That's because you didn't look properly

Randomly corrupting images is a common problem with them:

link

I thought of doing it a few months ago, but it seems that the
Fotodiox M42->P/K adapter is no longer made. Something similar off
ebay should do.

You could try the Revuenon seems a simple enough conversion.

I did try on a 135mm lens that I had in OLY fit. I had the same
makers zoom in a Pentax and the two mounts just about swapped
over. I switched it back later because I wanted to use the zoom.

That's Funny!!

Far too many buttons on that Get one off ebay
with just one button

Most £10 lenses now cost £150

There is a difference and I've looked at the ones for f/5.6 and the new lens is still brighter than the other three. I would be concerned about that. It means f/5.6 isn't f/5.6. We need someone else to test their lens to see if it's just a one off? Plus another test to see if it happens in Av this test was all MF.

Maybe catch is focus was the reason

The bokeh is really nice on the shot of the doll.

I sold a M 200mm f/4 because the zoom was better than it at 200mm
Never really found anything to beat it even the A 70-210mm

With increased file sizes you have to use a system that will allow older photos to be archived on another drive.

I store everything initially by year so the first directory will be:

Pentax_Photos_2010_Vol_01

I'd start a new Vol_02 when Vol_01 has about 80GB in it. Makes BUP's
easier. Probably better on another partition so if a partition gets
damaged you don't lose everything.

Dirs off this have venues or locations:

Ashurt_Beacon

Martin_Mere

Three_Sisters_Nature_Reserve

or some might be lumped together

Lens_Tests_Outside

Lens_Tests_Indoor

Inside the above dirs sub-dirs are by date and are usually
just the dir off the SD card copied over and renamed.
I wish Pentax would let us set the dates of dirs in the
camera. So these are renamed YR-MNTH-DAY:

10-08-21
10-09-18

Anything important in a dir might be added after the date:

10-08-21_Meercats

I always keep the original filename and if I need to change it
just add the new name to the end. This way I can always search
on the original filename.

_igp4593_Meercat_001.jpg

Because the camera counts from 0001 after 9999 you could
change one of the letters in the filename to A B C D etc
at each increment. Or rename the files.

A_igp4593_Meercat_001.jpg

I put a txt note in each dir stating the lens used etc.

Important Dirs will have MD5 checksums created by Total Commander
File Manager. Really important ones will have 15% of PAR2 recovery
files.

To index my HDD I use a freeware program called Locate32
http://locate32.net/
This is really fast and lets you specify search just photos and
if you put in meercat it will list all the photos with meercat
in the title. Clicking the file launches my viewer. I can also
put txt files in each dir with the name as a note and Locate32
will find them. i.e. taken_with_Jims_Nikon.txt

An old habit from the Sinclair QL days is always using underscores
rather than spaces in filenames they may eventually finish up on
a system that doesn't like spaces.

Not sure about the 35mm DA LTD but some lenses are easily adjusted for infinity focus. I think there's an item on Ricehigh's about it.

A LTD needs careful attention so Pentax is the best bet. It should be free as well because it sounds like a manufacturing defect.