Patent: Canon EF 100-400 f/4.5-5.6 DO

[Canon Rumors]

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<p>A new patent showing an optical formula for an EF 100-400 f/4.5-5.6 DO has made an appearance. The patent also shows what appears to be a new 70-300 f/4.5-5.6 DO optical formula. Canon appears to be continuing their investment in diffractive optics R&D, though we haven’t seen a new DO lens in quite some time. I don’t think we’ll see a new 100-400 with the technology, and with the current 70-300L being pretty small and light, I’m not sure we’d see a new 70-300 DO either. It’s good to see they continue to develop the lens concepts though, and hopefully we see some new ones in the coming years.</p>
<div id="attachment_16563" style="width: 447px" class="wp-caption alignnone"><a href="http://www.canonrumors.com/wp-content/uploads/2014/05/2014_89385_fig01.png"><img class="size-full wp-image-16563" alt="EF 100-400 f/4.5-5.6 DO IS" src="http://www.canonrumors.com/wp-content/uploads/2014/05/2014_89385_fig01.png" width="437" height="429" /></a><p class="wp-caption-text">EF 100-400 f/4.5-5.6 DO</p></div>
<ul>
<li><span>Patent Publication No. 2014-89385</span>
<ul>
<li><span>Publication date 2014.5.15</span></li>
<li><span>Filing date 2012.10.31</span></li>
</ul>
</li>
<li><span>Example 1</span>
<ul>
<li><span>Zoom ratio 3.78</span></li>
<li><span>Focal length f = 103.00-200.00-388.94mm</span></li>
<li><span>Fno. 4.63-5.24-5.83</span></li>
<li><span>Half angle ω = 11.86-6.17-3.18 °</span></li>
<li><span>Image height Y = 21.64mm</span></li>
<li><span>228.82-273.58-303.10mm total length</span></li>
<li><span>BF 69.48-90.93-105.73mm</span></li>
</ul>
</li>
<li><span>Example 6</span>
<ul>
<li><span>Zoom ratio 4.00</span></li>
<li><span>Focal length f = 72.50-135.00-289.99mm</span></li>
<li><span>Fno. 4.44-5.04-5.85</span></li>
<li><span>Half angle ω = 16.62-9.10-4.27 °</span></li>
<li><span>Image height Y = 21.64mm</span></li>
<li><span>143.91-177.69-203.15mm total length</span></li>
<li><span>BF 39.10-39.10-39.10mm</span></li>
</ul>
</li>
</ul>
<p><strong>Source: [<a href="http://egami.blog.so-net.ne.jp/2014-05-24" target="_blank">EG</a>] </strong></p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>
<p> </p>

 

[lol]

I'd like to see a new updated 70-300 DO. I used to have the current one. It was a bit poor wide open but decent at f/8, but what really struck me was the size. The 70-300L isn't even close to being as small.

If they were to release a new 70-300 DO, improving on the weaknesses of the old one, at a similar size, I could see myself looking at it once again as a travel lens.

 

[preppyak]

Canon dropping the new 100-400 as a DO lens would make for some interesting reactions

 

[traveller]

Unless Canon have made a breakthrough, then DO whilst an interesting concept, is not ready for use in mainstream lenses like the 100-400mm replacement. An important update such as this simply has to prioritise superb optics over light weight, not to mention the price of DO lenses in relation to their conventional counterparts!

 

[wtlloyd]

Canon dropping the new 100-400 as a DO lens would make for some interesting reactions

+1 exactly what I was thinking. :

One can only wonder if there isn't some technical issue they think they can resolve in time and then capitalize on, else why pursue the technology without releasing new lenses?

 

[lol]

Looking at the current DO compared to the L, the DO is slightly cheaper.

I think DO has promise, but only if they bring it into the mainstream and out of the odd niche it has now. I think there is space for a reasonable quality mid range lens, placed between the non-L and L, especially if smaller size was a contributing factor. May go nicely with a 100D as a small(er) DLSR setup.

