First Experiences with a DSLR
edited: Sunday, February 11, 2007
By Sam Sillen
Rated "G" by the Author.
Posted: Saturday, February 10, 2007
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Where do you start with digital SLR photography?
It may seem simple enough at the very beginningóset everything to auto, point the camera at the subject and press the button. But get off on the wrong foot and youíll have to backtrack at some stage.
Basically, a digital SLR (Single Lens Reflex) camera is a light-tight box crammed to the gills with very clever and expensive technology, and you can attach a wide range of lenses to it. Straight out of the pretty box it may come with a fairly basic zoom lens, but donít assume that this would stop you taking arresting images with it.
Once the lens is attached to the camera, the new SLR photographer will need to insert a charged battery and a memory card on which new images can be stored. Todayís DSLRs produce fairly large images (measured in megabytes and pixels) so itís wise to invest in cards that will hold quite a lot of images, say 2 gigabytes. Higher capacity cards are available and cost more but if anything goes wrong itís easy to lose a very large number of images simply because they were all recorded on the one card. Perhaps several smaller cards are a better approach.
So with a suitable memory card and a fully charged battery in the camera the photographer is ready to shoot. And thatís very often where the disappointment begins! Poor images are usually the result of poor technique. Itís rarely the fault of the new camera. Understanding the basic controls of a DSLR will certainly boost confidence but images that are frequently blurred and improperly exposed will just lead to endless frustration and disappointment.
So what can we say about technique?
Well, it may help to firstly understand what actually happens when you first press down on the shutter button to record an image. Light passes through an adjustable hole in the lens called the aperture. A mirror that lets you see through the lens when you look in the viewfinder swings up for a moment and a mechanical device known as a shutter makes a precise timed movement allowing the light that holds the focussed image to strike the sensor (see Nikon image below). The sensor sits just where the film does in a conventional camera.
In an instant the information gathered by the sensor is passed as a stream of electrical signals that are converted into digital data before being processed by an electronic imaging Ďengineí.
But if the scene being recorded is quite dull, the shutter will have to stay open longer to make sure the image is properly exposed. What happens then? If the photographer is holding the camera in his hands, many details in the scene will not be recorded in exactly the same position on the sensor because of unavoidable movement. Itís very difficult and often impossible to hold a camera still enough at longer exposures. Thatís one reason why experienced photographers put a camera on a good tripod so that it canít move during exposure.
To put this information another way, itís usually, but by no means always, bad technique to hold a camera in your hands in low light without flash. But as explained in the cameraís manual, by increasing the ISO number the cameraís electronics and sensor can be made more sensitive to light. At ISO 100 in low light there is a good chance that the recorded image will be blurred if itís not on a tripod.
Another factor that can cause (or eliminate) camera-shake is the focal length in use. For example, a very wide focal length such as 17mm at ISO 100 may not result in a blurred image on a dull day simply because the enormous angle-of-view makes slight movement of little importance.
A general rule-of-thumb is to make sure the shutter speed is slightly ahead of the focal length. What does this mean? Well, if a lens is set to a focal length of 80mm make sure the shutter speed is set to a higher number, say 125th of a second. And even so, be sure to hold the camera as steady as possible. Camera-shake is less noticeable in smaller prints, but on the computer where you see everything at full-size you may find that the image you considered sharp on the cameraís LCD screen is in fact blurred. If this is the case a larger print will only make it more obvious.
So we begin the see that proper technique is very important indeed. Thereís no getting away from it! So when practising with a new camera it might be best to set the ISO to 400 if itís a dull day and take plenty of images of family and friends, or go for a walk in your own locality. If you donít have a tripod yet, try setting the camera on a wall and make the aperture in the lens very small (a number like 16 or 22 Ė the bigger the number the smaller the hole) so that the exposure time is automatically increased. People walking past will blur or even disappear! Flowing water will begin to look like cotton wool.
The new digital photographer should note that higher ISO settings (like 1600) can result in something called noise. It looks like tiny specks sprinkled here and there across the image, more noticeable in areas where thereís not a lot of detail. So for cleaner-looking images itís preferable, if possible and appropriate, to use a much lower number like 100. Lower ISO settings can be beneficial during image processing too.
Itís also important to learn that a DSLR camera is always trying to average out the tones in any scene it recordsóit gathers them together and calculates an exposure that wonít make allowances for large expanses that are either very bright or very dull.
In other words a scene where a polar bear is (hopefully!) sleeping on snow will turn a disappointing grey if the photographer doesnít override the cameraís settings and let more light in. At the other end of the scale, a black Labrador standing in the shade of very dark evergreen bushes will be overexposed because the camera will be aiming for a middle exposure and that will let too much light in.
And in the context of exposures, it's very important learn all you can about histograms as quickly as possible. A histogram is a graphical representation of the distribution of tones in an image. You'll find them in software and on the back of your DSLR.
Obviously there's a lot to learn, but good SLR technique is essential. With practice the new SLR shooter will quickly learn to avoid the typical frustrations that can quickly dampen enthusiasm.
The Role of the Computer
Apart from good technique the new DSLR shooter needs to get the images on the memory card into a computer thatís reasonably powerful. Once there it will be necessary to edit them to make sure they look their best. A card reader is handier than connecting a camera directly to a computer.
The card reader is connected to the computer all the time and the used card is simply inserted into it. The card will quickly show up as an icon which when opened holds a folder or folders where the new images have been stored by the camera. These can be easily viewed and copied to a new location on the computerís hard drive.
Beyond question the proper editing of digital images is a huge subject that we canít go into here, but be sure to invest in competent software especially designed to edit digital images in detail (see above). Itís pretty important too to buy at least a few really good books on this subject written by very seasoned digital photographers.
If youíre new to DSLRs you may be thinking about joining an online photo-forum where you can share your experiences with more experienced photographers. But a word of warning: donít be too quick to accept advice. Sometimes personal preferences and an innocent lack of experience will only compound your difficulties and cause further confusion. It's preferable to rely on good photo magazines. Read the more practical articles carefully, perhaps cutting them out as you go along and keeping them on file. Best of all, totally immerse yourself in several very good down-to-earth books on the subject.
Good luck with your DSLR photography! Itís an absorbing and satisfying hobby.