10-08-2013, 04:15 PM
It certainly does help a lot when you want pinpricks of the full spectrum of light at the same time. On the 135L the reds are quite off focus if green/blue are, limiting it more towards narrowband filter applications. It is also good for detecting the sensor isn't sufficiently perpendicular to the optical plane.
<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.