As I understand it is important to have a good match of pixel size, focal length, and seeing conditions to optimize sensitivity and resolution. So it all comes down to arcseconds per pixal. Reference this link
http://www.stanmooreastro.com/pixel_size.htm
and conveniently he has a link to calculate arc secs per pixal
http://www.stanmooreastro.com/Pixel_size_calc.html
John