Like many Australians, this year my partner and I have decided to holiday close to home and, having a long-standing interest in geology, we thought a trip to New Zealand’s thermal regions would provide us with some great picture-taking opportunities and, at the same time, provide a chance to explore some radically unfamiliar landforms.
We investigate why digital camera lenses have more depth of field than 35mm lenses – and how it affects your photography.
I had recently been challenged by shooting some high-contrast scenes with my digital camera (with mixed results) and this prompted me to research the subject of Dynamic Range as it relates to both film and digital imaging generally. I also have a flatbed scanner and a film scanner, so the subject has been lurking in the back of my mind for some time.
Have you ever noticed small darkish patches in areas of blue sky in landscape photos taken with your digital SLR? They’re probably produced by dust on the image sensor. In most cases, it’s not on the sensor itself, but on the filter or protective glass that covers it. The result is the same; it shows up on digital photos. Not all of them, though; in most cases, dust is only visible in shots with large areas that have minimal detail when the shot was taken with a small lens aperture.
For the first half of the 20th century, photographers had to gauge exposures without a light meter. It was common at the time for film packets to have a set of exposure guidelines printed inside them to help photographers obtain correctly exposed pictures under a range of typical lighting conditions. Many photographers still use these guidelines, especially for tricky lighting conditions, when difficult-to-meter subjects like large areas of snow or wedding groups containing white dresses and black suits can produce incorrect exposure readings.
Different places and different times of day can affect the colours you capture in a digital photograph and all image sensors are designed to reproduce a wide range of hues and tones accurately. From the harsh desert sunshine to the misty rainforest; from sunrise to dusk; indoors and out; your camera should be able to produce pictures that capture the colours and atmosphere of the place and time of day.
The normal distribution of tones in a digital image produces a smooth histogram with every one of the 256 tonal levels occupied. In a correctly exposed image, the peak of the graph is in the centre and the graph tapers down at each end to the 0 and 255 points.
Clouds have been a popular subject with photographers since panchromatic film made it possible to differentiate them from the sky in photographs! They still remain popular. The inclusion of interesting clouds can make a landscape shot, and they are often worth photographing simply for their structural beauty. However, photographing clouds can present some problems for digital photographers.
Expect to hear a lot more about colour fringing in digital photos as the pixel counts for compact digicams continue to rise, while sensors become smaller. At the same time, expect to see the true reasons for colour fringing misattributed more often than not. To ‘put you in the picture’ (so to speak), if you see coloured fringes along edges in a photograph it can be attributed to one of two effects: chromatic aberration or blooming. The problem is deciding which one is the cause.
The burst (or continuous shooting) mode on a digital camera is a new feature for those who have never used a film SLR but a familiar one for most SLR users. However, the way it works – and the options provided – are quite different on digital still cameras (DSCs). Whereas film cameras were dependent on how quickly and accurately the motor drive could jump the film through the film gate, digital cameras rely on the speed of the data processing system and the size of the internal ‘buffer’ memory where the image is stored while it awaits processing.