Photo Jottings

• Best control of flare and ghosting; The two Sigma’s, with the Tokina way behind.
• Best distortion signature; the Tokina, and a close second is the Sigma 10-20mm F/3.5.
• Best focusing accuracy, the Sigma’s aren’t great, but are adequate; the Tokina is awful.
• Best value for image quality alone; stopped down, the Sigma 10-20mm F/4-5.6, or the Tokina if you don’t care about AF.
• Best value all around; the Sigma 10-20mm F/3.5 because of the distortion signature, build, and optical quality.

10-11mm centers

The less expensive and slower Sigma 10-20mm F/4-5.6 is a little soft in the centers at F/4, while the other two look great.  As you stop down, the differences aren’t so clear, but the constant aperture Sigma and Tokina have the best contrast at all apertures.  Also, the slower Sigma is brighter in these center crops, which makes it seem like it has less contrast.  All images have the same shutter speed with indicated apertures, but I could’ve backed off a third of a stop on the slower Sigma to match the others, although that won’t add resolution.

10-11mm mid-sections

The mid-sections look fairly close in resolution, however, I do see slightly less contrast on the slower Sigma.

10-11mm corners

The Tokina extreme corners are really sharp compared to the others.  There is no clear winner between the two Sigma’s, although I do see some color fringing on the fast Sigma HSM lens.  Just a reminder; the Tokina has a slight resolution advantage because it starts at 11mm, the other two at 10mm, so the Tokina has less area to cover.  I didn’t adjust the distance.

16mm centers

All center crops at 16mm look quite close in resolution.  The slower Sigma actually has F/5 at 16mm, but I used F/5.6 to keep the apertures all the same.

16mm mid-sections

Both the Sigma lenses look pretty sharp in the mid-sections at all apertures, but the Tokina is having problems with contrast, especially at wide apertures.

16mm corners

The Sigma HSM and Tokina extreme corners look awful at 16mm compared to the slower Sigma, that’s a surprise.  Stopping down helps the Tokina more than the Sigma HSM, but they never quite match the sharpness of the slower Sigma.

20mm Centers

There isn’t much difference in the centers at 20mm, but notice how sharp the Sigma HSM is at F/3.5!  Obviously, the Tokina doesn’t go to 20mm, that’s why those crops are missing.

20mm mid-sections

The 20mm mid-sections are about the same as the centers in sharpness.

20mm corners

If you look carefully, you can see the slower Sigma has a very slight advantage in sharpness in the corners at all apertures, although that wouldn’t be noticeable in real pictures.  I see magenta/cyan color fringing in the Sigma HSM crops, look along the rocks at the bottom, and shadow/sun transitions on the tree branches.

That’s it for this comp, new one below!