New MFA method
- Thread starter digital paradise
- Start date
- Status
AlanF said:
Can you elaborate on the difference in target+methodology you're using between DotTune and whatever MFA method you're using for "recalibration"? For DotTune are you tuning to a flat DOF vs a 3-D DOF using the other MFA method? I'm asking because when DotTune is used against a flat target with no DOF reference (chart on wall), then you're tuning an unknown point within the DOF plane. It could be you're tuning at the very edge of the DOF range but you wouldn't be able to know this from a flat target. The alternative would be to DotTune against a target with a 3-D DOF reference, like a LensAlign target. I'd be appreciative if you could try this and report back the results. Thanks!
Upvote
0
Last night I used a patterned lampshade with a bulb behind it as I can do this at night easily. This afternoon, I printed a black + on white A4 paper and focused on that. I did the sloping ruler test on both reproducibly. I have also checked visually using the standard iso chart.
Upvote
0
From someone who is not a fan of either of the methods: you know very well that there are plenty who cant get it right with either simple ruler or FoCal.neuroanatomist said:AlanF said:
Thanks for the update (despite the bad new for DotTune® fans).
People from companies are known to spread confusion on the forums. Also, online forums are magnet for people who would go to absurd lengths to justified their biased views. Not long ago there was thread full of posts saying "6D is the best full frame camera made by Canon".
So, instead of taking stand at this point I would just wait and watch and try it myself next time I need AFMA.
Upvote
0
horshack said:
Please explain to me what a 3-D DOF ref is and how I obtain one. I would like to get your method to work. For the sloping ruler method, as well as using the + target and lampshade, I have printed the FoCal target. It's not that I do not know what 3D is, but I have never seen a LensAlign target, which I assume may be a low relief 3D, and I do not understand why a 3D target is necessary when a 2D target works for the do it yourself sloping ruler method etc.
Upvote
0
Page 4, Post #10. There is also a link to an article at DPreview. Some light reading 
http://www.fredmiranda.com/forum/topic/1187247/3#11352268
http://www.fredmiranda.com/forum/topic/1187247/3#11352268
Upvote
0
AlanF said:
The advantage of a LensAlign target is that the flat 2-D surface serving as the AF target is machined to be on the same focus plane position as the "0" on the ruler attached to the target, whereas home-grown solutions may not be able to guarantee this tolerance. The LensAlign target also has a sight reference built into it to assure alignment between the camera and the target.
Upvote
0
The "0" of my home grown system is placed in the same plane as the target. The ruler rests at about 30deg at the side of a cardboard box and the target is pasted on the front face. The line on the ruler that touches the target is the 0 point. The target is perpendicular to the line of sight from the camera. What is not working is the dot assist on manual focussing relative to focussing in live view. Does anyone use manual focussing and the dot assist regularly - the spread of 15-20 units is not impressive? Maybe my mistake has been to use the automatic focussing in live view and not tether to a computer and blow up for manual focussing in live view?
Upvote
0
One of the good things about FoCal is that it has a new software method for calculating an accurate focus using live view which uses a focal algorithm instead of either PD or CD built into the camera. It's very slow but meticulous.
IF you want to make sure the dot method is working best, you can use focal to obtain the perfect focus, switch to MF on the lens then continue with dot method.
Still, it is not accurate in my testing on both the 5DIII and 1DX but at least you can use it to ensure perfect focus prior to any testing.
IF you want to make sure the dot method is working best, you can use focal to obtain the perfect focus, switch to MF on the lens then continue with dot method.
Still, it is not accurate in my testing on both the 5DIII and 1DX but at least you can use it to ensure perfect focus prior to any testing.
AlanF said:
Upvote
0
You have lost a lot of your credibility with your nonsensical argument. You are underestimating the capability of some user to achieve precision (same or better than LensAlign). Even then, why is 0 important? Even if 2D target is aligned to 2; you could look around 2. Finally, how is 0 alignment relevant to AFMA by your method? If you need complex 3-D target you got one irrespective.....horshack said:
Are you CEO of LensAlign resorting to drastic measures to boost sales?
