Cropping?

[cuivenion]

I'm fairly new to imaging and I'm still learning, especially the processing side. Is there a reason why people use different camera/telescope combinations to achieve certain Fov's, rather than having a wide field and then cropping down. I presume you must lose detail this way.

[richyrich_one]

Precisely

[MattJenko]

It depends on the type of imaging you do and the theoretical resolution you can achieve. Long exposure photography will experience a degree of atmospheric turbulence, which limits the resolving power and it is matching that theoretical resolution with different camera pixel sizes/telescope focal lengths that result in the many recommended combinations. Planetary fast frame rate imaging has less atmospheric turbulence to deal with and the resolution can be much higher, which results in another load of different camera/scope combinations etc.