Canon 100mm f2.8 af microadjustment

[Ravi8121]

What is the best distance do af microadjustment on a canon 100mm f2.8 L macro and 70-200 f2.8 L II

have spyder lenscal 5D III camera body

thanks for the help

[Kayaker72]

Hi Ravi8121

Welcome to the forum.

Looking here, it seems that Spyder Lenscal recommends that you set up the distance from your camera to the target to by "the same distance at which you would normally shoot each lens." They also provide a formula of distance normally used/focal length x 30 to 50 = optimum distance with an example of a 35 mm lens x 30 to 50 = 105 to 175 cm. I can be very literal, but their formula doesn't match their example (I suspect a typo or a translation issue and they meant for the "/" to be another =) so I can understand your confusion.

My recommendation would be that you follow the table set up by Reikan Focal. I would still pay attention to the Spyder instructions to make sure your camera is level and square to the target. For 100 mm Reikan is recommended a minimum distance of 40x the focal length or 4 meters. The 70-200 f/2.8 L II you will likely want to use two different distances (I did), a minimum of 3.5 m distance for 70 mm focal length and 6 m distance for 200 mm focal length. These distances all fit the 30 to 50 times the focal length guidance given by Spyder. I would also pay attention to the "distance you normally shoot" guidance. The 30-50 x focal length values are intended to be minimum. If you typically us a lens to shoot a greater distance, you may want to consider running your test with a slightly greater distance between you camera and target.

I hope that helps.

[HDNitehawk]

Most lenses 50x the length 50 x 100 is 1000mm, according to the conversion table I pulled up on google it is 196.85"

Now if you are shooting macro set it up and do it at the mfd which is .99'. I have never seen the instructions of any of the AFMA companies tell us that one. But I did mine. Hardest part is getting the light right that close, then that is always a problem with macro.

[Ravi8121]

Thanks for the help much appreciated