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<p><strong>New Patent
</strong>We’ve heard before that an EF 24-70 f/2.8L IS was in testing.</p>
<p><strong></strong>A patent has surfaced that has confirmed Canon testing such a lens. The Canon folks out there would be pretty accepting of such a lens.</p>
<ul>
<li><strong>Patent Publication No. 2013-182246</strong>
<ul>
<li><span>Publication date 2013.9.12</span></li>
<li><span>Filing date 2012.3.5</span></li>
</ul>
</li>
<li><strong>Example 1</strong>
<ul>
<li><span>Zoom ratio 2.75</span></li>
<li><span>Focal length f = 24.70-36.42-67.88mm</span></li>
<li><span>Fno. 2.91</span></li>
<li><span>Half angle ω = 41.22-30.71-17.68 °</span></li>
<li><span>Image height 21.64mm</span></li>
<li><span>164.87-172.85-196.79mm overall length of the lens</span></li>
<li><span>BF 39.07-44.44-54.56mm</span></li>
<li><span>20 pieces of 13-group lens configuration</span></li>
<li><span>Four four-sided aspherical</span></li>
</ul>
</li>
<li><strong>Example 2</strong>
<ul>
<li><span>Zoom ratio 2.76</span></li>
<li><span>Focal length f = 24.70-34.88-68.18mm</span></li>
<li><span>Fno. 2.91</span></li>
<li><span>Half angle ω = 41.22-31.81-17.61 °</span></li>
<li><span>Image height 21.64mm</span></li>
<li><span>165.79-174.26-199.67mm overall length of the lens</span></li>
<li><span>BF 38.47-42.81-58.00mm</span></li>
<li><span>20 pieces of 15-group lens configuration</span></li>
<li><span>Three 3 aspherical surface</span></li>
</ul>
</li>
<li><strong>Example 3</strong>
<ul>
<li><span>Zoom ratio 3.22</span></li>
<li><span>Focal length f = 24.70-39.67-79.43mm</span></li>
<li><span>Fno. 2.91</span></li>
<li><span>41.22-28.61-15.24 ° angle of view</span></li>
<li><span>Image height 21.64mm</span></li>
<li><span>161.98-171.74-200.99mm overall length of the lens</span></li>
<li><span>BF 38.35-46.17-57.64mm</span></li>
<li><span>20 pieces of 13-group lens configuration</span></li>
<li><span>Four four-sided aspherical</span></li>
</ul>
</li>
<li><strong>Canon patent</strong>
<ul>
<li><span>5-group zoom of positive and negative positive positive and negative</span></li>
<li><span>Antivibration (fourth lens group)</span></li>
</ul>
</li>
</ul>
<p><strong>Source: [<a href="http://egami.blog.so-net.ne.jp/2013-09-21" target="_blank">EG</a>]</strong></p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>
Even though the sigma might not be weather sealed or have the red ring, their new lenses are looking so fine and are performing top notch. I have faith in sigma! 
