Using a camera with a smaller sensor can be regarded as just another form of cropping, with the advantage that all the sensor MPx are concentrated on the cropped portion. This is a more compact solution than getting a dslr with more MPX with a view to the same result: a bigger image of the subject. It also avoids the increased f-stop from using a tc, and concentrates the image along the optical axis of the lens where its IQ is best. I have an old M43 camera - a 12MPx lumix G1, but rarely use it with my long lenses because its IQ just isn't as good as my K5/K3 or samsung NX20, and because those cameras have more MPx there isn't any image size advantage anyway. I do use the G1 a lot to check out old lenses of different mounts - I have adapters for all the main legacy mounts. But everything is effectively normal or telephoto FoV.
As long as the lenses used are up to the more concentrated demands of the small sensor this is a good way to go.
Last edited by marcusBMG; 06-09-2018 at 02:01 PM.