What makes "L" FD lenses so special?

All "L" lenses use some sort of special lens element. Conventional lenses(i.e. non-L lenses) tend to use conventional spherical, crown glass elements.

L lenses tend to use aspherical elements(as is the case for the 50mm 1.2L) to reduce spherical abberation, or fluorite or low dispersion glass to reduce chromatic abberation in really long focal length lenses.

L lenses are not necessarily better perfomers than their non-L counterparts-the L lenses are just generally faster. The 24mm f2, for example, gives better performance at all apetures than does the 24mm 1.2L.
The price, I think, on the used market is due to the fact that there's still quite a bit of stigma attached to L lenses. Most people will still pay a premium for them.

I believe it is quite fair to state that, in general, Canon's L lenses out-perform their non-L counterparts. This is certainly the case with one lens with which I have some direct experience: the FD 300mm f/4. The L version's chromatic aberrations are much better controlled. However, in most cases, there are no exact counterparts to the L lenses. And nowadays the most desirable Canon optics in terms of focal length vs. aperture are virtually all L lenses.

Some of the older, breechlock-style FD lenses used aspherical elements instead of special glass and were usually labeled as such, e.g., the legendary FD 85mm f/1.2 SSC Aspherical. I own one of these and it is a very nice lens, with very well controlled color. These lenses also usually have a premium associated with them.

On a side note, Michael, I've read that the 85 f/1.2 Asph isn't desirable for portraits because it renders such a sharp image. Would you say that's true?
Jim, I would be lying if I told you mechanical specifics, but the differences are seen in a more sturdy build quality, fast aperture, correction of abberations common in less expensive lenses such as spherical abberation, chromatic abberation, etc. In short, you get a sharper, cleaner image through fast glass built into a solid body. This is especially true when you compare cheap zooms to L zooms.

Robert, in answer to your question, I'd have to say honestly that I don't really know yet. I've owned my copy for a few weeks only, and so far the extent of my testing with the lens has been confined to our cat and some flowers and a few candids of my daughter. My early impressions of this lens are that it is not at all easy to use because of its razor thin depth of field. I have a split-image focusing screen with microprism circle in my F-1 (which I hate -- the focusing screen, not the camera), and I find that it doesn't work very well with a fast lens like this. On my list of future acquisitions for this camera is a plain ground glass screen. Back in the day, this was all I used in my old F-1s, and it's all I use in my Nikon F2, and I just prefer it.

Anyway, based on my limited use of the lens, I'd have to say that it's sharp, but not sharp like a macro is, and if shooting wide open, only the object on which one is focusing will be in focus anyway, e.g., the subject's eye. Chances are, the tip of the nose will be soft already, and the ears will be clearly out of focus. That's what was happening in the few shots I took of my daughter. The result overall was a rather creamy quality with a virtually wiped out background. Here's a not-very good example. Unfortunately, portions of her hair and her shoulder were in focus, but I missed her eye.

Canon F-1, FD 85mm f/1.2 SSC Aspherical @ f/1.2, Ektar 100, handheld. Shutter speed was 1/125 second.


At least I managed to get the following shot in focus. Canon AE-1 Program, FD 85mm f/1.2 SSC Aspherical @ f/1.2, Ektar 100, shutter speed 1/1000 second. The bokeh are rather busy, but they're only about 18" behind the flowers.

100% crop

Thanks for the responses. I meant to say originally that I have no "L" lenses, nor have I ever seen or handled them. Some day maybe, but I have not been disappointed with regular FD lenses.

the differences are seen in a more sturdy build quality, fast aperture, correction of abberations common in less expensive lenses such as spherical abberation

As I said above, this is not entirely true.
Lenses such as the 24mm f2, 135mm f2, and 400 4.5 are all top notch in terms both of build quality and optical quality.
They're not L lenses because they don't need to be.

Today in the EOS world, L lenses are also associated with better build quality and things such as weather sealing.

In the FD days, pretty much all professional quality lenses were constructed to equal standards, whether L lenses or not.

Robert, in answer to your question about the FD 85/1.2 Aspherical being too sharp for portraits, I have the FDn 85/1.2 L, and I'd have to say it's the best "portrait" lens (and best prime lens) I've ever used. And I have used more lenses than I could concisely list.

