Recommend me...

[Jason Greenberg Motamedi]

From what you have said, it does not sound like you want a true soft focus lens, but rather something fast with a smooth bokeh. If this is the case, for your 4x5 I think a f4.5 Tessar/Xenar or maybe even a Heliar (slightly softer than a Tessar) would be ideal. Any of these can be found in shutter. I would guess you are looking at $400+ for a 300mm f4.5 Xenar, and maybe $700+ for a 300mm f4.5 Heliar. Both can be found in factory mounted in Compound 5 shutters, and both will overwhelm (weight, bellows, and lensboard size) a 4x5 field camera.

[Paul Fitzgerald]

"A lens, to be used for portraits, in the 300mm range. Something that's easily mountable on a modern shutter."

"I'm trying to emulate portraits I used to get with my Canon 85 1.2L. I really liked the Brokeh."

Wollensak 302/4.5 Raptar (single coated tessar) Alphax shutter
Voigtlander 300/4.5 Heliar (late models are single coated) Compound shutter

"Also looking for something in the 600mm range for my 8x10."

You might want to tone that down to 420 - 500 mm, the added bellows and distance for 600mm can be a real problem. I know it sounds stupid but in practice it's a problem.

Voigtlander Heliar 600/4.5 big barrel + packard shutter = rare and very expensive
B&L Aero-Tessar 610/6 big barrel + packard shutter = fairly common and cheap

Stepping down to 420 - 500 gives you many more choices
Heliars, Tessars, Xenars, Dogmars, Ysars, ect.

[Pawlowski6132]

dude--what's the max bellows you got and what magnifications are you interested in....that will determine what you need....what is available will determine what you will use.

you want tight faces at 1:1---you'll need DOUBLE the bellows of the focal length...so if you got 30" bellows you'll need 15" lens and no more

That makes sense. So, if I had 30" of bellows and a 30" lens, I would NOT, necessarily, get 1:1 magnification right?

I guess I'm starting to confuse magnification with angle of view in determining the correct length of lens I need for headshot on 8x10.

[Mark Sampson]

A 30" lens extended 30" is focused at infinity. A 14" lens extended out 28" will give you a 1:1 image size. The plane of focus will also be 28" from the optical center of the lens. Of course you'll lose 2 f/stops from the bellows factor, so f/8 will be actually f/16.
I remember once trying to do full head shots with a friend and his 24" Artar on an 8x10 Wisner- achieving focus and composition was damn near impossible. A big studio camera, or a monorail on a studio stand, would be the tool of choice if I wanted to try that again.

[Ken Lee]

An 85mm lens at f/1.2 has the same depth of field (or blur) as a 170mm lens at f/2.4, which is the same as a 340mm lens at f/4.8.

That's being precise. If we loosen up a little, it's basically like a 360mm lens at f/5.6 or a 300mm lens at f/4.5

Although they are large, you can find plenty of f/4.5 Tessars, Heliars in shutter, in that size. The depth of field will be rather shallow, especially at portrait distance.

[johnielvis]

RIGHT---30" lens ALL the way out to 30" get you infinity--you'd need SIXTY inches for 1:1...

now 1:1 is PRETTY tight on 8x10...but it IS a solid face closeup--you may want a 15/14" lens to do that every now and again--but general portraits you may want to be back a little further--like "bigshot" distance--get maybe 1/2 : 1 magnification (get a 16x20 field in 8x10)....this is more like the usual...

use the focal length, f, times (1+Magnification) = total bellows draw--this follows from the lens equation 1/s + 1/s' = 1/f.

so you use f(1+M) = s'

OR.... (1+M) = s'/f = (f+extension past infinity)/f = 1 + extension/f

so M = extension/(focal length)

M=1 (1:1) gives bellows draw = s' = f(1+1) = 2f...or two times the focal length

M=.5 (1:2 or .5:1--half scale) gives bellows draw = s' = f(1+.5) = 1.5f......so with 30" of bellows draw the longest lens to get 1:2 is 30"=1.5f or f= 20" focal length.

or extension = 10" for a 20" focal length gives M = 10/20 = .5 (or .5:1 or 1:2) this is 10" of extension on top of 20" for 30" total focal length.....

re-visit algebra...it's fun fun fun.

[johnielvis]

OH exposure correction for time is

bellows factor = (1+M)^2....so at 1:1 you get (1+1)^2 = 4===4x the exposure...this is TWO STOPS

for .5:1 you get (1+.5)^2=2.25 (so 1 second of exposure is now 2.25 seconds) OR you convert to stops like so stops = log(bellows)/log(2)...so in stops this is log(2.25)/log(2) = 1.17.....so like slightly more than one stop...call it one stop.

for EXACTLY one stop you need (1+M)^2 = 2....this give a magnification of sqrt(2)-1 or .414:1 magnification.....and bellows extension is the same, sqrt(2)-1...total bellows draw is sqrt(2)*focal length in this case....

[johnielvis]

I love this kind of stuff.....

[Paul Fitzgerald]

Hi there, optical formula are great, cool and groovey BUT completely useless for real world, practical applications. All of the lenses available have different optical construction and mounting styles moving the exit pupil to where ever they wish.

To test my theory I setup a static target and focused a variety of lenses and I'm right.

Camera = Ansco 5A double extension studio 8x10
target = 60" from lens board
bellow draw = lens board to GG

lenses =
B&L 11x14 tessar
400/4.5 = 20"
Heliar
14"/4.5 = 17.5"
420/4.5 = 23"
480/4.5 = 26.5"
Dogmar
420/5.5 = 20.5"
480/5.5 = 26"
500/4.5 = 29" (mounts mid-barrel)
Extra Rapid
Lynkeioskop 19"/6 = 26.5"
Verito 18"/4 = 21"
Vitax 16"/3.8 = 23.25" (rear cell well behind flange)
Varium 19"/4 = 26"
Voigtlander Petzval 20"/5 = 24"

B&L Aero-Tessar 610/6 = 41"

Yes, moving up to 600mm from 500mm does make a really large difference in bellows draw at portrait distance, much easier to stay 500mm and below.

[SAShruby]

Fujinon 250mm SF, they go in $300-$500 range, I have one for sale in pristine condition.