shutterbug

all-season tires....LOL  good comparison...chicken rib chicken rib...

good portrait lens from Sony...probably a Zeiss lens...but it's well over 1k....what's your budget?

shutterbug

75-300 can give you good background at 300mm, but 300m x crop factor = insane distance from your subject + fairly fast shutter speed.  Will that work for you?

IMO, it's not a very good portrait lens.

50/1.4 is probably a better choice for portraits in your price range

shutterbug

I think 50/1.4 will fit your needs

shutterbug

What difficulty are you having with full body portrait?  Don't you need to just stand further back?  Maybe you want to tell us what problem you're having.

You lens is absolutely capable for fast moving subjects...just use safe shutter speed if you want to freeze action, or if you want motion blur, then use slightly slower than safe shutter speed.

shutterbug

if you stand further back (i.e. full body shot) the background blur will be less even with the same f stop.  Try to shoot at max aperture.

shutterbug

hm...I think it goes like this....

Basically, you get the same DOF using the same lens if you shoot from the same distance, no matter what sensor size you have (crop or FF).  The difference in what people see in DOF is probably because they usually need to stand back further from the subject using crop body so the DOF is not as shallow.