[jstevewhite]

So, to sum up , I think steephill (posting on a similar thread in the other forum 'Front focus with manual lenses') summarised the issue best:

"As has already been said the focus confirmation indicator is a bit vague, try getting focus confirmation from both directions i.e. from infinity then from minimum focus and you will see this easily. This happens because the AF system which provides the focus confirmation signal is also a limited aperture system. It is good enough when stopped down but again not good enough for wide aperture work."

But this does not accurately describe the situation, at least for *my* camera. If I didn't get accurate focus (most of the time, of course) with my 180mm, I would return the camera. Wide open, 180mm f2.5 (which has razor-thin DOF) works very well with CIF. Before I got the Katz-Eye, I had to depend solely on focus confirmation anyway, because the stock screen was way off (calibration wise), and I got consistently sharp images @f2.5, 180mm.

[Smeggypants]

Understanding Camera Autofocus

An AF lens 'hunts' for focus. Consider how AF lens 'hunts' for focus in low light. The same 'search', 'find', 'adjust' actions happen in good light, but so fast it seems the lens moves directly to focus, when in fact it has performed those same steps in milliseconds.

Contrast AF will always hunt becuase it when the subejct is OOF it doesn't know whether it is front or behind.

With phase focus it does know so theoretically there should be any hunting. Of course in practise there is a degree of hunting, but in really good light it zips straight there.

Autofocus: phase detection


Autofocus: contrast detection

[aliasant]

I have ordered new shims and hopefully they will be here Monday latest.
Today I have constantly FFd about 5-10mm. Not much perhaps but at Macro 1:1 range its a mile.

[dankoBanana]

let me get this straight? the k5 focus confirmation with MF is unusable? or just worse than with the k20d or k7 ?
this kind of puts a damper on my plans of acquiring the A 50/1.2

[jstevewhite]

let me get this straight? the k5 focus confirmation with MF is unusable? or just worse than with the k20d or k7 ?
this kind of puts a damper on my plans of acquiring the A 50/1.2

Several people on the forum report that their cameras do not produce reliably in-focus images using focus confirmation on K-5. Mine did not either, before firmware 1.03, now works fine - at least as well as my K20D, which also "misses" on occasion. Furthermore, you can get a split rangefinder screen from e.g. Katz-Eye, calibrate your screen, and focus very accurately with that - more so than the AF confirmation, even on mine. I recently tested catch-in-focus with an 85mm f1.4 and it produces reliably in-focus images (with an occasional miss); I tend to use the split-rangefinder with lenses like that, but the confirmation beep almost always accompanied the alignment of my rangefinder images. So, what this means is YMMV. If possible, test the body you plan to purchase with a wide-aperture manual focus lens.

[Smeggypants]

let me get this straight? the k5 focus confirmation with MF is unusable? or just worse than with the k20d or k7 ?
this kind of puts a damper on my plans of acquiring the A 50/1.2

No it's not unusable, it just has caveats. Use the LV contrast focus with the A50/1.2

[Gimbal]

Use the LV contrast focus with the A50/1.2

Is that even possible with a MF lens?

[simico]

Is that even possible with a MF lens?

I guess he really meant and wanted to say: use LV (with 8x or 10x magnification) to manually focus your MF lens. That's what I do with my A 100 macro lens. It's soooooo easy to focus manually in LV with 8-10-12x magnification

[jolepp]

I guess he really meant and wanted to say: use LV (with 8x or 10x magnification) to manually focus your MF lens. That's what I do with my A 100 macro lens. It's soooooo easy to focus manually in LV with 8-10-12x magnification

Also often very convenient when the camera is on tripod .

[JohnBee]

Just to update, I've finally had the opportunity to test three other K-5's and come to a sound conclusion as to whether my K-5 behavior is normal or not. See: https://www.pentaxforums.com/forums/pentax-k-5-forum/140731-k-5-manual-focus-...ml#post1469684

Thanks for all who participated in this.