Posted by Tim Cady - Sales Associate Berger-Bros Camera on August 09, 2016
There are numerous and age-old opinions about the difference in quality between fixed focal length lenses (primes) and variable focal length lenses (zooms).
Just to clarify a few definitions. Prime lenses are a fixed focal length lens.
Examples are: 20mm, 35mm, 50mm, 85mm, 200mm, 300mm, 400mm and even 1000mm.
What that means is that these lenses will only have these focal lengths and when attached to the camera this is the only focal length that can be seen through the camera.
Zoom lenses are defined as a lens with variable focal lengths. Many different focal lengths are available to the camera now in one lens and the user can zoom through each variable focal length allowed by the lens.
Examples are: 14-24mm, 24-70mm, 70-200mm, 150-600mm and even wide range zooms that cover 16-300mm.
Even though the prime lenses have but one focal length, the maximum aperture in the lens is usually larger than zooms. Example: 50mm f/1.4 vs. 24-105mm f/4.
These again are the maximum aperture openings but all of these lenses can be “stopped down” to a smaller aperture to affect depth of field or lighting conditions.
Now some zooms are getting larger maximum apertures such as f/2.8 and even 1.8 but some primes lenses have a maximum aperture of f/1.2.
A very large aperture lens can give a shallow depth of field for stunning out of focus backgrounds or shooting in very low light usually associated with prime lenses.
A zoom lens can combine many lens lengths in one so there are fewer lenses to carry.
In the distant past, prime or fixed lenses were the norm and all film SLR or rangefinder cameras usually came with a fixed focal length lens such as a 50mm f/1.8. If one wished for a different focal length one would get a different lens suitable to the type of photography involved from ultra wide angle to super telephoto. This might require a large amount of lenses depending on the desired working distance or angle of view.
In the recent past, manufacturers have come up with zoom lenses for DSLR’s that would lighten the load so photographers would have many focal lengths in just one or two lenses and recently these zooms had reasonably large maximum apertures, mostly f2.8.
Now to the meat of the matter.
There has been some argument about the image quality difference between zoom lenses and primes, notably sharpness and resolution.
In years past, this might have been true but today with the use of computer aided design, zoom lenses and prime lenses seem to be equally as good. One might see an ever so slight difference by enlarging the image to a very large percentage and doing a little pixel peeping. The winner possibly being the prime lens. But for all around purposes, they are pretty much on par. One might also use primes for strictly video because of the camera movement and rigs and sliders to capture slow cinematic scenes in low light as well. One might use zooms to shoot landscape, portraiture, events and studio to crop the image or compose easier right in camera,
So the bottom line is, use the right lens for the right type of photography and you'll certainly get professional results with this in mind.
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