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-   -   AF fine tuning and micro adjustment with FoCal ver. 1.8.1 (http://www.nanpa.org/forums/showthread.php?t=968)

Jorda75078 03-24-2013 10:17 AM

AF fine tuning and micro adjustment with FoCal ver. 1.8.1
 
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It has been about nine months since I last ran AF fine tuning with my camera bodies and all of my lenses. During that time, the software that I normally use for this calibration, FoCal, has undergone a number of changes. With the recent purchase of a new lens, I decided it is time to try FoCal again. You can see the results of that testing in the attached file.

I don’t always read the documentation for software before I run it the first time, but I learned the hard way that I must do so for AF fine tuning and micro adjustment software. The vendors sneak in new features, and you can miss them unless you read their docs.

I started with the QuickStart document followed by the Testing Guide. Both contain excellent testing information and advice and do a good job of setting AF fine tuning expectations. However, there are places in the Testing Guide where the author under states issues. For example when talking about how test stand vibration can impact test results, the author states: “Therefore, for the duration of the test, it’s best to not jump around near the camera!” In my experience with any AF fine tuning calibration, it takes far less vibration than a floor moving from you jumping around to significantly throw off your AF fine tuning.

As indicated in the Testing Guide, FoCal gives you a lot of feedback when you are running the Target Setup portion of the software. You get this feedback because your computer is tethered directly to the camera body, and the software can see through your camera using live view. You will not get that kind of hand holding with calibration software that does not include tethering the camera to the computer.

By the way, you have to keep reminding yourself that the author does not read Nikon manuals, so when he/she says microadjustment, Nikon owners should read that as fine tuning. When he/she says AFMA, read that as autofocus fine tuning adjustment. By the time you get to the end of the user guide, you will have the hang of it.

The fully automatic test mode described in the Testing Guide is only available in the Plus and Pro versions as described in section 7 of the user guide. Even if you plan to do most of the AF calibration manually while running the software, you should consider buying the Pro version because you get more controls over test settings.

After reading through the QuickStart and Testing Guide, you will be prepared for the full user manual. The Windows version is 132 pages in length…a lot of reading. Do not skip sections in this manual if you want to get the best AF adjustment you can get with your camera and lenses.

The user manual provides excellent advice for test target and camera setup. However, the software tests many of these setup aspects either before a test starts or during the tests and warns you if a setting is not recommended.

The camera setup guidelines were updated after version 1.6, and the new ones cover both Canon and Nikon settings appropriately. However, I still do not agree that IS or VR should always be turned off…especially for lens over 400mm under low light conditions, but you have to make that call.

When doing testing, I always do the Target Setup first followed by Fully Automatic AF Microadjustment. That way, I know I have the target locked in and I know I have the best AF fine tuning I can get for the lens. I can then run Aperture Sharpness or AF Consistency tests with confidence I am getting the best results I can get.

Please note that the user manual says all camera settings that will be changed by the software are stored first and restored by the software after the tests are completed. I recommend that you save the settings yourself on a camera image storage card before you start testing because FoCal can fail to restore your camera settings if the software fails to execute properly. Software bugs have caused that to happen more than once for me….and it did again today.

As with its competitor FocusTune, FoCal now lets you turn off test result points when you perform AF fine tuning. If you are an expert user and know how statistical analysis and curve fitting is done, you can right click on data points on the results graphs and turn outlier points off. If you are not an expert, you should let the software do all of the curve fitting for you to determine the right AF micro adjustment set point.

If you want to save AF fine tuning reports for later study, you can only do so with the Pro version. I find this to be a valuable tool. I have gone back many times and reviewed past test results reports. I have also compared older results reports with new ones to see what has changed since the last time I ran an AF fine tuning operation. If you drop and camera or lens (or both together), you should rerun your AF fine tuning calibration and compare the new results with the older results to see what if anything has changed. That information may help you decide if you need repair on the camera or lens or both.

The user manual says you will receive target alignment arrows (tips) to show you what you must do to get proper target alignment with the camera/lens. I found that I sometimes received these tips, but there were times when the software told me the target was not aligned but provided no alignment tips. I just had to keep working at the alignment until I got the green checkmark indicating all was well.

Section 9 of the user manual is where I spend most of my time. I wish Nikon supported the fully automatic autofocus microadjustment described in this section, but I have to live with Manual Setting Change Mode (MSC) as a part of the fully automated procedure to calibrate my Nikon D800e. I understand that FoCal can automatically adjust AF in less than three minutes for some Canon bodies. Normally, it takes me 12-15 minutes to do so with my Nikon bodies because of the manual AF fine tuning adjustments I have to make and the pauses I do to prevent hand-induced vibration during the adjustment.

After you start the Fully Automatic Autofocus Microadjustment, you will get continuous feedback on the progress of the AF fine tuning whether you have to do manual adjustments or the software runs in full auto. You get to see a Predicted AFMA on the top right of the computer screen and color coding indicating the quality of that predicted adjustment. Normally the color coding will progress from red to yellow and finally to green indicating a good quality process. If you see the color coding going the other way, then you can expect problems with the final tuning. If the number of clicks passes the FoCal trip point before the final adjustment is determined (you can raise the trip point with FoCal Pro) and the color code is red, you need to stop the calibration procedure and make some corrections.

While testing all of my lenses on several occasions, I experienced the red color code and exceeded the FoCal shutter click warning point only when testing my 200-400mm zoom with a teleconverter on it. I have the Pro version of the software so I could raise the ISO setting for the tests and leave VR turned on. With those changes, the shutter speeds were high enough and vibration reduced enough to allow the calibration to progress to a high-quality AF fine tuning point.

Another feature called Target Optimization is included in the Pro version of FoCal. This feature helps you calibrate longer telephoto lens that accentuate any camera/lens movement caused by wind or tripod instability.

This latest version of FoCal also allows you to limit the AF fine tuning adjustment range. If you know a lens is either back or front focusing, limiting the AF tuning range to the positive or negative side of the full -20 to +20 range will result in less camera clicks to determine the AF fine tuning point, and will speed up testing.

A new FoCal capability called Turbo Calibration test in the Plus and Pro versions allow Canon testers to perform the entire AF fine tuning operation without a single shutter click. This TurboCal mode demands a totally sharp LiveView focus at the start of the test sequence. You also have to switch from autofocus to manual focus on the lens after the LiveView focus. Obviously, this test demands attention to details and careful handling, but the results are fast and cause minimum shutter click impact. (Note: I have not run this calibration test because I do not own a Canon DSLR; maybe some of you can comment about this test.)

If, after reading all of the above, you decide automatic AF tuning is not for you, FoCal offers a manual AF fine tuning procedure in which you control all of the elements just as you would before you met AF fine tuning software. The advantage to the manual FoCal method is the software analysis that is performed at the end. This mode is like having a LensAlign FocusTune module inside FoCal. You get to choose how much automation you want to live with. What more could you ask for?

I will answer that question when I report on the other tests you can do with FoCal in addition to AF fine tuning.

Before I get questions regarding the reliability of FoCal, let me just say this. Reikan Technologies has had software quality assurance issues from the first version I tried last summer. I have experienced versions that appeared to be stable and bug free. However, during my testing of version 1.8.1 today, it took me considerably longer than normal to do my AF fine tuning with a new lens because software bugs kept locking up my computer. I had to restart the software three times and change from RAW to JPEG image analysis before I could get it to run AF fine tuning successfully.


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