Using an APS-C lens on a full frame camera is generally a bad idea, since you'll (generally) have extreme vignetting. Some full frame cameras can actually be damaged by having APS-C lenses attached Focal length is a physical property of a lens, so a full frame lens on an APS-C body will look the same as an APS-C lens of the same focal length.
Because the image sensor on Canon APS-C cameras is 1.6 times smaller than a 35mm camera, you multiply the listed focal length of the lens by 1.6 to determine its equivalent. If you’ve used a full-frame camera or know the focal lengths, crop factor can be very helpful in choosing your EF-S lenses.
Among interchangeable-lens digital cameras equipped with an APS-C image sensor as of January 2019, based on Sony research, measured using CIPA-compliant guidelines, and internal measurement method with an E 18-135mm F3.5-5.6 OSS lens mounted, Pre-AF off and viewfinder in use. Best Sony FE-Mount Lenses for full-frame and APS-C. The following lenses are designed for Sony’s full-frame Alpha cameras, on which they will deliver their stated focal length; i.e. a 50mm lens will deliver a 50mm effective focal length. If you’re using an APS-C Sony mirrorless camera, such as the Sony Alpha A6600, or Sony ZV-E10, these Full-frame sensors measure the same as 35mm film, which is 36 x 24mm. Meanwhile, smaller APS-C sized sensors measure in at either 23.6 x 15.7mm (Nikon, Pentax, Sony, Fujifilm) or 22.2 x 14.8mm (Canon). That makes full-frame about 2.6x larger in terms of total surface area size. As you can see, the difference between APS-C and micro four thirds is a bit less than the difference between full frame an APS-C. In fact, the area of an APS-C sensor is about 1.6 times the area of a micro four thirds sensor, albeit with an aspect ratio of 3:2 for APS-C rather than 4:3 for micro four thirds. Not all APS-C sensors are the same Sony make a full-frame camera for seemingly every market niche - the A7R for landscapes, A9 for sports, A7S for video, A7 for all-round, and the A7C as a super-compact option. And in January 2021 they launched the flagship Alpha 1, a stunning camera that takes all the best features from the other Alpha series models and combines them into one The Sony a6600 APS-C Mirrorless Interchangeable Lens Camera offers Real-time Eye AF and 5-axis image stabilization. Explore more features at Sony.