As I mentioned the other day, Canon's "L" designation is not actually a nomenclature for a premium product line. Rather, it denotes lenses which make use of one or more of a specified list of advanced technologies and that meet certain prescribed conditions. Canon's Chuck Westfall tells me that the list is the same now as it was in the late 1990s*, except for one thing: a few years ago, Canon added the requirement that any L lens be capable of covering 24x36mm or "full-frame."
But for that newest condition, several of Canon's best EF-S lenses would be L lenses.
One criterion that will earn a lens the coveted L designation is if it uses a ground-and-polished aspheric element. Canon, however, now mostly uses so-called "GMo" or glass-moulded aspherics. Although Canon did not invent GMo technology (I believe Kodak did**), originally it was usable for only very small-diameter lenses, and Canon perfected the use of the technology for larger-diameter elements of the kind needed for SLR lenses. GMo elements still have a high rejection rate and are thus more expensive than ordinary spherical elements, but they're much less expensive than ground-and-polished aspherics.
Original Canon 28mm ƒ/2.8 was introduced at the tail end of the era when lenses of this specification had to be small, light, and cheap. The new replacement is essentially a specialty lens, and has many
deluxe features...and a price to suit.
And that's what made the outgoing EF 28mm ƒ/2.8 "non-IS" lens pictured here remarkable at the time of its introduction in April of 1987. The lens had five elements, but the outermost element was the largest GMo aspheric element Canon had used in a commerical lens up till that time***. Since, by rough consensus, an aspheric element does the work of two spherical elements, the EF 28mm ƒ/2.8 was better corrected than other manufacturers' 5-element 28mms. (The lens was also notable for having almost no distortion.) So for that reason the outgoing lens is something of a minor landmark in the history of Canon lenses. It seemed quite exotic to me at the time.
Taken with the EF 28mm ƒ/2.8 "non-IS." Photo by Mandeno Moments.
Today, a 28mm ƒ/2.8 has become essentially a specialty lens, rather than a standard wide-angle that most every photographer will carry. The upcoming replacement, while not an L lens, has many features that it wouldn't have if the market conditions of 1987 still prevailed: rear focusing, ring-type USM, full-time manual focusing, optical image stabilizing...and, yep, several (Canon doesn't specify) GMo aspherical element surfaces.
*I know people are gonna ask, but I don't have the official list from Canon. Chuck has probably sent it to me twice over the decades, so I'm not gonna ask again.
**This was recently cited in an article about Kodak's downfall. It seems Kodak invented the technology for small-diameter press-moulded aspherics, but essentially gave the technology away because nobody at Kodak could think of a practical commercial application for it at the time it was developed. That was before cellphones became common; small-diameter press-moulded aspherics are now used in virtually all cellphone cameras. In the immortal words of Rick Perry, oops.
*** It wasn't the first. The FD 35–105mm ƒ/3.5–4.5 of 1985 was the first Canon lens to use a GMo aspheric element.
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Original contents copyright 2012 by Michael C. Johnston and/or the bylined author. All Rights Reserved.