p.8 #1 · DotTune: New AF tune technique, no photos required
Thank you for the quick response.
Unfortunately changing the global default value still won't bring my focus far enough forward. This is confirmed by photos taken as well as the dot tune method.
Again, this is in a macro situation (105mm VR) with a wide open aperture. Perhaps I'm expecting too much?
p.8 #2 · DotTune: New AF tune technique, no photos required
If you're making sure to leave the AF enabled and using the half-press of the shutter and the lens still wont give a solid confirmation at either end of the +/- 20 tune scale for either the lens-specific or worse, the all-lens default value, then the lens definitely needs to be sent in for adjustment.
p.8 #4 · DotTune: New AF tune technique, no photos required
TightLines wrote:
Understood.
I'm very new to the concept of body to lens calibration. Out of curiosity, what's to say it's a lens issue and not a camera issue?
It can be either or a combination. My D800 has a backfocus bias that requires -12 with all my lenses. If you combine that with a lens which also has a backfocus bias then you can get to the point where -20 isn't sufficient. Have you tried tuning other lenses on the body?
p.8 #5 · DotTune: New AF tune technique, no photos required
I've tried with a 60mm AF-S and have found a backfocus bias but not quite as strong as the 105mm. With the 60mm I have been able to find a value, -17, that will reliably give me the green dot when running your DotTune test. Since the camera is out of warranty I suspect I will have to take this to someone locally to fix. I hope it won't be a big bill.
p.8 #6 · DotTune: New AF tune technique, no photos required
I haven't tried this yet but want to. I have one question about something that doesn't make sense to me. If you achieve critical focus in LV before starting the tuning then wouldn't it always show solid green dot at 0. If its already critically focused and in MF mode won't it show the solid green dot for all AF tune settings?
p.8 #7 · DotTune: New AF tune technique, no photos required
mysh wrote:
I haven't tried this yet but want to. I have one question about something that doesn't make sense to me. If you achieve critical focus in LV before starting the tuning then wouldn't it always show solid green dot at 0. If its already critically focused and in MF mode won't it show the solid green dot for all AF tune settings?
It'll only show a solid green dot if zero is part of the confirmed tuning range. The AF tune value adjusts what the AF system considers "in focus" from the POV of its phase-detection mechanism. For body+lens combinations requiring AF tuning, what is in focus to the imaging sensor (LV critical focus) will appear OOF to the PDAF system, thus you wont get a solid dot until you set a tune value that adjusts the phase-detection measurement. I described this in more detail here.
p.8 #8 · DotTune: New AF tune technique, no photos required
Just for reference I went to Nikon Melville a week or two ago to get my lenses and body calibrated for AF. (I believe only the two Nikon repair centers-Melville and the one in CA-can do autofocus lens/body calibration)
It was $305 per lens and $143 for the body (d810).
p.8 #9 · DotTune: New AF tune technique, no photos required
Below are the calibration numbers for my three lenses:
105mm: -20
60mm: -17
16mm Fisheye: -20
Came to these by shooting a ruler in mm's at an angle and looking at 100% crop. Think this body is far enough out of whack that the dot tune method simply won't work.
Cope - thanks for the pricing details. $143 would be worth it on the body but I fear they would claim it's acceptable and not actually adjust anything.
Snapsy - quick question about the global adjustment values you linked me to in another thread. My take away was that each increment of the "default" value corresponded to roughly 2x of the adjustment for the individual lens. I spent quite a bit of time playing around with this on my camera and have come to the conclusion that changing the default settings has NO impact on my focus fine tuning. Really bizarre. Say I set the fine tune adjustment to -20 and my focus was ballpark ok, changing the global value on top of that definitely does not move my focus point (as confirmed in images). To further test things, I set my lens specific fine tune back to 0 and changed only the default to -20, again, no difference (left with a strong back focusing bias).
p.8 #10 · DotTune: New AF tune technique, no photos required
snapsy wrote:
1. Enter Live View and establish critical focus on a high-contrast subject. For cameras with poor LV clarity (D800/E), you may want to take a photograph and evaluate it on the computer to confirm critical focus. I recommend the focus chart here.
