How to calibrate the Canon Canon EF 180mm f3.5L Macro USM AutoFocus Telephoto

[tdehan]

I am curious how to calibrate the Canon Canon EF180mm f3.5L Macro USM AutoFocus Telephoto using the Datacolor Spyder Lenscal?  The instructions say to multiply the mm by 25 to get the length to set the Lenscal away from the lens in order to perform the calibration.  However, for this lens that would be a huge distance away and not the distance I shoot at with this lens.  Any help here is much appreciated.

thanks!

[kvbarkley]

I can only tell you what Bob Atkins says:

"The lens testing chart I'm going to use can be printed on 4x6 card. Now a 4x6 target isn't very big, so the idea is to print a number of them and place them in the center and at the corners of a larger chart. For APS-C sensor cameras I usually place them on a 15"x22" background and if that fills the frame, the magnification of the system will be around 1:25 which for a number of reasons is a good number to show the typical performance of a lens. If you were doing lens testing using a full frame DSLR, you'd put the targets at the center and corners of a 24" x 36" rectangle to get the same magnification ratio."

I don't know *why* a factor of 25 is desireable, but it seems to be. It is probably a good compromise between near field and infinity field.

[ebiggs1]

"The instructions say to multiply the mm by 25 to get the length to set the Lenscal away from the lens in order to perform the calibration."

That is roughly 15 feet.  That is a problem?

[Waddizzle]

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@tdehan wrote:

I am curious how to calibrate the Canon Canon EF180mm f3.5L Macro USM AutoFocus Telephoto using the Datacolor Spyder Lenscal?  The instructions say to multiply the mm by 25 to get the length to set the Lenscal away from the lens in order to perform the calibration.  However, for this lens that would be a huge distance away and not the distance I shoot at with this lens.  Any help here is much appreciated.

thanks!

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The Dot Tune method recommends 50x the focal length.  

If you want to calibrate at your typical shooting distance, then by all means do it.  It is always best to set an AFMA under actual shooting conditions, including lighting conditions.

[tdehan]

I never said 15 feet is a problem. The lens is a macro lens and I am typically no further away form my subject than 4.5 feet...sometimes closer.

[Waddizzle]

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@tdehan wrote:
I never said 15 feet is a problem. The lens is a macro lens and I am typically no further away form my subject than 4.5 feet...sometimes closer.

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Typically when I use that lens, my rig is mounted on a tripod, and I am focusing manually, using Live View at 10x zoom.  I rarely shoot macro photos handheld using auto focus.  When I do, it is typically bees polllnating flowers.

[tdehan]

I never stated I am using the lens hand held....

[jrhoffman75]

See Item 2 fom Canon AFMA guide. If most of your use is at macro distances calibrate at that distance.