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6x6TLL
17-Sep-2018, 08:00
I've been doing some research, been curious about trying out LF at some point, and have been reading about lenses.

One thing that isn't clear to me, most lenses seem to be of some "standard" design, requiring approximately the same bellows draw as focal length to focus at infinity. There are special telephoto designs that allow shorter bellows draw for full focus.

What I'm curious about is angle of view and focal length. In MF, where I've spent the last 20 years, if I want to foreshorten the distance between a subject, the midground and background, I know that I can use a telephoto lens, from 150-300mm or so to get that effect. The opposite also applies, if I want to create an impression of even greater space and distance, making distant mountains almost tiny in the background, I can mount a wide angle lens, 35-50mm or so to achieve that. In both cases my subject could still be the same size and distance from the camera, but the perspective between subject and the rest of the composition would change.

My question is does this carry over to working in LF? Will a 4x5 camera with a 450mm lens create the same foreshortening, or on the other end, will a 75mm really create more distance? Or does it not work the same way due to the bellows and movements, and one uses movements instead to create some of the same effects?

Hope my question makes sense.

Bob Salomon
17-Sep-2018, 08:09
Exactly the same. Except you can control the plane of sharp focus as well as the shape of the object and the apparent placement of the camera by using camera movements.

If you are shooting 6x6 with a Rollei SL66 you can also control the plane of sharp focus but you would still not have the other movements.

Leigh
17-Sep-2018, 08:30
Hi 6x6,

The distance from the rear lens node to the film equals the optical focal length.
This is true for all lenses, by definition.

But the location of th rear node relative to the physical lens varies greatly.
For example, "normal" lenses have a rear node near the shutter plane.
Wide-angle lenses have a rear node significantly behind the rear lens element.
And telephoto designs have the rear node way out in FRONT of the front lens element.

You need to consult the datasheet for each lens to determine where the rear node is.

The spec that determines bellows draw is called the "Flange Focal Length", or FFL.
That's the distance from the lensboard to the film.
It may be quite different from the optical focal length.

- Leigh

Pfsor
17-Sep-2018, 08:49
What I'm curious about is angle of view and focal length. In MF, where I've spent the last 20 years, if I want to foreshorten the distance between a subject, the midground and background, I know that I can use a telephoto lens, from 150-300mm or so to get that effect. The opposite also applies, if I want to create an impression of even greater space and distance, making distant mountains almost tiny in the background, I can mount a wide angle lens, 35-50mm or so to achieve that. In both cases my subject could still be the same size and distance from the camera, but the perspective between subject and the rest of the composition would change.

My question is does this carry over to working in LF?

Imagine a lens that has the angle of coverage sufficient for a 4x5 film format. If you now limit, with a mask on the film plane, the format to a 6x6 film format the lens doesn't know it, the perspective neither, it is still the same, it won't reorganize itself because - on the film - you have limited the lens angle of view.

Corran
17-Sep-2018, 09:06
Perspective, and relationships between foreground and background, is controlled by the camera location. The lens only controls how much of what you see is projected onto the film.

Jim Jones
17-Sep-2018, 11:12
When shopping for LF lenses, consider the lens coverage in comparison to film dimensions. To use view camera front movements, the lens should cover more than the film size.

Bob Salomon
17-Sep-2018, 11:30
When shopping for LF lenses, consider the lens coverage in comparison to film dimensions. To use view camera front movements, the lens should cover more than the film size.

To use front or back movements! Especially if the camera uses base tilts!

Pere Casals
17-Sep-2018, 12:27
Just I'd add that in this chart:

https://lensn2shutter.com/angleofviewchart.html

You have the AOV for different focals and formats...

You can find the equivalent focal for LF format compared to a 35mm camera.

As it has been said yet, LF delivers same perspectives than smaller formats, motivation for shooting LF comes from other factors.

6x6TLL
17-Sep-2018, 12:29
Perspective, and relationships between foreground and background, is controlled by the camera location. The lens only controls how much of what you see is projected onto the film.

But the closer the camera is to the subject, the greater the amount of distortion, right? This seems most apparent in architecture and portraiture. The lens is determining the field of view (techically the angle of view, and together with the film dimensions determine the field). So I'd still want a 210-350mm lens on 4x5 for portraiture, right? A 150mm would be like a 50mm in 35mm, not the best choice in most cases for a portrait.

Corran
17-Sep-2018, 12:43
Perspective distortion will be more apparent with wider lenses, especially in the corners of the frame. For portraits it depends if you mean full-body, headshot, or something in-between. Plenty of folks use ~150mm lenses for portraits - a longer lens is not a hard and fast rule for this. But in some cases it's probably a better choice.

