p.34 #2 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
On a Canon body should I be using Live View autofocus or quick mode before switching to manual focus to achieve proper results? I've been using quick mode but that isn't always giving me accurate focus, whereas when I tried Live View autofocus the image seems to be sharp. I've been having a load of issues with my sigma 150-600, focus is off at different focal lengths and different distances at varying amounts but is most noticeable at 600mm and at further distances (past 50 feet). I'm attaching my results using quick mode autofocus in live view, I don't see much of a pattern and both my cameras are giving quite different results too. Some of the infinity results are blank, haven't completed that fully.
p.34 #3 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Noel West wrote:
On a Canon body should I be using Live View autofocus or quick mode before switching to manual focus to achieve proper results? I've been using quick mode but that isn't always giving me accurate focus, whereas when I tried Live View autofocus the image seems to be sharp. I've been having a load of issues with my sigma 150-600, focus is off at different focal lengths and different distances at varying amounts but is most noticeable at 600mm and at further distances (past 50 feet). I'm attaching my results using quick mode autofocus in live view, I don't see much of a pattern and both my cameras are giving quite different results too. Some of the infinity results are blank, haven't completed that fully.
The * means that the true low end value was beyond -20 and the high was -15 so I chose -20. ...Show more →
Yes in live view did you switched off the OS ? How do you trigger the camera ?
Did you updated the lens Firmware ? Also there is a new one coming out today but i haven't seen it yet
your first distance to M.A. should be at 2.6m or 8.5 feet
p.34 #4 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Just to make sure, using the 5D3, 4th menu under camera icon i.e. SHOOT4
- Live View shoot = Enable
- AF mode = Quick Mode
First - AF on the target, then hit the start/stop button to enter Live view followed by pushing the magnifier button twice (left side 3rd button up from bottom). This puts you in 10x view. At this point you fine tune the focus using the lens ring. Once done, get out of Live view and switch lens to MF before proceeding.
There is a procedure to determine a value when it goes off the 20 point scale. Snapsy has discussed it a number of pages back. Here is an example of how to do it, basically you slightly defocus the lens and redo the procedure.
* 1st DotTune produces +15 through +20 (still confirmed at +20, so 6+ point range)
* 2nd DotTune with defocused lens produces +5 through +12 (8 points in the range i.e 5,6,7,8,9,10,11,12)
* The effective DotTune range is +15 through +22 (15,16,17,18,19,20,21,22) Therefore 22-15=7 / 2 = 3.5 so actual AFMA s/b either 15+3=18 or 15+4=19
(+15 starting point, with 8 point range from 2nd DotTune applied). Midpoint is 18.5 (use 18 or 19)
p.34 #5 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Noel West wrote:
On a Canon body should I be using Live View autofocus or quick mode before switching to manual focus to achieve proper results? I've been using quick mode but that isn't always giving me accurate focus, whereas when I tried Live View autofocus the image seems to be sharp. I've been having a load of issues with my sigma 150-600, focus is off at different focal lengths and different distances at varying amounts but is most noticeable at 600mm and at further distances (past 50 feet).
Doesn't the Sigma dock allow for 4 or 5 different AFMA distances?
p.34 #6 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Thanks yes I followed all of those instructions. I think part of the problem is I have to do the testing 32 times, 16 for each camera, at 4 focal lengths and 4 distances. The infinity distance is the most difficult.
p.34 #7 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Thanks for the reply Schlotz, I have been following those instructions. It is interesting that on my 1D Mk IV body where I am getting images quite out of focus at 400-600mm and at great distances that the camera focuses incorrectly in quick mode but gets much closer (if not perfect) using the live view focus mode. Must be as it is using contrast detection for focus as opposed to the af chip in quick mode.
It is difficult to fine tune focus using live view outdoors and at long distances as you get a lot of camera movement, I may try using my laptop using eos utility to see the image on a larger screen. I may also have to try doing the testing indoors as I haven't been able to find a day without wind which makes it much more difficult as well. As long as I am lighting the target (using a 12" x 18" pattern that is the updated version on the dot tune website) well I am assuming I should get as good results as if I was outdoors but I can see the live view image much better and not have to deal with wind.
I am testing at those 4 different AFMA distances as shown in the two charts below. I want to redo the infinity testing as I wasn't getting reliable data:
p.34 #8 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
No question that wind is a killer. When I do my 400 2.8 I set control of the IS to a separate button (i.e. not activated by AF control) this way I can activate it only during the 10x focus dial in. This makes the fine tuning easier.
