<blockquote>
<p><br /> The 35mm f/1.4 Sigma has had glowing reviews. It's a pain to focus, though - you really need to get the USB dock and tune it.</p>
</blockquote>
<p>this actually hasn't been my experience at all, using the sigma 35/1.4 with a D3s, i've gotten some great action shots of flamenco dancers which would have been framed way too tight with a 50mm. Shooting flamenco is a real litmus test for focusing, as the movements are wild, unpredictable, and sudden.</p>
<blockquote>
<p><br /> I'm not sure that 35mm is "clearly" the better length for FX, but I do agree that 50mm falls between "interestingly wide" and "isolating the subject".</p>
</blockquote>
<p>sorry, should have clarified that i was kidding (sort of). it's all subjective, but my experience parallels John's--i havent used my 50/1.4 much since getting the 35/1.4.</p>
<p>OTOH, i did choose the 50mm-equivalent 35/1.4 for my Fuji mirrorless system over the 35mm equivalent 23/1.4, despite the latter's stellar reputation, but mainly because i didn't want to duplicate the 35mm FOV of my x100. i also have a 21mm-equiv. 14/2.8 for the Fuji system; on an upcoming planned trip to Mexico, i plan on bringing a bag of primes along with an x100 and maybe a Nikon J1 w/ two zooms. i anticipate using the x100 in tandem with the 14mm mounted most of the time on the XE1, while the 50/1.4 equiv. Fuji will probably be the main low-light lens.</p>