Originally posted by Schraubstock
In case of a crop camera there is a benefit to be perceived because your target subject appears larger in the view finder and that sure enough makes hunting down birds, for example, easier.
I wish people would finally understand this. Sticking a 300mm for lens, for example, onto a crop camera is not metamorphosing it into a 450mm lens.
Cheers
I'm not sure you actually own these cameras. The wider field of view on a K-1 with the same lens makes it easier to find birds, but they are smaller in the SOC file when you photograph them.
The tighter pixel density of a K-3 gives you a larger subject image with the same lens and distance, and more subject resolution.
Sitting in my blind and switching bodies from a K-1 to a K-3, I get both a larger bird among the background because of the narrower FoV. I get 24 MP where the K-1 can only put 15.
How is that not "more reach?"
What you say would be true its the same pixel density. But at least in Pentax land, APS-c and FF do not use the same pixel densities. So effectively a K-3, K-70, or KP will give you "more reach" with the same lens. 300 on APS-c is about the same as 400 on a K-1 in terms of the subject size and resolution, in SOC file.
So that's why folks say APS-c give you more reach. It's a bit of a simplification but still more accurate than saying a K-3 doesn't give you more reach than a K-1.
Since you are probably cropping anyway, the K-3 gives you a larger (in pixels) more detailed (in real world measurement) image.
I seriously don't understand how anyone could look at the images posted above and not understand that the K-3 gives you more subject resolution and size in the area of the crop sensor. The K-1 only gives you more resolution if you don't have to crop. In birding, you almost always have to crop. With APS-c you have to crop less.
But to be technically correct, it's the higher pixel density in the APS-c bodies that gives them more reach, not the sensor size. It just so happens that 24 MP end APS-c bodies have higher pixels densities than 36 Mp FF bodies do. A technical anomaly leading to confusion in the ranks.
That all condenses into "a K-3 gives you more reach than a K-1, with the same lens." based on a sampling of of SOC images. If you leave APS-c and FF sensor sizes out of it, it's pretty straightforward. If you shoot a small subject from the same lenses from the same position, the K-3 will give you a 50% larger image with 30% more detail. Instead of a 300mm lens, you'd have to shoot 400mm FF to get the advantage of the 36 MP sensor, same sized subject, same resolution.
That would be my sticky.
Or to use a real world example, I accidentally went out to my blind yesterday with the K-1 on my 500mm lens instead of my K-3. What a disappointment. I fuddled around K-1 style for a while, realized how severely limited I was, and went back to the house and switched. I won't knowingly do that again.