How much wider is 17mm over 24mm?

I currently have the 24-105 and 70-200 f/4 IS lens. I'm thinking about adding a 17-40 but don't know if it's worth it because I'll only be gaining an additional 7mm. Will the additional 7mm in width make a significant difference? I own both a 5d II and a 40D. If the difference is not that much then I'll probably go in a different direction and get the Sigma 50 1.4 for its low light and bokeh advantage. Unfortunately, I only have funds for just one more lens.

The difference between 24 and 17 is quite significant. It's not "just 7 mm", because 17mm is 30% shorter than 24mm. The math doesn't exactly work out this way, but it's similar to the difference between 100mm and 70mm.

If you find yourself stuck at 24mm a lot and wish you could go wider, then the 17-40 or other wideangle might be worth it.

yeah, 17mm is a L O T W I D E R than 24mm. Hell, 20mm is even a lot wider. If you don't think it's enough range though, consider the sigma 12-24mm. 12mm on FF is O H M Y G O D W I D E ! ! !

go to a camera shop and try it out on your camera body to see what it looks like.

See:
http://www.tamron.com …cal-length-comparison.php

The linear magnification factor going from 17 to 24 is 1.4X. This means that the area of view is 1.4 X 1.4 = 2X as large. IOW, the FoV of a 17 mm covers twice as much as a 24 mm.

That is a very significant difference, and is why I will hold on to a lens that will do 17 mm, besides a 24.

Kind regards, Wim

A 35 has a horizontal angle of view of 54 vertical of 38
A 24 has a horizontal angle of view of 74 vertical of 53
A 16 has a horizontal angle of view of 98 vertical of 74

So there is a progression of horizontal and vertical changing places.

A 17 is horizontal 93 vertical 70.5.

So it is almost the same difference from 35 to 24 to go to 17 (16 would match up perfectly). Does 24 seem significantly wider than 35 to you?

Thanks for all your comments. Gives me a lot to think about.

jacobsen1 wrote in post #7802381
12mm on FF is O H M Y G O D W I D E ! ! !

Yeah it's nuts.

At the wide end a few mm makes a HUGE difference!

yogibear wrote in post #7802326
How much wider is 17mm over 24mm?

Remember all those fishing stories about the one that got away? How it's *this* big (gesturing with arms). That's 17mm.

yogibear wrote in post #7802326
I currently have the 24-105 and 70-200 f/4 IS lens. I'm thinking about adding a 17-40 but don't know if it's worth it because I'll only be gaining an additional 7mm. Will the additional 7mm in width make a significant difference? I own both a 5d II and a 40D.

Does it need to work with both bodies? Because the Canon 10-22 on the 40D is a great WA lens.

If you think about the difference between 17 and 24 mm being 7 mms..imagine the difference between a 17-40 and a 14 2.8L

14 2.8L on full frame made me go O H M Y G O D THIS IS WIDE!

hollis_f wrote in post #7803101
Does it need to work with both bodies? Because the Canon 10-22 on the 40D is a great WA lens.

I primarily use the 5d ii these days so I would need a full frame lens.

Here ya go:

http://forums.dpreview​.com …rum=1029&messag​e=24020518