Focusing range of Goerz Dagor 305mm 6.8 for portraits?

[wallpaperviking]

Hi,
I have access to a friends 8 x 10 and a Goerz Dagor 305mm 6.8 and am looking to do some close up portraits with it. As I understand it, to focus at infinity, the lens is 305mm away from the film plane. For a close up portrait, just wondering how far the bellows is likely to be away from the film plane?

Would about 450mm be about right?

Do I need to factor in any bellows light loss when working out an exposure?

I have attached a reference to show how close I am talking about.

Thanks in advance!

[Corran]

Yes, infinity focus is achieved at roughly the focal length, while a 1:1 magnification is achieved at twice that. That headshot is probably close to 1:1 on an 8x10 camera, so 450mm will probably not be enough, and yes you definitely will have to contend with bellows light loss.

[wallpaperviking]

Yes, infinity focus is achieved at roughly the focal length, while a 1:1 magnification is achieved at twice that. That headshot is probably close to 1:1 on an 8x10 camera, so 450mm will probably not be enough, and yes you definitely will have to contend with bellows light loss.

Thanks so much! Much appreciated!

If you could take a guess, how much bellows draw is 1:1?

[ghostcount]

Thanks so much! Much appreciated!

If you could take a guess, how much bellows draw is 1:1?

From one of our esteemed members...

http://www.kennethleegallery.com/html/tech/bellows.php

[Bernice Loui]

1 : 1 or "life size" double the focal length. Example:

12" Dagor would need about 24" of bellows to image 1 : 1 or life size and there will be two f-stops of light loss.

Keep in mind if your portrait sitter is about 24" to the camera, consider how your sitter might feel about being this close to the camera and how would this portrait be lighted?

Typical 12" Dagor full aperture is f6.8, Optical performance happens at about f16, add two f-stops for light loss (1 : 1). This puts light at your portrait sitter at about f32 which will need to be achieved by light intensity or duration of exposure.

One more thing, sitter movement can be a problem. If duration of exposure is used any portrait sitter movement will result in blur. If a strobe is used, consider what happens to your sitters eyes and vision once that strobe goes flash.


Bernice



Thanks so much! Much appreciated!

If you could take a guess, how much bellows draw is 1:1?

[wallpaperviking]

Amazing! Thanks so much! :)

[Pere Casals]

Here you have the formulas http://www.kennethleegallery.com/html/tech/bellows.php

At 1:1 magnification, bellows draw = 2 x focal length and exposure compensation is 4x or 2 f/stops.

So for 1:1 you need 305mm x 2 = 610mm. Add the distance from the rear nodal point to the lens board, this Focal-FFL, (FFL is flange focal distance), it can be (a guess) 30mm more so around 635mm of bellows. You may substract the film plane to belows rear frame distance. So the 24" Bryan Said.


The most used formula is this:

1 / Focal = (1 / Distance) + (1 / Extension)


1/305 = 1/D + 1/420 (I take 420mm instead 450mm bacuse the nodal point can be displaced say 30mm inside)

1/D = 1/305 - 1/420 = 0.00089773614

D = 1/0.00089773614

D = 1114


With 450 bellows extension you may focus the Dagor at around 1114mm distance.

it can vary a bit depending on the rear nodal point displacement inside the camera.


You can focus a bit closer if you consider DOF if lens is stopped.


Subject distance used is the one from Front Nodal Point to subject. In dagor can be inside the front cell, I guess.

[Jim Galli]

Some folk enjoy doing the math and enjoyment is what we're after, but your sitter may roll her eyes if you produce a slide rule and start doing calcs after you've told her to not move a muscle. Another way, I do it all the time, is to bring along a 6 foot tape rule with a millimeter scale. Measure the aperture opening. (just hold it out front) Then measure approx half way between front and rear elements to the ground glass. Off to the side is plenty good enough. 20mm hole and 540mm bellows; divide 20 into 540 = 27. You're at f27 = f22 1/2 on your meter. Now, if you like doing calc's and your sitter is also married to you and very patient, ignore me. Most folk do.

[Pere Casals]

Jim, one question, what aprox focal has the front element of a Symmar convertible used alone ? (relative to the full lens focal), I'm to disassembly one to use it alone...

____________________



Then measure approx half way between front and rear elements to the ground glass.

In a dagor perhaps we should take the midpoint on the rear cell

Measuring the aperture diameter as seen from the front is right, but for the distance we should take the rear node position, I ask...

[Jim Galli]

With a combined anastigmat I just measure from the aperture control ring to the ground glass. With a single anastigmat like a Single Turner Riech group I guess at halfway mid point of the lens glass. I don't know what the front is on a Symmar. Might be double. They weren't symmetrical like the G-Claron's.

