Learning how to control depth of field with your camera isn’t too difficult, but do you know the science behind how it works? This uber-educational 20-minute video lesson gives a thorough explanation of depth of field and the different factors that affect it. It was made by artist Justin Snodgrass, and is also available for download (and in parts) over on his website.
When learning about ISO, you’ve probably heard that the lower the number, the lower the noise and the higher the image quality, but did you know that this isn’t always the case? The reason is something called the base (or native) ISO of a camera — the ISO achieved without amplifying the data from the sensor. This is usually somewhere between ISO 100 and ISO 200. Why does this matter? Bob Andersson of Camera Labs explains:
We all know that using high ISO numbers results in more sensor noise. More surprising, perhaps, is that using an ISO number below the native ISO number also degrades the image.
An interesting example is that when shooting on a Canon EOS 1Ds MkII, ISO 50 has roughly the same signal to noise ratio as shooting at ISO 800. This explains why the lowest possible ISO numbers can only be accessed through custom functions on some cameras.
You might have seen examples of Photoshop’s Content Aware Scaling feature in action, but do you know what goes on behind the scenes that allows it to magically work? This presentation from the SIGGRAPH 2007 conference sheds some light on the technical mojo that allows you to manipulate the size and shape of photos in crazy ways.
This is one of the most intense do-it-yourself videos I’ve seen, showing how to hack a Canon 18-55mm kit lens into a super macro lens for extreme closeup shots. It involves sawing, disassembling the lens, using wires from a floppy drive cable, and all sorts of advanced awesomeness. Unless you’re extremely good with your hands, you probably won’t be trying this, but it’s very interesting to watch nonetheless.
Last Friday an anonymous poster on the photography board of 4chan sparked a discussion that rippled into the blogosphere after freezing their camera to see whether ISO performance improves at lower temperatures.
They stuck their Sony A350 into the freezer for 15 minutes, and posted the following before and after comparison of noise at ISO 3200:
Regardless of whether or not these results were fabricated, it has long been (though perhaps not widely) known among photographers that digital cameras have better ISO performance (i.e. less noise) at lower temperatures, which is why sensors are often cooled for astro-photography. Other photographers also report improved ISO performance when shooting in very cold environments.
Zodiac Light did an interesting experiment in which a Canon 350D was cooled, and the amount of noise measured. They found that cooling the sensor resulted in a 40% drop in the amount of noise.
Obviously you shouldn’t freeze your nice camera to test this out yourself, but it’s an interesting fact to know, and could be useful if you’re interested in long exposure photography.