Fixed vs Ranged Aperture Lenses


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buckwheat

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Nov 15, 2004
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Can anyone explain the pros / cons of getting a fixed lens like a 50mm f/1.4 vs a lens that has a 1.4-2.5 aperture?
 

buckwheat said:
Can anyone explain the pros / cons of getting a fixed lens like a 50mm f/1.4 vs a lens that has a 1.4-2.5 aperture?

I am not sure if there is such a lens as a lens with a fixed aperture.

A lens that says 50 mm f1.4 means that the widest aperture is 1.4, but it may close down to something like f22.

A lens that says 1.4-2.5 usually a zoom lens. At the shorter end of the zoom, the widest aperture may be f1.4. At the longer end of the zoom the widest aperture may be 2.5. This "variable" aperture in zooms are usually seen in lower end zoom lenses. The better ones have fixed aperture throughout the zoom range. The best I have seen are fixed at 2.8. Not that they cannot be made to be f2 or wider, but I think the cost will be so phenomenal that one will have to sell wife and kids to purchase these!

I have never seen a variable aperture from1.4 to 2.5 in zoom lenses. But then, the latest digital equipment may have things I am not aware of.
 

buckwheat said:
Can anyone explain the pros / cons of getting a fixed lens like a 50mm f/1.4 vs a lens that has a 1.4-2.5 aperture?

there is no such lens as 50mm f1.4-f2.5 :eek:


I think you are comparing zoom lens with fixed and different aperture values.

e.g
1. fixed aperture = EF28-70mm f2.8L

2. different aperture = EF28-105mm f3.5-4.5 USM


the advantage of fixed aperture lens over different aperture lens is you can use the longest focal length at the wide open

e.g.

you can use EF28-70mm f2.8L ==> 70mm @ f2.8

you cannot use EF28-105mm f3.5-4.5 USM =X=> 105mm @ f3.5 , you can only use 105mm @ f4.5
 

thanks guys, appreciate the help...
 

buckwheat said:
thanks guys, appreciate the help...

clear my doubt as well :bsmilie:
 

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