p.29 #1 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
dodgyexposure wrote:
I decided to have another go at dot tune, but I'm still getting inconsistent results.
I decided to adjust my 24-70 II. Tele end was no trouble - I tested at about 3-4m, and an adjustment of -1 was indicated. This adjustment gives me good results at various focal distances. Not that the pre-adjustment results were bad at 70mm, of course, given the small adjustment. It's the consistency that I'm interested in here.
A different story at 24mm. First, I did the dot tune test at about 1.2 - 1.5m (i.e. 50x focal length) - indicated a required adjustment of +10. I took some general shots of my son at a longer focus distance (i.e. normal environmental portrait distance of 2-4m), which were clearly OOF.
I then redid the dot tune test at about 4m - the same distance as I did for the long end. This gave an indicated adjustment of -4. Better results in the 2-4m general shooting test. But some testing at closer focus distances clearly showed front focus at an adjustment of -4.
My conclusion? At the wide end, my 24-70 needs different adjustment at different focussing distances. Is this normal? What do I do, just put the adjustment somewhere in between? This is what I have done, setting it back to zero.
That sigma hub allowing adjustment at different focussing distances sounds good . . .
Try tuning at infinity, using a natural subject like a distant building or mountain - I've found that produces the best results for lenses with distance-specific AF variability. For such lenses if I tune near MFD then middle-to-infinity distances are poor but if I tune to infinity then near distances are good as well.
p.29 #2 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Anyone try to see how consistent the contrast detection focus is on their camera with certain lenses. I tried did the dot-tune method multiple times in succession with the same lens camera combo and most of the time the center point comes out within 2 of each other however one combination I was getting a variation of 8 point.
p.29 #3 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
“Dot-Tune” - Mis-Adventures..?
Hello:
I tried to use - as best I could figure out how to, doing the “Dot-Tune” procedure, on the Canon 1D Mark III camera,
and the Sigma 50mm, f/1.4 EX DG HSM (non-ART) - lens combo.
Center-Point AF / One-Shot mode
I tried to make sure (as best as I could to understanding), set up the camera’s AF settings to be as simple, and straight-forward - (I hoped) to expedite the “Dot-Tune” setup methods.
I had a target - about (50x the focal length - so 50 x 50mm = 2,500mm ) - which I then, used an online convertor, found this to use -
therefore to me - 8 foot was reasonably close enough I felt?
I did the tests, in my kitchen, and I did use the overhead kitchen lighting, not super bright, but the way it is… thought bright enough?
I started with the camera and lens mounted on a tripod, solid (I feel) foundation.
I went to Live-View Mode (and I didn’t realize it), BUT - at least on this camera, there is NO AF - ONLY MF (Manual Focus)…
So, I did obtain as best as I could get it on the rear LCD screen - MF - sharp AS POSSIBLE - but - (not “razor sharp” though - like I would have liked to see in getting.)
I was pleasantly surprised to be honest… that I could NOT get a SUPER - detailed - SHARP (Crisp image). (Maybe the Live-View focus is never super sharp?)
Anyways - moving along - I started with the suggested AF @ MA setting at ZERO 0 - and tried to obtained a STEADY BEEP, and LED (green) IN FOCUS confirmation LED.. NEVER HAPPENED, It beeped, and the LED flashed, and never stayed ON. (for the 5 seconds), like Dot-Tune instructions suggested to do.
It continued to do this throughout the ENTIRE - “Dot-Tune” procedure, walking down both directions of the AF MA scale, ZERO to +20, and vice-versa in the opposite direction: ZERO to - 20.
Not once did the GREEN LED AF confirmation stay lit.
It Beeped, and flashed like to say “HEY WE HAD / HAVE AF Confirmation” - so I took a shot anyways.
Hence, NEVER got any usable scale of AF MA settings to use..
Advice?
(I am going to try this with OTHER Canon branded lenses, to see if this is an issue..?)… If so, what could it suggest or mean?
p.29 #4 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
ELSELS wrote:
Anyways - moving along - I started with the suggested AF @ MA setting at ZERO 0 - and tried to obtained a STEADY BEEP, and LED (green) IN FOCUS confirmation LED.. NEVER HAPPENED, It beeped, and the LED flashed, and never stayed ON. (for the 5 seconds), like Dot-Tune instructions suggested to do.
