Focusing a Nikon 50mm f/1.2 Ai-S (at f/1.2) on Nikon DF
I have a really neat manual focus Nikon 50mm f/1.2 Ai-S on a Nikon DF.
I have no problem focusing this (using Nikon's green arrow/dot focusing points) manually at f/3.5 or larger (which looks incredible). However, when I try to open this up at f/1.2 - 2.0 I miss 90% of the shots because they are out of focus even if the green dot focus point says it is in focus.
Other than swapping out the focusing screen to a split focusing system, is there a way to more reliable way to focus this neat lens at f/1.2-2.0?
What are some tips and tricks to using this lens?
I have no problem focusing this (using Nikon's green arrow/dot focusing points) manually at f/3.5 or larger (which looks incredible). However, when I try to open this up at f/1.2 - 2.0 I miss 90% of the shots because they are out of focus even if the green dot focus point says it is in focus.
Other than swapping out the focusing screen to a split focusing system, is there a way to more reliable way to focus this neat lens at f/1.2-2.0?
What are some tips and tricks to using this lens?
You might find using liveview (Ideally magnified) for critical focusing better at really wide apertures. This will help mostly with stationary subjects as the extremely narrow depth of field will mean that even a tiny movement of the subject or camera position will mean the focus will be out.
There’s not much you can do when using the viewfinder as far as I know!
There’s not much you can do when using the viewfinder as far as I know!
Quote:at f/1.2 - 2.0 I miss 90% of the shots because they are out of focus even if the green dot focus point says it is in focus.
The green dot is an approximation rather than the precision of zooming in on a rear monitor.
Apologies if I have the wrong end of the stick but does the DF have focus adjust?
My D7000 needed a slight adjustment to get spot on focus using the viewfinder.
Maybe put the camera on a tripod and focus at f1.2 using the rear screen and see if that is sharp.
My D7000 needed a slight adjustment to get spot on focus using the viewfinder.
Maybe put the camera on a tripod and focus at f1.2 using the rear screen and see if that is sharp.
I had an f1.2 50mm for a while and found it all but impossible to nail focus with a D3X, which was the major reason for selling it.
i have had my 55mm f1.2 for donkey's years. It was even hard to focus on my F2A. (yes i am that old 
).
in my d4 I eventually changed the screen to make focussing with some manual teles easier andit helped a lot.
On the d800 I just try a few shots in doubt. To be honest, I have it for bokeh and not for sharpness which start a f2 at its best.
).in my d4 I eventually changed the screen to make focussing with some manual teles easier andit helped a lot.
On the d800 I just try a few shots in doubt. To be honest, I have it for bokeh and not for sharpness which start a f2 at its best.
It was pointed out to me many years ago that in the time between focus and pressing the shutter the photographer can move more often than not rock forward which would become apparent with very wide apertures, since I was made aware of the issue ( > 25 years ago) I don’t have an issue with retaining focus accuracy with very wide apertures such as my 56mm f/1.2.
Quote:It was pointed out to me many years ago that in the time between focus and pressing the shutter the photographer can move more often than not rock forward which would become apparent with very wide apertures, since I was made aware of the issue ( > 25 years ago) I don’t have an issue with retaining focus accuracy with very wide apertures such as my 56mm f/1.2.
A static subject and a tripod can be useful
Assuming a 6'6" focus distance at f1.2 Nikon quotes a combined depth of field i.e. for both both in front and behind the point of focus added together of a little less than 1 inch - meaning focus has to be accurate to better the 1/4 inch to get the subject sharp.
Nikon's standard (from a 1996 catalogue) is based on film criteria - greater resolution is normal with modern digital cameras.
The lens in the illustration has seen considerable service - it might benefit from a new lens bayonet if the existing one is well worn and affecting focus accuracy.
