MicroAF (Test please)

[Csae]

I had this weird notion, that a properly focusing lens will show the resolution lines on a monitor / Tv

( I find the monitor on a bright page, like the DCRP works best, the TV is too easily seen by the AF and won't show a small misfocus)

Would someone with a tripod, MicroAf adjustement and 5mins try it out ?

If i focus manually, i can make the monitor show its lines, my 50 1.8 for example, will not show these if i let it AF, so i guess its front/back focusing just a tad.

Adam, i remember hearing you talking about investing into a lens-align, give this a go and let me know, if you don't mind :) might come out cheaper for you.


Oh and for clarification, i didn't do the whole 45 Degree, my lens was very much perpendicular to the monitor, so it was either showing lines all across it, or nowhere. I suppose better results could be received from a special page and aiming at it at 45 Degrees, but im not up to it untill i know theres hope for it.

[Csae]

Bump, this works suprinsingly well at 45degrees, and i've tested several shutter speeds with the same effect.

(I was worried shutter speeds were the cause of the resolution lines)

Would someone with a mark2 or 7d try it already, could save ya a bunch on car insurance! I mean lensaligns.

[adam75south]

wow, that's pretty cool. i guess my 50mm f/1.4's AF is right on! I didn't use a tripod though, just handheld it.

what i've been doing is taking something with small(but sharp) writing on it(lately, an aveeno bottle) and taking a square on picture at just about every micro adjust position(focus away, then on the subject), then i use lightroom's compare feature to put them side by side til i pick the sharpest one. when i try focus charts at 45 degrees, i'm pretty sure i do something wrong because it's never right.

anyway, this is a cool little test here.

shot at f/1.4, 5d mark II & sigma 50mm f/1.4

[VTEC_EATER]

Funny you bring this up, I just adjusted my lenses last week with this focus calibration method:

http://www.northlight-images.co.uk/article_pages/cameras/1ds3_af_micoadjustment.html

It seems to work pretty well. I tried the 45 degree chart and it always showed front focus. I had my Sigma and my 50mm at +18 to correct the front focus, but after this last test they are at +2. I cant get the 70-200 tested very well though. At 200mm I need to be 60 feet away to test it. Unfortunately I could not get far enough back in my apartment to adjust it accurately. I think I need to bring the laptop outside for some better testing methods.