p.37 #2 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
gschlact wrote:
It's pretty unbelievable that Canon still has not implemented the Dot Tune method in their firmware for all the camera that support MFA.
I suspect it'll happen eventually. They actually have a patent on an automated technique (PDF) that looks similar to what Nikon implemented on the D5/D500.
p.37 #3 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
gschlact wrote:
It's pretty unbelievable that Canon still has not implemented the Dot Tune method in their firmware for all the camera that support MFA.
p.37 #4 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
The Moire method appears interesting and I tried it a couple of ways. First with the "alternative method" of using AF followed by LV then adjusting the focusing ring forward/backward to maximize the moire figure out ff/bf and then dial in some MA. Too labor intensive. Then I tried the method of LV followed by AF and looking for lens ring movement and then dialing in MA based on that. Again, too complicated. Next up I tried a modified moire method as the target in LV followed by AF adjustment using dottune. Next, to confirm the dottune values, I again used the moire target in LV followed by pressing the AF and watched for any lens movement - there was none suggesting that the dottune values were correct. The results were there were some major adjustments to both the 70-200 and 24-105 by several MA's at both tele/wide which were originally set by using the dottune outside with a static target and minor correction to the 16-35 by approximately +-1MA. The 50 and 85were spot on. So, let's see how it pans out when I try the lenses in real life...
p.37 #5 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
After using the modified Moire/Dottune method, I tried out the lenses on a standard DLRkit target from various distances. So far, it appears spot on. Today, I tried to calibrate my SIgma 150-600 "S" and was unable to do so. It requires calibration at 4 focal lengths (150, 250, 400, 600) and at four distances (9.2, 20, 48, inf. ft.) I tried using the modified Moire/Dottune and then switched to just a large target. Either way, the values I received were so far off that I just abandoned it. Then I tried to go back to the method of using LV followed by AF, looking for lens movement, and then dialing in compensation. That failed as well and I could never get concordance. We'll see what Sigma says...
p.37 #6 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
EGrav wrote:
Dot Tune is not very consistent and reliable for Canon cameras. Too subjective dealing with confirming focus. Supposedly works great with Nikon because different way of confirming focus.
I never could get Dot Tune to work for me and any of my Canon camera bodies or lenses. I'd take the combo out after Dot Tune adjustment and come back with lots of soft images. I gave up and bought Focal. Dot Tune seems like it should work but either I didn't follow procedure properly or something was just off with me, but it wasn't for lack of trying. Whatever the issue it didn't work reliably.
p.37 #7 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
NCAndy wrote:
I never could get Dot Tune to work for me and any of my Canon camera bodies or lenses. I'd take the combo out after Dot Tune adjustment and come back with lots of soft images. I gave up and bought Focal. Dot Tune seems like it should work but either I didn't follow procedure properly or something was just off with me, but it wasn't for lack of trying. Whatever the issue it didn't work reliably.
FoCal finally started working well for me at Version 2. The latest version is even better - the target setup isn't as finicky. You just have to be somewhere on the target, not exactly in the center. Also, I had Home Depot print larger targets (a couple of dollars) and BRIGHT lights ((halogen shop lights.) Large target for long glass and regular target for short glass. Works great and quick.
Today, I MA'd my new 5D4 and 5 lenses + TC's. Lenses were from 15 mm to 600mm. Re-did a few to spot check. All were within a few tenths. (You can get readout in tenths now.) I use their recommended distances ( 50x for lenses under 200 and 20x for big glass.)
Quick and no errors.
I don't have any connection with FoCal. Just waiting for MA to be built in to Canon cameras. Dot Tune is too subjective and I had the exact same problems as you. This is a known problem with Dot Tune and Canon bodies. YMMV
p.37 #8 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
So I sent the Sigma lens in for calibration. I was extremely impressed by Sigma service and it was on par with or better than CPS. The turn around time was terrific and they sent the lens back expertly packed and protected. Preliminary testing in low light demonstrated that the lens was nailing the focus perfectly. Thanks Sigma for a job well done.
p.37 #9 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
For me, the automated version of DotTune in MagicLantern works very well for me when calibration is carried out near infinity.
