# help: AFMA dottune in magic lantern - with Sigma 50mm 1.4 ART all over the place



## filo64 (Jul 8, 2015)

Hi there,
I was going to try Magic Lantern's dottune AFMA, but I can't get it to work sensibly with my Sigma 50mm 1.4 ART. Visually I would set it at an AFMA value of ca. +10, but Magic Lantern's dottune produces the strangest measurements. With one focus target it is confident that values from -100 to +100 are all in perfect focus, with another, finer focus target some of the scanned AFMA values are of lesser confidence, but there is no middle area which produces better results: neither around my estimate of +10, nor around 0 or any other value. Magic Lantern then suggests to set an AFMA value of 0. Has anyone experienced this? Am I missing something? Other lenses seem to behave similarly. What to do?


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## neuroanatomist (Jul 8, 2015)

Were you using dottune or doNttune. 

Many have found DotTune to be inconsistent.


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## East Wind Photography (Jul 8, 2015)

Yeah I wouldn't use dot tune as its not very reliable. Just tape a newspaper to a wall and then take some shots using a tripod at each major afma setting. Once you determine which looks best then shoot some shots at each minor setting around that. Once you find the sharpest image that's the setting you should use.

Try to AFMA at the distance you use the lens the most as it can vary slightly based on focus distance.


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