Corran
17-Sep-2018, 12:46
This is a 150mm lens. Seems fine to me.

http://www.garrisaudiovisual.com/photosharing/bwpos-2248-e-softss.jpg

MAubrey
17-Sep-2018, 12:51
But the closer the camera is to the subject, the greater the amount of distortion, right? This seems most apparent in architecture and portraiture. The lens is determining the field of view (techically the angle of view, and together with the film dimensions determine the field). So I'd still want a 210-350mm lens on 4x5 for portraiture, right? A 150mm would be like a 50mm in 35mm, not the best choice in most cases for a portrait.
Since 150mm is the diagonal for 4x5, it'd be like 42mm for 35mm format. A 50mm would be more like a 180mm.

(obviously this assume equivalent diagonals rather than equivalent horizontal or vertical dimensions)

Bob Salomon
17-Sep-2018, 12:51
But the closer the camera is to the subject, the greater the amount of distortion, right? This seems most apparent in architecture and portraiture. The lens is determining the field of view (techically the angle of view, and together with the film dimensions determine the field). So I'd still want a 210-350mm lens on 4x5 for portraiture, right? A 150mm would be like a 50mm in 35mm, not the best choice in most cases for a portrait.

A good 150 does not distort. Straight lines will be straight, as long as the camera is not tilted to the subject.

What you are talking about is an optical effect called foreshortening. Objects closer to the lens are reproduced larger then things further from the lens. The wider the lensthe more pronounced the effect.

Pere Casals
17-Sep-2018, 15:05
A 150mm would be like a 50mm in 35mm

It depends...

For a near subject you give bellows extension, so the image grows because the focus breath effect in "unit focus" lenses, so a 150mm behaves like a bit longuer lens for close portraits.

This also happens with Mamiya RB67 lenses because you also focus with bellows.

Also it happens with Nikon 50mm f/1.8, that has unit focus, all glass separates from the film/sensor to focus near. It does not happen with the f/1.4 50mm, that has internal focus, displacing some elements inside.

The cheap Nikon 50mm f/1.8 is a very decent lens becuse it takes advantage from the efficient "unit focus" way, with the breathing relative drawback. LF lenses I know work like that.

Bob Salomon
17-Sep-2018, 15:15
It depends...

For a near subject you give bellows extension, so the image grows because the focus breath effect, so a 150mm behaves like a bit longuer lens for close portraits

Regardless of format, nobody takes portraits at infinity, they are always closer, so your comment is ridiculous!

Pere Casals
17-Sep-2018, 15:24
This is a 150mm lens. Seems fine to me.

http://www.garrisaudiovisual.com/photosharing/bwpos-2248-e-softss.jpg

Bryan, this is a really good shot, the tilt/swing delivers an amazing depth.

Pere Casals
17-Sep-2018, 15:31
Regardless of format, nobody takes portraits at infinity, they are always closer, so your comment is ridiculous!

Bob, consider that the AOV of a LF lens is narrower for a close subject than for a distant subject, because image circle grows with bellows draw, and you take less field than expected.

So the normal lens for a view camera has a longer focal for landscape than for portraiture, if as normal we consider the "standard" human eye AOV.

I guess that there is no doubt in that...

Look, the 150mm portrait that Bryan posted it's not like the typical normal 50mm potrait of a 35mm camera, it's a better portrait because the effective narrower AOV, like if it was done with a longer than 50mm lens in a 35mm camera.

Bob Salomon
17-Sep-2018, 16:10
Bob, consider that the AOV of a LF lens is narrower for a close subject than for a distant subject, because image circle grows with bellows draw, and you take less field than expected.

So the normal lens for a view camera has a longer focal for landscape than for portraiture, if as normal we consider the "standard" human eye AOV.
The normal lens for a format is the length of the format’s diagonal, or close to it. Period!
For 35mm a true normal is 44. something. For 45 it is 150. In actual use with 35mm a normal has been anything from near 44mm to 58mm on 45 lenses from 135 to 180 are in the normal range.
Whether you use them at their closest normal focusing range or at infinity they are still normal focal length lenses.
I guess that there is no doubt in that...

Look, the 150mm portrait that Bryan posted it's not like the typical normal 50mm potrait of a 35mm camera, it's a better portrait because the effective narrower AOV, like if it was done with a longer than 50mm lens in a 35mm camera.

MAubrey
17-Sep-2018, 16:20
Regardless of format, nobody takes portraits at infinity, they are always closer, so your comment is ridiculous!

It matters if you're comparing dramatically different formats, doesn't it? The magnification required for the framing gets less and as format gets smaller?

