What Does it Mean?
The term “DSLR” is a fairly new incarnation in the world of professional level photography equipment, and really only indicates the digital upgrade of the SLR technology. The SLR camera was functionally built for use with physical film, which was then developed in a more traditional dark room. In digital photography there is no need for this as it is captured as a digital file and processed and printed as a digital image. The format of the SLR camera set the blueprint for the DSLR and they are linked fundamentally and the differences in them is less about the type of camera and more about the storage format: physical film to digital files.
Single Lens Reflex
SLR stands for single lens reflex, which refers to the way that the lens is positioned. The light that forms the image goes through the lens and reflects off of a mirror and then heads to a ground glass. When you adjust the lens, as you do often with an SLR camera, it changes on the glass. The viewer looks into a prism that will then give you the image from the glass, which already went through the lens and mirror process. The mirror itself is positioned somewhat at the back of the camera, yet directly in line with the lens itself. The image then goes through a number of surfaces, exposing the film to this representation of the image through reflected light.
What the DSLR does is take the film out of the equation while maintaininf the single lens reflex format that it is built on. This does not necessarily change the way the image is formulated; yet film often produces a higher quality image than a digital file. This can still be up for debate and will likely change in the next few years of camera development.
One of the things that will be different when asking what is the difference between SLR and DSLR is the format for both the digital read out and digital control. While you may still look through a viewfinder instead of an LCD display, you will still be able to see the image once it is captured on a display of some sort. More than this, you will also be able to browse through images, alter the different ways that the sensor will interpret light, and be able to change the storage format that captures the image in a full size RAW format or compressed JPEG.
Same Basic Photography
The overall principles of photography will always remain the same, such as composition, usage of light, and technical specifications. It will not, however, protect you from the differences between the digital and film formats. In the same way that you have to compensate for different types of film stocks, working with digital formats will end up resulting in a different image type in a certain degree. You cannot necessarily expect to get the image quality on a lower end digital camera that you would with an SLR on appropriate film. This is both a combination between the camera type and the fact that it is imprinting the image on a format that does not always have the image clarity and style of film. At the same time, the level of compression and amount of storage you have on your available device is going to determine how much image information you have to work with when you go into photo editing.
When you are working with the camera, however, the base functions remain the same. The shutter speed, for example, will functionally work a little different yet the principle will be similar. The shutter works by opening up to allow light in, and on the conventional SLR camera this meant that it was exposing the film. The longer it is open, the more light is allowed in, and the more motion blur is allowed, so you have to negotiate where the shutter speed should be set. Now this simply refers to the sensor’s reading of the shutter control, yet for your image it will continue to be the same.
The bodies of the cameras may also be very similar, though many of the newer DSLR’s have a more sleek and smooth aesthetic. This means
that using SLR lenses on a DSLR are actually quite possible, as well as the other way around. Since they may be from the same manufacturer and have similar body construction you will find that using SLR lenses on a DSLR will be easy if they are set to be similar ahead of time. This will likely govern much of your DSLR purchasing choice if you already have a set of SLR lenses, and you can easily check with the company to ensure that your lens package will work on your new digital camera. For example, Canon lenses for their more standard SLR cameras are likely to work fine on their high end DSLR cameras. This cannot be set in stone unless it is verified by the company or camera store, but this is an easy check and most lenses are going to be easily compatible. This can even extend beyond brands and end up working across platforms.
Source: Author’s own experience.