As Neuroanatomist points out
, Canon has re-designated the meaning of "-S" portion of the "EF-S" moniker.
"EF-S" initially stood for "Short-back Focus". One example of this designation comes from the 20 Years of Canon EOS
document that states:
"The launch of the EOS 300D also saw the debut of the new EF-S lens mount, the ‘S’ standing for ‘Short-back Focus,’ due to the fact that rear element of the lens is closer to the image sensor than in a regular SLR."
"If you look at the Canon Technical Report for the EF-S 18-55mm f/3.5-5.6 USM
, you'll see the notation, "*The "S" in "EF-S" comes from "Small image circle.""
Also, if you look at p. 128 of EF Lens Work III
(it's in section 7, The Basics of Interchangeable Lenses...), there's a notation that, "* Some of the EF-S lenses does not employ a short back focus optical system." Yes, that's grammatically incorrect, but correctly quoted, and highlights the fact that while all EF-S lenses have a small image circle, not all of them have a short back focus design (I believe, for example, that the EF-S 17-85mm does not have a short back focus optical design)."
(thanks Nuero and Sean)
Lens specs and measurements, distortion test results and vignetting test results have now been added to the Canon EF 500mm f/4.0 L IS II USM Lens Review
and the Canon EF 600mm f/4.0 L IS II USM Lens Review
Here is a roll-up of the planned new Canon DSLR and lens availability dates that I am aware of: Canon EOS 1D X
Canon Japan is stating "June 20, planned" for the arrival of this long awaited DSLR. Expect extremely limited quantities to be available for a long time. (thanks Kaz) Canon EF 500mm f/4.0 L IS II USM LensCanon EF 600mm f/4.0 L IS II USM Lens
Both lenses are shipping now in the USA including from B&H
. But, supplies are extremely limited and only the earliest preorders are getting filled. Canon EF 24mm f/2.8 IS USM LensCanon EF 28mm f/2.8 IS USM Lens B&H
just extended their expected availability date from June 17 to June 27. Canon EF 40mm f/2.8 STM Pancake Lens
Retailers are not stating the availability date for this highly-anticipated lens. The USA press release says "end of June". Canon EF-S 18-135mm f/3.5-5.6 IS STM Lens
The big USA retailers are not even showing this lens on their websites. The USA press release again says "end of June". Will these initially be available in Rebel T4i kits only? Canon EOS Rebel T4i / 650D DSLR
The T4i bodies are now showing up on retailer's shelves in the USA. (thanks "D")
The bodies and with-18-55mm IS II Lens kits showed up at Amazon
as I was typing this. B&H
lists the body and body w/ 18-55 II IS Lens as "Expected availability: June 18 2012". Adorama
is saying "Delivery scheduled to start June/18".
The Canon USA press release indicates that the Movie Kit bundle is expected at the end of June, but retailers are not listing the availability dates for this T4i version. Canon EF 200-400mm f/4L IS USM Ext 1.4x Lens