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Author Topic: lens calibration  (Read 6090 times)

scottkinfw

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Re: lens calibration
« Reply #15 on: December 18, 2012, 02:45:07 PM »
I can't wait to see what everyone's experience is.

I had several bodies and Llenses sent off to Canon for calibration prior to an African safari, and got more stinkers than keepers.  Poor focus (front, back), all kinds of light.  Worse than when I sent them in. 

sek
Hi everyone,

my question is ,

does anyone know what Canon "does" when they take both the body and lens for calibration?

I sent in my 24-70II since I noticed that it's not as sharp as my friend's copy (we bought them one week apart). I also mentioned that it's back focusing and that I've tried using AFMA but haven't got it right and would appreciate if that can be looked at too. To my surprise I was told that AFMA "shouldn't be used" except for "special" cases. I said, that I've been doing it all the time with all my bodies and lenses. After I sent a complaint to the person in charge of after sales/ warranty, I got a call saying that the "bad focus" is because I set AFMA and that it's stored in the ROM of the Lens.. My first words "Bull $hit" I couldn't help myself. It was obvious the person talking wasn't technical. I asked, so you mean to tell me that if I set AFMA for the 24-70II on my 1DX those settings are stored on the lens.. Reply.. YES.. .. I explained why this was complete Bull$hit.!! by asking "so that means, I can't use this lens on my other camera bodies.. SILENCE..

Long story short.. I was asked to send my my 1dx which they just "reset" ALL my AFMA settings and they re-flashed the ROM on both the 1dx and 24-70II  and asked me to "retry".

I just finished testing using lensalign, (didn't feel like using focal pro). my manual testing resulted in (-4,-4).. Same as what I got with Focal Pro on the first day I got the 24-70II.

Any thoughts.. the CPS guy I spoke to wasn't very helpful.. He kept insisting that I should use the multicontroller/joystick to "SELECT the focus point"

you can imagine my frustration explaining DOF and that the little red square that's on the object tells me where I focused, and that object isn't sharp, hence SOMETHING is wrong. I asked him, do you take photos, he replied yes, I said I'm sorry but you're no photographer.. kinda mean, but I couldn't help it!!!!

Ok Rant over!!!!!!
sek Cameras: 5D III, 5D II, EOS M  Lenses:  24-70 2.8 II IS, 24-105 f4L, 70-200 f4L IS, 70-200 f2.8L IS II, EF 300 f4L IS, EF 400 5.6L, 300 2.8 IS II, Samyang 14 mm 2.8 Flashes: 580 EX II600EX-RT X 2, ST-E3-RT
Plus lots of stuff that just didn't work for me

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Re: lens calibration
« Reply #15 on: December 18, 2012, 02:45:07 PM »

JEAraman

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Re: lens calibration
« Reply #16 on: December 19, 2012, 04:00:38 PM »
Yeah, I read your advice in the past and at the time was having EV readings in the 8~10 range (which I thought was enough). With the same EV, testing on my other lenses, I had no problems. However, my macro 100L and my 50 1.4. would never even finish; it would just say that too many tests and still inconsistent. I will have another go sometime soon and try to get at least EV 12 and will see if that makes a difference.

thanks for the advice :)


in fact, I do have focal pro but I wasn't getting a consisten result.

Usually, there are two reasons for inconsistent results with FoCal - an unstable setup and/or not enough light.  I started running tests on the main floor of my house, hardwood flooring, and even with a stable tripod me or my kids walking by perturbed the results.  I moved the setup to the basement, concrete slab floor, no more problems.  I use LOTS of light - 3 150 W-equivalent tungsten lights at a distance of 12-14" from the target.  FoCal reports the EV reading for the test, mine are in the 11-12 range.  If you're below 10 EV, that can cause problems.

Basti187

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Re: lens calibration
« Reply #17 on: December 19, 2012, 04:34:39 PM »
just calibrated my 5dm3 with focal plus as I noticed that my shots are being far from sharp.

had EV of 6-7

100-400mm W+6 T+13
24-105mm W+5 T+15

That is quite hardcore isn't it? Btw does +1 stand for 1mm or cm?
« Last Edit: December 19, 2012, 04:36:20 PM by Basti187 »

neuroanatomist

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Re: lens calibration
« Reply #18 on: December 19, 2012, 06:16:42 PM »
just calibrated my 5dm3 with focal plus as I noticed that my shots are being far from sharp.

had EV of 6-7

100-400mm W+6 T+13
24-105mm W+5 T+15

That is quite hardcore isn't it? Btw does +1 stand for 1mm or cm?

