Fixed vs. variable focal length lenses?

[Meathook Jones]

What are the +/- of both types? Thanks

[tofuboy]

The simple ones...

fixed (prime lenses)
Pro: sharper, cheaper
cons: requires more lenses to cover the focal lengths you want

variable (zoom lenses)
Pros: flexibility of zoom (not needing to change lenses
cons: not as sharp, costs more

[robertwgross]

Hmmm. Fixed focal length lenses are one single length, so trying to perfectly frame up your subject would require you to move back and forth a lot. Fixed lenses tend to be slightly sharper than their variable cousins, and they tend to be slightly lighter in weight. They cost slightly less, also. In many cases, the fixed lenses can be faster (in terms of aperture).

Variable focal length lenses can be zoomed out and back, so you would find it easier to frame up your subject. Variable lenses sort of act like an infinite number of fixed lenses in one package.

If you are dealing with static subjects, you can move up and back with a fixed lens, and you can switch over to another different fixed lens, etc. That takes some time, but with a static subject, that does not matter.

On the other hand, if you are dealing with moving subjects, like wildlife, it gets complicated. If a deer might pop up in front of you at 200 feet, and then it might pop up at 40 feet, you are not going to want to fool around with changing to a different fixed lens. You'll have about two seconds to get the shot off, so I would vote for a zoomable lens here. For sports like baseball, if you tried to shoot only the first baseman from the right field line, you could do that easily with one fixed lens of the right length. But then if you needed to frame up the left fielder, that one lens wouldn't be right. You would need to switch to a different lens, and that would be awkward.

So, it just depends on your subject matter. I prefer zooms.

---Bob Gross---

[drisley]

Advantages:

Primes (fixed):
- Generally sharper corner to corner
- ....... faster auto focus
- ....... lighter (especially for lenses with larger apertures)
- ....... cheaper (hard to gauge since the prime only covers one focal length)

Zooms (variable):
- Generally more convenient
- Easier to frame subject

[MDJAK]

http://photography-on-the.net/forum/showthread.php?p=8586010&posted=1#post8586010

[DreDaze]

http://photography-on-the.net/forum/showthread.php?p=8586010&posted=1#post8586010


haha...why did you bring this thing back from the dead?

http://smileys.on-my-web.com/repository/Confused/confused-2.gif

[gasrocks]

Maybe someone is going after the record for the oldest thread on the first page.