Your statement regarding quick mode vs live view is confusing. The whole purpose of using live view in Dot Tune is to manually adjust what the camera has already focused on via the 10x view. Assuming you have the AF control on the * button you are to first focus on the target using the * button. Once that's done, let go of it. Go into live view 10x and turn the lens focus ring to fine tune the focus. Do NOT touch the * button during this process.
p.34 #9 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
I was also using IS to try and help at the longer focal lengths but I think I'll try again indoors or on a perfectly calm day.
Sorry If my post was confusing, I was just trying to say that the two live view focus (live view / quick) modes give different focus results. For example, my 150-600 lens is severely front focusing at 600m and at 50ft distance. If I use the quick focus mode (mirror flips up) it is front focusing but if I use live view mode (contrast detection focus?) it is actually focusing correctly. I use the dedicated af-on button on both my cameras but am switching the lens switch to mf after using the af-on button to focus.
I only brought that up as it seems to me that using live view focus mode seems to always focus correctly, i.e no afma adjustments are necessary whereas quick mode relies on entering appropriate afma correction.
The important part in relation to this thread is to make sure that what you are focusing on in live view and at 10x is tack sharp before going on to perform the dot-tune method.
p.34 #10 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Ive found dot tune to be a bit inconsistent, even the automated version in Magic Lantern. The easiest way is to send your gear to the manufacturer sadly. My 5d3 85 1.2 and 135 brought into Canon and all came back perfect at 0 AMFA.
p.34 #11 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
I agree that it is inconsistent. I tried two different targets, both printed at 12x18 and was getting completely different results with each target. I bought the sigma usb dock and entered the 16 numbers I generated (after about 8 hours work) and will go do some more testing to see if it worked. Otherwise I may need to send the lens in since it is severely front focusing on two camera bodies at long distances and at longer focal lengths.
p.34 #12 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Noel West wrote:
Thanks yes I followed all of those instructions. I think part of the problem is I have to do the testing 32 times, 16 for each camera, at 4 focal lengths and 4 distances. The infinity distance is the most difficult.
Only one Camera can be M.A. at the time the lens doesn't keep multiple Data info for multiple cameras at the same time ,
That means you can M.A. many camera's as you want but you must keep your data written on paper because every time you enter a new M.A. it delete the old one ....
So camera A ,B ,C ,D have it's own data that you save on paper if your last M.A. was saved with camera D and you want to use camera B you must re-write the lens with camera B data.
p.34 #13 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
thepiecesfit wrote:
Ive found dot tune to be a bit inconsistent, even the automated version in Magic Lantern. The easiest way is to send your gear to the manufacturer sadly. My 5d3 85 1.2 and 135 brought into Canon and all came back perfect at 0 AMFA.
I would agree and I find it's a band-aid solution at best. People have been using this method since ~2007 albeit not with the same catchy name. If the gear cannot be calibrated perfectly at all combinations of focal length and subject distance (extremely rare for a zoom), it should be exchanged or sent along with the body for factory calibration in my opinion.
p.34 #14 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
thepiecesfit wrote:
Ive found dot tune to be a bit inconsistent, even the automated version in Magic Lantern. The easiest way is to send your gear to the manufacturer sadly. My 5d3 85 1.2 and 135 brought into Canon and all came back perfect at 0 AMFA.
The automated version of DotTune in Magic Lantern produces the same AF tune value (within +/- 1 increment) for every invocation on a given locked focus. It may not produce the same value across different focus attempts but that's a function of how precisely the camera has been focused before performing the tuning operation, which is variation variable shared by every tuning method.
p.34 #15 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
CanadaMark wrote:
I would agree and I find it's a band-aid solution at best. People have been using this method since ~2007 albeit not with the same catchy name. If the gear cannot be calibrated perfectly at all combinations of focal length and subject distance (extremely rare for a zoom), it should be exchanged or sent along with the body for factory calibration in my opinion.
Can you share a reference from 2007 of this method being used? Nikon's implementation of their automated tuning method in the D5/D500 appears to function in the same manner as DotTune (based on the description provided in their tech sheet), so apparently Nikon finds value in it even if some don't share that opinion.
p.34 #16 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
Can you share a reference from 2007 of this method being used? Nikon's implementation of their automated tuning method in the D5/D500 appears to function in the same manner as DotTune (based on the description provided in their tech sheet), so apparently Nikon finds value in it even if some don't share that opinion.
I don't have the time to dig around for 8-9 year old forums posts with no easily searchable key word, sorry An employee at a local camera store was talking about this general method way back in the day when the D3 was still new and everyone was excited about AF fine tune, that's where I very first heard of it myself.
Nikon's automated implementation on the D5/D500 just compares CDAF to PDAF as far as I can tell, which has been the most basic way to do it since the beginning - there is no mention of viewfinder focus indicator unless perhaps I missed something. With the D5 apparently already out in some parts of the world, we should see the finer details on the process revealed soon enough. Automating the AFFT process and making it quick & easy will primarily be useful for quickly determining if you need to exchange a lens or not, and may be quick enough to be done in a camera store, which I think could be very useful.
I think lens returns & exchanges are going to go way up after the D5/D500 because customers are going to now have a numerical value generated by the camera itself to 'prove' a lens is out of calibration using an easily understandable quantitative scale. How I see this happening is they will run the calibration at a few combinations, and if the values are different across the range, it probably can't be reliably tuned and people will exchange it. As far as I know it still only stores a value for a single combination of focal length and distance which is again at best a band-aid solution for most people, especially if you're picky.
p.34 #17 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
CanadaMark wrote:
I don't have the time to dig around for 8-9 year old forums posts with no easily searchable key word, sorry An employee at a local camera store was talking about this general method way back in the day when the D3 was still new and everyone was excited about AF fine tune, that's where I very first heard of it myself.
Nikon's automated implementation on the D5/D500 just compares CDAF to PDAF as far as I can tell, which has been the most basic way to do it since the beginning - there is no mention of viewfinder focus indicator unless perhaps I missed something. With the D5 apparently already out in some parts of the world, we should see the finer details on the process revealed soon enough. Automating the AFFT process and making it quick & easy will primarily be useful for quickly determining if you need to exchange a lens or not, and may be quick enough to be done in a camera store, which I think could be very useful.
I think lens returns & exchanges are going to go way up after the D5/D500 because customers are going to now have a numerical value generated by the camera itself to 'prove' a lens is out of calibration using an easily understandable quantitative scale. How I see this happening is they will run the calibration at a few combinations, and if the values are different across the range, it probably can't be reliably tuned and people will exchange it. As far as I know it still only stores a value for a single combination of focal length and distance which is again at best a band-aid solution for most people, especially if you're picky....Show more →
Nikon's D5/D500 mechanism uses CDAF to focus and then likely cycles through all the PDAF AF tune values to find the one with the strongest PDAF focus confirmation. It's the same method used by DotTune but automated - the feedback from the focus confirmation is sampled directly by firmware from the same mechanism that drives the VF rangefinder display. It's how the automated version of DotTune in Magic Lantern works on Canon bodies - the ML firmware samples a firmware PDAF confirmation flag in memory, the same flag that is used to drive the VF confirmation dot.
p.34 #18 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
snapsy wrote:
Nikon's D5/D500 mechanism uses CDAF to focus and then likely cycles through all the PDAF AF tune values to find the one with the strongest PDAF focus confirmation. It's the same method used by DotTune but automated - the feedback from the focus confirmation is sampled directly by firmware from the same mechanism that drives the VF rangefinder display. It's how the automated version of DotTune in Magic Lantern works on Canon bodies - the ML firmware samples a firmware PDAF confirmation flag in memory, the same flag that is used to drive the VF confirmation dot.
If it ends up working exactly like that, it sounds like they just automated the most obvious way to do it using a guess & check algorithm that people have been doing manually for years. Definitely still a time saver, and I am curious to read about it in detail. I wonder if it could also be done by taking pictures and comparing edge contrast, but I imagine that would be far more complex. Regardless, like I was saying, I think they are going to see lens returns & exchanges go way up! I can see it now... "The camera says the lens is out by -15, I need to exchange please."
p.34 #19 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
CanadaMark wrote:
If it ends up working exactly like that, it sounds like they just automated the most obvious way to do it using a guess & check algorithm that people have been doing manually for years. Definitely still a time saver, and I am curious to read about it in detail. I wonder if it could also be done by taking pictures and comparing edge contrast, but I imagine that would be far more complex. Regardless, like I was saying, I think they are going to see lens returns & exchanges go way up! I can see it now... "The camera says the lens is out by -15, I need to exchange please."...Show more →
Many times the best inventions are those which are obvious in retrospect. If it was obvious to Nikon they would have implemented it years ago. Btw Canon has a patent on a similar technique. There's no need to take pictures because the PDAF differential can be sampled from the AF sensor once perfect focus has been established (either via CDAF or manual focus).
p.34 #20 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes
Thanks so much for starting (and staying active on) this thread. Definitely a much easier way to microadjust. I do have one question that (I don't think) has been addressed:
When I did dot-tune I noticed that I had lenses with quite small ranges (6 steps) of acceptable focus and others with much larger ranges (14 steps). Does this have any meaning?
An employee at a local camera store was talking about this general method way back in the day when the D3 was still new and everyone was excited about AF fine tune, that's where I very first heard of it myself.