Sigma 16-20 f/2.0 DG Art for FF!

The Tokina was made for crop cameras and starts at an effective 17-18mm full frame equivalent... zoom ratio, after 1.6 factor is approximately 30%.

jrbdmb wrote in post #16591458
I personally would rather see a smaller / cheaper / sharper 16mm prime than a zoom with such a small range of focal lengths.

There are already so many UWA primes to choose from, but when it comes to sharp UWA-zoom lens, Nikon is the only one who truly delivers.

The 17-40L and 16-35L II is crap, in terms of corner sharpness.

Ginga wrote in post #16592998
There are already so many UWA primes to choose from, but when it comes to lower distortion UWA-zoom lens, Canon is the only one who truly delivers.

The Nikon 16-35 and 14-24, are crap in terms of barrel distortion.

There I fixed that for you...

The 14-24 has an advantage in corner sharpness wide open, but not much stopped down. The Nikon 16-35 and 17-35 are abysmal for corner sharpness.

Canon_Lover wrote in post #16594822
There I fixed that for you...

The 14-24 has an advantage in corner sharpness wide open, but not much stopped down. The Nikon 16-35 and 17-35 are abysmal for corner sharpness.

Even if your "fix" is completely true, who in the world would choose low distortion over corner sharpness? One is automatically corrected by any modern RAW converter, while the other is uncorrectable.

If this rumored 16-20 f/2 is a reality, I'll be interested as a full-frame user. It wouldn't take much to make it the sharpest UWA zoom for Canon users.

FWIW, I'm now on Nikon and while I haven't tried the 16-35 or 17-35 yet, the 18-35G is far sharper in the corners than my 17-40L was. Samples I've seen indicate that the 16-35 also has an edge over either Canon option, even if it's still weak in the extreme corners. The 14-24 absolutely dominates both Canon lenses, even stopped down.

Nathan wrote in post #16591779
The Tokina was made for crop cameras and starts at an effective 17-18mm full frame equivalent... zoom ratio, after 1.6 factor is approximately 30%.

Yeah. A full-frame 16-20 would be relatively similar in concept to the Tokina 11-16 for crop, if a bit more narrow in zoom range.

Nathan wrote in post #16591779
The Tokina was made for crop cameras and starts at an effective 17-18mm full frame equivalent... zoom ratio, after 1.6 factor is approximately 30%.

Ratios stay the same regardless of crop factor and either way, it is a 1.45x (45% change in focal length) zoom.

brettjrob wrote in post #16594964
Yeah. A full-frame 16-20 would be relatively similar in concept to the Tokina 11-16 for crop, if a bit more narrow in zoom range.

It's quite a bit smaller zoom range. Tokina is like 17-26mm in FF terms. 26mm is farther from 20mm than it sounds. If they could have at least gone to 24mm it would seem a lot more useful. As is, I still say they may as well have made an ~18mm prime.

Modification above: When I typed 17-18mm, I meant that the wide end on the Tokina starts somewhere between 17mm and 18mm. As pointed out by tkb, the full equivalent range is 17-26mm in FF terms.

That said, how do you calculate zoom ratio anyway?

Nathan wrote in post #16595007
Modification above: When I typed 17-18mm, I meant that the wide end on the Tokina starts somewhere between 17mm and 18mm. As pointed out by tkb, the full equivalent range is 17-26mm in FF terms.

That said, how do you calculate zoom ratio anyway?

just divide the two ends. 16/11 = 1.45

For a 70-200 that 200/70 = 2.9

Am I the only one that thinks that 16-20 is a BIG 4mm? I mean I would guess most would have it at 16 90% of the time, but still.

That said, I would rather see a 16 prime at 2 or even 1.8 if possible, but If it optically performs like a prime because of the short zoom then they are basically delivering...if this even comes out....

tkbslc wrote in post #16595053
just divide the two ends. 16/11 = 1.45

So my math was wrong and I didn't understand how to take the ratio.