[VaughnA]

I've had my K-x for about a year and a half and love it. But although I get sharp photos I never felt that I got SHARP shots like I see around here in the lens club threads. I'd do some PP and they looked good enough that nobody really noticed. But it still bugged me, especially after getting my limiteds. They were sharper but still not dead on, I'm a semi-pixel-peeper so it bugged me a bit. I figured I needed to learn a bit more PP technique.

So saturday I decide to do a few tests with the FA31 and it's immediately evident that it's back focusing. I do the google and find the debug menu instructions. It's set to -20, I don't have time to calibrate so I just set it to zero and take a few shots which make it clear that it was not set correctly for the FA-31. Yesterday I tried it with my 55-300 and it was a noticeable difference in sharpness. I'm not sure if the previous owner (I bought used) or Pentax set it for that offset but evidently it was wrong. I'm going to spend a little more time to carefully calibrate.

So if you buy a used body it might be worth your time to check the debug menu. I've spent over a year without optimum sharpness. I'll look on the bright side now, I can go out and play with my new sharper lenses.

[newarts]

Good story, thanks!

[photolady95]

Yeah, thanks, Vaughn. Where is the debug menu because I bought my K-x used also, but looking in the manual, I couldn't find that setting. Is this setting for jpg shots or RAW? I shoot strictly RAW format, so if it is for jpg it wouldn't do me any good.

[rawr]

Where is the debug menu

https://www.pentaxforums.com/forums/general-technical-troubleshooting/130514-...cs-please.html

has the basics.

The OP's post illustrates the virtues, however, of not playing with the debug menu unless you really know what you are doing, and what the consequences may be.

[photolady95]

I don't think I'll mess with debug mode. My photos come out sharp enough for the lenses I use. Most come out tack sharp anyway. I do understand what needs to be done, but today wouldn't be a good day for me to muck about in this option.

[rawr]

Without going through the whole procedure to enable the debug menu, I recall that you can check if your camera has the debug menu options turned on by holding down the A/V button while turning on the camera. If you already have the debug options enabled you will see some extra items on the menu that relate to AF calibration.

[UnknownVT]

The OP's post illustrates the virtues, however, of not playing with the debug menu unless you really know what you are doing, and what the consequences may be.

What he said....

Sometimes it is very difficult to determine exact point of focus - there is some inconsistency - I hasten to add it is probably mostly the user.
Bearing this in mind - probably should not be too hasty in making any adjustments in the focus department.

The trouble is - once we have something like the debug menu - there is a real tendency to want to fiddle - to see if we cannot get "even better" performance.

The factory has equipment to do the adjustments with some precision, and it is hard to improve on this by sight only -
so only if a focusing error is detected with some consistency that this kind of an adjustment should be made.

Just to throw in another possible complication - different lighting can make a difference - especially artificial light, attempting "critical" adjustments under the wrong lighting conditions can throw off the focus for other more normal lighting conditions.

[VaughnA]

What he said....

Sometimes it is very difficult to determine exact point of focus - there is some inconsistency - I hasten to add it is probably mostly the user.
Bearing this in mind - probably should not be too hasty in making any adjustments in the focus department.

The trouble is - once we have something like the debug menu - there is a real tendency to want to fiddle - to see if we cannot get "even better" performance.

The factory has equipment to do the adjustments with some precision, and it is hard to improve on this by sight only -
so only if a focusing error is detected with some consistency that this kind of an adjustment should be made.

Just to throw in another possible complication - different lighting can make a difference - especially artificial light, attempting "critical" adjustments under the wrong lighting conditions can throw off the focus for other more normal lighting conditions.

I agree it's not for everyone but my point is that with a used camera it's possible that the previous owner mucked with it. I believe that was my case. It wasn't a marginal difference. I've got hundreds of bird shots with my 55-300 and the absolute sharpest bird shot was taken after the calibration reset yesterday afternoon. I have some as sharp that were taken with Manual focus but AF shots seemed to just miss. That was one of the clues, I seemed to never get as sharp with AF as with MF on the 55-300.

Again, I haven't even calibrated. I just reset it to zero and gave it a go. IF I recalibrate I do know to do it outside, SR off, tripod and a flat high contrast target.

[photolady95]

Without going through the whole procedure to enable the debug menu, I recall that you can check if your camera has the debug menu options turned on by holding down the A/V button while turning on the camera. If you already have the debug options enabled you will see some extra items on the menu that relate to AF calibration.

Not already set on mine. But as to others, I am not mucking about with my new to me, K-x.

I think one of the things I do need is, new glasses. Right now I shoot without them, using the Diopter settings and sometimes, I'm not sure if sharp is what I see in the viewfinder. I do not use LV. And I shoot MF primarily.

[UnknownVT]

Again, I haven't even calibrated. I just reset it to zero and gave it a go.

In your particular case - it seems that you set the camera back to factory settings.

Your experience shows that you detected some degree of mis-focus - with some consistency.
The debug menu showed that somebody had made adjustments from zero -
setting to zero probably reset it back to factory settings.

This is probably what I would have done too - if I had detected a consistent mis-focus.