Experimenting with Lens AFMA

Zee Char wrote:

1. Impossible with a flash. You need continuos lighting.

2. The more precise the better but most walls can be used and you can use a small level or bubble level on your cam. You use a product like Lens Align if you want to be more precise. I just use a wall. I'll put a level on it to make sure it is not out badly as some older homes can be.

Well, that's what I was struggling with; I used the bubble level on the tripod and the target to make sure they are parallel vertically. But aligning the middle of the lens to the target (horizontally) wasn’t so easy - I might use the wrong approach/technique. Tried many times, but I always felt like I had to very slightly tilt the camera upwards or downwards to be spot on middle, but I didn't want to tilt it.

3. A mixed bag. Your guess is as good as mine. One Canon document says 50X, another says the distance you normally shoot at, 3rd party says 20X and others MFA at MFD. In the manual Canon says for best results to MFA at shooting location

I came across an article that explains when a lens settles down so I use the recommend distances which are manual due to the lens lengths and crazy distances you need at 50X.

http://s449182328.websitehome.co.uk/focal/dl//Docs/FoCal%20Test%20Distance_1.1.pdf

On line calculator. I did adopt FoCal and it is pretty accurate. I just try to level both the target and cam as best I can. It does really matter because if you MFA at different distances you will get different results thus Canon's at location recommendation which is impractical unless you are shooting in a studio at the same distance all of the time. The newer cameras that have a short and long end settings helps with that problem.

http://www.reikan.co.uk/focalweb/index.php/online-tools/test-distance-target-size-calculator/

Thanks for the link. Had seen that one before, but wanted to understand the thinking bedind the calculations .

Cheers,