[Pere Casals]

With a combined anastigmat I just measure from the aperture control ring to the ground glass. With a single anastigmat like a Single Turner Riech group I guess at halfway mid point of the lens glass. I don't know what the front is on a Symmar. Might be double. They weren't symmetrical like the G-Claron's.

OK, thanks!

[Jim Noel]

Some folk enjoy doing the math and enjoyment is what we're after, but your sitter may roll her eyes if you produce a slide rule and start doing calcs after you've told her to not move a muscle. Another way, I do it all the time, is to bring along a 6 foot tape rule with a millimeter scale. Measure the aperture opening. (just hold it out front) Then measure approx half way between front and rear elements to the ground glass. Off to the side is plenty good enough. 20mm hole and 540mm bellows; divide 20 into 540 = 27. You're at f27 = f22 1/2 on your meter. Now, if you like doing calc's and your sitter is also married to you and very patient, ignore me. Most folk do.

The last statement is key. If married for more than a few years, she may have far less patience for this. don't ask how i know.

[Bob Salomon]

1 : 1 or "life size" double the focal length. Example:

12" Dagor would need about 24" of bellows to image 1 : 1 or life size and there will be two f-stops of light loss.

Keep in mind if your portrait sitter is about 24" to the camera, consider how your sitter might feel about being this close to the camera and how would this portrait be lighted?

Typical 12" Dagor full aperture is f6.8, Optical performance happens at about f16, add two f-stops for light loss (1 : 1). This puts light at your portrait sitter at about f32 which will need to be achieved by light intensity or duration of exposure.

One more thing, sitter movement can be a problem. If duration of exposure is used any portrait sitter movement will result in blur. If a strobe is used, consider what happens to your sitters eyes and vision once that strobe goes flash.


Bernice

Since the 305 is a short normal for 810 when shooting a head that close you will have foreshortening. That means that things that are closer to the lens will reproduce larger then things further away from the lens. If head on that will result in a very large nose.
If shot from slightly above that will result in an exaggerated forehead and a larger nose. If from slightly below a larger chin. From a side a larger ear.
To prevent exaggerated faces you need a longer lens or shoot from further away.

[Mark Sampson]

Mr. Salomon's advice is very good here.
Look at the work of Chuck Close (paintings or photographs, doesn't matter) if you want to see what LF portraiture done close-up with a short focal length looks like.
It works for him, but shooting up your subject's nose has never appealed to me. (Must be my early training and practice as a commercial portrait shooter.)

[Pere Casals]

OP: a natural face perspective is obtained around 3m. We remember other people's faces like when they are at some 3m.

If you want that then prepare a well longer lens and bellows.

Otherwise Nose Jobs are not good or bad, YMMV.

Yousuf Karsh mainly used a Commercial Ektar 14" (around 360mm), but most of his work was not mug shots.



will have foreshortening.

Bob, let me add that we have consolidated scientific terminology for that: "Nose Job"




Look at the work of Chuck Close (paintings or photographs, doesn't matter) if you want to see what LF portraiture done close-up with a short focal length looks like.
It works for him, but shooting up your subject's nose has never appealed to me. (Must be my early training and practice as a commercial portrait shooter.)

In the modern times nose foreshortening is a general trend... because of smartphones.

Everyone likes the images he makes (:)) and as smartphones are well wider than normal, best is liking the nose. Of course software can make a botched job to patch that.

When we send a selfie with WhatsApp... first the nose arrives and later comes the rest of the face.

hmmmm.... modern times.

Otolaryngologists sure are happy, beyond they sure like modern selfies, more and more people want to care his nose.


____________________________________________________________


OP: let me show you a kind of LF protraiture I like a lot (YMMV):

https://mecacolor.files.wordpress.com/2013/09/marte4x5-tmx-100-1a.jpg?w=640

This shows some mastery, in focus-movements management, in illumination and in controlling film to render a 3D feel, the eye sees the depth, this is something I'm trying to learn (sorry if this was not asked and not wanted to know). Of course it's only a personal taste, nothing else.

[Bob Salomon]

OP: a natural face perspective is obtained around 3m. We remember other people's faces like when they are at some 3m.

If you want that then prepare a well longer lens and bellows.

Otherwise Nose Jobs are not good or bad, YMMV.

Yousuf Karsh mainly used a Commercial Ektar 14" (around 360mm), but most of his work was not mug shots.




Bob, let me add that we have consolidated scientific terminology for that: "Nose Job"





In the modern times nose foreshortening is a general trend... because of smartphones.

Everyone likes the images he makes (:)) and as smartphones are well wider than normal, best is liking the nose. Of course software can make a botched job to patch that.

When we send a selfie with WhatsApp... first the nose arrives and later comes the rest of the face.

hmmmm.... modern times.

Otolaryngologists sure are happy, beyond they sure like modern selfies, more and more people want to care his nose.


