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A patent for two cinema lens optical formulas has been made public. Both formulas are for wide angle lenses, one is a 12-32mm t/3.5 and the other a 15.5-47mm t/2.8. NAB 2015 is just over a month away and we do expect at least one cinema lens announcement from Canon.</p>
<p>Full patent specs are after the break.</p>
<p><!--more--></p>
<p><strong>Patent Publication No. 2015-34858 (Google Translated)</strong></p>
<ul>
<li>Published 2015.2.19</li>
<li>Filing date 2013.8.8</li>
</ul>
<p><strong>Example 1</strong></p>
<ul>
<li>Zoom ratio 2.50</li>
<li>The focal length f = 12.50 18.75 31.25mm</li>
<li>Fno. 3.50</li>
<li>Half angle ω = 51.21 39.67 26.45 °</li>
<li>Image height Y = 15.5mm</li>
<li>Overall length of the lens 193.59</li>
<li>BF 42.84</li>
</ul>
<p><strong>Example 2</strong></p>
<ul>
<li>Zoom ratio 2.81</li>
<li>Focal length 16.00 26.88 45.00</li>
<li>Fno. 2.80</li>
<li>Half angle of 44.18 30.05 19.06</li>
<li>Image height Y = 15.5mm</li>
<li>Overall length of the lens 247.38</li>
<li>BF 43.27</li>
</ul>
<p><strong>Canon patent</strong></p>
<ul>
<li>Negative positive and negative positive 4-group zoom</li>
<li>Inner zoom (the second group)</li>
<li>Inner focus (rear group of the first group)</li>
</ul>
<p>Source: [<a href="http://translate.google.com/translate?sl=auto&tl=en&u=http://egami.blog.so-net.ne.jp/2015-03-05" target="_blank">Egami</a>]</p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>
