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Author Topic: Automatic Microfocus adjustment software  (Read 46170 times)

Mt Spokane Photography

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Re: Automatic Microfocus adjustment software
« Reply #45 on: January 15, 2012, 10:12:21 PM »
Hey Mt Spokane Photography,

I'd like to ask you if you could give your opinion about my testing and especially about the conclusions I made about it. This was my first run and I haven't done much MFA fiddling this far, so I'd like to know if I'm going in the right direction.

Also, what kind of target illumination system did you have?

Thanks in advance,

Janne

I noted users having issues with the -91 AFMA in the beta, supposedly he found the issue, but he also pulled out the testing beyond + 20 or -20.

I've used several methods to try AFMA, and my results improved things, but were dependent on my ability to detect visually the difference in focus points, and my old eyes struggle at that. Lens Align had the best results.

There are some images of my lighted table earlier in the thread.  The lighting level has been between ev 11 and 11.9 which is nice and bright.  I have 12 four foot CRI 98 fluorescent bulbs with electronic ballasts (no flicker) they are about 2 ft or less from the target.  four bulbs on each side and four above.

Some things I noticed that affect results:

Vibration is a killer, a really sturdy tripod is needed, and just walking accross the floor of my wood floor studio will mess up the testing.

Use the large target for telephoto lenses and get further back.  My space is limited, I could use a long hallway and get 40-50 ft, but I'd have to move a lot of things and setup new lighting, so I haven't bothered for now.  Once winter is over, I may setup a long distance setup for testing lenses, but its not a priority.

Most of the tests were running over 30 exposuers, so I set the software to do up to 50 before stopping.

Some lenses are just plain erratic.  I have no way of knowing if this is a single lens issue, or if it applies to the lens part number.  Once users start sharing their results, that might become apparent, however, different setups may influence results as I found out.

I'm going to be shooting a few thousand low light images at a theatre event this coming week, so it will be interesting to see if the images are sharper.  I'll be checking carefully at the start.  I've found nothing to complain about in the past, so I'm dealing with a very a small improvement in most cases.

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Re: Automatic Microfocus adjustment software
« Reply #45 on: January 15, 2012, 10:12:21 PM »

japhoto

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Re: Automatic Microfocus adjustment software
« Reply #46 on: January 16, 2012, 06:04:23 AM »
Body: 7D. Distance to target: 3.1m.

This one stood out for me, didn't you change your camera to target distance at all during the testing?

For example for your 85mm the proper testing distance would be 4.25m and with your 70-200mm @ 200mm it would be 10m etc.

Just a thought.

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Re: Automatic Microfocus adjustment software
« Reply #47 on: January 16, 2012, 06:45:31 AM »
SOFTWARE UPDATE: the release of FoCal 1.1


The important updates are as follows:

- Addition of support for the Canon EOS-1Ds Mark III and Canon EOS 50D.
- Addition of a new Manual Mode which allows you to analyse images you take yourself, and this works with Canon and Nikon cameras.
- PDF Report generating capability from the Fully Automatic test and Manual Mode tests in FoCal Pro.
- Bug fixes and minor improvements.

FUTURE:
Support for the 1D Mark III and 1D Mark IV is currently being added and will be released for FoCal 1.2, currently planned for release at the end of January

Mt Spokane Photography

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Re: Automatic Microfocus adjustment software
« Reply #48 on: January 16, 2012, 12:40:48 PM »
Body: 7D. Distance to target: 3.1m.

This one stood out for me, didn't you change your camera to target distance at all during the testing?

For example for your 85mm the proper testing distance would be 4.25m and with your 70-200mm @ 200mm it would be 10m etc.

Just a thought.

The proper testing distance is the distance you use the lens at.  I photograph small birds, and get as close as possible.  Adjusting the focus a long ways off makes no sense for me, but it is likely what others will use.

I'm pretty cramped right now in my studio and really busy, so I'll re-arrange things at some point so I can have up to about 40 feet of clear view.

