You don't need a "full-frame"-sensor D-SLR to do wide-angle photography
By Mike Stensvold
Small-Format Wide-Angle Zooms
Canon Canon offers the EF-S 10-22mm ƒ/3.5-4.5 USM zoom for its APS-C D-SLRs. These include the EOS 20D and 30D, and all EOS Digital Rebel models (original, XT and XTi). Note that Canon’s EF-S lenses can’t be mounted on the discontinued EOS 10D, even though that camera has an APS-C sensor.
Because Canon’s APS-C sensors are slightly smaller than most, the focal-length factor is 1.6x instead of 1.5x. Thus, the EF-S 10-22mm lens frames like a 16-35mm zoom on a 35mm SLR—a superwide angle indeed.
Canon users also can choose among four wide zooms from independent lens makers: Sigma’s 10-20mm ƒ/4-5.6 EX DC, Tamron’s 11-18mm ƒ/4.5-5.6 Di II LD Aspherical (IF) and Tokina's 12-24mm ƒ/4 AT-X AF PRO DX, plus Tokina’s 10-17mm ƒ/3.5-4.5 AT-X AF DX Fish-Eye zoom. The latter provides a 180-degree field of view (measured diagonally, at the 10mm setting), along with the expected fish-eye barrel distortion (i.e., straight lines that don’t go right through the middle of the image are curved toward the edges of the frame). Sigma also offers a 12-24mm ƒ/4.5-5.6 EX DG superwide zoom that can be used with digital and 35mm SLRs; its image circle covers a full 24x36mm image area.
Nikon Nikon's APS-C-format wide-angle zoom is the 12-24mm ƒ/4G ED-IF AF-S DX Zoom-Nikkor, which frames like an 18-36mm on a 35mm camera due to the 1.5x focal-length conversion factor of all Nikon D-SLR image sensors.
Nikon users also can choose among the same independent-lens makers’ wide zooms offered to Canon users—see the Canon section.
Fujifilm doesn’t make D-SLR lenses, but its FinePix S3 Pro and S5 Pro cameras accept Nikon-mount lenses, with the same 1.5x focal-length multiplier.
Olympus, Leica and Panasonic All Four Thirds System cameras accept all Four Thirds System lenses. Currently, there are two really wide zooms for the format: Olympus’ 7-14mm ƒ/4.0 and 11-22mm ƒ/2.8-3.5 Zuiko Digital optics. Since the Four Thirds System image sensor is smaller than APS-C sensors, the focal-length conversion factor is 2x. Thus, the 7-14mm frames like a 14-28mm on a 35mm SLR, the 11-22 like a 22-44mm. Four Thirds System cameras currently include Olympus’s E-1, E-330 and E-500, Leica’s Digilux 3 and Panasonic’s Lumix DMC-L1.
Pentax and Samsung Pentax offers both the smc-P-DA 10-17mm ƒ/3.5-4.5 ED-IF full-frame fish-eye zoom and smc-P-DA 12-24mm ƒ/4.0 ED AL (IF) wide zoom for its D-SLRs. Both lenses can be used with all Pentax D-SLRs, and because of the sensors’ 1.5x focal-length factor, frame like 15-26mm and 18-36mm zooms on a 35mm SLR.
Pentax D-SLRs also will accept the Pentax-mount version of Sigma’s 10-20mm ƒ/4-5.6 EX DC zoom and full-frame 12-24mm ƒ/4.5-5.6 EX DG zoom. Samsung’s D-SLRs take Pentax lenses, with the same 1.5x focal-length factor.
Sigma Sigma’s 10-20mm ƒ/4-5.6 EX DC zoom comes in a mount for Sigma D-SLRs as well as Canon, Nikon and Pentax. Sigma’s D-SLRs (the SD9 and SD10 have been discontinued, but the new SD14 is due soon) have a 1.7x focal-length factor, so the 10-20mm frames like a 17-34mm on a 35mm SLR.
Sony Sony offers the SAL 11-18mm ƒ/4.5-5.6 DT zoom, which was designed specifically for its DSLR-A100. The focal-length factor is 1.5x, meaning the lens frames like a 16.5-27mm on a 35mm SLR.
Sony D-SLRs accept Konica Minolta’s Maxxum-mount lenses, but none of those was designed specifically for APS-C image sensors. However, Sigma and Tamron produce Sony-mount versions of their 10-20mm and 11-18mm APS-C-format zooms, respectively, and these can be used on the A100 camera. Sigma’s full-frame 12-24mm ƒ/4.5-5.6 EX DG zoom also can be used.