From easy to use with any target, any distance in field about your method, the fine print is creeping in - You need to buy LensAlign target, just to test the method? If someone has to spend $$'s, FoCal already works well!!!!
Upvote
0
comsense said:
I suggested a LensAlign target only for those that want to DotTune to a precise point within the DOF range. It's not necessary to the process. I'm not affiliated with either LensAlign or FoCal. Also, as an FYI, LensAlign is coming out with their own software product to compete with FoCal: http://www.tapestalk.com/2012/10/focustune-the-rumors-are-true.html
Upvote
0
I wonder if Focal Method "TurboCal" is using similar technique as "DotTune" to perform MFA prediction in 30 Seconds with no shutter activation in an automated way.
http://www.reikan.co.uk/focalweb/index.php/2013/02/focal-1-8-release-candidate-available-for-focal-pro-users/
http://www.reikan.co.uk/focalweb/index.php/2013/02/focal-1-8-release-candidate-available-for-focal-pro-users/
Upvote
0
Jaguar2012 said:
Thanks for the link! I agree, they might be doing something similar to DotTune, provided the Canon SDK+USB interface provides a way to both change the AF tune value programmatically and also feed the PDAF evaluation information over USB to the computer as well.
Upvote
0
If you don't want ability to focus to a precise point within the DOF, why would you bother to AFMA? I am amateur here with fewer shutter clicks than most but I have about 10 Canon lenses, mostly primes. And none of them would need AFMA if I did not want that precise a focus. Maybe you are missing something in terms of explanation!!!horshack said:
Upvote
0
comsense said:
Aren't you asking a group who are discussing how to achieve precise focus why they would want to do this, ...if they didn't want to do this?
Well yeeesss, if you didn't want to focus precisely, then you wouldn't need to adjust your camera/lens combo to focus precisely!
Am I missing something?
Upvote
0
Larry
Comsense is not saying he doesn't want to have precise focus. He is complaining that Horshack hasn't explained clearly what he meant in his reply to my earlier message, Horshack also confused me, and he hasn't replied to my last questions to him, four or five posts back.
Comsense is not saying he doesn't want to have precise focus. He is complaining that Horshack hasn't explained clearly what he meant in his reply to my earlier message, Horshack also confused me, and he hasn't replied to my last questions to him, four or five posts back.
Upvote
0
DOF is defined as the range of distances between the camera and subject that will be rendered with sufficient sharpness for a given viewing or print size. Since DOF is not a precise point but instead a range, when you tune to a 2-D object you can't be sure what the balance of front/rear DOF will be relative to the 2-D point you're tuning to. This is fine if you'll be shooting with enough DOF for everything you need to be sharp, or if you're shooting 2-D real-life subjects. However if you're shooting in DOF-limited situations (small DOF, like f/1.4), many times you'll want to know or specify the precise balance of DOF relative to where the AF is tuned to, for example when shooting a portrait where you want both the eyes and nose to be in focus vs eyes and ears or eyes and hiar.comsense said:
Upvote
0
I understand DOF. For good or worse, I have physics/spectroscopy background. What you have still not explained is why LensAlign target is so critical compared to 2-D target with precisely placed ruler? On practical note, you need AFMA only when you are using larger apertures/ small DOF except for rare manufacturing/ quality control failures. And front/back focusing you refer to as 'balance' is actually part of performing AFMA. So, essentially you are saying that one needs to find front/back focus with LensAlign target to use your precise dot tune? What I also fail to understand is that if you get that far, it does not take a lot more to do AFMA. So why bother with dot tune? If i have to spend money/time why not on something that works for sure? Again, neither against nor for; just trying to understand.horshack said:
Upvote
0
- Status
Similar threads
