All that happens is the "equivalent" 105-300 mm lens on a full frame sensor and our 70-200 mm lens on a 1.5x APS-C sensor simply see the same field of view (and because the smaller sensor crops its view smaller, normally it would need to use a shorter lens to compensate to still show the same wider view). It's like two different film sizes, IF
Lens Multiplication Factor Calculator. This online calculator allows you to calculate the 35mm equivalent Focal Length for a specific sensor size. You can find information on the sensor size in your camera in the manual, product information of the manufacturer of on DPReview.com. More information on the how an why of the Lens Multiplication
For example, APS-C cameras typically have a crop factor of 1.5x or 1.6x. Since the GFX system has a sensor that is larger than full-frame, we can expect our crop factor to be less than 1. In other words, 35mm full-frame equivalent focal lengths will be wider than the quoted focal length for any given GF lens.
Lenses designed to cover an APS-C format, can, again all things being equal, offer resolution every bit as good as an equivalent lens (adjusted for focal length correction) for full frame, and
The SIGMA 10-18mm F2.8 DC DN | Contemporary is the world's smallest and lightest ultra-wide angle zoom lens for APS-C cameras *2, with a length of 62.0mm, a maximum diameter of 72.2mm, and a weight of 260g *3. The lens can be carried around with ease or attached to an APS-C mirrorless camera and a gimbal to create an ultra-portable video setup.Fewer dies can fit onto the silicon wafer. Obviously, this means that fewer full-frame sensors than APS-C or APS-H sensors can be made in each batch, which dramatically drives up cost. (200 APS-C sensors will fit on a 8" wafer but just 20 full-frame sensors will fit in the same space.) A larger portion of the wafer is wasted.
Think about what APS-C mode is used for: it's used for lenses which project a smaller image circle. Those lenses are designed to illuminate an APS-C sensor which is half the size of a full frame sensor. In APS-C mode, on an A7R5 or any other full frame camera, only the APS-C part (inner part) of the sensor is used.Lens focal length conversion table of 135 / 35mm small format cameras, medium formats, 6x6, 645, 6x7, and APS-C format. Lenses from 15mm to 135mm with angle of views, ultra-wide angle lenses to telephoto lenses. Focal length conversion for medium format image sensors of 44x33, 48x36mm. Converted values are matched with availability of lenses I thought the field of view would be the same whether that lens is on an APS-C A6600 body or the full frame A7C body set to crop mode. I understand that using a full frame lens on the A7C in crop mode will increase the focal length by a factor or 1.5x but not when using an APS-C lens. Maybe I am mistaken. 4ZLSi.