So, IIRC, in effect this would crop the images prior to exposure/capture, rather than cropping a “full sensor” image later as part of post-production manipulation on a PC?

I suspect the end result of both might well be pretty similar in terms of image quality/pixel counts etc, in which case I guess the full vs cropped argument comes down to how often you would use full frame images “uncropped”?

If you are going to crop most of your full frame shots (either via camera settings, or in post production ofterwards) to make up for the lost “telephoto” effect (that you would have gained by using a cropped sensor), then is it worth the extra expense of going for a full frame body?

I shoot a lot more than just aircraft in flight, which most of the time require some cropping anyway. For me the advantages of a full frame body especially are at the wide-angle end and the better high ISO capabilities. I’ve been a keen photographer for half a century now and over time I’ve built quite an arsenal of Nikon lenses, all of which can be used on full-frame bodies. Therefore the full-frame camera’s feel a lot more natural to me than Nikon’s DX camera’s. Cropping in-camera does indeed give a similar result to cropping in post-processing. However using the 1.2x and 1.5x modes have a few advantages: smaller files, slightly higher frame rates and increased buffer sizes. Therefore for me the 36 MP full-frame camera’s, with their fantastic pixel count reserves and dynamic ranges, are the most versatile camera’s I’ve ever used. Don’t get me wrong; there are many great crop-sensor camera’s available which can deliver great results, but they just are not the thing for me.