23 replies to this topic

[colinrobson]

Some 800s had focus issues from new - Thom Hogan did an article on how to test http://www.bythom.co...00autofocus.htm

 

Thewre are also several other reports about issues with the repair procedure etc in his 2012 archive.

[PeteAtkinson]

"Anyone knows the FNP (Front Nodal Point) of the Nikon 16-35 f/4 VR for use with a 9 inch Dome port on full frame?"

 

I measured it crudely as 103.5mm in front of the camera lens mount surface, at 16mm. As far as I understand it, this is where the centre of curvature of the dome should be located. So you need to measure the internal radius of the dome, best done by trial and error with thin card and a pencil and compasses.

This spot in the lens is also known as the no parallax point and the apparent front entrance pupil.

If anyone has a more accurate measurement (Jean??) I'd love to hear about it!

[Kelpfish]

Anyone knows the FNP (Front Nodal Point) of the Nikon 16-35 f/4 VR for use with a 9 inch Dome port on full frame?

 

There seem to be different indications on port extensions from manufacturers: Subal says it needs a 90mm extension ring, Seacam says 70mm. I have used it with my old 60mm extension ring on a 8-inch dome port and I am not sure if this is the right set-up.

 

With the exact FNP one can measure the correct extension needed following the dome port theory....

Buddy,

 

What 9-inch dome port are you using with Subal? I'd also be very interested in what extension ring to use.

 

Joe

[buddy]

In the past I have used Subal's 8inch Domeport (DP-FE2/3) with an 65mm Extension ring. But I plan to change it into Subal's DP-230/4 with 90mm extension ring (as recommended by Subal for 16-35 f/4). This is the larger 9 inch Dome port (I believe it is the same as the one from ZEN). There is even a 10 inch super dome port from Subal, but I consider this one not optimal for me in terms of portability and price as well.

But before doing the switch I am going to measure the actual FNP and with this to measure the exact extension ring lenghts for my rig, when I have more time...