# Lens micro-adjust for 5D3



## fotoray (Mar 21, 2012)

I've downloaded and am reading the user manual while waiting for my 5D3 to arrive. The AF microadjustment described on p. 104-109 has new capability (to me) that allows for separate calibration at each focal length extreme of a zoom lens. The manual calls these settings W (wide) and T (telephoto). Once these settings are stored in the camera for a specific lens the adjustments for other focal lengths are automatically scaled by the camera based on the W and T settings. 

I previously have attempted calibrating my EF-S 17-85 zoom with my 7D using the LensAlign MkII tool. The 7D allows for a single microadjustment - obviously a limiting choice for zoom lens. Seemed like a capability only for prime lenses.

The W and T settings may have been in 1D models for quite some time, or it could be new to the 5D3, and likely the 1D X too. 

Does anyone have any experience with the W and T capability and can comment on its effectiveness?


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## neuroanatomist (Mar 21, 2012)

Storing two values per lens is new for the 1D X and 5DIII, not available in any previous body. 

So...you're one of the first! Time permitting, can I ask you to satisfy a curiosity? How does it vary across the range? Simple experiment, since the AFMA value is recorded in the EXIF and displayed on the review image with full info (at least, in previous models). Pick arbitrary ends, say -10 and +10 or 0 and +10, then shoot at a few points in the zoom range. Is there a gradual transition between the values, or an abrupt transition at some point? I suspect the former, but the manual doesn't make it clear. 

Thanks!


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## fotoray (Mar 21, 2012)

neuroanatomist said:


> Storing two values per lens is new for the 1D X and 5DIII, not available in any previous body.
> 
> So...you're one of the first! Time permitting, can I ask you to satisfy a curiosity? How does it vary across the range? Simple experiment, since the AFMA value is recorded in the EXIF and displayed on the review image with full info (at least, in previous models). Pick arbitrary ends, say -10 and +10 or 0 and +10, then shoot at a few points in the zoom range. Is there a gradual transition between the values, or an abrupt transition at some point? I suspect the former, but the manual doesn't make it clear.
> 
> Thanks!



Thanks for your feedback Neuro!

Footnote at the bottom of p.108 of the manual says, as you may have seen

"When shooting with the intermediate range (focal length) of a zoom lens, the AF's point of focus is corrected relative to the adjustments made for the wide-angle and telephoto ends. Even if only the wide-angle or telephoto end has been adjusted, a correction will be made automatically for the intermediate range."

This is the only explanation I could find. I take it to mean a linear(?) interpolation of the W-T adjustments.

If so, it might not be as simple for a zoom lens with a variable aperture like my EF-S 17-85 f/4-5.6 zoom. What role does the variable aperture play in computing the adjustment for the intermediate focal lengths?

After my 5D3 w/24-105 f/4L arrives in early April, I'll be able to use the W-T adjustment method and test the intermediate focal lengths. Maybe the linear interpolation assumption can be observed/not?


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## Turbocharged (Mar 21, 2012)

if you go to a canon repair center, they can calibrate the W and T separately for older models.

on my 5D3, the 24-70 and 70-200 2.8L II focus pretty much dead on all the time, no need to calibrate, i can only tell you that this function is there if you need it. however my 50 1.4 is +8 to +15 depending on the light source and aperture.


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## SomeGuyInNewJersey (Mar 26, 2012)

Turbocharged said:


> if you go to a canon repair center, they can calibrate the W and T separately for older models.
> 
> on my 5D3, the 24-70 and 70-200 2.8L II focus pretty much dead on all the time, no need to calibrate, i can only tell you that this function is there if you need it. however my 50 1.4 is +8 to +15 depending on the light source and aperture.



I asked here --> http://www.canonrumors.com/forum/index.php/topic,4889.0.html ealier about Canon Repair Centers. Do you know whether they will do the work while you wait if you walk-in? Or is it a drop off and we'll call you in a few weeks when its done?

I have a new 5d3 and I think a few of my lenses have varying degrees of mainly foreward focusing issues... the new kit lens seems particularly bad. Its my first full frame so rather than trying to do it and corrections myself I thought it would be good if I could call into the Canon places thats an hours drive away and get them to look at my lens camera combos for me...


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## K-amps (Mar 27, 2012)

I had to calibrate my 70-200 f2.8 mk.II + 2x iii combo (it stores the lens plus extender as a separate record vs. lens only). A +4 nailed it on the T and +2 on the W.

Tested it in the Garden. I was standing, Aiming on the ground on this dandilion.... was impressed at the detail retrieved. 400mm handheld.


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## awinphoto (Mar 27, 2012)

SomeGuyInNewJersey said:


> Turbocharged said:
> 
> 
> > if you go to a canon repair center, they can calibrate the W and T separately for older models.
> ...



I could be wrong but I think they are in a first come first serve basis. In some trips, they turned around my CPS repair on the same day and others I had to wait 3 days while standard turnaround is 6-7 days or so. Feel free to give them a call but you may have to wait in line based on prior orders received.


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## SomeGuyInNewJersey (Mar 27, 2012)

awinphoto said:


> I could be wrong but I think they are in a first come first serve basis. In some trips, they turned around my CPS repair on the same day and others I had to wait 3 days while standard turnaround is 6-7 days or so. Feel free to give them a call but you may have to wait in line based on prior orders received.



Thanks, If I decide to do it I'll give them and call and check out what they have to say on their time frames before I drive down there. Given the 5d3 is newly released I'm guessing they are going to be busy.

Which location did you go to? Or did you ship your gear to them?

I've just seen a link to a simpler looking procedure for trying the Micro Adjustment process on the post below... I'll probably give that a try before I go and spend somebody at Canons time on it...


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