____________________________________________________________


OP: let me show you a kind of LF protraiture I like a lot (YMMV):

https://mecacolor.files.wordpress.com/2013/09/marte4x5-tmx-100-1a.jpg?w=640

This shows some mastery, in focus-movements management, in illumination and in controlling film to render a 3D feel, the eye sees the depth, this is something I'm trying to learn (sorry if this was not asked and not wanted to know). Of course it's only a personal taste, nothing else.

No, it is not a “general term”. It is a technical term. And the result of seeing it on a phone screen is very different then seeing it on an 810 contact or an enlargement.

[Pere Casals]

And the result of seeing it on a phone screen is very different then seeing it on an 810 contact or an enlargement.


Bob, I apreciate you add that nuance, but a nose job is a nose job, we have two kinds, with common cold or without it:

195203
https://www.dxomark.com/xiaomi-mi-mix-3-front-camera-review/

[goamules]

Jim, why measure half way between the lens nodal and the ground glass? I always measure the entire distance.

[wallpaperviking]

Thanks so much for all your replies, greatly appreciated!

Any guesses as to what focal length might have been used for the sample image I originally posted? It is taken by Paolo Roversi and shot on 8 x 10 polaroid, back in the day when it was still produced.. I was under the impression he used a Goerz Dagor 305mm 6.8 by seeing images he has taken himself of his camera/lens setup but to be honest, he could be using anything....

I don't see an over exaggerated nose in the sample but maybe you guys do? The other thing would be to simply crop into a more "normal F.O.V" shot, essentially making it a longer" lens...

Could this be possible?

Thanks again!

[wallpaperviking]

Thanks so much for all your replies, greatly appreciated!

Any guesses as to what focal length might have been used for the sample image I originally posted? It is taken by Paolo Roversi and shot on 8 x 10 polaroid, back in the day when it was still produced.. I was under the impression he used a Goerz Dagor 305mm 6.8 by seeing images he has taken himself of his camera/lens setup but to be honest, he could be using anything....

I don't see an over exaggerated nose in the sample but maybe you guys do? The other thing would be to simply crop into a more "normal F.O.V" shot, essentially making it a longer" lens...

Could this be possible?

Thanks again!

[Pere Casals]

I don't see an over exaggerated nose in the sample but maybe you guys do?

This is Emily's "regular" face:

195322

She has a tiny nose, so foreshortening does not show "an over exaggerated nose". If it was Streisand then we would have another effect. Nose jobs are a YMMV.



The other thing would be to simply crop into a more "normal F.O.V" shot, essentially making it a longer" lens...
Could this be possible?


Yes, of course you can crop, but you can also use a reducing back to 5x7 or to 4x5, so you don't waste film.




Any guesses as to what focal length might have been used for the sample image I originally posted?


I guess that image has some foreshortening, given his "regular" face.

We don't know the format and edition, my guess is that if it was a 8x10 shot then focal could be around normal focal, perhaps around 360mm, but this is only a guess from the face deformation I perceive compared to her distant shots.


Just use a DSLR with a zoom to see the face deformations you have at different distances, then take the equivalent focal for 8x10.


195323

https://www.fireflyphotography.co.nz/the-art-of-taking-a-pro-headshot/foreshortening/


If you like the 50mm then take that dagor and shot close. If you like the 100mm then use around 600mm and shot from 2m to 3m far.

[reddesert]

If one uses an 8x10" camera to image a 16x20" subject, which is kind of like a tight head and shoulders composition, one is working at a reproduction ratio of 1:2. That means a lot of bellows extension. A 300mm lens will be working at 450mm extension (and the lens to subject distance will be 900mm). At this point we have to stop talking about the 300mm lens as "normal" lens because the extra extension counts. From a perspective point of view, you have the same perspective as any other lens at 900mm subject distance.

I don't have an 8x10 camera, but it seems to me that the way to address this question is to figure out where you want to position the camera for the desired perspective, and then ask how much bellows extension you have / can afford. You will need a lot of bellows to focus a 600mm lens at 1:2.

[Corran]

With large format, the magnification of the image becomes significant. Obviously with smaller formats, you aren't anywhere near a 1:1 mag for a headshot, because the film is not large.

Perhaps this interesting thread from Ken Lee is relevant here:
https://www.largeformatphotography.info/forum/showthread.php?101143-Focal-Length-and-Angle-of-View-when-closer-than-infinity

[Jim Galli]

To the OP, I think the original image you showed could have been done with 12" Dagor. Lot's of good advice here, but sometimes you have to be careful not to let all the helpers cause analysis paralysis. Gearheads, (or lensheads as it were) we err on the side of overthinking stuff. Put the lens on the camera and get to work. You'll do fine.

