I wasn't perfectly pleased with the whooping crane images from the other day so I went out to find similar subjects closer to home to use as subjects for some lens testing.  Fortunately the sandhill cranes are moving into the area more and more; finding them in cornfields is less chance and more certainty now.  They make great subjects for evaluating the autofocus on a lens because they are usually a similar tone to the background and their narrow neck is a good test for where in an image the camera is actually focusing.

What I found wasn't that surprising although it is interesting.  I'm comparing the Nikon 300mm PF lens on a D800 to an Olympus 300mm f/2.8 on an E-5.  The sharpness of cranes standing in a cornfield is OK but it is inferior to the sharpness of the same cranes flying against a clear sky.  It's almost as if the camera has a harder time finding a plane of focus when the image is messy and has a narrow tonal range (tan cranes standing in a tan cornfield) but when the image is clean and contrasty (tan birds alone against a solid blue sky) the focus is sharper.  Maybe it's just my imagination but it is frustrating - hard to know just what quality of shot I'll get at the time. 

Anyway, I did find some good subjects.  Here is a pair rooting around for insects in a mowed field.  This is with the 300mm Olympus lens from about 20 yards away, shooting through the window (they don't wander off as fast when I stay in the car!).  I don't have a comparable image using the Nikon 300mm because I overexposed too much for the images to be useful.  Still, it's a nice shot, don't you think?

OLYMPUS DIGITAL CAMERA

This is another image using the Olympus 300mm, from about 100 feet away.

OLYMPUS DIGITAL CAMERA

And here's the same subject using the Nikon 300mm, about the same distance.

Maybe it's just me but it seems the Olympus is slightly sharper than the Nikon.  Or it could be I'm just being picky.  Here's a different subject. First, the Olympus lens:

OLYMPUS DIGITAL CAMERA

Then the Nikon lens:

For both I was focusing on the left steeple, meaning my subject was a different color than the background with high contrast.  Here the difference in sharpness doesn't appear that great.  Zooming in on details, though, there is a noticeable difference.  The Nikon lens is on the left, the Olympus on the right.

Granted, some pixel-peeping is needed to see the difference but it is there.  I'm still pleased with the Nikon 300mm given its ease of use and sharpness most of the time, especially when photographing flying birds while hand-holding the camera.  For critical sharpness at a distance where I expect to crop the image quite a bit and use a tripod the Olympus will be my first choice.

Always good to know the limits of equipment so surprises can be lessened.