Nikon users!!!!! can anyone answer this?

This is a Nikon question. Which would yield the better results in
shooting small birds with the same 500mm lens: A full frame 36MP D800 cropped in to fill the frame with the subject, or the smaller sensor D300s which is a 50% crop to start with but only 12MP?

The extra DR for the D800 will help sometimes. A problem with my D300 is that I end up too close sometimes for medium sized birds that turn up. Again, advantage D800. The extra resolving power of the D800 may help with a lens like the 300mm Nikkor prime, But I doubt that it will make much difference with the 500mm. You might get less vibration out of the smaller APS mirror at moderate shutter speeds. The D800 has a little less texture at lower ISO. Some complain about the D300 noise, but I actually like the texture of these files. It's pretty much splitting hairs. I would choose the D800 for the benefits of full frame, but for long lenses only, I might consider one of the newer 16 or 24mp DX models which would be an upgrade in some respects. You might find the raw burst rate of the D800 which has to buffer huge files, somewhat limiting.

D800 for sure, imo. My recently-posted itty bitty Bushtit is a good example - it is about 10% of the frame, and only the D800's 36 mp would allow this.
However, as Bob mentions, the D800's burst speed is disappointing for BIF. I'm still using the D300s for most BIF shots, which is fine, I guess.

Sandy

The D800 would certainly give you a higher quality image, but with birds don't you want to shoot on continuous and shoot a lot of frames quickly? The 300s might have a higher frame rate than the 800.

Thanks everyone for your info. and have a Wonderful Christmas!!

As one who shot a D300 for years, I just went through this exercise. If you're asking about pure IQ, the cropped D800 image will be superior to the D300 shot with the same lens at the same distance. More pixels, better ISO performance, and better dynamic range. It also focuses faster and with less light. The only real down side is frame rate (4fps vs 7fps). But in DX mode (which is what you asked about) the D800 can hit 6fps with a grip mounted and using lithium batteries.

A couple of weeks ago I did some non-scientific testing by shooting action shots with both bodies. The D800 in DX mode outperformed the D300 hands down. But I guess for twice the price it should

I would sit tight and wait for the D300 successor. It will blow away the D800 for birding and cost significantly less $$. The D800 has very slow fps.


Kent in SD