You might want 1:4 for an 8x10 portrait, but you certainly wouldn't want that for 120 film or 35mm and the extension affects image less and less.

Pfsor
17-Sep-2018, 16:32
You, Bob and Pere, don't understand each other because both of you speak about the same thing but defined differently. And I think Pere is the culprit of the misunderstanding.
Bob defines the normal lens with its focal length, Pere defines the normal lens with a given AOV.
And of course, a shorter lens can give the same AOV value (if focused at a closer range) as a longer lens focused at infinity. But this fact doesn't make yet a shorter lens the "normal" lens - otherwise it would be completely impossible to define a normal lens, as all lenses could then reach the given AOV, depending on their focused distance...
Pere, the point is that we define the normal lens with the lens focused at infinity (and its AOV corresponding to this case). Otherwise you just mud the waters!

Bob Salomon
17-Sep-2018, 16:37
It matters if you're comparing dramatically different formats, doesn't it? The magnification required for the framing gets less and as format gets smaller?

You might want 1:4 for an 8x10 portrait, but you certainly wouldn't want that for 120 film or 35mm and the extension affects image less and less.

No, portraits are usually taken at about the same distances, regardless of format. If you are using lenses appropriate for portraiture for each format.
You want to be close enough to the subject to direct them and relate to them. Except for some environmental distant portraits.

Pere Casals
17-Sep-2018, 16:45
The normal lens for a format is the length of the format’s diagonal, or close to it. Period!

Bob, the definition of normal lens is a bit more loose: "a normal lens is a lens that reproduces a field of view that appears "natural" to a human observer". https://en.wikipedia.org/wiki/Normal_lens

yes, "typical" used values are the diagonals, to guess what it will be "natural".

But a 150mm LF lens for portraiture looks longer than "natural", because that, you know it very well, some consider 135mm also a normal focal for 4x5.



Analyze next situation:

Imagine we shot a landscape with normal (I.F.) lens for the 35mm camera and a with view camera lens that takes horitzontally the same field, exactly same mountains in the image.

But as we make a close shot, with same distance for both cameras it will happen that the LF camera will take less horizontally because image growth upon additional bellows extension.

There we have a discrepance, depending on if we account for focus breath or not.

doesn't the circle grow when focusing near ? Well, the aparent focal grows proportionally the same than the circle !

This is because in (45) LF "normal" is between 135 and 150, depending on subject distance

Leigh
17-Sep-2018, 16:48
Shooting distance and focal length for portraits are chosen to make the image look "normal".
They both depend critically on the format in use.

You don't want the focal length too short because the nose looks too large relative to the ears.
You don't want the focal length too long because the whole face looks flat.

- Leigh

Pfsor
17-Sep-2018, 16:52
Bob, the definition of normal lens is a bit more loose: "a normal lens is a lens that reproduces a field of view that appears "natural" to a human observer". https://en.wikipedia.org/wiki/Normal_lens



Yes, the "natural" field of view - but with the lens focused at infinity!! Otherwise any shorter lens can be the normal one, if focused at a more or less distant subject and you cannot have 10 different normal lenses than are normal just for a certain focusing distance! You got it?

Pere Casals
17-Sep-2018, 17:26
Yes, the "natural" field of view - but with the lens focused at infinity!! Otherwise any shorter lens can be the normal one, if focused at a more or less distant subject and you cannot have 10 different normal lenses than are normal just for a certain focusing distance! You got it?

Professor, what in fact is "normal" (or not) isn't the lens itself, but the angle of view of the whole system. You may know that the angle of view of a view camera changes with bellows draw... so it's about that.

I'm pretty sure that Bob has sold truckloads of 150mm sironars, not extrange, a 150mm delivers a great natural look for general photography, and a great longer than normal look for close half body portraiture... so perhaps it's the most useful (45) LF glass !!!

Anyway YK used the 14" for 810, what it would be a 180mm for 45.



Shooting distance and focal length for portraits are chosen to make the image look "normal".
They both depend critically on the format in use.

You don't want the focal length too short because the nose looks too large relative to the ears.
You don't want the focal length too long because the whole face looks flat.

- Leigh


Beyond exceptions, we may want to shot a portrait from some 3m, to prevent a "nose job", and then we pick the glass that from that distance it frames what we want, isn't it ?

Pfsor
17-Sep-2018, 17:38
Professor, what in fact is "normal" (or not) isn't the lens itself, but the angle of view of the whole system. You may know that the angle of view of a view camera changes with bellows draw... so it's about that.


