L lens purely for aps sensors

[Robster]

Do we not think it is about time Canon produced an L lens range for there APS sized sensor bodies.
As we have the likes of the 50D and now the 7D which are high end APS models we need more than the EF-S lens range.
although they will fit you all know you just cant get a wide enough angle.

[donoreo]

I think something is missing here. L lenses are all EF mounts, which fit crop sensor models. Even EF-S lenses are still "cropped". Lenses are all listed by their full frame lengths, even EF-S ones. So the canon 55 -250 EF-S is multiplied by 1.6 times being 88 - 400. It is not just Canon that does this, they all do, except Nikon and Sony use 1.5 times.

Then again I may be missing what it is you are talking about

[anglefire]

Canon will never produce an L just for crop cameras. Why would they, as it would limit half the market.

They produce EF-s lenses for one reason. Cost.

Though they do make some EF-s lenses that are very good and could be considered a L lens - the 60mm Macro and 17-55 are two that spring to mind.

[flake]

The 17 - 55mm f2.8 is certainly a case in point, not a cheap lens even when compared to L grade lenses, but it indicates that Canon have no intention of marketing an EF-s lens as an L even when it has the quality to do so.

[Robster]

Yes the L lenes will fit but my point is it would be nice if Canon could produce say the 17-55mm in a L lens, the only L lens in my mind that is any use at the wide end on a APS body is the 16-35mm & the 17-40mm, otherwise its all telephoto and there is nothing for general use.
My Ultrasonic APS lenses do not produce results any thing like my L lens.
Its not a case of half the market the fact is the APS bodys are Canons bread and butter.

[flake]

There's a good reason why the L lenses are better performers tha your Aps -C ones. They are all designed for FF and therefore use the sweetspot to give better resolution and contrast. When you use these lenses on a FF camera they perform very noticeably less well. I borrowed a 17 - 40mm L for a test last week on a 5D MkII and the corner resolution is so poor that hardly any detail is resolved. Not a one off problem either, photozone said the extreme borders were so poor wide open they couldn't measure the resolution, but on a crop sensor it's a different story.

Putting a red ring around a lens and calling it 'L' doesn't magically make it perform better, which is what you appear to be saying. The 17 - 55mm would have probably been designated an L if Canon had wanted to produce an APS-C version, they didn't and all that's missing is a designation letter, I don't see why that is such an issue.

[anglefire]

I'm not going to say anything about photozone, because it will only be derogatory.

If you look http://www.the-digital-picture.com/R...0&LensComp=398

You can compare different lenses on different cameras (Not always the one you want mind you).

The corners, that Flake is so concerned about, are actually not as bad as Photozone make out. Comparing it to the 17-55 and the 17-40 is the better bet.

And in the real world, where it actually matters, the 17-40 is fine. And on a crop will be slightly better (You can compare the two on the above site with a 50D)

Finally, I do agree with Flake on one point at least. What's in a letter? "L" is stands for Luxury, nothing more.

[Robster]

Hi anglefire

thanks for the link I have found it rather interesting.

[flake]

Just a note about the Digital picture, it's not what I'd call a neutral site reviewing only Canon kit and some third party ones, it can be rather partisan in its approach which does occasionally fly in the face of accepted opinion.

What I was trying to illustrate is the way which an image degrades at the extreme edges regardless of the particular lens, some of them are worse than others but they all do show it.

The graphs which anglefire has posted show a centre resolution of something like 38 line pairs in the centre at f/4, but at the extreme edge this has fallen to somewhere around 18 which illustrates the problem.

The other problem is resolution, the higher it is the more noticeable the problem becomes, putting a FF lens on a crop frame camera means that the resolution will be quite high across the frame, so it won'r be as noticeable, but put the same lens on a FF and it will perform very differently, and this is the problem when you use an APS-c lens on a camera, because you have the same issue with border resolution that the FF cameras have. If that's something you don't like then stick to FF lenses where you can't see it as much.

I'll try to post some 100% crops tomorrow to show what happens. I've seen this effect on virtually every lens I've used, (some more than others) I thought the camera might have been faulty, but it's just the effect described above.

[anglefire]

Yes the site is biased, but with the samples, they are reasonably carried out and comparisions can be made.

(I've no idea where you get your numbers from Flake, unless you have copies of the charts)

If you really want a decent 17mm lens, then you should look at the TSE17mm - though its not as good as the new 24TSE.

But, I repeat, in the real world and not pixel peeping, then I really can't see an issue.



Ok, its not taken with the latest high res cameras, but is full frame.

Oh, and somewhere else to look at real pictures is http://photography-on-the.net/forum/...d.php?t=134756