How does FOCUS ASSIST work on the D3/D3X?

[glenerrolrd]

Since I use primarily zeiss and converted leica r lenses with my Nikon D3/D3X bodies.....I am into Manual Focus. The new D3X seems to front focus 4-5CM at 2M .

If this was using AF, the camera calibration feature could be used to fine tune specific lenses ..but I believe the AF of the camera to be accurate. Non CPU lenses can not be adjusted?

Its my understanding that the AF system works completely independent of the focusing screen (off the sensor or a separate AF sensor?) But how does the FOCUS ASSIST that is helpful for MF lenses work?

The screen and the focus assist seem to agree exactly.

It would be very helpful if someone could confirm my understanding of the two focusing systems and how the FOCUS ASSIST works.

 

[glenerrolrd]

I screwed up this question.....I should have said how does the Electronic Rangefinder work..not focus assist. I have been told that the ERF works off the AF system. If so can I assume if the AF is on ..then the ERF is also on ?

I guess I am stuck with testing this with Live View.

 

[tjv]

I believe the focusing screen can be out of alignment or calibration and can be adjusted with shims. I've also heard there are some small screws than can adjust for front or back focusing problems. When my D700 was out, the ERF was spot on, suggesting a screen problem. Sure enough, I consulted a tech and he adjusted it for me and it's now spot on.
Hope this helps.

 

[glenerrolrd]

My problem is that the screen and the ERF seem to agree yet the images are slightly front focused. This is either ME (a technical term) or the AF system is off. Hopefully its ME and I will just adjust my technique a little.

 

[D.Keymn]

How does FOCUS ASSIST work on the D3/D3X

As above but will any of this type work,eg 25,26 28 etc?

cheers steve