I'm not a fan of soft-focused portraiture, but am a fan of creamily smooth bokeh and DOF control for portraits, and the 85/1.2 L delivers these peerlessly. My aversion to soft focusing is partly because my main subjects are my young children (whose skin is unblemished anyway), and partly because, to put it somewhat tautologously, I like at least part of my subject to be well focused. Also, soft focusing tends to remind me, quite creepily, of soft core porn from the seventies, and I'd rather not be reminded of that!

I prefer the E screen of the F-1 to the Nikon K screens in Nikkormat and Nikon FE cameras but for critical focusing with a medium telephoto I prefer the L D screen. The grid lines provide a sharpness reference which a plain matte screen doesn't. My fastest Canon lens is a 55/1.2 FL. I wouldn't guess that it's as sharp as the 55/1.2 Aspherical or 50/1.2L. From what I know it has the same formula as the 55/1.2 FD, with older coating. It has very nice bokeh. Each lens has different bokeh. I prefer to close an 85 or 100 down to at least f/4 for a portrait. All of my Canon lenses are non-L types. I find the 85/1.8 New FD, both versions of the 100/2.8, the 135/2.5 FD SC and the 100/3.5 FL to all have nice bokeh and good sharpness. Recently I have been using an 85/1.8 FL for portraits with good results. For a short time there was an 85/1.2 Zeiss lens for the Contax SLRs. I wonder how it compares to the two 85/1.2 Canon lenses.
One of my favorite portrait lenses is the 100/2.5 Minolta MC. I don't know how a 105/2.5 Nikkor (early or late version) at f/4 compares to a 100/2 New FD or 85/1.2 Aspherical/L also used at f/4. If I don't need to get quite as close then a 135/2.8 Nikkor QC or K is also very nice. The two L lenses I might be interested in getting would be the 85/1.2 and the 300/4. I have so many good standard lenses in various mounts that I don't know how much I would appreciate the 50/1.2L. When I think of lenses I have like the 28/2 FD SSC, 35/2 FD SSC and New FD, 50/3.5 FD SSC and New FD, 85/1.8 New FD, 100/2.8 FD SSC and New FD, 135/2.5 FD SC and 200/2.8 New FD non-IF, they are already very good even without being L lenses. If you can't get a certain shot without a faster lens then an L might be your only choice. If that isn't the case then there are plenty of good non-L models to choose from.

Just another take on "L" lenses....

Some will say that certain non-L lenses are better than their L counterparts.

Very wide maximum apertures and extremes of focal length are the big challenges in lens design. These properties introduce certain optical problems that need extra help to counteract.

The "L" indicates, as has been said above, that the lens makes use of some exotic technology to solve a problem. In the wide-angles, standards and short telephotos, "L" means an aspherical element to control aberrations such as distortion, spherical aberration or coma. The L technology allows a faster lens without objectionable optical defects. Hence, the 24mm f/1.4L, the 50mm f/1.2L, and the 85mm f/1.2L, and the 20(24)-35mm zoom.

In the long telephotos, "L" means either ultra-low dispersion glass or fluorite element(s), which allow a much more complete control of chromatic aberration--the inability of a lens to focus all colors of light simultaneously. So lenses like the 300mm f/4L, 300mm f/2.8L, 400mm f/2.8L, 500mm f/4.5L, and 800mm f/5.6L can produce images virtually free of any color fringing. The exotic glass doesn't hurt in enabling those fast maximum apertures, either. And don't forget to count the outstanding 80-200mm f/4L zoom.

There are some FD lenses that have garnered a reputation as being "as good as an L lens." The 135mm f/2.0 may be the most celebrated of these. It's not an L lens, simply because they didn't have to resort to the expensive, exotic techniques--it was that good on its own.

Build quality among New FD lenses depends more on their intended price point and market, as well as date of introduction. It's not difficult to partition the line into low cost, medium cost, and premium lenses. There is so little perceptible difference in build quality among the medium and premium lenses that it hardly bears notice. The only lenses in the line that are clearly different are the low-cost lenses introduced late in the timeline, and these were influenced as much by general manufacturing trends in the industry as by any design dictum, I think.

Older breechlock FD lenses are inevitably built tough, but so was everything else in those days. But even these lenses have subtle internal differences depending on their price point. There is even sometimes some plastic in these "all-metal" lenses.

If you can afford to stop down a bit, you'll be hard put to tell any FD lens from another, except perhaps if you are making huge enlargements. Even the least expensive ones are capable of excellent performance.