Process APO Nikkor 600mm questions - 10x12 Camera

[blue4130]

So I am in the process of building a 10x12 tailboard camera with the intention of using it as a studio portrait camera. I have pretty much all of the design figured out as far as front and rear standards, and general construction. I have a line on a decent priced APO Nikkor 600mm process lens in barrel. The thing that is making my head spin is trying to figure out how long I should make my rear rail extension. Hoping that someone with have some help as far as...
A) What is the flange to film distance at infinity?
B) How much bellows will I need for a decent mid-chest head shot? (I don't need to go super tight)
C) Is 600mm even a decent focal length for this project? (I usually shoot with "standard" lenses on 35mm, 6x7 and 4x5)

Thanks to anyone who can help me.

Vance

[karl french]

I shoot 10x12, but haven't done any portraiture with it, though I have done a fair bit lately with 8x10. Like for 8x10, I think a lens slightly longer than 'normal' would work out best for portraits. I'm of the mind that 360mm is really the sweet spot for 8x10 portrait lenses, so I would think something in the 450-480mm range would be just right for for 10x12.

The 600 Apo-Nikkor is going to be quite sharp for portraits. You might consider something a bit more forgiving. At portrait distances a 420mm Heliar (or a 42cm Tessar) be a lovely choice. There are many fine barrel lens of roughly 18" to choose from.

Just to be on the safe side I'd plan on at least 28-30" of bellows extension. You're most likely to be working at around 24" of extension.

[MAubrey]

For 10x12, you'll probably want 1:2 magnification, so maybe 800 to 900mm of extension. I'd say go for the full meter of bellows just to have some flexibility. Currently, I'm building an 11x14 and I'm going with 42", which is just over a meter.

[Dan Fromm]

https://onedrive.live.com/redir?resi...t=folder%2cpdf

Do you mean 600 or 610 Apo Nikkor. The 600's image circle is a bit small for general photography on 10x12, will be fine for portrait work.

I've always understood that a good focal length for portraiture was ~ twice normal. If you believe that, 600 mm or so is more or less right for a portrait lens on 10x12.

[blue4130]

I was looking at the 600 APO nikor. The camera will be dedicated to portrait work and will not be leaving the studio. My goal is simple portraits on 10x12 x-ray film, so I am not concerned about movements. I can't recall where I read the image circle, but I seem to recall that it was enough for 10x12. (hope I am right - the lens has scratches on the front element that should "soften" the image a bit, and at a price that I can't pass up)

Thanks for all the help everyone.

[karl french]

The 'normal' focal length on 10x12 is 400mm. You certainly don't want an 800mm lens for portraits. Quite impractical considering the bellows you'd need at portrait distances.

[Tracy Storer]

I've been using a 600 Apo-Nikkor on 20x24 as my wide/normal lens for the last couple years. It'll be FINE on 10x12(if a bit long, as Karl points out.).Specs on paper(for the demanding hi-res reproduction work for which it was originally marketed) and real world portrait/scenic shooting demands are very different things.

https://onedrive.live.com/redir?resi...t=folder%2cpdf

Do you mean 600 or 610 Apo Nikkor. The 600's image circle is a bit small for general photography on 10x12, will be fine for portrait work.

I've always understood that a good focal length for portraiture was ~ twice normal. If you believe that, 600 mm or so is more or less right for a portrait lens on 10x12.

[tgtaylor]

WOW!! Then the IC of the 610mm Apo-Nikkor is sufficient for general photography with a 16x20 and a 20x24 camera!

Thomas

[Mark Sampson]

I don't do LF portraiture so I wonder about this... some people suggest that a process lens will be 'too sharp' for portraits. Given the relatively large aperture needed and its corollary, minimum DoF, would it matter much? I do appreciate those who like the soft lenses, and have learned a lot from Mr. Galli among others, even if I don't care to work that way. I'd love to see your results when you get your setup working.

[Drew Wiley]

Apo Nikkors are hard-sharp... I mean, tack sharp. But the out-of-focus background blur or "bokeh" tends to be a bit obnoxious. So you might want to employ soft background fabrics without busy details, just as portrait studios have done for eons for similar reasons. But having a 600 will give you a nice shallow depth of
field.