[Soupdragon]

For those who believe the myth about AF fine adjustments on a D300, here are the "Gotcha's".
This operation is NOT the same as a factory calibration.

Extracts from the D300 users manual:

AF Fine Tune:
Fine-tune focus for up to 12 lenses. AF tuning is NOT recommended
in most situations; use only when required.

Which ties in nicely with:
U
AF Tuning:
The camera may be unable to focus at minimum range or at infinity when
AF tuning is applied.

I think the sales blurb is mis-leading as it makes people believe they can calibrate their lenses when in actual fact they can't.
This is poor form indeed.

[VinnyP]

Originally Posted by Soupdragon

For those who believe the myth about AF fine adjustments on a D300, here are the "Gotcha's".
This operation is NOT the same as a factory calibration.

Extracts from the D300 users manual:

AF Fine Tune:
Fine-tune focus for up to 12 lenses. AF tuning is NOT recommended
in most situations; use only when required.

Which ties in nicely with:
U
AF Tuning:
The camera may be unable to focus at minimum range or at infinity when
AF tuning is applied.

I think the sales blurb is mis-leading as it makes people believe they can calibrate their lenses when in actual fact they can't.
This is poor form indeed.

I'm not sure what the problem is. If you pull focus far enough back then of course a lens will not be able to focus at infinity. But most decent lenses can focus well beyond infinity to so you'd need to pull it back a long way. I only had one lens that benefitted from fine tune (85mm 1.8) and it made a slight improvement but it still focuses at infinty. This isn't like factory calibration that is not as precise as fine tune since it can't match it exactly to your body, for my 2 bodies the calibration was different for each body.

[Dabhand16]

Vinny - I've not done any calibration/fine tuning as yet. Did I get the procedure right in this post?

[VinnyP]

I printed out a target I downloaded off the net that you shoot at 45 degrees but couldn't get on with that as it needed really precise alignment. I ended up using a metal precision ruler on it's side on a windowsill since it was easier to move the ruler around rather than keep messing around with the tripod. At first I took the shot then checked the focus on the screen but I found an easier method, all I did was use phase detect AF in liveview and zoom in on the liveview image off the sensor. If on AF it was focusing at 150mm but on the sensor 152mm was sharpest then you pull it back until it is at 150mm.
NB you can't use the live view contrast detect AF just the mirror flip down phase detect.

Edit.. Another NB Remember to just to look at the sharpest point of focus. At first I thought all my lenses were out because I wasn't thinking and was trying to get the centre of the in focus area at my focus point. We all know that DOF is not centred on the focus distance. Nikon recommended a tape measure wrapped around a bottle IIRC that could also work.

[Dabhand16]

Thanks for that Vinney. The angled method is quicker for sure, but I was not sure that as the graduations either side of the focus point will be closer/further from the camera, if that would affect the tuning.

I know that the graduations are quite small, but also didn't know how critical the fine tuning is.

[VinnyP]

Originally Posted by Dabhand16

Thanks for that Vinney. The angled method is quicker for sure, but I was not sure that as the graduations either side of the focus point will be closer/further from the camera, if that would affect the tuning.

I know that the graduations are quite small, but also didn't know how critical the fine tuning is.

I am not sure, I had the ruler at an angle not sure if it was exactly 45 degress but enough that they markings were different distances away. Once I was fairly happy I took some confidence shots on a few thigs to be perfectly sure. I do know I love liveview for critical manual focus stuff like macro and product shots.

[Dabhand16]

If it worked for you, that's good enough for me

I think my concerns are probably groundless and you don't have to be 100% exact to achieve an improvement.