Just noticed something about my kit lens

Phal · 24 Oct 2012 at 18:10

18-135mm F3.5-F5.5 IS STM

I always saw the description of my lens listed with F3.5-F5.5 but I never quite realised what this meant until today when I noticed that the max aperture automatically changed to 5.5 at full zoom compared to 3.5 at min zoom.

Just wondering how common this is? I've seen some lenses with a variable max aperture whereas others just list one fixed aperture. I assume this is just down to the design of the lens itself?

jorzeh · 24 Oct 2012 at 18:15

Phal said:
18-135mm F3.5-F5.5 IS STM

I always saw the description of my lens listed with F3.5-F5.5 but I never quite realised what this meant until today when I noticed that the max aperture automatically changed to 5.5 at full zoom compared to 3.5 at min zoom.

Just wondering how common this is? I've seen some lenses with a variable max aperture whereas others just list one fixed aperture. I assume this is just down to the design of the lens itself?

All cheapo lenses do this, This is why the 24-70 f2.8s are expensive because its fixed throughout the zoom range.

Raymond Lin · 24 Oct 2012 at 18:20

And why I would pay £15,000 if they make a 14-200mm/1.2.

Although the front element would be massive!

Phal · 24 Oct 2012 at 18:22

Yeah I figured it must be a cost thing

It's not a bad lens but it just amused me that I hadn't noticed several months later lol

It'll have to do till I get my hands on something shinier

An Exception · 24 Oct 2012 at 18:24

I'd pay 15k just for a 14-85 1.2 Lol.

Raikiri · 24 Oct 2012 at 18:55

Raymond Lin said:
And why I would pay £15,000 if they make a 14-200mm/1.2.

Although the front element would be massive!

That lens would be bigger than you Ray.