Smallest, smaller, small

Walked out to get the paper yesterday AM and carried my camera, mounted with my 50mm lens. Looked up in my tree and saw a house finch with a nice red breast. Took the shot you see below (this lens is fixed focus, no zoom, and I'm NOT climbing up there...)

See my subject?

Bring the picture in the house. Crop. What do you know? A few more birds are up there!

 Crop a little more.

 And, finally, get down to my original target. The lack of stabilization, and the fact that I'm now computer-zoomed to about 200%, is degrading the sharpness of the image. Conclusion? 50mm is too small to shoot small birdies...