First off, I'd add light and try again.  Your results may be ok, but IIRC FoCal recommends at least EV 8, and they used to recommend EV 10.

Each unit if AFMA represents 1/8 of the depth of focus for that lens at max aperture, so the absolute value actually depends on the lens. So, if you need +8 or -8, you're off by a full depth of focus.  Note that depth of focus is related to depth of field, but is measured at the sensor, so the units are actually down in the micrometer range of physical distance. 
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Basti187

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Re: lens calibration
« Reply #19 on: December 20, 2012, 11:37:59 AM »
just calibrated my 5dm3 with focal plus as I noticed that my shots are being far from sharp.

had EV of 6-7

100-400mm W+6 T+13
24-105mm W+5 T+15

That is quite hardcore isn't it? Btw does +1 stand for 1mm or cm?

First off, I'd add light and try again.  Your results may be ok, but IIRC FoCal recommends at least EV 8, and they used to recommend EV 10.

Each unit if AFMA represents 1/8 of the depth of focus for that lens at max aperture, so the absolute value actually depends on the lens. So, if you need +8 or -8, you're off by a full depth of focus.  Note that depth of focus is related to depth of field, but is measured at the sensor, so the units are actually down in the micrometer range of physical distance.

Interesting! Well I was unhappy with the unsharp photos from my 5dm3 so as I said I calibrated it last night, but I went out today taking photos of wolves and again the photos don't come out sharp :/ it is very frustrating! I will try to calibrate again tomorrow with adding some daylight to it. What also wonders me is that for example I used my 100-400 on the t2i and got some amazing sharp shots whilst on my 5dm3 it is just not. I tried all kind of different AF settings...but I will calibrate again with more light and report back!

rpt

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Re: lens calibration
« Reply #20 on: December 22, 2012, 12:48:57 PM »
Yeah, I read your advice in the past and at the time was having EV readings in the 8~10 range (which I thought was enough). With the same EV, testing on my other lenses, I had no problems. However, my macro 100L and my 50 1.4. would never even finish; it would just say that too many tests and still inconsistent. I will have another go sometime soon and try to get at least EV 12 and will see if that makes a difference.

thanks for the advice :)


in fact, I do have focal pro but I wasn't getting a consisten result.

Usually, there are two reasons for inconsistent results with FoCal - an unstable setup and/or not enough light.  I started running tests on the main floor of my house, hardwood flooring, and even with a stable tripod me or my kids walking by perturbed the results.  I moved the setup to the basement, concrete slab floor, no more problems.  I use LOTS of light - 3 150 W-equivalent tungsten lights at a distance of 12-14" from the target.  FoCal reports the EV reading for the test, mine are in the 11-12 range.  If you're below 10 EV, that can cause problems.
If FoCal cant finish, either your camera is shaking or the light is flickering - or both. I had exactly the same issue. Turns out the tripod's raised center column and CFL bulbs were both to blame...

Changing to incandescent bulbs and lowering the central column sorted the issue out and Focal worked like a dream. Like neuro said, if the floor adds to shake, you need to sort that out too...

rpt

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Re: lens calibration
« Reply #21 on: December 22, 2012, 12:50:58 PM »
just calibrated my 5dm3 with focal plus as I noticed that my shots are being far from sharp.

had EV of 6-7

100-400mm W+6 T+13
24-105mm W+5 T+15

That is quite hardcore isn't it? Btw does +1 stand for 1mm or cm?

First off, I'd add light and try again.  Your results may be ok, but IIRC FoCal recommends at least EV 8, and they used to recommend EV 10.

Each unit if AFMA represents 1/8 of the depth of focus for that lens at max aperture, so the absolute value actually depends on the lens. So, if you need +8 or -8, you're off by a full depth of focus.  Note that depth of focus is related to depth of field, but is measured at the sensor, so the units are actually down in the micrometer range of physical distance.

Interesting! Well I was unhappy with the unsharp photos from my 5dm3 so as I said I calibrated it last night, but I went out today taking photos of wolves and again the photos don't come out sharp :/ it is very frustrating! I will try to calibrate again tomorrow with adding some daylight to it. What also wonders me is that for example I used my 100-400 on the t2i and got some amazing sharp shots whilst on my 5dm3 it is just not. I tried all kind of different AF settings...but I will calibrate again with more light and report back!
Please read my post above...

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Re: lens calibration
« Reply #21 on: December 22, 2012, 12:50:58 PM »