Basic question regarding sensors and sharpness (resolution).

Lettermanian wrote:

I feel I should know this, but thought I'd ask anyway. Is a 1-inch sensor with 20mp (i.e. the Panasonic FZ1000) going to produce a sharper image than a 16mp m4/3 sensor (such as in the GX-7)? I have the GX7 and use the 20mm f1.7ii, an Oly 12-50mm, and a Panny 45-200mm lens, and sometimes I just don't get the resolution/sharpness/detail in my photos that I would like. I've seen pics taken by the FZ1000 and they seem sharper/more detailed than the images from my GX7. It seems logical that the 1-inch sensor with 20mp (more pixels for surface are) should produce more detail than the larger sensor with only 16mp. Is this right? Or is there some formula that debunks this? I'm considering the idea of a bridge camera, and like what I see of the results from the FZ1000, but will I get "sharper" shots?

I have some spectacularly sharp images from my 6mp Nikon D100, which had 6mp.

There've been some very well done comparisons of images shot with 20mp 1 inch sensors, 16mp micro 4/3 sensors, and full frame sensors.  I used to carry the Sony 20mp RX100 point and shoots, which had excellent lenses, but images I got from it, printed large, were about the same in terms of detail resolution as images shot with my mft gear at 16mp.  My 12mp D700 looked about the same as my 16mp mft images.

Some of it is related to how smaller sensor sites mean that teeny bits of movement destroy critical sharpness, so the smaller those sites get, the better your technique needs to get.  I see a lot of people with Nikon D800s (36mp) who are routinely getting the equivalent resolution as if they were shooting a 12mp camera.  Some of it is related to the glass over the sensor, whether they've kept the anti-moire (which reduces resolution) or not.

Resolution is how fine of detail you can see in an image.  Resolution is affected by things like contrast, the algorithms used for calculation, and sharpness, and when sensors are of equal size, pixel count.  Resolution is also related to the lens' qualities for contrast, sharpness, and various types of aberrations.  Many times a lens that was awesome at 12mp is garbage at 24mp.  Been there, done that, way too many times.  I no longer buy compromise glass... if I can't afford the top end, I do without the lens.

Sharpness is related to how sharp an edge between two different brightnesses is... you can have great sharpness with relatively little resolution.  There are a gazillion ways to ruin sharpness, and ain't no pixel count gonna save you.  Images can LOOK less sharp if they're not decent contrast, but be very high resolution.

Pixel count affects resolution - you can't get to the same resolution with 12mp as you can with 16mp WITH A SENSOR OF THE SAME SIZE.  Pixel count has nothing to do with sharpness.

I now use a GM5 for my pocket camera.  Much better images than the 1 inch Rx100 printed at 16x20 and 20x24, but every bit as small and light.

Thom Hogan actually did a nifty analysis recently of different sensor sizes and pixel counts over time.