Fixed Focal Length Free for all

Fixed Focal Length Free for all

The debate has been raging for years.  No, I’m not referring to the Chocolate vs. Vanilla great divide, as a photographer I know the biggest raging dispute is the Zoom vs Prime lens debate.

If you are not familiar with those terms, Prime lenses are often referred to as fixed focal length lenses, and as the name implies, they are of a fixed focal length.  Zoom lenses allow the user to zoom across a range of focal lengths.

Focal length and speed

The two most important aspects to consider when choosing the right lens are focal length and speed of the lens.  The focal length of a lens defines the level of magnification and the angle of view on the subject.  While the speed of the lens simply refers to the maximum aperture (smallest f/stop) the lens supports – a wider aperture allows for more light meaning you can shoot at faster shutter speeds. 

Prime lenses are typically more costly than zoom lenses, but they provide better quality optics with faster speed, whereas zoom lenses provide the most flexibility.  The decision to use a prime lens should be made carefully depending on the subject matter of choice.

Wide-Angle

Wide-angle lenses are up to 35 mm in length.  They allow for more of the scene to be included in the frame and can help to emphasis difference in size or distance between objects in the foreground and background. 

Dunhuang, Gansu, China - September 12, 2018 : Panorama of tourists at camel rides at Singing Sand Mountain dunes of Taklamakan Desert, Dunhuang, China.
Dunhuang, Gansu, China – September 12, 2018 : Panorama of tourists at camel rides at Singing Sand Mountain dunes of Taklamakan Desert, Dunhuang, China.

Photo © Karen Foley – Dreamstime.com

A typical wide-angle prime lens will be a 28mm.  They are often the lens of choice for landscapes.  The very nature of the sweeping landscape subject matter makes the choice of the wide-angle lens a natural one.  This also applies when trying to frame a small subject in the foreground – such as a flower or rock formation – in contrast to the size and magnitude of a background – like a mountain or a lake because the wide-angle lens will give the best separation of foreground and background.

Normal

A “normal” lens is usually in the range of 40 to 80 mm and provides a “realistic” or “normal” representation of the subject without distortion.

Mature Woman Among Rusting Metal in Junk Yard
Mature Woman Among Rusting Metal in Junk Yard

Photo © Karen Foley – Dreamstime.com

Therefore the prime lens of choice for studio portrait and wedding photographers is a 50 mm. It’s suitability for making great candid street photography also makes it a great choice for travel photography.  It can also be used to capture the individual panels used to stitch together panoramas due to its lack of lens distortion.

Telephoto

Telephoto lenses start around 100 mm and can extend to 600 mm and beyond.  The longer the focal length, the more magnification of the subject will occur.

football player in action makes a tackle in the game
football player in action makes a tackle in the game

Photo © Ponomarencko – Dreamstime.com

The major benefit of using a Prime telephoto lens for sports or wildlife photography is the speed of the lens.  Stopping the action of fast moving sports requires shooting at shutter speeds in the range of 1/1000, 1/2000 or even 1/4000 second, and these can often be shot in less than optical lighting conditions.  This lens will give you the best performance in those conditions.

Ultra wide-angle

Ultra wide-angle lenses are ones where the focal length is shorter than the short side of the sensor – less than 24 mm for full frame or 15 mm for cropped sensor DSLRs.  Ultra wide-angle lenses, like the fishery lens – offer a larger depth of field, but will introduce severe distortion, and as such are usually limited to using for special effects only.

Macro

If macro work is your passion, you are best to invest in a good Macro lens that can provide a 1:1 (life size) or better ratio.  The challenge with shooting tiny subjects is that most lenses have a focal distance too great to capture the details of small things.  The use of a normal lens with extension tubes can provide a relatively good work around, but comes with a cost to the depth of field. 

Jumping Spider - Macro Close Up
Jumping Spider – Macro Close Up

Photo © Jordan Roper – Dreamstime.com

Macro lenses are usually prime fixed focal lengths in a variety of options.  The guiding principles above can help choose the one right for you.

Regardless of the choice, you make for your Prime lens, remember that you don’t have to give up the zoom feature completely.  Zoom with your feet – get closer or farther from the subject, move up or down for different perspectives on your subject.  Zoom with your imagination – use the lens in a non-traditional way for greater creativity.

So the next time you are asked if you fall on the Zoom or Prime side of the argument, you have all the information you need to defend your choice wisely.

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