And you don't have the camera in live-view and are using AF, not MF, right?
p.29 #11 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Two possibilities - 1) the focus you manually set while in LV is not critical focus and thus once you exit LV the camera doesn't keep a steady AF confirmation dot in the VF or 2) the 1D Mark III by design doesn't keep a steady AF confirmation dot even when focus has been set correctly. I don't have a 1D Mark III on hand to verify #2 but you can do the following to check - outside of LV, set the camera+lens to AF and autofocus onto your high-contrast target. Then switch the body+lens into MF and see if you get a steady confirmation. If you don't then the 1D Mark III doesn't keep a steady AF confirmation even though the camera has arrived at what it thinks is correct focus. Do this experiment a few times to eliminate any misfocuses.
p.29 #12 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Hello snapsy:
If I did things the correct method, - I have the 1D3 + Canon 85mm, f/1.8 for this particular test.
The body doesn't have any "separate" AF/MF selection choice, but the lens does have AF/MF setting.
I had the camera+lens in "AF" mode, locked focus on the target - held the shutter release button - 5 secs. (or more), and the LED (AF confirmation, stayed lit).
I then, without "touching the lens' focusing ring", clicked the lens' AF to MF.
Re-aimed at the target, NO - steady Confirmation, it BEEPS, BLINKS, and keeps repeating, it did not (in the case) stay on, as in the AF mode.
So, then - knowing this (at least with this 1D3 and the Canon 85mm, f/1.8 lens combo, means what?
I am guessing do I "walk the scale of -20 / +20 and if so, what purpose, will it eventually "find / detect" some setting - / + where it refuses to LOCK AF?
Thank-You for your continued support and help in the matter.
p.29 #13 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Great. Just to be clear, when you say you "re-aimed at the target", does this imply camera movement? Or was the camera locked-down on a tripod from the time you engaged the AF on the target, verified it remains confirmed for 5 seconds with AF still on/held, and then switched to MF and verified the confirm repeats with beeps and blinks rather than holding a solid confirmation. I want to just be sure there was no camera movement between any of these steps.
p.29 #14 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Hello:
Both ways - I had camera and lens locked-down on the tripod - with AF enabled on the lens, the shutter release 1/2 pressed - AF (BEEP), Green Dot (AF confirmed) - held for 5 secs - SOLID - steady lit.
Turned AF off (the lens switch), to MF setting, it did NOT remain SOLID, it beeped / blinked . over and over.
Then I thought, (I guess it might make a change)? - took camera off the tripod, repeated the process, AF on lens enabled, pointed (aimed) at target - steady 5 secs. SOLID AF confirmation.
Turned off AF over to MF on lens, repeated = same thing on MF - it did NOT remain SOLID, it beeped / blinked . over and over.
p.29 #15 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
If that's the case then it sounds like the 1D Mark III behaves different than all other Canon/Nikon bodies in that it doesn't keep the dot continuously illuminated in MF mode when focus has been established. So to DotTune the body use the same procedure described in the video but change the criteria for what represents a "solid confirmation" - instead of relying on a continuous confirmation, use the single flashing dot (or single beep) instead. It'll produce less precise feedback than relying on the continuous method but it should get you to the right midpoint. Good luck and please report back your results!
p.29 #18 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Hi Tony:
I am starting to consider the camera has "major" AF issues, across the board.
I tried a quick test, shooting a subject, outside my upstairs apartment window...
using the Canon 1D3 and the Canon 85mm, f/1.8 lens, (switching gears - from trying to work with the Sigma 50mm, f/1.4).
I had the AF MA - centered @ ZERO [0] = NO MA applied, One Shot, AF mode, center AF point, ISO 100, @ f/1.8 to purposely push the shutter speed HIGH - to (help) eliminate any camera shake.
Shutter speed was @ 1/8000 !
I even went so far to rest the camera (bottom) / base plate on the window sill metal frame, for added stability.
I used both - Shutter Release AF / and BBF AF.
Achieve AF confirmation BEEP, SOLID green DOT in the viewfinder, took the shots..
p.29 #20 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
ELSELS wrote:
Hi Tony:
I am starting to consider the camera has "major" AF issues, across the board.
I tried a quick test, shooting a subject, outside my upstairs apartment window...
using the Canon 1D3 and the Canon 85mm, f/1.8 lens, (switching gears - from trying to work with the Sigma 50mm, f/1.4).
I had the AF MA - centered @ ZERO [0] = NO MA applied, One Shot, AF mode, center AF point, ISO 100, @ f/1.8 to purposely push the shutter speed HIGH - to (help) eliminate any camera shake.
Shutter speed was @ 1/8000 !
I even went so far to rest the camera (bottom) / base plate on the window sill metal frame, for added stability.
I used both - Shutter Release AF / and BBF AF.
Achieve AF confirmation BEEP, SOLID green DOT in the viewfinder, took the shots..
