Both my daughters swim in the summer, so I spend a lot of time around the pool. The WR of the DA* lenses and the K5II come in handy as I'm always getting splashed. Here are a few from last week, still working out getting comfortable with various AF variations, etc ... on new equipment (last summer used an OM-D kit). Very pleased with image quality from both the 16-50 and 50-135. C-AF definitely is weak in the Pentax system, but trying to find ways to work around it.

Love the 50-135, although it lacks a bit of reach. I just purchased a 1.4 Tamron to help at the long end during the day (I need the 2.8 speed for other times, so opted for the 50-135 over the 60-250).

Thanks for looking ...

[Kerrowdown]

C-AF definitely is weak in the Pentax system, but trying to find ways to work around it.

This may sound daft, but have you tried manual focus, you get choose precisely what you want in focus, rather than the camera second guessing. It may feel a little odd at first, but do persevere the results will come.

[jeffryscott]

This may sound daft, but have you tried manual focus, you get choose precisely what you want in focus, rather than the camera second guessing. It may feel a little odd at first, but do persevere the results will come.

Thanks ... I've been shooting for over 30 years, most of it professionally. I'm familiar with manual focus Even with its weaknesses, AF is overall better than MF. Modern AF is much faster than all but very few can manually focus. You have to learn the strengths and weaknesses of each system and learn how to make them work for your style of shooting. This is true regardless of system. I'm still getting a feel for how the AF on the Pentax system works, and what the best setup for me is.

[Canada_Rockies]

Have you tried catch-in-focus? It works in some situations for me.