[AnnieK5]

Can I use a Manual lens and still set to Auto focus mode?
Which settings could or should I use if switching between Manual and Auto lenses?
What's the difference between Manual and Auto focus lenses in terms of shooting a sharp image?
I currently have two manual lenses should I buy a couple of A lenses?

You have all been such a great help to me with my sometimes basic questions.

AnnieK5.

[Adam]

The short answer is yes, if you use a manual lens in AF mode, the camera won't release until the photo is sharp. This gives rise to a very useful technique:
Catch-in-Focus Tutorial - Articles and Tips | PentaxForums.com

Exposure settings are the same because focus is unrelated to them, though some manual focus lenses are also manual aperture (i.e. no "A" setting on the aperture ring), which opens up a whole other can of worms:
How to use/meter Manual & M42 Lenses on all Pentax DSLRs (K-1, K-3, K-5, K-30, etc) - PentaxForums.com

"A" type lenses are much easier to manage in everyday shooting IMO.

Also, if you have AF lenses, they are generally more convenient and let you shoot faster in certain situations.

[Pentax Syntax]

Depending upon the lens type you may have to change some settings to allow the shutter to be released with manual aperture. For ‘A’ lenses that is not necessary. As far as focus goes, you should get autofocus confirmation in the viewfinder with sound effects :-). The modern viewfinders are not great for manual focus since they lack a split-prism or other focusing aids so the focus confirmation is a plus. In addition, live view can a great help with manual focus particularly with focus peaking if you have that available on your particular camera body.

[IgorZ]

Hello AnnieK5, I wouldn't feel the pressure to buy any auto focus lenses, unless you really needed them. I have been shooting for years and bought my first autofocus lens 4 months ago. Whether you need one or not is for you to decide. I got one (and then another!) because I thought it would help me take photos of kids who move around too much. But the reality was that I was missing lots more photos with my autofocus lenses, than with manual focus. Until I learned how to use them. So when I shoot landscapes I use manual focus, when I shoot portraits and ask my kids to pose, I use manual focus, when I want to capture their play and use wider apertures, I use auto focus.

If you use a manual focus lens, you won't get auto focus. I believe in that case you can use either Manual or Auto focus setting, as autofocus won't work anyway.

You can use autofocus lenses in manual mode - in that case you just focus it manually, like your manual lenses.

Regarding sharpness, it's not really a matter of autofocus. Improperly focused photos might appear not sharp, but it's just because they are not in focus. People with less than optimal eye sight might get better photos with autofocus. Zeiss lenses are some of the sharpest and they are totally manual.