17-40mm F/4 L or 16/35mm F/2.8 L I

[RustyTheGeek]

I have a friend who has the 17-40 and I have the 16-35 v1.  I love my 16-35 and I use it all the time.  She's happy with her 17-40.  They are both great lenses and you'll be glad you have either one.  Wish I could help you decide but alas...

Maybe rent them before buying?

[RustyTheGeek]

Go with the 17-40mm. For L standards, the 16-35mm MkI isn't good at all.

I disagree.  Maybe you got a bad copy.

[RustyTheGeek]

For the same price, the 16-35 would be the better option. When stopped down to F4, it is as sharp as the 17-40 and you have the advantage of being able to use F2.8 when you want to.

I agree with this but I also agree with the fact that the 17-40 is lighter and also that the 5D3 may be able help you compensate for the one less stop with ISO.  You'll be happy with either one!

[AudioGlenn]

I'm in a similar predicament.  coming from the 10-22 on a crop, I really liked 10mm.  My main concern isn't the extra stop of light as I will probably be shooting at f/5.6 to f/8 anyway.  I've read that in UWA lenses, 1 mm makes a big difference.  Is the difference between 16mm and 17mm significant?

[msmith0807]

I'm in a similar predicament.  coming from the 10-22 on a crop, I really liked 10mm.  My main concern isn't the extra stop of light as I will probably be shooting at f/5.6 to f/8 anyway.  I've read that in UWA lenses, 1 mm makes a big difference.  Is the difference between 16mm and 17mm significant?

Canon has a decent lens comparison tool so you can see the difference in focal lengths.  Give it a try, hope it helps. http://canonlenses.ca/Get-a-wider-perspective

I just recently went through the same decision process as well.  Bought a 5d3 about a week ago and was trying to decide on what UWA to get to replace my 10-22.  Decided on the 16-35 f2.8 II.  So far I couldn't be happier with my choice.

[killswitch]

I'm in a similar predicament.  coming from the 10-22 on a crop, I really liked 10mm.  My main concern isn't the extra stop of light as I will probably be shooting at f/5.6 to f/8 anyway.  I've read that in UWA lenses, 1 mm makes a big difference.  Is the difference between 16mm and 17mm significant?

Canon has a decent lens comparison tool so you can see the difference in focal lengths.  Give it a try, hope it helps. http://canonlenses.ca/Get-a-wider-perspective

I just recently went through the same decision process as well.  Bought a 5d3 about a week ago and was trying to decide on what UWA to get to replace my 10-22.  Decided on the 16-35 f2.8 II.  So far I couldn't be happier with my choice.

OMG, this is awesome. I am facing the same dilemma as AudioGlenn, this comparison tool is what I have had been looking for to confirm the 1mm difference between 17-40 and the 16-35!!! Thank you so much for sharing!!!