What might work best for me...

McSpin wrote:

I have an application where I need a large depth of field and as low noise as possible. The subject is moving and in relatively low light and only 1-3 feet distance. Shutter speed has to be at least 1/160 and I can't use a flash. If I switch to a small sensor camera - like a 1" sensor, I'll triple the depth of field at a given camera setting and the same focal length. Therefore, I can use a lower ISO to achieve the noise level I'm looking for. I don't think I need the extra resolution of the larger sensor since these images are for web-viewing only.
I've been analyzing the pros and cons of each, but thought maybe someone else had a similar situations and has done the hands-on comparison. So, is it a wash if I use a small sensor with greater depth of field at a lower ISO, or would there be an advantage, since I don't need the extra resolution of the larger sensor?
I'm currently taking these shots with a k-50 and a K-3. Typically, the ISO is around 6400 at the aperture and speed I need. The photos are a bit noisy and noise reduction reduces detail too much. I experimented with a K1 and the depth of field was so small that I had to reduce aperture size a lot - which gave me images similar to the others since the ISO had to go even higher to compensate.

A crop of a larger sensor will give you the same result as a small sensor if they are covering the same scene and same perspective.  If the small sensor has more pixels than the cropped large sensor it mean high pixel density / smaller pixel size which probably means more noise.  A KP will give you 1-2 stops lower noise than your K-3 (based on my experience)

Doug