1- Astrotracer : only proposed in Pentax SLRs, since K-3II (K-1, KP, K-1II) ; previously and otherwise available with O-GPS-1 add-on module.
Don't use it.
2- Pixel-shift : only on Pentax SLRS, since K-3II (K-1, KP, K-1II ; some other makers produce resolution enhancement via multi-exposure like Olympus and Fuji).
Use it regularly to photograph art work.
3- Composition adjustment : only on Pentax SLR, since K-5.
Nope.
4- AF precise adjustment : first on Pentax SLR, since K-10D.
Use regularly.
5- TAV mode : only on Pentax SLR, since K-10D (equiv. to M mode + ISO auto on GR III ; and other brands).
Use all the time for long lens work.
6- Green button : only on Pentax SLR, since MZ series.
Use all the time.
7- Sensor shake reduction : first on Pentax K-10D (and Minolta 7D)
Use all the time.
8- Effective "all weather"/"weather resistant" sealing : systematic on Pentax SLR, after K-S1 ; and in Pentax new lenses since a few years.
Use all the time.
9- Pentaprism versus pentamirroir : systematic on Pentax SLR, since K-S1
10- In-body raw development : first on Pentax SLR, since K-10D
11- DNG raw format : first on Pentax, since K-5 (and Leica).
Use all the time.
Read more at:
Eleven Pentax "specific / distinctive features" : do they impact your photography ? - PentaxForums.com