07-19-2010, 05:36 PM
If you need to change length fast and still track accurately I don't think you can beat the push-pull. My worry is that a 100-400 mk2 as and when it eventually happens wont remain push-pull. For such a lens, there is potentially a lot of glass to move, and that takes more force than on smaller lenses... the twisting motion could be more challenging unless they keep the moving elements to an absolute minimum.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.