I see so many photographers using DSLR cameras who are obviously not professionals. How many are freelancers hoping to earn some income, or keen photography enthusiasts looking for flexibility to create their works of art is unclear, but many are just using them for travel and personal event records. There is nothing wrong with that, but once you enter the world of DSLR gear, you had better be repaired to spend money. The desirable accessories including optional lenses seems endless. You will end up questioning your motive…am I becoming an enthusiast, or do I have aspirations of trying to earn income from my new passion, because I am spending quite a bit of money here!
Today’s digital compact cameras take pretty good quality photos in all kinds of lighting situations, with the better ones aimed at those wanting to be a little more creative in their photography, offering manual options that are needed to move from recording events to creative art images. However the cost of some of these high-end compacts puts them in competition with entry-level DSLR cameras, which might account for the number of DSLR cameras being used by snap-shooters. By snap-shooters, I refer to people just wanting a record of a time, place, or situation. Nothing fantasy, or artistic, just a record as seen by your eyes.
While the cost of some of the top-end compacts is close to that of entry-level DSLR cameras, the compact is definitely smaller, lighter and easier to carry around, with many of them able to slide into your pocket, so you can take them almost everywhere. The DSLR camera makes its’ presence felt. When you take it out you do so with photography deliberately in mind.
If you have decided you are really interested in photography as a hobby, or passion, you will undoubtedly be seeking the DSLR camera and equipment. An entry-level DSLR camera is the perfect choice to start with, not just because it suits your budget at this stage, but also because they make it easier on the learning curve than jumping in the deep-end with a complex fully featured pro-sumer or full professional model–small steps at a time! At some point down the line you might want to expand your passion, moving up a notch in quality and ability. This is when you might consider out laying bigger bucks for higher-end equipment. With the DSLR systems, lenses are independent of bodies. Many experts in photography will tell you an entry-level DSLR is quite capable of producing images as good as higher-end cameras, so why go to the unnecessary cost of upgrading! There is merit in that and unless you are going to expose your entry-level DSLR camera to the rigors of professional use and the elements, you would be better spending your money on the glass—that is the lenses you use!
When you chose a brand, make sure that brand offers many accessories, as these can be life purchases that carry over when you upgrade your DSLR bodies over time. Your lens will make the biggest impact on the quality of your images, so make sure your brand choice has a good range of quality lenses, as these seldom need upgrading and can be used on the next body you might upgrade to. As lenses are the most important component to image quality, I am going to tell you what I know about lenses.
Not all lenses are equal! You need to consider the focal length ranges, the build reputation, the size & weights, the physical parameters, the optical quality, cost and warranties. In general a fixed focal length lens, often referred to as a primary lens because it has a fixed wide aperture over the entire focal length, which in this case is fixed, will be of higher optical quality than a non-prime lens such as the majority of zoom lenses available.
There are seven properties to optical quality:
- Centre sharpness
- Edge sharpness
- Light fall-off
- Flair & ghosting
- Chromatic Aberration
Centre and edge sharpness are self-explanatory. However because bodies can come with different sensor sizes and aspect ratio crops, not all lenses are going to be compatible with each body type, even though they have a common mount so they fit each other. The standard is based on the 35mm film format. However digital sensors come in a number of different sizes, so while a lens made for the full 35mm size sensor will work on any sensor size, the reverse is not true. A lens specifically designed for a smaller sensor will not be too successful if used on a larger sensor body! Lucky, to date most manufacturers only offer two lens types for their entire ranges: Full frame and APS-C cropped lenses—Olympus being an exception on the APS-C, having a different aspect ratio. You can use the full-frame lenses on both body types, but the APS-C type lenses can only be used on APS-C sensor sized bodies. Edge sharpness and distortion is not so much of an issue where an APS-C format body uses full-frame lenses. If you are going to spend big money on lenses, make sure they are full-frame format lenses, so you don’t have to part with them some time in the future if you decide to upgrade to a full-frame DSLR body.
Light fall-off is the reduction in brightness from the centre of the lens to the edge. It is otherwise known as vignetting. The better the quality of the lens, the less light fall-off. Again as above, any light fall-off is reduced where a full-frame lens is used on an APS-C sensor body. Light fall-off also varies with adjustable focal length, as in zoom lenses, usually more prominent at the wide-angle end.
Distortion is often most pronounced at the edges of a lens, but can occur at the centre. Most distortion occurs at each end of the focal length range on zoom lenses. Pin cushion distortion at the long end and barrel distortion at the wide end. The greater the zoom range, the more likelihood of distortion! The distortion in a zoom lens can vary with its’ focal length setting and can be quite pronounced in a cheap zoom lens.