« Last Edit: January 16, 2012, 04:14:18 PM by Mt Spokane Photography »

neuroanatomist

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Re: Automatic Microfocus adjustment software
« Reply #49 on: January 16, 2012, 01:07:39 PM »
This one stood out for me, didn't you change your camera to target distance at all during the testing?
The proper testing distance is the distance you use the lens at.
[/quote]

Exactly.  It's important to note that the testing distance does make a difference in the optimal AFMA value.  I'm listening to beep-click-click as FoCal works it's way through a test...but my results so far indicate that testing at 50x focal length (recommended by Canon/FoCal) vs. 25x focal length (recommended by LensAlign) can make up to 5 units difference (i.e. over half of the depth of focus at max aperture).

Other preliminary observations - software has some trouble with fast lenses, e.g. 85/1.2L II, 35/1.4, 135/2, especially at the 50x distance (gives inconsistent results error, but sometimes it succeeds); never an issue with f/2.8 and slower lenses, and while it could be vibration (hardwood floor over basement), with the 85L the shutter speed was 1/4000 s which should be sufficient to avoid any problems with shake.  It still has a few bugs (sometimes it reports no change is necessary, while the analysis report disagrees), and it crashes occasionally (twice yesterday, three times so far today).  But overall, it's a good program, and will no doubt improve with time.
« Last Edit: January 16, 2012, 04:08:21 PM by neuroanatomist »
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Kahuna

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Re: Automatic Microfocus adjustment software
« Reply #50 on: January 16, 2012, 02:27:30 PM »
May I ask a really  stupid question....Please  :o

I see that there have been some fairly significant adjustments made.  I understand the adjustment of one "step" varies depending on the max aperature of the lens but I have seen up to +17 adjustment made on an 85mm f1.8.  That seems like quite an adjusment.  Would you not see this in the photo's IQ? 

neuroanatomist

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Re: Automatic Microfocus adjustment software
« Reply #51 on: January 16, 2012, 03:21:22 PM »
I see that there have been some fairly significant adjustments made.  I understand the adjustment of one "step" varies depending on the max aperature of the lens but I have seen up to +17 adjustment made on an 85mm f1.8.  That seems like quite an adjusment.  Would you not see this in the photo's IQ?

Without that adjustment, you'd definitely notice it.  If you're 'off' by one or two units (or more with a slow lens like f/4 or slower), you'd probably not notice.  More than that, or with a fast lens, you'd notice.  Not on every shot - with more distant subjects (deeper DoF), errors are less evident.  Also, AF is not 100% accurate.  On a non-1-series body, with a perfectly calibrated lens you might get 8-9 out of 10 shots having acceptable focus, and 1-2 misses.  With a large adjustment needed but not made, those 1-2 misses might actually be hits. 

That sort of thing is a clue that you need adjustment, or need to repeat it.  Say you drop your camera and the relative positions of the image and AF sensors are changed, even by a fraction of a millimeter.  That means your lenses may no longer focus correctly.  In fact, that exact scenario happened to me last October - I was out walking with my two young daughters, my 5DII with 2x II and 70-200mm f/2.8L IS II hanging from a BlackRapid strap from the tripod collar.  The height and angle were at just the right place to push the lens release button, and the camera twisted and dropped.  AFter that, all of my lenses needed an adjustment of about negative 8 units relative to their previous adjustment value.  After that incident, I noticed that while I still had some keepers, my OOF rate went up dramatically.  Re-adjusting all my lenses corrected that issue.  FoCal is easy enough to use, and fast enough (less than 3 minutes per test, with MLU delay increased to 2 s), that I will probably retest lenses every couple of months.
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Re: Automatic Microfocus adjustment software
« Reply #51 on: January 16, 2012, 03:21:22 PM »

Freshprince08

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Re: Automatic Microfocus adjustment software
« Reply #52 on: January 16, 2012, 04:02:55 PM »
Body: 7D. Distance to target: 3.1m.

This one stood out for me, didn't you change your camera to target distance at all during the testing?

For example for your 85mm the proper testing distance would be 4.25m and with your 70-200mm @ 200mm it would be 10m etc.

Just a thought.

You're right, this distance isn't ideal, however I'm pretty space limited in my current setup unfortunately! I'll see if I can try a few different distances with some of my wider lenses.
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Mt Spokane Photography

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Re: Automatic Microfocus adjustment software
« Reply #53 on: January 16, 2012, 04:24:04 PM »
This one stood out for me, didn't you change your camera to target distance at all during the testing?
The proper testing distance is the distance you use the lens at.

