There's a lot more to high ISO performance than just sensor type (CCD vs CMOS). There's also pixel pitch and the sophistication of the camera's on-board processing too. And the D300's new CMOS sensor actually has
more noise at lower ISOs than the old CCD ones do! At 200 and 400 there's visible noise on the CMOS, but not on the CCD. They're about even at 800, and from there on up the CMOS looks cleaner. Considering I shoot at iso400 all the time, I'm not so hot to upgrade to a D300 with a CMOS if it's going to have more noise than a CCD at 400. Then there's pixel pitch. The fewer number of megapixels, the larger each photo site is, and the better sensitivity you'll have. The D40 is only a 6MP camera, so the photosites are nice and big and the camera has great high ISO performance. The pixel pitch is similar to that of the Nikon D3! The D40 is also the last camera Nikon has made with the 6MP CCD sensor, which means it also has the latest and best on-board image processing and NR techniques applied out of any other 6MP camera they've built.
The end result is that the D40 performs brilliantly at high ISO. It's not quite as good as a D300, but it holds its own. It's definitely better than any of the 10MP CCD cameras by at least a stop.
Here's one at 1600, straight off the camera:
And here's another one at 3200, also straight off the camera:
And then with just some noise reduction in post, and nothing else.
Here's a high ISO comparison shootout:
http://www.kenrockwell.com/tech/iso-comparisons/2007-10/index.htm
I think the little D40 is 2nd only to the Canon 5D in that test! It maintains detail very well even up to 1600/3200 and has a nice clean noise pattern. The D200 smudges out too much detail and loses sharpness. And the XTi and 40D do a bit better job of maintaining detail and sharpness than the D200 and stay about even with the D40, but both of the Canons have ugly chroma noise. You can start to see it at 800, and from 1600 onwards its very visible. The D40 maintains detail well
and it has a pleasant noise pattern too.
For image quality, I don't think one can really say with a straight face that one system delivers truly better quality than the others. Provided both cameras are setup properly, both will give equally good results. A key thing with the Nikons though is that there's FAR less that you have to keep track of and worry about as far as setup goes. With fully programmable Auto ISO, Auto Contrast, Auto Sharpness, and Auto Saturation, you can just shoot and not have to worry. Auto ISO is great and prevents a lot of missed shots. And never in over 30,000 shots on my Nikons have I ever had a JPEG with messed up contrast. But I see contrast issues on Canons all the time. Yet another thing they have to keep track of. Nikon makes it easy to get great results, and the vast majority of the time the JPEGs are so well processed that there's no real need to mess with RAW for me.
As far as feel and ergonomics, I don't know what it is about Canon bodies but they just do not fit my hands well at all. The control placement seems odd, there are some wheels and buttons that I just can't reach at all, and on top of that the menu system has never made any bit of sense to me. Sure if I was a professional I could adapt to anything including Canon, but if I can get equal or better image quality out of Nikons *and* they're far more comfortable and ergonomically agreeable to me, then why would I want to even bother with Canons?
For build quality, I have zero clue what some of you are complaining about on the D40. I think it's much better built than the equivalent Canons. No it's not as sturdy as my F100, or a D300, or any of the pro bodies. It's a cheap consumer body. What the heck are you expecting? Maybe the one you held in the store was dropped a few times and did have pieces falling off of it, but that's not the camera's fault.
Here's two recent favorites taken with the D40:
pretty much straight off the camera here:
minor lighting adjustments here:
^ Oh and that photo was taken with one of the lenses that doesn't AF on the D40. Oh the horrors of manual focus, LOL. Just select the AF sensor you want to use (which are still active), manually turn the focus ring, and watch for the focus confirmation dot in the lower left corner of the viewfinder.
I like the D40 so much that I'm planning to take just that on a week long vacation in a few months. The compact size and lightweight make it ideal for travel. And its output is subjectively
better than my D80! Things look a bit cleaner and crisper, the auto white balance is a bit better, and the noise at high ISO is better too. It's truly a great little camera, and many pros have them as a backup because they know how great and capable they are too.