Bokeh is the faint blurred rings and iris shapes on highlights in the out of focus areas of an image, particularly from backlit and out of focus areas in the frame. Most prominent in shallow depth-of-field work with bright highlights such as the sun reflecting off the ripples and waves in the out of focus background (or foreground) of an ocean shot. It is caused by the lens iris, or diaphragm shape. Good quality lenses will address this with more blades used in the iris.
Flair and ghosting is the result of direct light hitting the front lens element and picking up the reflections from light reflected back the other way off an internal element–even the sensor, producing a ghost like reflection. This is addressed with lens-hoods for flair and super multi-coating of lens elements for both. The quality of the glass used in the lens also determines the amount of flair and ghosting. Lenses designed for digital cameras have further coatings applied to reduce problems from light reflected back off the sensor, which was not a problem with film. Something to bare in mind when using older lenses from the film days. The more elements used in a lens the more the chances of flair and ghosting! As zoom lenses use more elements than fixed focal length lenses, they are more likely to suffer from any flair or ghosting.
Chromatic aberration is seen as coloured fringing along the edge if objects in high contrast to the background. Usually purple in colour, but can also be green, or red. This again is a sign of a lower quality lens, but might also be influenced by the camera sensor quality. It is most apparent at the long end of a zoom lens in contrasty light and when an image is viewed at 100 %.
In summary, choosing a lens requires a little homework. You are never going to get the perfect 24mm to 600mm zoom lens with no distortion, light fall-off, flair and ghosting, chromatic aberration and perfect sharpness from edge-to-edge across the entire zoom range at all apertures! You need to compromise one thing against another. That means you need to know the purpose for which you need the lens. For sport and nature for instance you need a fast long lens. Distortion would be of a relatively low concern, while chromatic aberrations, flair and ghosting would be of major concern. For panoramic landscapes or wide-angle interiors, distortion and light fall-off is of a higher concern. For building architecture flair and ghosting is not so important, as you usually can choose the light via the time of day, but distortion is a major concern with all those horizontal and vertical lines. In fact for professional quality architecture work, a Tilt-Shift lens would prove invaluable to correct the perspective, particularly in wide-angle work.
Most general photographers will have a need for all focal lengths from time-to-time, but most commonly from 24mm (full-frame), to 200mm (full-frame), with perhaps a longer lens in their arsenal. To cover this range with quality optics, you will need at least two lenses, one to cover the wide end, another to cover the longer end. If you are using an APS-C format body for wide-angle work, then you might not have a choice but to purchase an APS-C type wide-angle lens. You should however have no trouble covering 40mm to 300mm with two full frame lenses. You might want to complement this with a third wider angle lens specifically designed for the APS-C body, as full frame lenses get very expensive when you go wider than 24mm.
A general photographer taking landscapes and street scenes might find they most commonly use focal lengths around 28mm to 35mm, while for portraiture 135mm. It is good under portable studio lighting to get back a bit from the lights, in which case a focal length range between 70mm and 200mm is handy. A wedding or function photographer using a camera mounted flash for low light indoor action shots will find a short fast lens with a focal length of 24mm to 70mm most handy.
For interior work, a focal length ranging between 14mm and 24mm is handy and even better if it has tilt-shift ability. For nature–wildlife and outdoor sport, a fast long lens between 200mm and 500mm is most useful. A long prime lens of greater than 400mm and faster than f/4 is also very useful. You could consider hiring what you need for special events, as some of these lens parameters lead to very expensive lenses.
If you are using these full-frame lenses on an APS-C cropped body, their focal lengths will be multiplied by the crop factor: 1.5x for most and 1.6x for Canon. You may need a third super wide-angle lens to get the wider angle. So for a range from 28mm to 135mm on the Canon APS-C body using full-frame lenses, the full-frame lenses would need to range from 17mm to 85mm. In view of the expense of full-frame wide-angle lenses under 24mm, it just might make more sense to use an APS-C lens on the APS-C body at the wide-angle end. When you decide to upgrade your APS-C body for a full-frame body, you will have to let this lens go with the APS-C body.
One third-party wide-angle lens that has built up a reputation of high quality is the Tokina 11mm to 16mm APS-C crop zoom lens and it’s brother the 12mm to 24mm wide-angle APS-C crop zoom. Canon also makes a full-frame 14mm wide-angle fixed focal length prime lens in its’ professional “L” series range–of superb quality for that focal length, however put it on an APS-C cropped camera and the focal length becomes the equivalent of a 22mm on a full-frame body, where as the APS-C specific lens focal length remain as stated.