I have both bodies and decided to do a low light high ISO test in order to make some decisions going forward.

I posted the results to YouTube here : D800 vs 5D3 High ISO Video - YouTube

Play 1080p FULL SCREEN to see how it really goes!

Check out the sharpness of the D800 compared to the 5D3 in lower ISO, but then see what happens when you get to 4000+ (which is what I often need).

The 5D3 has more faithful colours.

Focusing was manual on the purple book.

Check the sharpness of the DVD cases to the left, then the noise on the chairs and finally the curtains as the ISO goes up.

hi david
nice !

what lens? so your saying your keeping the 5d?//....
on the verge myself of buying d800 or 5d
thanks

john

Wow, the 5DIII's lowlight response is incredible, it just doesn't seem to get noisy no matter what you do! That said the detail is pretty mushy, even from low ISOs. The D800 has a clear resolution advantage all the way through, I wonder how the image from each compares once you add noise reduction to the D800's footage (the Canon clearly does it internally), I wonder if there's enough detail in the Nikon to end up with a simliar result to the Canon once you get rid of the noise in post?

The D800 can be de-noised up to about ISO3200 and after that it starts needing so much noise reduction that it's unusable in my opinion.

The 5D3 does sharpen up better than the D800 de-noises, but is never quite as sharp as the D800 at lower ISO.

The sharpening on the 5dmarkIII is "perceived" sharpness. The D800 is "actual". What i mean is when you add sharpening in post you are adding small halos to the pixels to essentially make them "appear" sharper. Sharpness natively (like D800/E) is "actual". The more resolution you have, the more MP the sharper the image. It is also dependent on pixel pitch as well.

I have shot the 5Dmark2 and D800E in the same environment. I have shot @ 3200 ISO on the D800E (no moire either) and required very little noise reduction, yet even with neat video, there is still more sharpness than a 5Dmark2 or 3 with sharpening added.

Now, if we have a perfectly lit scene shooting @ ISO 800 or below, the D800/E will just be plain sharper, flatter, and overall better.

If you notice the lamp, and the DVD case, all the whites on the 5D are blown out, look over at the D800, while they are still overexposed there has got to be a full stop difference in dynamic range. In video below ISO 800 there is almost 3 stops between these two cameras.

Another thing to consider is I record video with the Atomos Ninja 2. So I am avoiding the compression where some of the noise is introduced. (something canon cant do). so I get even more resolution.

With the ninja recording in ProResHQ and nicely lit situations using flat settings I can achieve an amazing amount of lattitude and easy post grading. Its tack sharp, and there is no amount of editing, low light performance or sharpening that can be done to make the 5Dmk3 perform anywhere even close.