Re: HELP: D3100-->D7000 or Nikon 85mm f/1.8G AF-S and/or Nikon 50mm f/1.8G AF-S Lens?
I think the difference between a D40 and a D7100 is more than megapixels. The dynamic range of the sensor and ISO performance is in a different league. We went from 6mp D70 to 12mp D300 to D7100 (wife) and D800 (me). Each was a big leap in IQ. On a bright day the D70 could get cracking sharp images, but we live in the UK so that doesn't happen often.
The only thing I would say is that you need to take more care with higher mp cameras as they show any failings.
Go for the glass. Both are excellent prime lenses. I have the 24 Mp D7100 and, to be truthful, other than being able to use my D glass, my 6.2 Mp D40 takes equally good photos. I think you will really only notice a difference if you blow up your photos to poster size (and I mean BIG). For most of us the extra Mp is not really important.
I think the difference between a D40 and a D7100 is more than megapixels. The dynamic range of the sensor and ISO performance is in a different league. We went from 6mp D70 to 12mp D300 to D7100 (wife) and D800 (me). Each was a big leap in IQ. On a bright day the D70 could get cracking sharp images, but we live in the UK so that doesn't happen often.
The only thing I would say is that you need to take more care with higher mp cameras as they show any failings.