Reader question

Today, another reader question that I think may interest others. Reader (and student in one of my workshops) Chuck asks:

I wanted to ask you a second question since my class – this time about Canon lenses:

I’m looking for a wide angle Canon EF lens, and I’m seeing two choices:  17-40MM L F. 4.0 lens and for literally twice the price, a 16-35MM F2.8 lenses.

Having heard you educate about ISO abilities & Lightroom capabilities and seeing your picture of lenses ( I’m wondering why you choose the more expensive 16-35MM F 2.8. over the 17-40MM F 4.0  I read a lot of praise for the F2.8 lens and mixed praise for the F4.0 lens…. but just wanted your perspective please on these two L series lens before I make the purchase.


Great question, Chuck.

First of all: either lens would be superb. They are both high quality “L” lenses. On a full frame camera like my 1Ds this is a very wide angle lens; on a crop camera like my 7D this is a wide-to-standard lens. All great.

So why do I go with the 16-35 f/2.8 instead of the 17-40 f/4?

Two reasons.

  1. A wide lens is easy to keep in focus all over the place, focus from the tip of your nose to infinity. The wider, the easier this gets. But what if I do not want that? What if instead I want selective sharpness, with a really, really blurry background? Then on a wide angle lens I need very low f-numbers to achieve that. F/2.8 is better than f/4 (which is better than f/5,6, and so on). ISO will not help here.
  2. Light. A wider lens lets in more light. One more stop may not seem much, but in the low light environments I often shoot in, that extra stop can be the difference between a lost shot and a good shot. ISO can of course help, but in that case the more expensive lens can be the difference between me having to shoot at 3200 ISO and being able to do it at 1600.

That’s why I chose the 16-35. The 17-40 would also be a super l;ens, and if you do not need the extra depth-of-field control and you do not shoot very dark environments all the time, the 17-40 will be great as well. I used to own one and loved it.

Why is the 2.8 twice the price? It has literally twice the glass in it, that’s why (a larger aperture means more of that expensive optical glass). So it’s not just marketing!

Advice: go into your camera store and hold both, feel them, try them out. Then, you will know. And since either choice will be superb, you will be happy!


5 thoughts on “Reader question

  1. I had the same dilemma choosing an ultra-wide zoom for a 5dmk2 last year. In the end I chose the 17-40 mostly due to cost, the 16-35 is only about 60% more, but it was still a big jump. 17-40 might even be a bit sharper at f/4, but it wasn’t an issue either way. They’re both such awesome lenses in the end, the 17-40 is also the cheapest weather sealed lens to boot! I admit there have been a few times where I’ve wished to have another stop for low light though, so food for thought.

    Having used the 14mm f/2.8L version 2, I hope to add that to my camera bag next, it is absurdly sharp despite being so fast and dramatically wide. What a piece of optics that is…

  2. in low light environments…having the extra stop definitely helps. i have experienced it myself…

    that said, do you still use a speedlight in low light conditions with the aperture opened as large as it can go?

    • Very much so, Richard. In low light environment (club, anyone?) you need every single stop you can get. I sometimes have to use my prime 35mm lens set to 1600 ISO, f/1.4 and 1/15th second, just to get light into the background in those awfully dark environments. That is extreme, but it proves the point, I hope.

      • in the situation you mentioned (1600 iso, f/1.4 1/15th), how would you position the speedlight? closest wall? or just up to the ceiling

        • That utterly depends on the circumstances. Closes wall or ceiuling, preferably, but sometimes straight at the subject, or bounced off a Honl bounce card, or even using a Fong Lightsphere.. Whatever works.

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