I have Sigma DP3 Merrill (it's a special digital camera with a non-interpolating multi-layer sensor), which, besides being capable of very high quality results,

I have Sigma DP3 Merrill (it's a special digital camera with a non-interpolating multi-layer sensor), which, besides being capable of very high quality results, is a perfect teaching camera, because it's both digital and utterly unforgiving of any mistake in technique. I've loaned it to friends for learning purposes to great effect.