Moire' pattern MFA

Anybody heard of or tried moire' pattern lens calibration?

I have scan read a few articles on the subject but can't quite get to grips with how it works.

fordmondeo wrote in post #18758744
Anybody heard of or tried moire' pattern lens calibration?

I have scan read a few articles on the subject but can't quite get to grips with how it works.

You're on an MFA kick, aren't you?

I've tried this method, though it's been a while. Used this site here: http://www.northlight-images.co.uk/camera-af-microadjustment/

Basically, you use a pattern shown on your computer screen, and then manual focus via Live View until you see a moire effect. Turn off LV, and then hit the AF... if you see movement in the distance window on the lens, then you adjust MFA. Repeat until you see no movement. Not sure which direction on the lens equates to closer/further MFA values.

I didn't like this method because it leaves too much in question regarding the movement in the AF window, and just how much movement requires how much MFA adjustment. My favorite MFA method is to first use the DotTune method to get me in the ballpark, and then just go out and shoot a lot, and over time dial in small MFA adjustments if I see any consistent front or back focus. I'm talking a few weeks of shooting. Another program I use is FoCal, but for longer lenses >400mm it becomes a challenge due to the amount of space required, proper lighting, ensuring you have the target perpendicular to the sensor, etc.

The problem with all of this MFA business though, is that your values fluctuate depending on distance to target, the quality and type of light, air temperature. It can start driving you mad because one day your stuff will be on point, and the next things are slightly soft. Don't let it get to you, trust your gear and only make changes over time after you see trends. Just go out and shoot, don't sweat this stuff too much.

LOL.

The truth is, I just got rid of my 1dx2 and am the happy owner of a 5d mk4.
Sadly it does not like my lenses as much as the 1 series.

I just wanted to find a simpler more repeatable way of doing the best I can re adjustments.

My two biggest headaches are my 85mm 1.2 mk2 and my 100-400 mk2, probably because they are my two most used optics.
Granted the 85 1.2 has always been a bit hit and miss but I'd grown to just expect the 100-400 to do the job.

The big aperture primes are the most challenging because of the small DOF at f/1.2 and f/1.4. The reason is that AF itself isn't exactly consistent, every time you re-focus the camera it could choose to hit on something very slightly different on the subject, and that may trick you into thinking that your MFA value is off.

For the 100-400, I like to use the trunk of a tree with grass around it, as the grass will give you a good indicator if your DOF is shifted behind or in front.

As repeatable and simplistic, try the Dot Tune method. It's quick, easy and free.

Having read your first reply, I think I'll get it as close as I can and then tune it further if a trend develops.

Thanks for your time.