Okay, the plot thickens here...
I originally was 'jacked up' by seeing the Nikon Zfc. The beautiful trad styling and compact size etc. One thing led to another - thinking that sensor size was the 'thing' to look for. (The ZFc is morrorless but not full-frame, it's DX only ). So I started to look at affordable full-frame alternatives like the D600. Because the ZFc doesn't have a full frame sensor. The thing is (well two things), 1: It's the 'look and feel' of the ZFc I like and that's missing from the big fat alternatives. And B: the more research I do, the less important the Sensor size seems to be.
The ZFc has twice the digital capacity of my D90. ... Approx 20mp as opposed to 12mp. So maybe I go back to my original ZFc idea?
The thing is you're only looking at a small portion of what makes up a digital camera. It's not all about sensor size or Megapixels. You also have to consider the vast advancements made in technology when comparing cameras. The Zfc is generations newer than the other cameras we've been discussing. Newer more powerful processors, new sensor technology and other factors all come into play. What about burst rates? Max shutter speed? ISO range?
Sensor size does matter, but it's more limited than many might have you believe. A FF sensor is going to be better in low light, but at the same time you can't expect a FF sensor/processor in a generations-old camera to have a big advantage over a new APS-C sensor/processor. In this case 9 years newer, which in the world of digital cameras is a lifetime.
The other thing to consider is pixel pitch, or size. You may be getting more pixels, but they're smaller. Given the same size sensor, squeezing 20 million pixels as opposed to 12 million results in smaller pixels. That results in less light gathering ability for each pixel. This would be a bigger concern on an old camera, not as much on a newer camera for reasons already cited.
You've already said low light isn't an issue for you. Given that, then I don't think going with a crop sensor of any size is going to be a problem. I have friends who shoot professionally with Micro Four Thirds and are very successful. One guy I know shoots for colleges and his M-4/3 shots are enlarged to wall size and displayed in entry halls.
One thing to be aware of: With a DSLR, the viewfinder is a look directly through the lens. Not so with mirrorless. On a mirrorless camera, the viewfinder is electronic, a small TV screen of what the sensor sees. It may take a bit to get used to it, but the advantage is you have a view of what your finished shot will look like, including depth of field and lighting. I prefer the EVF over the optical, when I shoot my old DSLRs now I find it frustrating. Not saying one is better than the other, just that I've developed a preference.
You're probably aware that the Zfc uses a different lens mount, and you'll need an adapter to use your current lenses or will need to replace them with Z-Mount.
Considering the above, and faced with the same options, I would choose the Zfc. And yeah, it's a damned sexy camera!
