If the 24L, 35L, & 50 f/1.4 all have the same constant max aperture...

What is lacking in the 50mm f/1.4 that doesn't qualify it as an L lens when the 35mm and 24mm have the same max/constant aperture? I realize that the 50mm FL has the 1.2 max aperture lens that is an L and even the older 1.0.

I guess the same question can be asked about the 85mm FL to a certain degree. Although, there are no other L lenses with the 1.8 max/constant aperture to compare it to.

Now, the 135L is technically slower than the 50 f/1.4 and the 85 f/1.8. However, it qualifies for the red ring. How is that?

Just something that I have been pondering for a while.
Can anyone offer any additional information? I apologize if this information is posted somewhere else, but I did a search and came up empty.

Thanks,
-KRUSH

L designation has nothing directly to do with max aperture. It's build quality and composition of the glass used that gives the L designation. Generally they will have larger max apertures than lenses of the same focal length. For the 50 f/1.4 to be designated L it would probably have to be dust/moisture resistant and contain UD or aspherical elements. This is why they are considerably more expensive.

well its kind of like the Sigma 50mm F1.4 HSM lens costs more than the Canon equivalent.... it just is!

"L" series has more to do with build quality and overall quality of the lens more than anything IMO.... Its just like Canon 17-55 F2.8 IS lens cost an arm and a leg and even matches "L" series lens in IQ but it is not an "L" lens because it has inferior build quality, no weather sealing, etc.

haha, KCMO Al just beat me to it with his post!^^^^

KCMO Al wrote in post #9248199
L designation has nothing directly to do with max aperture. It's build quality and composition of the glass used that gives the L designation. Generally they will have larger max apertures than lenses of the same focal length. For the 50 f/1.4 to be designated L it would probably have to be dust/moisture resistant and contain UD or aspherical elements. This is why they are considerably more expensive.

That's not always true.
There are several L primes that aren't sealed. (24L, 35L, 85L...and 135L even)

Well, once can safely assume any new L that comes out in the future will be sealed...(such as the 24L MKII)

In addition to what has already been said, the L glass typically has special elements, like ground glass asphericals, UD (ultra low dispersion) glass and or flouite elements, etc.

The Block diagrams at the canon camera museum can explain it better:
24L
35L
50/1.4
and for reference
50L 1.0

Canon does not have one specific set of features that make an lens an 'L' but there are several that are found in some combination on most:

Constant aperture zooms

Fast aperture for focal length (note that f/1.4 is not especially fast for a 50mm lens, while f/2 is fast for a 135mm lens and crazy fast for a 200mm lens. This is one reason the 50/1.4 is not an L).

Build level including weathersealing (another reason the 50/1.4 is not an L, and while the build of the 28/1.8 and 85/1.8 are nice they are not as nice).

Ring USM (another reason the 50/1.4 is not an L)

JeffreyG wrote in post #9248274
Ring USM (another reason the 50/1.4 is not an L)

Now, is there a difference between Ring USM and just USM?

There's two types of USM, Ring usm and Micro Motor usm. All the Ring USM lenses will be FTM (Full Time Manual) focus. All the micro-motor USM will not be FTM with the exception of the 50/1.4 It is the only micro-motor USM with FTM. Most of the small USM lenses (read "cheaper") will have Micro Motor.

There's better explanations out there I'm sure, but this will give you the basics: http://www.canon.com …museum/tech/roo​m/usm.html
And one more with even more detail http://photonotes.org …inner-faq/lenses.html#ftm

Here's another USM type explanation: http://kwc.org …2005-04-19.canon_usm.html

And of course just because a lens has ring USM, doesn't mean they can focus very fast...i.e. 50L & 85L.

JeffreyG wrote in post #9248274
Canon does not have one specific set of features that make an lens an 'L' but there are several that are found in some combination on most:

i'm just going to be picky here:

JeffreyG wrote in post #9248274
Constant aperture zooms

there are 2 current L zooms that are not constant aperture - 28-300L and 100-400L.

JeffreyG wrote in post #9248274
Fast aperture for focal length (note that f/1.4 is not especially fast for a 50mm lens, while f/2 is fast for a 135mm lens and crazy fast for a 200mm lens. This is one reason the 50/1.4 is not an L).

what about when a non-L has a larger aperture than a L?
case in point: 100/2 vs 100/2.8 L IS

JeffreyG wrote in post #9248274
Ring USM (another reason the 50/1.4 is not an L)

not including non-modern Ls, this point seems pretty convincing. BUT, what about the tse 24L II?

i guess the bottom line is that no one really knows what makes canon decide whether a lens is a L or non-L.

And what the heck is up with the S-L-O-W 800mm f/5.6? I mean, if I'm paying $12K for a lens, it should be faster than the kit lens.

generally L's -> build quality, glass, some are environment sealed (ex 50L is), AF motor accuracy...
having said that, L lenses aren't without flaws (some major).

besides , if your 50 f/1.4 is giving you the images you want, then why do you care about "L" badging/ring ?
but if youre ultra curious, perhaps rent a 50L and compare it with your 50 f/1.4 and see if its worth it to you.

I think people mis-read my post. To be clear, most L lenses have certain common features (a few lack some of these) like ring -USM, good build, FTM, weathersealing, metal mounts etc.

All L lenses have one or more special characteristics like these:

Very broad zoom range with relatively fast aperture (considering the zoom range and focal length):
100-400, 28-300, 24-105.

Constant Maximum Aperture zoom.
16-35, 24-70, 24-105, 17-40

Fast for focal length.
24L, 35L, 50L, 85L, 135L, 200/2.8L, 200/2L etc etc)
f/1.4 is really fast for a 24mm lens. It is only so-so for a 50mm lens.
And as noted above, f/5.6 is really fast for an 800mm lens (or even a 400mm lens).

Difficult and special wide angle coverage:
14L, TS-E 17L, TS-E 24L - These lenses have a very difficult job to cover a 35mm sensor.

Finally - special macro features
180L, 100L - combination macro and hybrid IS.