Friday, December 6, 2013

Sigma 18-35 1.8 Revisited; Where to Get It

Back in April of this year, Sigma surprised everyone by announcing the Sigma 18-35 f/1.8, the first zoom lens for a large sensor that had such a wide constant f/1.8 aperture.  Some even thought it was a late April Fool's announcement.  But it was real. 
Then people wondered what kind of image quality compromises we would have to put up with to get such a fast lens.  When DXO tested the lens in September, everyone was astounded that not only was the Sigma 18-35 the fastest zoom lens, it was also the sharpest APS-C zoom ever.  In fact, at its least sharp focal length, 35mm, it was almost as sharp as the legendary Sigma 35 1.4.
But at the end of the day, I decided not to get one.  The Sigma 18-35 1.8 on APS-C has a depth of field that is like a 24-50 f/2.8 on full frame, and I already had the excellent Nikon 28-70 f/2.8, plus the Sigma 35 1.4, and I would prefer either one to a 24-50 2.8 full frame lens.  So I passed on it.
Meanwhile I still enjoyed the Sigma 35 1.4.  It's super sharp at any aperture, has a distinctively shallow DOF, has gorgeous bokeh, and has a very versatile and useful focal length.  It's my second-favorite full frame lens (behind the Nikon 85 1.8G), only because the autofocus was inconsistent (sometimes accurate, sometimes not).  It didn't help that the Nikon D600 has a small AF area.  At the same time, using the 35 1.4 on the D600 precluded me from using the 85 1.8 on it at the same time.  So I started looking for other alternatives that would solve both autofocus issues, such as the Sony RX1 (which has 35mm f/2.0) or perhaps the Sony A7 or A7R (if they could get Sigma's support).
Enter the Sigma 18-35 1.8.
Apparently, the Sigma 18-35 has a trick:  it can be used on full frame at 35mm.  I've had APS-C lenses that were usable on full frame at longer focal lengths, such as the Tokina 11-16 2.8 and the Tokina 10-17.  I haven't seen that with any of my previous Sigma lenses, such as the Sigma 10-20, or 50-150 non-OS.  But someone posted a sample of the 18-35 @ 35mm on full frame (a Canon 5D2):  
It looks pretty good!  If the Sigma 18-35 is usable on full frame, then I could use it by itself on the D600 if I want to use just 35mm, and its aperture would almost be as wide as the 35 1.4, and if I want a 2-lens setup, I could use the 85 1.8G on the D600 and the 18-35 on the D7000. :)  No I wouldn't get the same amount of background blur at 24mm f/1.8 on the D7000 as the 35 1.4 on full frame, but at least if I really wanted to have a blurred background I could use the 18-35 at 35mm f/1.8 on the D7000 (with a change in perspective).
My concern is how the corners look at 35mm on full frame.  On the Tokina 11-16, the corners were very soft on full frame.  On the Tokina 10-17 fisheye, the corners were marginal.  With the 18-35, the corners look at least usable at laptop viewing sizes (see the tire on the bottom right corner of the sample).  So this solution might actually work for me.

EDIT: saw this comparison of vignetting (the 28mm and 35mm no-hood look like they might be mixed up)  Also, I couldn't evaluate the corner sharpness from these samples.
The Canon mount of the Sigma 18-35 is readily available but the Nikon mount is hard to find right now.  It's available online but only gray market (therefore no support), or at significant premiums.  Meanwhile if you're interested in this lens you might check your local camera store.  In Los Angeles, Samys has it for the MSRP of $799 (plus tax).  Other local stores might have it as well.  I sold my Nikon 28-70 2.8 and actually placed a deposit on the 18-35, but I think I'm going to have to wait due to many big expenses (including property taxes).  When I can sell more of my stuff perhaps I will try it out.