Exactly.  It's important to note that the testing distance does make a difference in the optimal AFMA value.  I'm listening to beep-click-click as FoCal works it's way through a test...but my results so far indicate that testing at 50x focal length (recommended by Canon/FoCal) vs. 25x focal length (recommended by LensAlign) can make up to 5 units difference (i.e. over half of the depth of focus at max aperture).

Other preliminary observations - software has some trouble with fast lenses, e.g. 85/1.2L II, 35/1.4, 135/2, especially at the 50x distance (gives inconsistent results error, but sometimes it succeeds); never an issue with f/2.8 and slower lenses, and while it could be vibration (hardwood floor over basement), with the 85L the shutter speed was 1/4000 s which should be sufficient to avoid any problems with shake.  It still has a few bugs (sometimes it reports no change is necessary, while the analysis report disagrees), and it crashes occasionally (twice yesterday, three times so far today).  But overall, it's a good program, and will no doubt improve with time.
[/quote]

Have you tried this with the larger target for the 85L at 50X distance?  I haven't, but I am wondering it it would help.  The software sometimes has difficulty finding the target, and if I move closer, it does better. 

I've had a number of crashes as well.  I was in a hurry, and am still pressed for time (aren't we all), or I would have written up bug reports for repeatable errors.

It is definitely a work in progress, but I've found it usable, even with crashes.  Having the analysis curve helps me decide if I want to use their AFMA value, or pick my own, which I have done in a couple of cases.

Apparently, the latest version lets us save the analysis data, but, for now, I'm not goiing to rerun all my lenses on two different bodies just to save the data.

neuroanatomist

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Re: Automatic Microfocus adjustment software
« Reply #54 on: January 16, 2012, 04:49:07 PM »
Have you tried this with the larger target for the 85L at 50X distance?  I haven't, but I am wondering it it would help.  The software sometimes has difficulty finding the target, and if I move closer, it does better.

Apparently, the latest version lets us save the analysis data, but, for now, I'm not goiing to rerun all my lenses on two different bodies just to save the data.

No, I haven't tried the larger target, although I printed it just in case (and used the small macro target with the 100L, actually). 

Interestingly, I'm running the 135L now, and it had issues finding the target at 25x focal length, but not at 50x.  The 135L is also giving the inconsistent results warning (I edited my post above).  The 70-200 II is up next.

It does have trouble estimating the distance, and I'm wondering if that's Canon's 'fault' or FoCal's?  I know from the EXIF that Canon reports out two relevant values, 'focus distance upper' and 'focus distance lower' (not sure what these mean, if they define the DoF, or are confidence intervals, etc.).  But for example, with the 135L it's warning in the Info window that the recommended distance is 6.8 m, and I'm testing at 8.1 m.  Now, I'm pretty sure that 135mm x 50 = 6.75 m, and that converts to 266 inches, and I'm also pretty sure that I know how to use a tape measure - I doubt that I've managed to mis-measure by 4.5 feet!  Oh well, I'm not bothered by it, but it's worth noting.  If it is, in fact, Canon's 'fault' I wonder what that says about the distance information transmitted for E-TTL II flash metering...
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neuroanatomist

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Re: Automatic Microfocus adjustment software
« Reply #55 on: January 16, 2012, 05:13:47 PM »
I've had a number of crashes as well.  I was in a hurry, and am still pressed for time (aren't we all), or I would have written up bug reports for repeatable errors.

I'll be submitting one for the no adjustment necessary error.  It just reported that the current value of -3 was correct and no adjustment was necessary, when the analysis window clearly shows -8 is the best value (and reports -8 as the optimal value in that window).
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Mt Spokane Photography

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Re: Automatic Microfocus adjustment software
« Reply #56 on: January 16, 2012, 06:24:41 PM »
I've had a number of crashes as well.  I was in a hurry, and am still pressed for time (aren't we all), or I would have written up bug reports for repeatable errors.

I'll be submitting one for the no adjustment necessary error.  It just reported that the current value of -3 was correct and no adjustment was necessary, when the analysis window clearly shows -8 is the best value (and reports -8 as the optimal value in that window).

I noted that one multiple times.  I thought it was because it failed to find a better setting, even though it predicted a different setting.  I also noticed it predicting say a -3 setting, and then setting to a different one.  Looking at the bell curve, it appeared to be the right one.

