Oxymoron? AF fine tune manual lens

[armando_m]

Is it possible to fine tune the green dot indicator on a manual focus lens ?
I'm guessing the lens needs to be chipped so at least the camera knows what lens is mounted ... ? other than manually tagging it in the manual lens menu

I have a 50mm f1.8, if I use the green dot for focus confirmation the focus is in the ball park and ok for web images ,
I get better results by observing the image get in and out of focus and settling for a middle point
all of these while using the lens wide open, smaller apertures are easier to handle

[Bjørn Rørslett]

One cannot "AF Fine Tune" a manual lens in the strict sense of course. What can be done is first verifying the camera mount is not misaligned (this is much more common than most users think), and that the dioptre power of the finder is correctly set for one's eyesight. My eyes tend to change during the day so I frequently have to adjust the ocular perhaps 2-3 time each day. When you adjust the dioptre, focus the lens to 1m and point the camera to a neutral well out-of focus background.

CPU-modifying the lens ('chipping') usually makes light metering much more accurate, but I admit whether or not this also improves the 'green dot' function hasn't been tested. This because I don't use that approach myself. I use the ground glass. Perhaps replacing the 'B'-type screen of your camera to a split-image or micro-prism type will help your manual focusing to a significant degree.

[armando_m]

When you adjust the dioptre, focus the lens to 1m and point the camera to a neutral well out-of focus background.

Thanks Bjorn

whats the intent of doing the 1m focus ?  I supose so it doesn't  distract from distinguishing when the indicators are in proper focus ?

Yes I do adjust the dioptre , and installed a DK17 magnifier, if I focus while pressing the DOF button I can see better when things get into focus, that is of course if i'm not using it at f1.8

[Bjørn Rørslett]

Standard setting for Nikon finders is -1 dioptre which is equivalent to eye focus at 1m.

[David H. Hartman]

Wondering: does the default AF Fine-Tune setting affect the Green Dot? The default setting is what will be used with an AF lenses if AF fine tune is on and no value is recorded for a particular lens. At least that's what I understand the default is for.

I don't have an opinion as I've found the green dot to be fairly useless. There is too much slop in when it's on and when it's off.

Dave