 

[dolina]

I wonder how much more Canon could charge for a 100-400 DO that is half the weight & size of the current 100-400 L.

 

[PhotographerJim]

I have the current 70-300 DO, I use it often. I love the small size & light weight. For all the bad opinions it gets it really is a great lens. I don't know why most people are so negative about it, I'd buy it again. It does have less contrast, but there is a camera setting for that. Dial it in, and you're good to go.

Granted, I didn't buy it new, $1400 seems too much for it. I got an almost new one for $550, I guess that's one benefit of all of the negative reviews

 

[Mt Spokane Photography]

Canon is and has been developing a radial diffractive (anomalous dispersion )optics that is basically a resin lens filled with minute particles, rather than the old design that uses multiple layers of gratings.

So far, they have been unable to come up with good enough process control to get a high yield. Those particles need to disperse perfectly to get the refractive index just right for each color. Since they continue to put out patents using the new technology, they must feel that its possible to make it work.

The patent 100-400mm design is 11.9 inches long at 400mm, the existing 100-400 is 10.91 inches(max). Apparently, this is a solution that allows for a very high quality lens, but its not smaller, its larger.

 

[lol]

The size is an interesting observation. Note the patent shows the DO element is relatively small and inside the lens. The existing 70-300 DO and 400/4 DO has the DO element at the front of the lens so relatively large.

On the existing 70-300 DO lenses, I don't think there's a contrast problem myself, but it is very prone to glare which reduces contrast. So shooting into bright lights is something to be particularly careful with. Maybe using it further in, that wont be as much a problem any more.

 

[Don Haines]

One can only wonder if there isn't some technical issue they think they can resolve in time and then capitalize on, else why pursue the technology without releasing new lenses?

Definitely agree.

The nature of R+D is that there is no guaranteed outcome, but if you don't try new things, you are doomed to failure. The first DO's that I saw were quite poor quality... but they have been steadily getting better... Who knows where the research will lead!

 

[tron]

The patent 100-400mm design is 11.9 inches long at 400mm, the existing 100-400 is 10.91 inches(max). Apparently, this is a solution that allows for a very high quality lens, but its not smaller, its larger.

+1 I was about to protest about the size when I saw your post. This is not the size of a DO lens. Not even for a very sharp one.

 

[Darkmatter]

Shouldn't the continuing improvements in nano-particles help with things like a lens coating?

 

[dufflover]

I think it's good to keep pushing DO technology but it would only really make sense when used for superteles. Though I wonder if that would make them more or less expensive than the already jacked up price of the mkIIs.

A new 400/4 DO or 500/4 (or cheaper/better 500 5.6 DO) would be nice options to have. *end dreaming*

 

[AvTvM]

So far, Canon DO lenses have never been good enough, small enough, or cheap enough to be of any interest to me. I do not expect this to change anytime soon.

 

[wsmith96]

So what is special about DO? I never really paid any attention to those lenses.

 

[mustafaakarsu]

So what is special about DO? I never really paid any attention to those lenses.

This is the idea behind diffractive optics, but at the moment it's more developed for sure.
http://en.wikipedia.org/wiki/Fresnel_lens

 

[xps]

I hope Canon improves this technology. I owned a 400 DO IS, nearly 10 years ago, but the optical quality was not that, I thougt it would be. There was an aberration in the left upper corner that caused in an distorsion in this area. So I changed to the 300mm 2.8. And that was an very good decision.

 

[Mt Spokane Photography]

So what is special about DO? I never really paid any attention to those lenses.

A DO lens element is able to bend light more sharply without introducing chromatic abberations. Canon's resin lens can do this, but it is apparently extremely expensive to build. They probably get a very small yield.
This equates to a very expensive lens, which is not going to sell, just to shave a little weight off.

 

[Rudeofus]

Can you actually apply an antireflective coating to a fresnel lens like on a normal lens? Would such a coating be effective against flare on a fresnel lens?