I turn on the analysis window and watch as it clicks the various shutter points.  I can easily predict the correct AFMA long before the software does it with its curve fitting.  I guess the human brain is still better at things like this than computers.

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Re: Automatic Microfocus adjustment software
« Reply #57 on: January 17, 2012, 10:26:11 AM »
@Mt Spokane Photography,

Thanks for the info on the lighting, I'll have to find a way to improve that aspect at least on the longer distances. My illumination values were at around 8EV with the longer lenses, so testing for example the 300L f/4 proved to be quite difficult.

That also made it seem like the 300mm was the most erratic lens, but I'm pretty sure it's not. It's quite snowy here right now, which improves the light levels, so if the weather is right, I might even do an outdoor winter test with the lens :)

For the shutter cutoff setting I also used 50, since 30 never seemed to be enough.

By suggesting the 50xFL "rule" I didn't mean that one should be a slave to that, but it just seemed that it wouldn't be the best option to check all lenses at just one distance from the target. I also photograph small birds quite often, so I did multiple distances with my 70-200II (which always seemed to land on -2).

@neuroanatomist,

I also experienced quite a lot of crashes (haven't tried the new 1.1 out yet). And also the "no correction is required" - bug feature came to be familiar. This is why I did multiple passes to compare the results so that I could pick the best out of them. I don't know if this behavior is due to focus errors on the lens, on the body or does the software take previous runs into account and determine that no correction is needed when the last run was more accurate. It might just as well be just a bug though.

For me the distance was working quite well when working close to the target (checked with a tape measure) but at longer distances it didn't show anything. It also didn't find the medium target anymore when I was testing my 24-70 @ 70mm and 70-200 @ 70mm, so that was at about 3,5m. Again this might have something to do with inadequate lighting on the target, so I'll get back to you on that after testing it with better lights.


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Re: Automatic Microfocus adjustment software
« Reply #57 on: January 17, 2012, 10:26:11 AM »

neuroanatomist

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Re: Automatic Microfocus adjustment software
« Reply #58 on: January 20, 2012, 03:36:14 PM »
I have completed a few days worth of testing cameras and lenses with FoCal.  I have the Pro version, and I'm running it on a 17" MacBook Pro (Core i5, 8 GB RAM) with the software installed on a Parallels virtual machine running XP SP3, allocated one physical core (2 virtual cores) and 3 GB of RAM.  Most of the testing was with v1.1, although the first day was done with v1.0 (v1.1 was released the afternoon of the first day I spent running tests). 

My overall impression is very good, with a couple of caveats. The software is easy to use, although there were several random crashes.  There are still a few bugs in the software, for example, it sometimes reports that the current adjustment is optimal, when looking at the detailed analysis data shows that a different one is best (supposed to be fixed in the next release).  Also, the Zoom view during target setup is based on the last location of Live View AF (i.e. from the last time you use it before lauching FoCal), so for that feature to be useful you need to launch Live View and center the AF rectangle. 

As mentioned above while the testing was very straightforward with f/2.8 lenses and an f/4 lens, faster lenses gave it some trouble, sometimes resulting in a 'inconsistent results obtained so far' message (although allowing it to continue anyway often generated an excellent curve fit).  This happened more often with the 5DII than with the 7D.

Setup was straightforward - the target search tool did a good job with most lenses/distances that I tested, although sometimes not, particularly with longer lenses at longer distances with the 5DII. The time taken for a test run was very short - even increasing the mirror lockup to 2 s (default is 1 s), test runs took less than 3 minutes. My setup consisted of the target taped to a wall, lit by three 150 W-equivalent gooseneck lamps pointed at the target from about 2' distance. The FoCal documentation recommends at least 10 EV, although it states that down to 5 EV will work; my lighting setup gave between 11 and 13 EV depending on lens and distance. Camera on tripod, with hotshoe bubble level to square it to the wall and a tape measure on the floor.

Comparing the results to what I obtained manually using the LensAlign Pro for the same lens/focal length/distance, the results were very similar - spot on for fast primes, and within 1-2 units for slower zooms (where there are usually a couple of values that yield good results due to the deeper DoF). If I tested like I have with the LensAlign, the whole process would be much faster with FoCal. It takes me about 45 minutes to calibrate a lens manually (one distance/focal length, 30 minutes for setup, image capture, and tear down, and 15 minutes for comparisons); the same process with FoCal would probably take less than 10 minutes.

