Mackguyver,

I too would like to thank you for taking the time to post your FoCal method. I have used the LensAlign

MKII, but never getting consistent results...that's why I am seriously thinking about buying FoCal.

I have a few questions, regarding calibrating zoom lenses. I have the 1DX and would be calibrating my

200-400mm 1.4X...I do know that you can calibrate at both ends of the zoom range, but would FoCal

recognize when I engage the internal 1.4x as well as the external 1.4x?

Thanks

Raptors, I am happy to pass along things I learn and yes, FoCal would recognize the lens via the EXIF data, and would give you the calibration for any focal length you choose. I'm guessing the 1DX treats this as two lenses in the AFMA settings, right? I see that DxO does that, so I'm betting that the camera sees a 200-400 1.4x and a 200-400 with 1.4 engaged or something like that and there are separate AFMA settings for each at W & T. If that's correct, then FoCal would work the same way.

Mackguyver,

Thanks...sorry for the delay, I have been out of the city for a couple of weeks. With the 1DX, the camera is able to save independent AFMA values for use w/ or w/o the built-in extender, as well as w/ or w/o the external 1.4x. Here are the 4 different profiles from the camera.

1) AFMA, focal length 200-400mm

2) AFMA with the built-in extender, focal length 280-560mm

3) AMFA with the built-in 1.4x extender and the external 1.4x, focal length 292-784mm

4) AMFA with just the external 1.4x, focal length 280-560mm

For the target set up, you recommend roughly 20x to 30x focal length. What is the procedure for zoom lenses? As I can calibrate at both ends of the zoom range, I gather you need to change the distance to target for each focal length?

Sorry for all the questions...thanks in advance

Raptors

I guess I didn't cover zoom lenses or think about all of the combinations when you add in (external) extenders, but that makes sense in terms of the number of possible profiles for the 200-400 1.4x (with or without the internal 1.4x and external 1.4x).

To answer your question, yes, you need to move the camera for the Wide and Telephoto measurements, and a wise man will take photos with every camera body he owns before moving the set up. Ask me how I know that .

Thanks Mackguyver...as I'm going to need a fair amount of space, I will have to wait till it stops snowing!!!

Thanks again for all your time and effort