by t2ton » Fri Aug 29, 2014 6:26 am
Just registered to tell my story and to warn someone.
First I would like to advice everybody - don't use the software and don't touch your AF, if you have good results with your camera.
Second, if you ignore the first one, make a BACKUP of EEPROM!!! This is the most important thing and you should not ignore it.
I'm really glad, that I had enough brains to do this before I started.
Ok. The story now:
My D80 with AF 50/1.8 D was placed on a tripod in front of the monitor. I found it quite hard to align the monitor really perpendicular to the lens.
First thing I didn't like was the interference rings on the monitor, which I saw when manually adjust the focal point.
After AF adjustment the central focal zone was EXTREMELY accurate, I was really amused!!!
But when I checked other zones, my amasement changed to the horror. 2 meters of back or front focus or AF just moved the lens and did not focus anywhere for some zones!!!
I found the original service manual for D80, d70, D50 and D90, but nowhere the right procedure with distances between the lens and screen was described...
So I tried again (3 times actually) with the same result, but now I looked on the monitor more thoroughly.. on the right plot the phase is shown and it was quite wavy!
SO my impressions why everything gone wrong:
Use of the LCD screen.. It has mostly round 60 Hz refresh rate. The phase of the light is also changing, that influence on the AF calibration. In service manual, and actually during the adjustment procedure the use of "Fluorescent unit with high frequency" was advised.
Taking this into account, I printed 2 A3 list with black-white stripes and glue them together to increase the size of the screen. And tried again..
Phase was still wavy, but modulation amplitude definitely decreased. AF also was good, but somehow only for central and upper focusing zones. Lower zones still gone crazy. I think, the light conditions (fluorescent lamp with 100Hz) were still inappropriate.
I flashed back EEPROM data. Next time I will use only AF shift option. Seems it is not so powerful like AF adjustment tool.
SO, for those who still want to try: make the backup, print the AF chart and use a daylight.