I also purchased FoCal and it doesn't work well at all. Followed their recommended distances etc.
As for Sigma lenses on Canon bodies, my conclusion after so many lenses over the years is there is very deep incompatibility between them. AF is totally inconsistent even after careful calibration.
Since we are on the topic of AF, I have another couple of observations to make:
(i) face detection using DPAF (dual pixel) isn't as accurate as what people think; contrast detection on the other hand is slow but more reliable
(ii) 80D does not seem to permit AF during magnified live view; every time AF button or shutter is pressed, the camera will automatically zoom out; this does not happen to other cameras. Anyone else has the same problem?
p.37 #11 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Ron,
You need to use the Live View (contrast detect)mode not quick view (which is the phase detect).
Don't forget to turn off Af on the lens once you achieve focus and start the MFA 'walk' of values. Don't not count any hesitance to focus as a good MFA value, they need to be a rapid 'beep' af confirmation.
p.37 #13 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
gschlact wrote:
Ron,
You need to use the Live View (contrast detect)mode not quick view (which is the phase detect).
Don't forget to turn off Af on the lens once you achieve focus and start the MFA 'walk' of values. Don't not count any hesitance to focus as a good MFA value, they need to be a rapid 'beep' af confirmation.
Quick View is not available in EOS Utility anymore. Arash had a MFA method using it.
p.37 #14 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
I decided to do this for my Canon 7D with my Canon 70-200 2.8 IS I and am a bit lost with the findings. I first measured at 70 and 200, but then after those being so different I decided to do 100 and 135 as well, this is what I found:
70 : -11 > +4
100 : +9 > +18
135 : -1 > +11
200 : +13 > +20 (so then I adjusted focus to capture the entire range and got -2 > +13 effectively making it +13 > +28)
Basically I am a bit lost from here. Does the lens need to be sent for cal? I don't have another Canon body or lens to currently test with.
p.37 #15 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Brett,
Looking at your numbers, the 100mm seems to not fit the pattern. (It is messier if you also list the mid point of each.
Unlike newer bodies, the 7d only lets you enter one MFA value, whereas new bodies let you enter one for the short end and one for the long end for each lens. The camera then interpolates in between. If you look at your 70,135,200 ranges, you can see the progression.
The bad news is that your 200mm is outside and doesn't overlap your other two ranges so it will always be front focused.
I would redo your dot tune test one more time. Remember to not include any hesitation in the af beep. If you still don't have overlap in the ranges, I would consider either selling the lens, getting a new body, or have lens calibrated. The calibration my guess is about $300. But if you sell your 7d for $450, upgrading body would be about 600 more, or you could sell and upgrade your lens.
p.37 #19 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Not sure about your question. DPAF will not help if a lens needs +-7 due to back or front focus. FoCal is experimenting with it. If enabled it gives a comparison between both to ensure a correct result. The example shows a one tick difference between the two. I have not tried it.
Contrast Detect cannot be adjusted and yes is far more accurate. I have used it as a base to help adjust MFA. I don't think Dot Tune works with CDAF in any way that I know of.
After reading about peoples experience using Duel Pixel it seemed the cons where files where much bigger and the adjustment in post was very small. Not sure how many use it. I was not aware that it helps AF as the article seems to suggest. Its did not say it slows things down but I can't remember the feedback about that. I have to read to a few times.
p.37 #20 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
In reading the article, it says that DPAF uses Phase Detect AF.
The feature you mention for post processing focus adjustment with the huge files I thought was called something else?
So the question I ask boils down to... If DPAF=PDAF
a) how do we get Contrast Detect AF in Live View instead of the dpaf/PDAF?
b) is dpaf PDAF different from the focus screen for non live view?
Contrast Detect af is used in dot tune to establish the proper AF prior to turning af on the lens to manual to start start tuning of MFA values.
