I recently bought a Nikon D 3100 and put it through its paces to see if it was really worth the money. I still have some more work to do but for shooting with 3 lenses once with the D3100 and once with the D40. The clear winner was the D40. Even at 6 mega pixels the D40 has much sharper image as the D3100 at 14 mega pixels. The video capture of the D3100 is nice but if I wanted a camcorder I would buy one.
One button auto focus with 11 points.
Has Video function
The shutter is quiet
The lenses are compatible with your lenses for the D40
It has a higher ISO range than the D40.
Ok that is all I can say nice about this camera
For 700 Dollars you think Nikon could make a camera that can take a photo of a strait line. Nope at 1:1 it is soft as hell.
The Battery is not compatible to any of the older cameras if you want an upgrade to your D40 go with the D5000 it is still soft compared to the D40 but the battery is still the same.
Looses the grid overlay that the 5000 had.
Quality, quality, quality of the photo at 14 mega pixels it bleeds worst than a magic marker on a water board.
In Video mode the noise in the video is not worth buying the camera for.
My D40 is an old battered war wagon that has over 100,000 actuation of the shutter. You can pick one up for around 200-300 dollars on the secondary market. I use it for field work and thought I was getting a nice upgrade that was still light in my hands and I would not have to spend tons of money getting new lenses for.
At 6 mega pixels I have to soften the photo because it picks up too much detail. At +1842 pixels to equal the size of the Nikon D3100 the 6 mega pixel D40 kicks its but in clarity, sharpness, and noise. The only camera that Nikon makes that has better clarity is the FX models of D2, D3 and better.
Cost the D40 is between 200-300 dollars on the secondary market.
The battery last for a good amount of time
Good field camera.
My D40 you have to press two buttons to get the auto focus to work.
Its temperamental in continuous shooting mode some times it locks up and wont shoot.
If you have the playback on and try to take another photo it locks up.
It has excessive noise in low light conditions.
I am very disappointed with the new Nikon D3100 it had allot of hipe and falls far short for expectations. The worst of it all is that I really wanted an up grade to the Nikon D40 capability and light weight. Some of the new features are much nicer like the quieter shutter and more focus points but in the end the true reason anybody buys a camera is for quality of the image. The Nikon D3100 has little better image quality than a point and shoot.
Nikon D3100 at 300mm, 70mm, and 50mm
Nikon D3100 then the D40