The advantage of FoCal is that it simplifies the procedure to the point where it's simple to test multiple distances and for a zoom lens, multiple focal lengths. Any particular adjustment you make is applicable for that focal length and that distance, and may not be optimal at other distances or zoom settings. With the exception of the 1D X, we're limited to applying a single adjustment value per lens - that means making the best compromise. The more data you have to help judge the best compromise, the better. 

I tested at 50x the focal length (recommended by Canon and FoCal), 25x the focal length (recommended by LensAlign), and for the 100L Macro, I also tested near the MFD using the small focus target. Without moving furniture around, the longest line-of-sight inside my house is ~35 feet, so I didn't test anything longer than 200mm (for which I'd set up outside, but daytime temps have been below freezing, and during the initial tests last weekend they were down in the single digits °F). For zoom lenses, I chose focal lengths loosely based on the zoom ratio, e.g. 3 focal lengths for a 2-3x zoom and 4 focal lengths for a 4x zoom.

Attached below are tabulated results for several lenses on the 5DII and 7D.  Several observations occurred to me when looking over the data. First, distance matters - in some cases, testing at 25x vs 50x makes up to a 7-unit difference in the optimal AFMA, which is nearly a full depth of focus for the lens at max aperture, i.e. will be easily noticeable in real-world shots.  For zoom lenses, different focal lengths give different results, and the progression is not necessarily linear nor unidirectional for a given lens (so, I wonder again how the 1D X will handle the two values for a zoom). 

On the 7D, the wider zooms seem to have much more spearation between values based on focal length and distance, e.g. comparing the 16-35mm II on the 5DII with a 5-unit gap (-5 at 16mm 50x to 0 at 35mm 25x), the same lens on the 7D has an 11-unit gap (-4 at 16mm 25x to +7 at 35mm 25x). Likewise, the 35mm prime shows a larger differential from testing distance (5 units on the 5DII, 7 units on the 7D). I wonder if this is due to the thinner DoF with the 7D (the distances are the same as with the 5DII, so the shot/framing is different, but under those conditions the APS-C sensor delivers shallower DoF). In general, the fitted curves for the same lenses were steeper on the 7D than on the 5DII, analagous to the difference bewteen a slower and a faster lens.

Other notable findings not evident from the data were that the testing was quite consistent.  Borrowing concepts for assay validation from work, I checked intra-run and inter-run variability, and both were quite low - repeating the same same lens/focal length/distance several times in succession yielded the same value (±1 for f/2.8-f/4 lenses), and re-testing after tear down and re-setup the next day yielded the same results. One exception was testing the 100L near the MFD, which gave more variable results; not a real problem since I almost always manually focus for macro anyway.

One other interesting observation concerned the target itself - for the first lens I tested, I decided to repeat the LensAlign manual method on the spot for a direct comparison to FoCal. After the manual test, on a lark I connected the camera to my Mac and ran FoCal with the camera pointed at the LensAlign. FoCal reported the same adjustment as it had with that lens using the printed FoCal target (which was the same as the manual value, too). Finally, the developer is quite responsive - good support is a critical part of new software!

In selecting an AFMA, I considered both the results at the different distances in terms of DoF for a given focal length, and also the distances which I commonly shoot for those lenses. For example, the value I chose for the 35L is biased toward the closer distance, since that's where DoF will be thinner; I picked the value for the 85L (even though there wasn't much difference) based on the fact that I usually shoot that lens at about 7-8 feet for portraits, which is ~25x the focal length.  For lenses like the 70-200 II, which I shoot at varying focal lengths and distances, I selected values biased toward the long end of the zoom range, since that's where DoF will generally be thinnest and focus most critical.
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Re: Automatic Microfocus adjustment software
« Reply #59 on: January 20, 2012, 03:47:33 PM »
I have completed a few days worth of testing cameras and lenses with FoCal...

Thanks Neuro.  Your tests with the software are very interesting and well articulated so those of us who are less informed (read: me) can digest it easily.  It looks like this software is a must for when I get the 1DX.

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Re: Automatic Microfocus adjustment software
« Reply #59 on: January 20, 2012, 03:47:33 PM »