k5 af adjustment

I have just replaced my k20d body with the K5 as the shop was offering such a good deal and decided that the first thing I should do is check focusing for my lenses. Anyway it seems that my 77 needs more than the adjustment allows. Even at the maximum of 10+ it still seems slightly out of focus.

I didn’t use a focus chart I had a newspaper flat on the wall. The reason I think it is still off is because at there is a significant increase in sharpness from f4 to f6.3. I do not think this should be the case. f4 and f6 should be of similar sharpness. Can anyone confirm this?

images are herelink

If the difference between f4 f6 should be negligible then it is a focusing error and needs more adjustment. Does this mean I have to take the body in or is it a problem with the lens?

Any comments would be much appreciated

maybe try a box of cerieal with a ruler angled on one side, focus on the flat subject then you can see if its of by looking at the ruler. also you can adjust more than + and - 10 by set all lenses at -10 then adjust that one by -10 i think, cant remember 100% but there is away.

Thanks for your comment that is a good idea. Actually after going here link I tried the moire test also and that gave the same result. I didn't try the focus chart at an angle because Pentax have said to me that it is not a good way to check the focus.

I gave u trying myself and went to Pentax service and showed them the results of the flat newspaper test. Ha ha, when the technician saw the f4 image and saw how soft it was compared to the f6'3 image he shook the lens to see if anything was loose They checked the lens and said the mtf figures and the autofocus was ok so they said they would have to keeo the body and adjust it to the lens I didn't really want to leave it as my daughter has a piano recital at the weekend so they said they would fix it by Friday and if not would lend me a camera which is excellent of them.

I am looking forward to getting it back as it feels good in the hand and the few images I have taken seem to be much cleaner than images taken with the k20d.

I thought the adjust all and adjust each wasn't cumulative ?
Pete

You are correct it isn't. I do not know how they will adjust it. I thought that if I was having to dial in so much adjustment that there may be a fault in the lens but they assured me that it can't be as it is an autofocus fault.

One question. Do you have any trouble with focus in indoor lighting?

Poor AF indoors was an issue, corrected wholly or partially in a recent firmware upgrade.

As to AF adjustment, there's a mechanical adjustment available to Pentax technicians. Be aware though, that if you send the camera and lens to them, and they adjust for your 77 (camera and lens could be at opposite ends of the tolerance range), then other lenses may be adversely affected, ie you won't be able to adjust them!

Thanks this is good to know. Obviously my daughters piano recital is indoors so I hope it is ok.

As for the focus issue I will just have to cross my fingers and hope it doesn’t affect adjustment of my other lenses.

I am a little disappointed though as this focus problem began 3 weeks ago after Pentax repaired a scratched apperture. They replaced the front assembly. This must have changed some characteristics of the lens. I noticed immediately that images were a little softer after the repair. When I pointed this out to Pentax they tested the mtf and autofocus of the lens and stated that it is ok. It is not a lens problem.

Thanks again for your comment.

Thanks again for the comments. Pentax fulfulled there promise of a quick repair. They replaced some parts in the camera body and seems to be working as it should.

Just one thing I noticed when I got home that the image counter in the displays top right hand corner is at over 7900 which is about 7700 more than it should be. I had had the camera 3 days and had shot about 200 images before I handed it over for focus adjustment.

It was pointed out to me that the camera will start counting from the number on the card so Pentax must have used a card with over 7000 images but I have tried several used cards and that number does not change except for adding the number of images taken after inserting the card. Surely Pentax couldn’t have ran up 7000 images when repairing the camera! Is there any way of checking the shutter count?

PhotoMe is an Exif viewer that lets you see it.

Thanks. Unfortunately that software is not compatible with Mac.

Don't you have Parallels? Even if you don't, VirtualBox apparently runs on Mac.

Failing that, if you stuck an image file online somewhere, I expect any number of helpful Windows users would be more than happy to check it for you.

Thanks for the quick reply but I have satisfied my paranoia with exif tool for Mac. 336 counts. But wait a minute perhaps that software might not be reliable. Better download something to check that!

Thanks again for your help.

I can't remember where I read this, but the solution is quite simple.

The camera remembers the last file number used on the SD card, and increments by one to use for the next picture.

First empty an SD card by erasing all.

Now take a single picture.

Remove the SD card, load it in your PC and change the filename to your desired image number. That image number should be set to the number of the last picture you took, or better, the shutter count as determined with PhotoMe or Exiftool.

Now you have to get the camera to forget the filenumber it got from the SD card used during the repair. Page 5 of the Record menu shows an option called 'Memory'. This option refers to what the camera should remember when you power off. The last item on the second page of this item is an option called 'File Number'. Uncheck it. Power off. The camera now forgets the last number used.

Now load the SD card with the desired file number on it, power up and take a single picture with it. It will be one more than the file number you set it to from the PC.

Now go back to Record menu Page 5, memory page 2, and restore File Number back on.

That's all there is to it. I wish I could credit the article this info came from, but I cannot find it at the moment.

Dick