L Lenses for crop bodies

[RichM]

I disagree. First, you have to take the sensor into account - you'll get better IQ out of the combination of L-lens and FF sensor than that lens on APS-C, even considering the soft corners of an UWA zoom. Second, an L-lens on crop won't necessarily outperform an EF-S lens - for example, the EF-S 17-55mm is better than both the 17-40L and 24-105L on the same crop body.

Since I don't have the EF-S 17-55, I can't comment on that lens. I have read that it is quite impressive, and some argue that it should be the EF-S 17-55L . However I am pleased with both the 17-40L and the 24-105L on my 7d, and enjoy the added bonus that I can use either on my 5d3 as well.

 

[Sporgon]

Surely there are plenty of L lenses for crop bodies. Just snap one on and start shooting.

 

[WPJ]

You'll notice I said "for a given focal length". To be completely precise, I should have said, "for a given focal length, maximum aperture, and minimum focusing distance". You can't really compare apples to oranges.

That said, making the lens smaller and lighter is just one possible option, obtained by using a similar number of elements and a similar design. Alternatively, instead of making the lens smaller and lighter, you could instead choose to provide a larger maximum aperture, add macro capabilities, or correct for CA and other artifacts more completely (which is arguably more critical when you're dealing with the higher pixel density on crop bodies). Either way, there's still a benefit over the full-frame glass.

but your not,comparing similar lenses, toss the 25-105, or you can't say that because the 24-105 is way better at 60mm than the 17-55 considering it won't go there.

and for the 17-55 vs the 17-40, that's f2.8vsf4, I would naturally expect the f2.8 to be better.

lets talk apples to apples, but really there is non.

my point is that there is nothing wrong with using,L glass on a crop

Perhaps...but the point seems rather moot for the original discussion concerning EF-S primes, since there's only one. Also, I wasn't questioning that an EF-S lens could be smaller and lighter than the same focal length/aperture in an EF lens, but rather your figure of 'two-thirds' the size.

Any L lens will perform just as good is not better on a crop as you won't get as much of the soft corners people always complain about.

I disagree. First, you have to take the sensor into account - you'll get better IQ out of the combination of L-lens and FF sensor than that lens on APS-C, even considering the soft corners of an UWA zoom. Second, an L-lens on crop won't necessarily outperform an EF-S lens - for example, the EF-S 17-55mm is better than both the 17-40L and 24-105L on the same crop body.