What's the quality that gives some lenses (like Minolta G) a "3D" look?

I think its not only contrast, but the photo compositon, the focused ball player, the out of focused players and also the dugout, which all are in the back ground.  Take any of them out and you may lose the 3D effect. Most photos with that 3D look just happens. You go out to the park to shoot butterflies, and come home with a snapshot that turns out to be one of your all time favorites. I took this a few years ago, and is one of my favorites photos. It has a 3D effect that I have not been able to duplicate. I have others that have a 3D look, but not like this one. When shooting flowers and such, I always try to make a conscious effert to do so.

Here is one of a butterfly, the little blue flower in front of the butterfly, created the 3D. Both were taken with 70-300G