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Canon 16-35 f/2.8 DO Patent

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Canon Rumors:
Share More lens patents This is an interesting DO patent from Canon. There seems to be a lot of them showing up, but no new DO products in a long while. I’ve been told the lack of an A+ filterable wide angle from Canon for a full frame camera will be addressed sooner than later. Yes, there’s Zeiss, but most want AF. Patent Publication No. 2011-145518
* Release Date 2011.7.28
* Filing date 2010.1.15 Example 1
* Focal length f = 16.48 – 24.00 – 33.95 mm
* Fno = 2.91
* Half angle of 52.70 – 42.04 – 32.51 °
* 4 aspherical surfaces
* Zoom Ratio 2.06
* Four-group zoom lens plus a negative sign
* Second lens focusing is performed by Inner Focus
* Solve various problems using the diffractive optical element
* The astigmatism of the telephoto kept in order, to increase the refractive index of the positive lens
* A high refractive index, chromatic aberration occurs
* Aberration and astigmatism in the center of the telephoto image has a correlation, it is difficult to simultaneously correct
* Made achromatic diffractive optical element, a positive lens astigmatism correcting high refractive index Source [EG] cr

Canon 14-24:
I think Canon has some extraordinary wide angle lenses, sadly though they are only prime (17mm tse and 24mm tse, maybe 8-15 fisheye?).  I could care less for af, but the versatility of the zoom would be most welcome!

pinnaclephotography:

--- Quote from: Canon Rumors on August 03, 2011, 09:20:46 PM ---I’ve been told the lack of an A+ wide angle from Canon for a full frame camera will be addressed sooner than later. Yes, there’s Zeiss, but most want AF.

--- End quote ---

Agreed.  Canon's only wide angle offerings that are optically competitive are the tilt and shift 17 & 24.  Beats me why Canon cannot seem to design a lens with decent corner performance; the 16-35L and 17-40L while convenient, lack the optical awesomeness of the Zeiss 2.8/21, 2/35, or the Nikon 14-24.  If Canon could replicate the Nikon 14-24 with Zeiss rendering/microcontrast, I would quite possibly trade a kidney for it.

While I don't personally see a terrible need for AF on a wide angle, I think I'm spoiled by the large viewfinders of full frame.  Without a large and precise viewfinder, manual focus lenses are of limited utility for most users.

Canon Rumors:
I added "filterable" to the post. The 14II and 17 TS are both great in my opinion, but neither is really the best landscape photographer solution.

If the 17-40 could be made sharp in the corners, the f/4 lens would be in every landscape photographers bag... well it pretty much already is.

pinnaclephotography:

--- Quote from: Canon Rumors on August 03, 2011, 10:40:41 PM ---I added "filterable" to the post. The 14II and 17 TS are both great in my opinion, but neither is really the best landscape photographer solution.

If the 17-40 could be made sharp in the corners, the f/4 lens would be in every landscape photographers bag... well it pretty much already is.

--- End quote ---

Yeah, any lens that doesn't take filters is kind of a downer for landscape work.  Unless one is willing to saw off part of an integrated lens hood and create/buy a custom Lee filter bracket...perhaps sometime I'll modify my Samyang 14mm to take rectangular filters at least...nevermind that the filters and mounting would be more expensive than the lens itself.  If relatively unknown brands like Samyang can create a 14mm that makes the 14L look like an optical joke for sharpness, CA, etc. (though Canon does redeem itself somewhat for distortion control) one would think that Canon might try at least a little harder to produce a decent AF wide angle.

The 17-40L is fine except at 17mm, which is terrible shame since most of the people using the lens probably use it at the wide end most of the time.  Past 20mm the output is perfectly acceptable in the sharpness category.  It would be understandable if the lens was only soft wide open, but the aperture seems irrelevant for 17mm...soft corners at any aperture.

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