[wallpaperviking]

Have just posted in another thread, so hope I am not overlapping too much but am just wondering if anybody knew if I could use one of these "single focus solutions"

https://www.rapidotechnology.com/products/front-variable-diopter/fvd-35a

attached in front of my Goerz Dagor 12 and not have the need to rack out the bellows so much?

Thanks in advance! :)

[Dan Fromm]

A shorter lens, even a Dagor, would cost much less.

[Will Frostmill]

Thanks so much for all your replies, greatly appreciated!

Any guesses as to what focal length might have been used for the sample image I originally posted? It is taken by Paolo Roversi and shot on 8 x 10 polaroid, back in the day when it was still produced.. I was under the impression he used a Goerz Dagor 305mm 6.8 by seeing images he has taken himself of his camera/lens setup but to be honest, he could be using anything....

I don't see an over exaggerated nose in the sample but maybe you guys do? The other thing would be to simply crop into a more "normal F.O.V" shot, essentially making it a longer" lens...

Could this be possible?

Thanks again!

You've gotten some great advice in this thread.

Three things:
1. How big noses appear in a picture (Leslie Strobel calls it "strong perspective") depends on how close the lens is. Set up your shot, but focus with the back standard, not the front standard. Moving the front standard moves the lens closer to the subject. Don't do that when you focus, do that when you frame.
Try it: set up a dummy at a distance you like for the framing you want. Use the back standard to get it into focus. Then try it the other way.

2. How much magnification you get depends on how far you have to rack out the bellows to get the picture. This is weird, because it doesn't show up as much of a factor with smaller cameras, and it mixes with our understanding of how focus works.

I've seen people get into fights just talking about it. If you really want to understand it, spend some time googling "focus breathing","unit focusing lens", and "close range correction" . The shortest possible version is this: your "normal angle of view lens", a 300mm on 8x10, has that normal angle when focused at infinity. By the time you've racked it out to 450mm from the lens to the film, what you see on the ground glass is a narrower angle of view. One like a 450mm lens at infinity.

3. Speaking of racking out the bellows, once you've got the lens that far away from the film, the light is noticeably dimmer. One way to understand it, is to realize that the aperture on your 300mm lens hasn't gotten any bigger to compensate for suddenly being on that 450mm lens. Or, alternatively, you could think of it from the film's perspective: gee, that bright circle way over there got smaller.

Jim Noel knows what he's talking about with calculating bellows. Make it easier. Put down painter's tape next to the tracks your rear standard rides on. Mark infinity focus. Then mark each focal distance you want to use, and do the math, once, for the fstop for each distance, and write it on the tape.

Finally, notice that classic 8x10 portrait photographers like Karsh and Avedon were often using 14" lenses for portraits. Not 24" lenses. On smaller formats, we'd double the focal length from 42.5mm to 85mm, or from 50mm to 100mm. But not for large formats. It's a puzzlement!

-----
References: Leslie Strobel's "View Camera Technique", 1976
Franke's notes on his Depth of Field and Angle of View calculator, which includes both real formulas at the link (https://www.pointsinfocus.com/tools/depth-of-field-and-equivalent-lens-calculator/#aovmethod) and a very very nice interactive calculator which covers both large format film as well as pretty much every digital format. Fun to play with.

[Bernice Loui]

Hint on 8x10 portraits, Kodak made their 16" Portrait Ektar for 8x10, consider why the folks at Kodak decided on 16" focal length or head/shoulder and similar 8x10 portraits.

2" difference in focal length might not appear to be that much, yet it DOES make a difference for 8x10 portrait work like this. Beyond lens focal length, lighting, composition and related is often equally or more important than just focal length.

Back in te 8x10 days, one of my faves was a 480mm f4.5 Schneider Xenar and 14" Kodak Commercial Ektar for these types of images. 480mm (~19") is about the upper limit and 14" (~360mm) the lower limit for focal length.


Bernice




You've gotten some great advice in this thread.

Finally, notice that classic 8x10 portrait photographers like Karsh and Avedon were often using 14" lenses for portraits. Not 24" lenses. On smaller formats, we'd double the focal length from 42.5mm to 85mm, or from 50mm to 100mm. But not for large formats. It's a puzzlement!

[lungovw]

I was tired of doing always the same calculation whenever I was asking myself "what can I do with this lens in this camera", so I made an online simulator that I can check in my mobile phone. One has to enter lens' focal length, film format and type of portrait, and immediately get the key figures providing a pretty good idea of how things will match up: bellows extension, lens to subject distance and exposure compensation. Recently I added depth of field in case also the intended aperture and admitted Circle of Confusion are informed according to film format. I have used it, many people I don't know have, and it works fine for a first appraisal. It is a way to bypass the "overthinking" Jim Galli pointed out, but also a way to avoid wild experimentation. I consider it a good compromise for those not having yet a good intuition, built over extensive experience with certain lenses and formats. The link is:https://apenasimagens.com/en/focal-length-distances-and-framing/