There are many reviews on this lens but none tells me exactly how I can manual focus it. Can I turn the focusing ring at AF manually or must I turn the switch at the camera body to MF first? It's an expensive lens so I do not want to do it incorrectly. This is the only comment I get from pentaxforum.
Manual focus
Manual focusing is a pleasure. And you might want to actually use that in many situation where the AF sensor is not targeting the exact position you want or in low light. The focusing ring is small, compared to old full-manual Takumar lenses, but it is just right to get your thumb and index on it while keeping the rest of your hand under the lens for stability (see Lens and Handling pictures), hence a very comfortable handling. The focusing ring is so smooth you can adjust very precisely with just one or two fingers. The ring rotates just a bit less than 90 degrees, which makes it very easy to move from one close subject to a further one. Perhaps the only regret on focusing is that the lens does not incorporate the famous Pentax mechanism allowing to quickly shift from auto to manual focusing. But that would certainly make the lens bigger for a feature you might not use that often.
Excuse me for my dumb question as I have never used a screw drive lens in my life except to adapt them on Canon's body for complete manual focusing.
Manual focus
Manual focusing is a pleasure. And you might want to actually use that in many situation where the AF sensor is not targeting the exact position you want or in low light. The focusing ring is small, compared to old full-manual Takumar lenses, but it is just right to get your thumb and index on it while keeping the rest of your hand under the lens for stability (see Lens and Handling pictures), hence a very comfortable handling. The focusing ring is so smooth you can adjust very precisely with just one or two fingers. The ring rotates just a bit less than 90 degrees, which makes it very easy to move from one close subject to a further one. Perhaps the only regret on focusing is that the lens does not incorporate the famous Pentax mechanism allowing to quickly shift from auto to manual focusing. But that would certainly make the lens bigger for a feature you might not use that often.
Excuse me for my dumb question as I have never used a screw drive lens in my life except to adapt them on Canon's body for complete manual focusing.