Jun 162009

Even when shooting images in raw format, it is typically easier to do simple sorting and sharing with jpg files. With Nikon *.nef raw files, it is possible to extract a full-resolution jpg image using the nefextract script. However, exif metadata is not automatically copied to this extracted jpg.

The tool that I use to manipulate my images according to their exif metadata is exiv2, and I can quite simply copy metadata from raw files to their corresponding jpgs (matching filenames, and all in the one working directory) with:

exiv2 insert -l./ -S.nef *.jpg

After sorting through the jpgs and deleting all but those worth keeping, I wanted to automatically remove the raw files of those deleted images. Sure enough, this is easily done with some bash shell magic:

for file in *??.jpg; do mv raw/${file%%.jpg}.nef 2> /dev/null rawKeep/ ; done

This command says “for each jpg file you find here, move the matching nef file from the subdirectory raw/ to the subdirectory rawKeep/”. I can then delete any files left in the raw/ subdirectory, as they mustn’t have a matching jpg.

People often ask my why I persevere with the “command line” (more technically the “shell”). It seems that they assume tools with graphical interfaces are more powerful and faster. These two routine tasks demonstrate yet again that the shell really is the most efficient way to do many common jobs.

Feb 022009

One of the really great things about storing photographs digitally is the ability to embed all sorts of information about the image in “metadata” within the file. When I shot film, I carried a notebook around with me that I tried to record exposure settings in (I was usually too lazy); I wanted to be able to learn from experience by looking at the settings I used to take a particular image. Digital cameras have trivialised this process, as they embed the exposure settings within each photograph.

But digital metadata is able to store much more than just the camera settings. In particular, it is becomming increasingly common to store location information (collected automatically by GPS). This is not so much to remind the photographer where they took the photo (most of us are pretty good at remembering that with reasonable precision), but it allows entirely new methods of displaying and browsing sets of photos.

Over the last few months I have experimented with various data acquisition and image display techniques for geo-tagging. This is a growing field, and so I’m sure there’s a lot more for me to learn. However, here are my findings and a quick demonstration of the results. Continue reading »

May 222008

While browsing some photos on Flickr the other day I came across an interesting artistic photography technique. It is known as the “Orton Effect” after a guy called Michael Orton, and involves superimposing a focussed image and blurred image (both overexposed) of the same scene. The effect is a mixture of sharp detail and blended colour that produces somewhat ethereal and emotionally engaging images. Orton developed the technique using slide film and physically mounting 2 images in a single slide frame, but it is easy to reproduce the effect with digital post-processing. Continue reading »

Oct 262007

My brother was down here in Canberra last weekend and showed me a very fun photography tool: hugin. It makes it relatively easy to stitch a series of photographs together into a panorama.

To test it out and play with some of its features, I took a series of photos around our living room. Here you can see the 8 photos from my camera, and the resulting panorama that hugin produced. Hugin not only moves the images around, but adjusts their rotation and barrel distortion to best line up control points that you identify on adjacent images. It uses enblend to give almost seamless stitching. Continue reading »

Sep 252007

Yesterday I succumbed to the special that Ted’s had on the cheap Nikon 70-300 long zoom. Normally $300, this is not at all a professional lens. However, it does have quite respectable Nikon optics and for the reduced price of $200 it was just too tempting.

I’ve already pointed it at the moon, and here is an un-cropped frame. It certainly brings things close, and would have been very useful during the recent lunar eclipse.

I’ll be back here to add more about this lens when I’ve had a bit of a play with it.

Jul 312007

For a while now I’ve been giving all my digital photos filenames that are meaningful to browse, useful to organise and easy (automated) to implement. The date is used to facilitate easy sorting, a few keywords are added to ease browsing, and the timestamp is added to ensure uniqueness. Thus, I end up with filenames like 20070731_a_great_photo_1425-39.jpg. Continue reading »