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The optical formula for a new EF 50mm f/1.4 has appeared. It looks like the lens has internal focus and an odd negative front element. We haven’t heard anything for a while about a new 50mm f/1.4, but it’s definitely needed.</p>
<p>Patent Publication No. 2015-138121</p>
<ul>
<li>Published 2015.7.30</li>
<li>Filing date 2014.1.22</li>
</ul>
<p>Example 1</p>
<ul>
<li>Focal length 49.10</li>
<li>F number 1.45</li>
<li>Half angle (in degrees) 23.78</li>
<li>Image height 21.64</li>
<li>Overall length of the lens 100.16</li>
<li>BF 38.10</li>
</ul>
<p>Canon patents</p>
<ul>
<li>Positive ShiboTadashi</li>
<li>Inner focus (part of the first group)</li>
</ul>