Hello, I am looking for a wide angle prime to use while kayaking the Ocklawaha River (Florida) and taking quick candid photos of our 12 lb Yorkie. The HD Pentax DA 21MM F3.2 is high on my list. The faster FA 20 F2.8 intrigues me, however, obtaining a decent copy might be problematic. Both lens should provide a wide depth of field setting allowing me to point and shoot. the Ocklawaha has a 4 - 6 MPH current, multiple obstacles so the less time fiddlling with K5IIs settings the better. Thought about the two 15MM primes but perhaps they are too wide for my stated purpose?

I am attempting to up date my K-7 firmware. Having no computer skills, the following instruction means nothing to me: "copy the above firmware file (fwdc220b.bin) to the root directory card". Can some, in laymen terms explain what I am supposed do? I have a Mac computer with a new formatted card in the SD slot.