2. Leave the body and lens set to AF and configure your body for back-button focusing if not already configured so. This is necessary to disable AF engagement for shutter half-presses, which you'll be using in steps 3 and 4. To configure back-button focusing, set the "AF Activation" option to "AF-ON only". For the D4/D800 this is option a4, the D3/D3s/D700 it's option a5, and for D600 it's option f4 and D7000 option f5 (for D600/D7000 the AE-L/AF-L button will serve as the AF-ON button). Do not set the body or lens to MF as an alternative to back-button focusing; doing so will increase the confirmed focus range and make DotTune inaccurate.
3. Look through the viewfinder to see if the camera thinks the subject is in focus. You'll need to half-press the shutter while doing this to keep the metering/rangefinder from going to sleep. If you see the green arrow pointing to the left, then the camera+lens is back-focusing, so you need to decrease the value of AF tune (negative adjustment). If you see the green arrow pointing to the right, then the camera+lens is front-focusing, so you need to increase the value of AF tune (positive adjustment).
4. Repeat step 3 until you get a green-dot from the rangefinder....Show more →
An FYI, the D750 does not give a green dot but a white dot.
After completing steps 1and 2 and confirming that I have set AF tune to 0 in step 3. I continue to get a solid White dot through a range of -13 to +20. I've assigned AF/ON to the AE-L/AF-L button for back button focusing. Focus was originally set using LV and center focus point. Lens then set to Manual focus.
p.8 #11 · DotTune: New AF tune technique, no photos required
TightLines wrote:
Below are the calibration numbers for my three lenses:
105mm: -20
60mm: -17
16mm Fisheye: -20
Came to these by shooting a ruler in mm's at an angle and looking at 100% crop. Think this body is far enough out of whack that the dot tune method simply won't work.
Cope - thanks for the pricing details. $143 would be worth it on the body but I fear they would claim it's acceptable and not actually adjust anything.
Snapsy - quick question about the global adjustment values you linked me to in another thread. My take away was that each increment of the "default" value corresponded to roughly 2x of the adjustment for the individual lens. I spent quite a bit of time playing around with this on my camera and have come to the conclusion that changing the default settings has NO impact on my focus fine tuning. Really bizarre. Say I set the fine tune adjustment to -20 and my focus was ballpark ok, changing the global value on top of that definitely does not move my focus point (as confirmed in images). To further test things, I set my lens specific fine tune back to 0 and changed only the default to -20, again, no difference (left with a strong back focusing bias). ...Show more →
The default setting only has an effect on lenses for which there is no lens-specific AF tune value defined. So you'll need to delete the existing AF tune entry for the lens.
p.8 #12 · DotTune: New AF tune technique, no photos required
MRomine wrote:
An FYI, the D750 does not give a green dot but a white dot.
After completing steps 1and 2 and confirming that I have set AF tune to 0 in step 3. I continue to get a solid White dot through a range of -13 to +20. I've assigned AF/ON to the AE-L/AF-L button for back button focusing. Focus was originally set using LV and center focus point. Lens then set to Manual focus.
Is that broad of a range normal?
85 f1.8G lens shooting @ f1.8
Large ranges for certain lenses aren't abnormal. Btw since your range included +20 the range might be a little wider (past +20); to know for sure you can try the slightly-defocused workaround to find the full width of the range and then apply it to the midpoint calculation.
p.8 #13 · DotTune: New AF tune technique, no photos required
snapsy wrote:
Large ranges for certain lenses aren't abnormal. Btw since your range included +20 the range might be a little wider (past +20); to know for sure you can try the slightly-defocused workaround to find the full width of the range and then apply it to the midpoint calculation.
Where are the instructions for the beyond 20 defocus workaround?
I'm trying to fine tune five different prime lenses on two different D750. Every lens is hitting either the +20 or the -20 range on each body.
p.8 #16 · DotTune: New AF tune technique, no photos required
newtophoto wrote:
What if my AF confirmation dot goes left and right and in between? Does it have to be a solid dot only?
In the video I point out a special case where if you get an equal number of flickering left and right rangefinder arrows (and an occasional dot) then that represent a confirmed value as well. Typically when this happens the confirmed range will be very narrow, sometimes as small as a single AF tune value.
p.8 #17 · DotTune: New AF tune technique, no photos required
I tried every range available and I am never able to get a solid dot. There is always a flicker with the arrow. I can maybe get it for 2 seconds of solidness, and then it'll flicker. Any ideas? Also, I don't have a tripod, so I'm doing this on a table. Not sure if that matters.
