The D40 would be fine for a professional to use if he/she wanted to. It is not the camera that makes the picture, but the person behind the camera.
Most pros would want a camera that was more sturdily built and was fully compatible with more lenses.

yeah,m but it doesn't autofocus old lenses, so you have to buy AF-S and AF-I lensens, and there are only a few of those.
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