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<p>A new patent showing the 600mm f/4 optical formula. Is Canon already working on the replacements to the current super telephoto lenses? It’s quite possible! Although I suspect we’re talking 7-10 years from now. These sort of patents could also be for technology that will appear in other lenses. Such as the upcoming replacement of the EF 800mm f/5.6L IS.</p>
<p>I do expect we’ll be seeing more DO lenses in the future. There seems to be an awful lot of patents for DO optical formulas. I suspect the cost of production is the hinderance to bringing these lenses to market at the present time. We already have <a href="http://www.bhphotovideo.com/c/product/973129-REG/canon_5176b002_ef_200_400mm_f_4l_is.html/bi/2466/kbid/3296" target="_blank">$11,000 200-400 f/4 lenses</a> and <a href="http://www.bhphotovideo.com/c/product/918849-REG/nikon_2205_af_s_nikkor_800mm_f_5_6e.html/bi/2466/kbid/3296" target="_blank">$18,000 800mm lenses</a>. I suspect we’re at the ceiling of what people will pay for a lens…. or not. :)</p>
<p><strong>Patent Publication No. 2014-26210</strong></p>
<ul>
<li>Publication date 2014.2.6</li>
<li>Filing date 2012.7.30</li>
</ul>
<p><strong>Example 1</strong></p>
<ul>
<li>Focal length f = 588mm</li>
<li>Fno. 4.12</li>
<li>Angle of view 2ω = 4.22 °</li>
<li>BF 56.0mm</li>
<li>Total lens length 374.7mm</li>
<li>Inner focus</li>
</ul>
<p><strong>Example 5</strong></p>
<ul>
<li>Focal length f = 588mm</li>
<li>Fno. 4.12</li>
<li>Angle of view 2ω = 4.22 °</li>
<li>BF 55.0mm</li>
<li>Total lens length 343.5mm</li>
<li>Inner focus</li>
<li>Diffraction optical element</li>
<li>Effect of the glass material</li>
<li>Fluorite (Fluorite)</li>
<li>In the long lens fluorite + total length, correction of chromatic aberration is easy</li>
<li>In short lens fluorite + total length, correction of chromatic aberration is difficult</li>
<li>Diffractive optical element (DOE)</li>
<li>Diffractive optical element can be corrected if the chromatic aberration</li>
<li>Flare caused by light diffraction</li>
</ul>
<p>Source: [<a href="http://egami.blog.so-net.ne.jp/2014-03-03" target="_blank">EG</a>]</p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>
