such as the cloud.
Organising may be:
flickr — not very generous
Panoramio — landscape photos
fotopic.net — esp. trains, buses [no longer available]
Picasa — more generous
Twitpic n.b. not very secure; don’t actually delete pictures when you think they have been deleted
There are also specialised sites; choose the site that suits you; for example, flickr has local Bradford forums. Use geotagged ’photos for geotagged sites. For uploading ’photos Pixelpipe [no longer available] is very good
National Media Museum distinguishes copyright status where possible
Crown Copyright expires after 50 years
US Federal Government material is not copyrightable
GPL but must supply a copy of the licence
Creative Commons — does not require you to supply a copy of the licence; you can use it to say there is no copyright
Image capture faults include:
blooming (digital cameras only)
sensor noise (= grain)
sensitivity (user setting)
aperture (per image)
→ shutter speed
Because JPEG has lossy compression, the quality settings on cameras (resolution, colour balance, saturation and contract and sharpness) and are all about JPEG — always use the highest quality.
geometry: rotate, straighten, perspective
colour: white balance/saturation
Use curves and histograms to compensate for under/overexposure; a posterised image needs a RAW image; always consider perspective.
add captions — use EXIF tags instead
ExifTool: date/time, camera details, location — n.b. Firefox extension lets you see when ’photo taken; use date/time if cross timezone or battery flat and wrong date; consider privacy implications
gpscorrelate: to add location to EXIF [now abandoned]
Fulla — to correct lens faults, e.g. barrel distortion, vignetting, chromatic aberration; n.b. needs a database of lenses — but owner now charges for details of latest lenses
Lensfun — possible free alternative to Fulla
JPEG — 8 bit
RAW — all proprietary
Luminance HDR AKA Qtpfsgui — HDR tonemapping
Enblend/Enfuse — Enfuse uses an algorithm to calculate most important pixels and uses three (or more) ’photos with different exposures to create a better ’photo; n.b. don’t bother with noise reduction
hugin — panoramics
David then listed the other topics one might cover and gave examples of a wide range of photographs which had been manipulated in one way or another. He argued that this had led to democratisation in that:
everyone is a journalist
everyone is an artist
everyone has freedom to use works
we have a better historical record.
We have lost
the ‘cathedral’ culture
the long term survival of images.