Canon 16-35 f/2.8 DO Patent

[Canon Rumors]

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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]

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.

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]

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.

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.

[NXT1000]

DO so far is an waste of time and money. They have 70-300, 70-300DO and 70-300L. What? Is that too much of the same?  400DOf4 which is blown away by 400L in IQ. Price between 300f4 and 400DOf4 is too wide. Just do not make any sense at all. Who is canon targetting?  This 16-35 f2.8 DO again, who will buy this? why not buy 16-35 f2.8L or 17-40L for price, why make another 16-35 DO??? Another waste of time and money.

[dstppy]

Anyone else thinking a $1800-$2500 price tag here?

[hippoeater]

Is the 16-35 f2.8 Mark II really that bad? I've been considering buying this lens and almost every review I have read has been extremely positive.

[macfly]

I hate to ask this, but what is the point DO? I just read some reviews of the 70-300, and they aren't good, so why do another one?

I have the 16-35mm, and while it is pretty sharp it isn't super sharp. I've been thinking about swapping to Zeiss as none of the Canon wides test that well, except the 24TS which seems to be the one absolute stand out in quality.

[dstppy]

I hate to ask this, but what is the point DO? I just read some reviews of the 70-300, and they aren't good, so why do another one?

I have the 16-35mm, and while it is pretty sharp it isn't super sharp. I've been thinking about swapping to Zeiss as none of the Canon wides test that well, except the 24TS which seems to be the one absolute stand out in quality.

DO just means it's going to be more compact if I understand correctly.

I don't know how the 70-300mm performs, but I have it's non-DO cousin and I'm not enamored with it.

[neuroanatomist]

I hate to ask this, but what is the point DO?

Besides compactness, a DO element significantly reduces CA.  Of course, the current 16-35mm II is reasonably sized, and doesn't suffer from substantial CA.  So it's a really good question!  I suspect Canon's answer would have to be, "Because we can."

[JasonM]

I hate to ask this, but what is the point DO? I just read some reviews of the 70-300, and they aren't good, so why do another one?

I have the 16-35mm, and while it is pretty sharp it isn't super sharp. I've been thinking about swapping to Zeiss as none of the Canon wides test that well, except the 24TS which seems to be the one absolute stand out in quality.

The primary purpose of diffractive optics (DO) is to reduce chromatic aberration (CA).  Using a DO element to reduce CA can allow the use of other lens elements with greater refraction than otherwise possible and can eliminate other elements needed to control CA such as in an "APO" lens.

[JasonM]

I hate to ask this, but what is the point DO?

Besides compactness, a DO element significantly reduces CA.  Of course, the current 16-35mm II is reasonably sized, and doesn't suffer from substantial CA.  So it's a really good question!  I suspect Canon's answer would have to be, "Because we can."

Good point.  Weight or size reduction wouldn't be significant so either they believe the DO design would result in higher IQ than the current 16-35MM II or Neuro is correct and Canon is just filing the patent "because they can" or to prevent a competitor from releasing it with claims it is better.

[dstppy]

I didn't see it anywhere . . . how likely is it to show up without IS?

[Mt Spokane Photography]

I didn't see it anywhere . . . how likely is it to show up without IS?

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