SLR Professional versus Digital Kit Lens: Premium Lenses compared to Consumer Zooms from Canon and Nikon
Professional lenses are better, but not necessarily in ways that might be expected.
A comparison of different Nikon kit lenses, conducted by Gordon Laing, showed measurable, but small, differences in image resolution (sharpness) when compared with a 50mm F1.8 prime lens - widely reputed to be one of Nikon's sharpest lenses. Such small differences will not be noticeable in normal usage.
Why Kit Lenses have to be good
Entry-level DSLRs and their kit lenses obviously out-sell cameras aimed at professionals. This means that the general public will form an opinion of the different brands, mainly on the basis of the quality of each brand's cheapest cameras and lenses, not their professional equipment.
It would therefore be commercial suicide for camera manufacturers to compromise on something as basic as image sharpness and give their own brand a bad name. Other, less obvious lens performance parameters (detailed in the next section) are sacrificed in order to keep the price of budget lenses low.
The real advantage of Professional Lenses
Professional lenses can be sharper than budget zooms. However, the differences are difficult to detect under normal usage.
The more significant improvement is in one or more of the following areas
- larger aperture (brighter)
- wider angle
- longer focal length
- higher zoom ratio
- more rugged mechanical construction (to stand up to daily hard use)
- faster focusing
- less distortion (straight lines will appear curved to some extent in all lenses)
- less vignetting (corners of photo are not darker than the center)
- closer focusing (macro)
- less veilling flare (higher contrast, more saturated color)
- more pleasant "bokeh" (out of focus background)
Professional and Kit Lenses Compared
It is important to have a realistic expectation of what each lens can do. Professional lenses should be chosen with specific performance improvements in mind. For example
- larger aperture to take photos in dim light, without flash
- wider angle for unusual, dramatic perspective views
Photographers who blindly buy an expensive "professional" lens and hope that their photographs will then magically, automatically improve; will be disappointed. They will be better served improving their technique through reading and attending courses.
Photographers can affect the quality of their images through
- proper focusing technique
- selection of exposure metering mode
- balancing of aperture, shutter speed and ISO speed
- proper holding technique or use of tripod
- appropriate use of flash
It is the person behind the camera that matters the most, not the lens in front of it.