Recessed lense board depth

[KEK]

Looks like i'm going to need to make myself a recessed lense board for my
90MM lense to work on my old B&J

I've never seen or used one of these and i'm looking for some advice on depth.

I'm going to start with a lens board i have so the depth would be about
9.5 mm and the max. i could make would be about 19mm

Thanks for any help

Kevin

 

[Nick Zentena]

Are you asking how deep to make it?

Start with figuring out what the flange focal length for your lens is.

You need enough depth that you can get to that distance. If you need movements you might need a bit more.

But too deep is a hassle if the board isn't very big. But I'm guessing the B&J board is a fair size.

 

[KEK]

How deep to recess the lense in the board is what i'm asking.

I'm going to show my ignorance. What is flange focal length?

From what i've read in the archives the deeper i go the more movements i'll have but will make it harder to adjust the lense

 

[Nick Zentena]

The flange distance is the distance the flange is when the lens is focused at infinity. In other words the smallest distance.

The greater for more movements depends on your bellows. With stiff bellows you might need to go deeper.

Which lens is this? Some 90mm need closer to 100mm to focus. Some are closer to 90mm.

 

[KEK]

It's a Nikkor 90mm SW f4.5

 

[Nick Zentena]

http://www.europe-nikon.com/product/it_IT/products/broad/439/specifications.html

97mm. The lens isn't on the English website so you're stuck with Italian.

At least that depth or you won't focus at infinity.

 

[KEK]

Thanks for the help Nick I'll give it a shot