Sigma's circular fisheye for Canon APS-C — a 4.5mm producing full circular images on crop sensors.
The Sigma 4.5mm f/2.8 EX DC Circular Fisheye HSM is a unique lens that produces full circular fisheye images on APS-C sensors. Unlike diagonal fisheyes that fill the frame with a distorted image, this circular fisheye creates a complete 180-degree circular image within a black border on the sensor. It is one of the very few circular fisheye lenses for APS-C cameras.
The 180-degree field of view captures an entire hemisphere in a circular image within the sensor area. The extreme distortion is the creative point — straight lines curve dramatically except through the exact centre. Sharpness is good within the circle. The f/2.8 aperture is relatively fast for a fisheye, useful for creative and astrophotography applications.
Canon EF-S mount in this listing — also available in Nikon F DX. The bulbous front element prevents the use of front filters. Weight is approximately 470 grams. Build quality is solid with the EX professional designation. HSM motor provides autofocus. The lens cap is a specialised bayonet design to protect the protruding front element.
Uncommon on the used market due to niche appeal. Check the front element carefully — its extreme bulge makes it vulnerable to damage. A specialist creative tool for experimental photography, immersive 360-degree panorama stitching, and dramatic artistic effects. Not for everyday use — this is a lens you reach for when you want maximum visual impact.