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Why Some Lenses Are Expensive. And, Would You Like a Lens?

by Erin Peloquin on December 8, 2009 · 10 comments

So, yes, I got that new Canon 7D for an early Christmas present.  And yes, I do love it!  My Santa, who is awesome and happens to be very handsome too, also gave me this fabulous 24-70 f/2.8 that so many of you recommended very highly!

canon 24-70

And here is the kit lens that came with the camera – a Canon 18-135mm f/3.5-5.6 IS (Image Stabilization).  Would you like to buy it from me? I’m selling it for $325 including shipping, which is nearly $100 less than Amazon’s list price and $125 less than B&H.  Read through this comparison, and if you’re interested, send me an email at erin @ TexasChicksBlogsAndPics . com.

canon 18-135

Why is the 24-70 was recommended so highly over the 18-135?  Both good lenses, but there are differences.

  • Weight – At 2.1 pounds, the 24-70 is over twice as heavy as the 18-135 (1 pound).  This isn’t a big deal to me (yet), but I haven’t taken the camera on vacation or for a long day at the zoo.
  • Speed - The 24-70 is a perfect example of what people mean by a “fast lens“.   Because the maximum aperture size is bigger (a 2.8 is bigger than a 3.5), the camera lets in more light.  Bringing in more light through the aperture means you need a shorter shutter speed for good exposure (the shutter is open to let in light for a shorter time.)  Shorter shutter speeds mean less time for the camera to move or your hand to shake while the pic is being recorded.  Less movement means sharper photos.  So, a faster lens is a good thing.  Phew. Did everyone get that?  Does it remind you of those crazy proofs we used to have to do in geometry?
  • Variable vs. constant aperture – No only is the maximum aperture different, but the 18-135 can only use the maximum aperture at shorter focal lengths.  So, if the camera is zoomed in to 70mm, the maximum aperture is only f/5.6.  At 18mm zoom, the maximum aperture is 3.5.
  • Amount of Zoom – obviously, the 28-135 zooms almost twice as far as the 24-70.
  • Wide Open Focus – ok, we’ve all heard that a lens is most sharp a stop or two under maximum aperture.  For the 24-70, that would mean an aperture of 5.6, and for the 18-135, that would mean an aperture of 5.6 – 8.  The left side of this image is the 24-70 at f/2.8, and on the right is the other lens at f/4.5 which is its maximum aperture at a 35mm zoom.

Wide Open ComparisonI took another shot to see if the results would be quite so drastic.

shot 3 widest apYou can definitely see a difference.  Not that my comparison is at all scientific. . . .  I did use a tripod and a remote.

  • Image Stabilizer - the 24-70 doesn’t have it.  This feature is great for improving focus in hand held photography, especially in lower light situations.
  • Price (oh yeah, the biggie.) – the 24-70 is almost $1300.  The 18-135 is $400.  (Unless you buy mine! :) )

So, is it worth it?  To me, yes.  I don’t mind the weight a bit and I love the flexibility that large apertures give me.  Having shot with variable aperture for so long, I really like the constant aperture on the 24-70.  However, the 18-135 is a great deal for the price, especially considering the Image Stabilization.  And if you need more zoom, the 18-135 might make more sense.  Plus, I think weighing 50% less is a good thing.

By the way, here’s something different abount the 24-70.  It zooms in reverse.  The lens is longer at 24mm than it is at 70.  (Don’t let this scare you if you get this lens.  I was beginning to question everything I learned about photography over the past couple of years when I first noticed it.)

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