Reikan Focal VS Dot Tune to AFMA lenses on a 7D2

[Don Haines]

I have heard claims that "Dot Tune" was a reliable method to AFMA a lens. I have also heard claims to the contrary. Most of those claims have been long on opinion and short on data, so I decided to give it a try myself on a 7D2.

The results are as follows: (under incandescent lighting)

150-600: dot tune (150 +9) (600 +14) - Reikan (150 +5) (600 +6)
70-200: dot tune ( 70 +7) (200 +4) - Reikan ( 70 +2) (200 +3)
17-55 : dot tune ( 17 +4) ( 55 +3) - Reikan ( 17 +5) ( 55 +9)
10-20: dot tune ( 10 +4) ( 20 +9) - Reikan ( 10 +5) ( 20 +17)
100: dot tune (100 -8) - Reikan (100 +5)
30 : dot tune ( 30 -2) - Reikan ( 30 +1)

I changed locations, repeated the test and got the following: (under flourescent lighting)
150-600: dot tune (150 +11) (600 +17) - Reikan (150 +5) (600 +6)
70-200: dot tune ( 70 +7) (200 +5) - Reikan ( 70 +2) (200 +3)
17-55 : dot tune ( 17 +4) ( 55 +3) - Reikan ( 17 +5) ( 55 +9)
10-20: dot tune ( 10 +3) ( 20 +7) - Reikan ( 10 +5) ( 20 +17)
100: dot tune (100 -10) - Reikan (100 +5)
30 : dot tune ( 30 +1) - Reikan ( 30 +1)

The observations are:
1) The Reikan values stayed the same between the runs
2) The Dot Tune values varied up to 3 units between runs
3) Reikan and Dot Tune only agreed once.
4) Reikan and Dot Tune can disagree by up to 15 AFMA units

If you look at the discrepancies under the two runs.
incandescent - 4, 8,5,1,1,6,1, 8,13,3
fluorescent - 6,11,5,2,1,6,2,10,15,0

it appears that Dot Tune is affected by fluorescent lighting.

A quick visual verification of the extreme cases indicates that the Reikan values are far more accurate that the Dot Tune values.

My conclusion. At least on a 7D2, don't waste your time using Dot Tune on your lenses, get Focal and do it right.

 

[neuroanatomist]

Thanks for testing and posting your results, Don. Your experience with DotTune being inconsistent and unreliable matches my own.

 

[AlanF]

My 7D II arrived yesterday morning and I spent about 5 hours with Focal calibrating my telephotos. First, I had to upgrade to Focal 1.9.10 to be compatible with the 7D II. But, that took about an hour before it would accept my password or the data provided originally by Riken. Then, the program kept crashing on the Mac. Sometimes it would quit after a few shots, sometimes at the end. And, it was freezing cold in the garden where I was using natural light. My wife asked if everyone had to do this with their lenses, clearly thinking I was obsessive. Anyway, the AFMA worked fine in the end.

Anyone else have problems upgrading Focal? When it works, it is great.

 

[eninja]

Thanks for this.
Just got 50mm L. After previously owning 35mm F2 IS and 40mm STM (which nail viewfinder focus almost every time) on my 6D.
Now, I got this doubt feeling every time I AF on 50L. So was thinking to purchase Reikan Focal. Or ask Canon service to AFMA which is more costly. (Get rid of the variable and Isolate the problem more).
And my 70D AF worst (not as good as my 6D) - idk if this is user error or expected.
On the other side, I am aware of focus shift. And still need to learn a lot regarding subject distance and F value. I tend to always use F1.2 no matter what subject distance. I am still in the learning experience stage.