DPReview.com is closing April 10th - Find out more

17-55 Aperture Advantage 2.8 New to DSLR

Started May 23, 2015 | Questions thread
Lemming51
Lemming51 Forum Pro • Posts: 15,278
Re: 17-55 Aperture Advantage 2.8 New to DSLR

If you're shooting at f/5.6 or smaller (larger f-number), then both lenses will give very similar result. Both the 17-55/2.8 and 15-85/3.5-5.6 have image stabilization to help hand-holding in low light with long shutter speeds.

The viewfinder AF works with aperture wide open, and many EOS cameras will AF with greater precision with f/2.8 and wider maximum apertures. And f/2.8 zooms often have more lens elements with better correction of optical aberrations than do f/3.5-5.6 zooms. Despite the shorter zoom range, the 17-55 has 19 lens elements (2 are Ultra-low Dispersion) compared to the 15-85's 17 lens elements using 1 Ultra-low Dispersion element.

Shooting the image with f/2.8 and larger aperture allows you to

  • give shallower depth of field, separating your subject from the background
  • use a higher shutter speed at the same ISO to freeze motion - both the subject's and yours if shooting hand-held

No right answer, both are very fine lenses. I chose the 15-85. YMMV.

-- hide signature --

Unapologetic Canon Apologist

 Lemming51's gear list:Lemming51's gear list
Canon EOS 40D Canon EF 50mm F1.8 II Canon EF-S 15-85mm f/3.5-5.6 IS USM Canon EF 70-200mm f/2.8L USM Canon EF-S 55-250mm f/4-5.6 IS STM +5 more
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow