fredmiranda.com

Moderated by: Fred Miranda

New fredmiranda.com Mobile Site

New Feature: SMS Notification alert

New Feature: Buy & Sell Watchlist

FM Forums | Canon Forum | Join Upload & Sell

1 2 3 … 26

28 … 37 38 end

Dot-Tune: Autofocus Fine Tuning in under 5 minutes

schlotz
Offline
• • • • •
Upload & Sell: On

p.27 #1 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

The hardest part is keeping the rig still at that distance to zero in on the target. Any sort of wind and its almost SOL.
Good luck!

Oct 29, 2014 at 07:54 AM

dkperez
Offline
•
Upload & Sell: Off

p.27 #2 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Tested the D810 with Nikon 500/f4 and a 1.4X.

I have a set of images from last weekend that show I'm focusing somewhat in front of the subject bird in the lake. I can see the sharp water/ripples in front of the bird. I figure somewhere around a foot in front. As I said originally, I'd post a small piece of an image that shows sharp water and a "getting soft" bird, but I don't appear to be able to add an image.

Anyhow, started with everything on the gymbal mount. After a couple tries I couldn't get a sharp focus in the display, which doesn't surprise me - figure 14X on the lens and 10X in the live view display, so EVERYTHING causes shake. As schlotz said, at 700mm it SHAKES and when there's any movement there's a lag in the live view display so you have to adjust wait, adjust...

I finally switched to the ball head and locked everything down and things were better. Ran the test 3 times and found I had a slight flicker at +4, solid at +5 - +7 and a slight flicker at +8.

The flicker doesn't change very much as I move away from where it's solid. I tested the full range just to be sure I'd be within the -20/+20 range. Had solid arrows at the end, so I started at zero. Had a slight flicker. Same at +1 - +4 so I went that direction because it appeared to flicker to the left arrow. Got different numbers on each test, but I figure that's because even locked down it was very difficult to get a "perfect" sharpness in live view.

Eventually I decided to go with +6. Now I need to find some subjects I can shoot and see if I've got it perfect or if I need to fiddle some more... Hopefully we'll get some sun again later and I can go over to the local river and give it a try.

Oct 29, 2014 at 03:45 PM

dkperez
Offline
•
Upload & Sell: Off

p.27 #3 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

the sun came out late this afternoon, so I scampered over to the local river where there were a LOT of geese hanging out. I tried to set up APPROXIMATELY the same distance I was last weekend (different place, different birds) and do some anecdotal testing......

I Started at zero, shot, marked, then went to +2, +4, +6, +8, +10, and +12. Then went to -2, -4, -6, -8, and -10.

Shot several images at each setting, using AFC and my normal aperture mode, but at 5.6, wide open for the 500 with a 1.4X on it.

According to the approximate focus distance I was about 55 meters from my subjects, which I think is a bit further than I was, but everyone says the distance thing on all the cameras is wonky.

In any event, in my testing, I can't tell any visible difference even at 200% on a 30" monitor between the +4 and +8 settings. By +10 the subject starts to look soft where I was focusing, but the birds BEHIND (maybe a foot back) are sharper - still soft, but not as soft.

On the other end, it's perceptibly softer at zero and as I go into the -2, -4, and so on it get back to the water in front being sharp and the subject being visibly soft.

I'm going to have to look critically, but I suspect I'll end up somewhere between +4 and +6. On some images, the +4 seems to be sharper, but the difference is minute if I'm even able to actually see it....

In any case, this method appears to work, even on such a trying setup as a very long lens.

One of these days I'll have to do the same thing with my 90mm macro 'cause sometimes it doesn't seem as sharp as it should and I'm not sure where it's focusing.

It would also be interesting to try my Nikon 70-200 with extension tube since that's when things get really critical 'cause DOF is so shallow. I'm almost always at 200mm and have a 36mm extension tube on when photographing butterflies and it would be good to have an adjustment value for when I'm doing that.

Oct 29, 2014 at 06:12 PM

bobsofpa
Offline
• • •
Upload & Sell: Off

p.27 #4 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Okay, I assume this may have been discussed before but 27 pages is a lot to try to digest. The video says to use wide open lens aperture for this adjustment. Why? When the camera focuses it uses wide open aperture and does not stop down the lens until the moment of taking the photograph. Therefore, it should not matter what aperture you have set when doing a dot tune adjustment.

Nov 13, 2014 at 06:22 PM

snapsy
Offline
• • • • • •
Upload & Sell: On

p.27 #5 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

bobsofpa wrote:
Okay, I assume this may have been discussed before but 27 pages is a lot to try to digest. The video says to use wide open lens aperture for this adjustment. Why? When the camera focuses it uses wide open aperture and does not stop down the lens until the moment of taking the photograph. Therefore, it should not matter what aperture you have set when doing a dot tune adjustment.

Some cameras automatically stop the lens down to the dialed-in aperture while in Live View, for example all Nikon bodies that have independent aperture lever control support (D800, D810, D750, D4, D4s, etc...). Failing to keep the lens at its largest aperture on these bodies during the LV focusing step will cause them to be tuned for the stopped-down aperture. That's actually useful in some circumstances when you want the adjustment to account for lenses with focus shift but of course that's not the typical scenario; this can be accomplished on Canon bodies as well by holding down the DOF preview while in LV during the focusing step (manual focus).

Nov 13, 2014 at 11:42 PM

bobsofpa
Offline
• • •
Upload & Sell: Off

p.27 #6 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

OK, since I am a Canon owner I never knew that about Nikon. So, as long as I keep my fingers away from the DOF button the set aperture should be no problem. However, just to be safe I will use the wide open aperture.

Nov 14, 2014 at 09:21 AM

bobsofpa
Offline
• • •
Upload & Sell: Off

p.27 #7 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Another question. For my macro lens should I perform the dot tune adjustment at 50 times the focal length (which would be 21 ft) or close in at about 2 to 3 ft. The close distance would be more representative of the way I use the lens. I have never used at at a range of more than a couple of feet.

Nov 15, 2014 at 09:20 AM

schlotz
Offline
• • • • •
Upload & Sell: On

p.27 #8 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Yes, if you mostly use a lens at one particular length.

Nov 15, 2014 at 09:41 AM

jcunwired
Offline
• •
Upload & Sell: Off

p.27 #9 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Hi,

First, thanks much for the procedure. I have a 7D body that frequently disappoints so it's great to have a method for quickly checking AF accuracy. I watched the youtube video once and dove in, everything was very straightforward. I found some difficulty in finding extreme ranges but continual checks back and forth quickly verified where AF was not immediately locking on.

I've done all of my lenses, a mix of EF and EF-S, primes and zooms. Everything looked great with all of them but my 16-35mm f/4. I'm not sure why, after zooming in 3-1 in lightroom, I'm seeing this color shift. This is occurring at DotTune from both 22ft and 5.7ft, 35mm and f/4. The image has been resized after crop to simulate what I'm seeing, focus is naturally off but that's not my concern. Since the lens is new I wonder if it's at fault? Any wisdom you can bestow will be most helpful.

For what it's worth, at 22ft the midpoint was +1, at approx. 6ft it was -3. Since I will use this primarily for landscapes the longer distance was decided, as per threads above. The color shift bothered me so I re-ran dottune at the recommended 35mm x 50 value.

Thanks in advance.

Nov 16, 2014 at 10:42 AM

Methodical
Offline
• • • •
Upload & Sell: On

p.27 #10 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

This method of AF tuning is pretty slick. I just started to work on my gear yesterday, however, I just ran into a small road block with Dot tuning the 1D3.

I'm trying to use DOT tune with the 1D3, however, the 1D3 can't AF with live view. Is manual focus my only option to get the initial critical focus, which I may not trust? Or can I go out of live view, AF, then re open live view and go from there?

Can anyone provide their method for Dot tuning the 1D3? I'd appreciate it.

Also, has anyone used the Magic Lantern's automated version of Dot tune? Looks interesting.

Thanks...Al

Nov 16, 2014 at 11:35 AM

snapsy
Offline
• • • • • •
Upload & Sell: On

p.27 #11 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

jcunwired wrote:

Hi,

First, thanks much for the procedure. I have a 7D body that frequently disappoints so it's great to have a method for quickly checking AF accuracy. I watched the youtube video once and dove in, everything was very straightforward. I found some difficulty in finding extreme ranges but continual checks back and forth quickly verified where AF was not immediately locking on.

I've done all of my lenses, a mix of EF and EF-S, primes and zooms. Everything looked great with all of them but my 16-35mm f/4. I'm not sure why, after zooming in 3-1 in lightroom, I'm seeing this...Show more →

Color fringing is normal on lenses when they're slightly OOF - it's actually a useful tool to help establish focus, esp because the color of the fringing changes between front and back focus (purple/green). Some lenses also have fringing even when they're in focus, esp. for high contrast subjects.

Nov 16, 2014 at 11:47 AM

snapsy
Offline
• • • • • •
Upload & Sell: On

p.27 #12 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Methodical wrote:
This method of AF tuning is pretty slick. I just started to work on my gear yesterday, however, I just ran into a small road block with Dot tuning the 1D3.

I'm trying to use DOT tune with the 1D3, however, the 1D3 can't AF with live view. Is manual focus my only option to get the initial critical focus, which I may not trust? Or can I go out of live view, AF, then re open live view and go from there?

Can anyone provide their method for Dot tuning the 1D3? I'd appreciate it.

Also, has anyone used the Magic Lantern's...Show more →

I actually prefer using MF in LiveView for the focusing step of DotTune. You can't go out of LV to AF for the focusing step since that AF will occur before you've established the optimal tune value and thus will be subject to focusing error.

The automated version of DotTune in Magic Lantern works very well and will match the results of the manual procedure.

Nov 16, 2014 at 11:51 AM

jcunwired
Offline
• •
Upload & Sell: Off

p.27 #13 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

snapsy wrote:
Color fringing is normal on lenses when they're slightly OOF - it's actually a useful tool to help establish focus, esp because the color of the fringing changes between front and back focus (purple/green). Some lenses also have fringing even when they're in focus, esp. for high contrast subjects.

Thank you snapsy. No matter what I do I cannot get this lens to focus as sharp as the others. At short distance it looks spot on, but if I drop back 20' or so and zoom into the test diagram color fringing occurs. I've gone through DotTune at 5' intervals from 5-25ft. with the same results.

I'll keep at it, there must be a sweet spot but I wonder if the lens itself is faulty. If I don't resolve this I always will have doubts.

Nov 16, 2014 at 01:36 PM

Methodical
Offline
• • • •
Upload & Sell: On

p.27 #14 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

snapsy wrote:
I actually prefer using MF in LiveView for the focusing step of DotTune. You can't go out of LV to AF for the focusing step since that AF will occur before you've established the optimal tune value and thus will be subject to focusing error.

The automated version of DotTune in Magic Lantern works very well and will match the results of the manual procedure.

Thanks for the feedback. I guess it's MF time.

Nov 16, 2014 at 02:32 PM

Davis B.
Offline
• • •
Upload & Sell: Off

p.27 #15 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Methodical wrote:
Thanks for the feedback. I guess it's MF time.

Thats the way I did mine. Seems to have worked.

Nov 17, 2014 at 07:49 AM

gschlact
Offline
• • • •
Upload & Sell: Off

p.27 #16 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Nov 17, 2014 at 10:18 AM

jcunwired
Offline
• •
Upload & Sell: Off

p.27 #17 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

^^ This is correct. Snapsy I believe is suggesting as a final step to manual focus in live view, which is the procedure I followed:

1. Switch to live view, AF on reference target
2. Turn off AF at lens
3. Fine-tune focus in LiveView
4. Turn off LiveView
5. Set AF Tune to 0 and proceed with range confirmation

Once I finished and recorded optimal value for each lens, I created test shots with AF both in and out of LV, imported to LR and checked accuracy. If either was off I started over again.

Nov 17, 2014 at 11:13 AM

Methodical
Offline
• • • •
Upload & Sell: On

p.27 #18 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

jcunwired wrote:
^^ This is correct. Snapsy I believe is suggesting as a final step to manual focus in live view, which is the procedure I followed:

1. Switch to live view, AF on reference target
2. Turn off AF at lens
3. Fine-tune focus in LiveView
4. Turn off LiveView
5. Set AF Tune to 0 and proceed with range confirmation

Once I finished and recorded optimal value for each lens, I created test shots with AF both in and out of LV, imported to LR and checked accuracy. If either was off I started over again.

He was answering my question about the 1D3, which can't AF in live view to establish initial critical focus. He's suggesting that he prefers to establish initial critical focus, via manual focus.

Nov 17, 2014 at 07:45 PM

Rusty1
Offline
• • •
Upload & Sell: Off

p.27 #19 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Works very well and the Magic Lantern version looks to be even easier.

Dec 05, 2014 at 04:21 PM

Focus Locus
Offline
• • •
Upload & Sell: Off

p.27 #20 · Dot-Tune: Autofocus Fine Tuning in under 5 minutes

Does the automated Magic Lantern version involve some sort of "hacking" or "jailbreaking" the Canon firmware to the camera? I have no trouble searching, but the threads I'm finding soar into source code so far over my head, I'm wondering if this Magic Lantern thing is something best avoided until after warranty?

Dec 11, 2014 at 05:31 AM

1 2 3 … 26 27 28 … 37 38 end
FM Forums \| Canon Forum \| Join Upload & Sell 1 2 3 … 26 27 28 … 37 38 end