Zooming

We visited Albuquerque's Rio Grande Zoo on a fine Autumn morning.  My intention was to test a restored Vivitar 70-210 zoom lens.  The testing, as it turned out, ended up being more about  the operator and the camera, my Nikon FE.

Given some heavy morning shadows and a desire to avoid camera shake I made a lot of shots wide open.  That showed up as some softness in the images.  I don't think that said much about the capabilities of the lens however.  With the lens fully extended, the small central focal spot on the screen tended to black out and critical focusing became very difficult.  

When I was able to stop down in good light the added depth of focus easily overcame any small focusing errors and the result was nicely sharp images.

 I had better results in the past with a 75-230 Yashinon zoom.  I think, however, that may have more to do with the fact that the Yashinon was mounted on my Pentax SP.  So, I need now to go back and look at the different possible combinations of lenses, cameras and focusing screens so I can actually sort out the meaningful comparisons to be made between my zoom lenses.