Sigma or Pentax?

<p>Wondering if anyone has experience with these two lenses:<br>

Sigma 30mm f/1.4 EX DC Lens ($489)<br>

Pentax SMPC-FA 35mm f/2.0 ($599)<br>

I am shooting a Pentax K7, and looking for a good 50 mm equivalent prime lens.<br>

For the record, I am leaning towards the Sigma.<br>

Thanks!</p>

<h1></h1>

<p>Can't comment on the Pentax from practical experience, but I use that Sigma regularly and like it very much. The difference between f/2 as your widest aperture and f/1.4 is not insignificant. The Sigma is remarkably useful wide open, and produces lovely bokeh. It's a fistfull of lens, though - quite the chunky little thing.</p>

Perry, I don't have either of these lenses, but can state that the Pentax DA* 55mm f/1.4 is a marvelous optic that is

extremely sharp, well-made, relatively lightweight, and water resistant! It also produces nice bokeh, and the SDM AF

behavior is excellent, at least, on a K-5. It's worth a look.

<p>The FA35/2 is a very good lens, and <a href="http://www.photozone.de/pentax/123-pentax-smc-fa-35mm-f2-al-photozone-review--test-report">sharper than average wide open</a>. That said, the new 35/2.4 has gotten pretty good reviews as well and is probably less than half the price. If it matters, these lenses (particularly the 35/2.4) are less than half the weight of the Sigma. I think if you want the speed, go Sigma but the Pentax lenses might be even better at the matching aperture settings. Another factor might be the HSM -- the Sigma 30 has been updated for HSM focus motor, right? If so, I think this will give you full-time-manual focusing which these Pentax lenses lack. On the other hand, I find Sigma's backwards (vs. Pentax) rotating focus rings a little annoying.</p>

<p>I thought the FA35 had been discontinued. That sounds a little steep, I would expect used copies for < $400.</p>

<p>Andrew, the Sigma 30 has always had f/t MF override and HSM. and focus rings dont really matter that much on a prime lens.</p>

<p>According to photozone, the pentax is slightly sharper at f/2, slightly worse at f/4, and better all around in the corners. so, it comes down to how much you will need 1.4. if you plan on shooting a lot of low-light stuff, the sigma is probably a better choice. if you only occasionally need to shoot at 1.4 but place more of a premium on corners, i would go for the pentax.</p>

<p> </p>

<blockquote>

<p><em> the Sigma 30 has always had f/t MF override and HSM. </em></p>

</blockquote>

<p>Eric,I don't think it did for K-mount, at least not always. I see you post much more frequently in the Nikon forum, perhaps you are more familiar with Sigma's F-mount releases. This lens has been around for a while, since before SDM support was available for Pentax. I'm not sure whether it does now or not--Sigma's own site suggests that it still uses screw-drive for Pentax (doesn't include "HSM" in the features listed for Pentax-K) and <a href="http://www.bhphotovideo.com/c/product/433041-REG/Sigma_300109_30mm_f_1_4_EX_DC.html#costumerReview">some reviews </a>(still pretty recent) suggest it doesn't. I say if this is important to you, buyer beware. When I wrote my earlier post I thought maybe Sigma had updated the lens (some of their lenses have been updated for Pentax in recent years) since initial release but now I'm even less convinced.</p>

 

<blockquote>

<p><em>and focus rings dont really matter that much on a prime lens.</em></p>

</blockquote>

<p>I have no idea why we would say focus rings don't really matter that much on a prime lens. Why should they matter any less on a prime?</p>

<p>ok, i wasnt aware there was a screw-drive version of the sigma. i have the nikon version and focus is pretty fast.</p>

<p>here's your original comment about focus rings: <em>On the other hand, I find Sigma's backwards (vs. Pentax) rotating focus rings a little annoying.</em><br>

<em> </em>hmmm, my sigma 17-50 OS moves in the opposite direction as most of my nikon lenses-- and my other two sigma F-mount zooms. this was pretty annoying at first and still trips me up. OTOH, i've never found the rotation of the focus ring on the sigma 30 to be an issue, <strong>particularly because there is none</strong>. the 30/1.4 is an internally-focusing lens and doesnt move during AF. it's a prime lens, so no zoom ring. and, in M/F override mode, the ring can be rotated both ways. maybe it's different in K-mount land, or maybe you were just generalizing.</p>

<p> </p>

<p>Thanks for all the feedback. The Sigma does have HSM, and I do shoot in low light situations; I am out at dawn and sunset a lot, so I want to try it. I will go with the Sigma (saving a hundred bucks) and if I don't like it I can always send it back before the thirty days are up. I am including a shot I took at 8 AM two days ago, about three miles from the house. It's the kind of shot am always looking for, and it sounds like the Sigma would be a big help in the fuure.</p><div></div>