K10D / 21mmDA auto focus defect.

Carl Weese writing on 'The OnlinePhotographer' site about the K10 problems with auto focussing the 21mm......

http://theonlinephotographer.blogspot.com/

He seems surprised that auto-focus intermitently fails....??!!! Since AF has always been 'hit and miss' on ALL AF cameras, it's not too surprising that the K10D is thus affected. This is just more of the same old problem,.....by the time you have realised that the 'technology' has cocked it up you have missed that great, non repeatable, image.........

Us old timers will give a wry smile,....however did we manage with those clunky old manual lenses?????

Good job we did.....!!

At least the focus mode switch on K10 looks like it will be easy to turn off and tape over..........

Viewfinder,

I've ventured into the arena of AF lately as my eyes are not what they usta was.

Know what's frustrating? Most of the situations that fool my eyes also fool the AF.

Very wide angle lenses always seem to be in focus, and I'm not surprised a 21mm can fool the K10D, they ALWAYS fool me.

Mid length lenses focus just fine, but are easy to focus manually as well.

Zooms, long and really long lenses in good light, focus quite obviously to my eyes, but often leave the AF searching repeatedly (and noisely - there goes the wildlife).

I now use most of my bulky, relatively dark, Auto Focus zoom lenses in Manual mode and wonder why I bothered. Faster ISO and smaller apertures for me.

Sigh

I suggest that the camera is set to centre-spot only focusing, otherwise madness ensues as the camera tries to guess which focusing point to use. Then you can focus, hold with a half pressure and recompose before taking the shot.

I find it works most of the time. If it doesn't, try focusing on something else at the same distance, hold and recompose as before.

There are some subjects though that will defeat AF, and MF will will be the best solution. Most of my macro work, for example, is done with manual focusing.

That article makes no sense at all.

I suspect, as JR was implying, that the people who are having problems with the lens are using the camera with the AF point set to Auto.

G

I'm finding that the more experienced I become as a photographer, the less I use auto-focus. I don't know if that means I am taking better pictures, though.

talking of manual focus, I note that the K10D has interchangable screens but that neither of the option screens available from Pentax has any sort of manual focus aid

Does anyone know if you can get a split screen focus aid screen from any 3rd party? also when they say the screens can be changed, do they mean by a normal person, or is it a case of having a service shop do it?

The K10 screens are apparently readily interchangeable by the user. The 'Ist' camera screens were available from independant makers, notably 'Haoda' and 'Katz-eye' so it is highly likely that they will be, or already are, available for K10D. Both these screens offer a split image rangefinder and a microprism ring.

thanks viewfinder, I just googled for Katz-eye and look what I found

http://www.katzeyeoptics.com/item--Katz-Eye-Focusing-Screen-for-the-Pentax-K10D-...

But there are warnings on that site that metering will be affected under some circumstances unless you opt for their "optibrite" treatment.

mmm indeed, I read the write up in full and it does not recommend using spot metering with a lens darker than F2, though it claims pattern and centre weighted modes are unaffected to at least F5.6

I've always wanted a DSLR with a split screen, but I'm not sure if I'm willing to trade spot metering for it.

I see the same with my DS and the 16-45 and 50-200. At the far ends of the focal lengths the camera has some difficulties focussing.
Just like something I posted a time ago, just check the line on autofocus.

http://www.murphys-laws.com/murphy/murphy-Photography.html

"Auto Focus - won't"

I honestly have not experienced any problem with this at all.

:

It is not allways the case, but I had a number of occasions that my DS tried to adjust the focus of the 16-45 beyond infinity after which the focus indicator flashes. Just pointing the camera a little differently solves this. Setting the focus point manually allso does the trick. I think that at 16mm the objects are sometimes so small that the AF has some difficulty making up the contrast differences. (in high contrast situations the problem is not there). I allso had it with the 50-200, but mainly when it was a little foggy outside. In bright sunlight, so high contrast, it works ok to.

I do have the feeling that for some reason the DS autofocus isn't as good as in my MZ-10 which focusses much quicker (Allthough a lot noisier at it).

My DS "hunts" a bit, particularly if the object is quite distant (over 50 metres), the K10D is much better in this respect!