Originally posted by calsan More simply:
You set to AV mode and leave aperture wide open, then set your ISO as high as you will accept for image quality. That way you will always get the highest possible shutter speed for the given light / ISO speed. This is what I use for birding.
I usually don't want to shoot birds with wide open aperture. The DOF is simply too thin, and my Sigma 70-300 isn't that sharp wide open.
So my approach is TAv mode, aperture fixed on f/8, shutter fixed on 1/250, and ISO floating.
To get back to the original subject of this topic: No, the K5 doesn't have Nikon's low shutter-speed restriction, but I think you can use TAv mode in a lot of the use cases you would use that nikon setting. Actually, it does resemble the nikon mode a lot: only, you don't specify a mininum shutter-speed, but only a fixed one.