K200D AF Adjust - Yes, it works!

Muggins · 2009-11-04T00:31:07+0000

Hey hey, Was a little frustrated with my K200D and new Sigma 30 1.4. Was very noticeably front focusing at wide apertures, which I why I bought the stinkin lens anyway. After a few days of reading posts where most people said it didn't work, I found this thread and tried it myself - http://www.pentaxforums.com/forums/pentax-dslr-discussion/75223-k200d-autofocus-fine-tuning.html I also typed out detailed instructions on exactly what I did. Use at your own risk but it worked fine for me: Holy-sh*t-house-mouse, it works. AF adjust on the K200D. Noticed some significant front focusing with my new Sigma 30 f1.4. A bunch of my pics from our friends Halloween party were OOF, but a few accidental shots were dead sharp, so I new it was just calibration. Ran the above commands but accidentally set it to -120 first time and WOW what a difference. Retested & trimmed that back to -50 and I think I'm good. Need to do some field testing next time I go to the pub for some low light portraits but after a few days of researching I'm happy this actually works . Notes for newbs running PCs, as I'm a complete newb and this took a few tries to figured it out 1. Completely unscientific calibration test I just used the Pentax quick reference guide as a testing plane instead of buying a thermometer like some others have suggested. Opened to a page with a bunch of text but with a line or two of open space in the middle. Wrote 'FOCUS' with a Sharpie in the empty space with some cross hash marks to the left and right. Had the camera on Gorillapod about 6 inches high and the focal point about 2 feet from the end of the lens. Make sure you're on single point center focus and the widest aperture you've got. Snap a few pics and see if the 'FOCUS' and hash marks are in the center of the in-focus area of the picture. Before adjusting mine, it seemed that the 'FOCUS' was blurry but a few lines of text in front of it were tack sharp = front focus (the actual in-focus zone is in front of where the camera thinks it is). After making adjustments, I'd walk around the room shooting things that would obviously show FF/BF to check my calibrations. Few pieces of Halloween candy on my kitchen table at slightly different distances was a good test. Also tried shooting close to (within 5 feet) and further (across the room about 10 feet). Repeat the test and the steps below few times until it's satisfactory. 2. How to make Text File Insert the SD Card & Reader into your computers USB and open a window for the SD Card through My Computer (mine was 'Removable Disc H:'). Right click over the empty space on the right side of the window, which brings up a menu. Scroll mouse down to 'New' which brings up another menu and towards the bottom is Text File (or Text Document for me in Vista). Click Text Document and badda-bing, you've got a fresh Text Doc. 3. How to edit Text File / Text Document The new Text Doc will be named 'New Text Document.txt'. Open & Edit the text document before renaming it! Open up the Text Doc and type in exactly [DEBUG_MODE EN]. Close & save (automatically prompts you to save in Vista). Right click the Text Doc icon and rename to 'MODSET.445' (no .txt at the end). A warning will probably pop up asking if you're sure you want to continue - click yes. 4. How to run Debug mode Enter the card back into the cameras SD slot, but do not close the door. Hold down the Menu button and turn the camera on. It should display two version numbers (mine were both 1.00.00.02), the screen dimly flickered a few times, then everything shuts off... scared the crap out of me the first time ! Turn the power switch back to OFF and shut the card slot door. Your camera is now off but in DEBUG mode. 5. How to find and adjust AF Adjust Turn the Power Switch back on (no need to hold Menu). The screen will flicker a little, then just show a blank dark glow. Press MENU - brings up the menu screen which looks pretty normal. If you scroll through all of the tabs, you'll notice some extra adjustments that aren't normally there...sneaky! Click the Right Button twice to highlight the Setup tab. Press Up Button twice (or Down Button a bunch of times) to reach 'AF TEST', then click Right Button to open the AF TEST screen. First is AF Area Test with options of 0,1,2,3. I just left it on 0, not really sure what this one does. Click the Down Button to highlight 'Focus Corr' to correct the focus. Left for Front Focus and right for Back Focus. Try going +/- 50 or 60 to start with and test/retest a few times from there. Press OK and you're done adjusting (at least this round), and turn the Power Switch back off. 6. Exit Debug mode back to normal operating mode Right now, your camera is still in Debug mode so every time you turn it on, it will still be in Debug mode and you can't take pictures. Take out the SD Card, pop it back in the computer and open up the SD Card Window. Rename the 'MODSET.445' Text Document to 'MODSET.445.txt' (and click YES if the warning pops up again). Then open the Text Doc, delete the previous text and enter exactly [DEBUG_MODE DIS]. Close & save, then remember to rename the Text Doc again, back to 'MODSET.445' (no .txt at the end). Plug the card back in the cameras SD slot, leave door open, hold menu & turn on. The screen will flicker, show those two version numbers and then go blank again. Turn the Power Switch off. You're out of Debug mode and back to normal. However I would go ahead and remove that text file, not sure if its the best idea to leave them on the card but that's just a guess. Might be a good idea to buy two tiny SD cards, one with Debug Enable and the other with Debug Disable prompts on them, so you could adjust in the field without a computer ? !? Each file is only 16 Bytes...hahah. Try this at your own risk, but I hope this detailed account of my experience helps. Mugs

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Muggins Muggins

52 posts
16 years

Posted 05/11/2009 - 09:59 Link

Tested the lens last night at a few pubs. Friggin fantastic. Got some shots in almost ZERO light by bumping the ISO up. The K200D still did plenty of hunting, and I definitely missed my fair share of shots in AF and MF, but I couldn't immagine more challenging conditions. Very happy with the Sigma. Now it's time to find a Sigma 70-200 F2.8 APO EX!

Chris - these calibration adjustments actually make me feel MORE confident in my gear. After reading hundreds of posts on "quality controll issues" with ANY brand of lens, it had me second guessing my gear on every OOF shot always wondering if I bought a shitty copy.

Now I know that 99% of all lenses (at least from Pentax, Sigma, Tamron, and the other good manufacturers) are perfect copies and any focus issues can be cheaply corrected. None of the "if you get a sharp copy" crap.