Pere, don't try to mud the waters - a lens gives a certain AOV on a film format. The AOV that it gives when focused at infinity defines or not the "normality" of the lens for the given format.
If you want to introduce there the fact that shorter lenses, focused on a closer distance can simulate the AOV of longer lenses focused at infinity you just throw the normal lens definition out of the window.

Yes, Pere has found out that a 75mm lens focused at a close up distance can give the same AOV as a 150mm lens focused at infinity. Therefore, Pere says, the 75mm lens is the normal lens in this case! Bravo! Now we can easily compare normal lenses for different formats - by choosing the focusing distance that gives a normal AOV of different lenses.
Good grief!

Bob Salomon
17-Sep-2018, 17:42
Professor, what in fact is "normal" (or not) isn't the lens itself, but the angle of view of the whole system. You may know that the angle of view of a view camera changes with bellows draw... so it's about that.

I'm pretty sure that Bob has sold truckloads of 150mm sironars, not extrange, a 150mm delivers a great natural look for general photography, and a great longer than normal look for close half body portraiture... so perhaps it's the most useful (45) LF glass !!!

Anyway YK used the 14" for 810, what it would be a 180mm for 45.





Beyond exceptions, we may want to shot a portrait from some 3m, to prevent a "nose job", and then we pick the glass that from that distance it frames what we want, isn't it ?

No, for classic portraiture you need the depth of field that holds resolution from the tip of the nose to the base of the ear. That means you focus on the base of the nose and dof covers the range.

That range will be controlled by the focal length of the lens and the film to subject distance.

At no time is the angle of view considered.

The above is for head and shoulder portraits.

You might vary this in situations where you want to include additional info, say a company logo in the background but, again, it is not the angle of view, it is focal length, distance and dof that the pro considers.

Leigh
17-Sep-2018, 17:56
No, for classic portraiture you need the depth of field that holds resolution from the tip of the nose to the base of the ear. That means you focus on the base of the nose and dof covers the range.
That range will be controlled by the focal length of the lens and the film to subject distance.
At no time is the angle of view considered.
The above is for head and shoulder portraits.Yep.

That's what we taught in photography school.

- Leigh

tgtaylor
17-Sep-2018, 19:15
I get practically the same FOV with my 150mm F5.6 Rodenstock Apo-Sirona s on a 4x5 as I get with the 120mm Nikkor SW, 75mm SMC Pentax 67 on a Pentax 67II, or with a 35mm Nikkor lens on the F6. There is a small - barely discernable = difference between the 4 FOV's but that difference is insignificant. If memory serves me correctly, the AOV on the Rodenstock is "a whopping 105°" which is how B&H put it at the time.


Thomas

Bob Salomon
17-Sep-2018, 19:39
I get practically the same FOV with my 150mm F5.6 Rodenstock Apo-Sirona s on a 4x5 as I get with the 120mm Nikkor SW, 75mm SMC Pentax 67 on a Pentax 67II, or with a 35mm Nikkor lens on the F6. There is a small - barely discernable = difference between the 4 FOV's but that difference is insignificant. If memory serves me correctly, the AOV on the Rodenstock is "a whopping 105°" which is how B&H put it at the time.


Thomas

Angle of view of a Rodenstock Apo Sironar S is 78°; 80° for an Apo Sironar or Apo Sironar W; 72° for the Apo Sironar N. On the longest lenses aov is slightly reduced due to the size of the shutter opening.
No Sironar, of any type is 100° or greater. That would be Grandagon,Grandagon N and Apo Grandagon series lenses.

Pere Casals
17-Sep-2018, 23:44
Angle of view of a Rodenstock Apo Sironar S is 78°; 80° for an Apo Sironar or Apo Sironar W; 72° for the Apo Sironar N.

Expanding your comment, these are the coverage angles, so perhaps we should say Maximum Angle of View that can be obtained with a Rodenstock Apo Sironar S is 78°, in the diagonal, and if format and bellows_draw exhaust all the circle, the maximum Hor/Vert view angles would be smaller (if not vigneting in the corners).

Of course a Sironar S won't deliver a 100º angle of view, as that design does not cover that.



No, for classic portraiture you need the depth of field that holds resolution from the tip of the nose to the base of the ear. That means you focus on the base of the nose and dof covers the range.
That range will be controlled by the focal length of the lens and the film to subject distance.



... and by aperture !

Colin Robertson
18-Sep-2018, 00:49
Good Morning 6TTL.
Everything you already know about shooting 35mm carries over into LF, just with different size lenses.
In 35mm the 'standard lens' is usually thought of as 50mm, but different manufacturers supplied bodies with anything from 45-55mm. In 5x4 the 150 is probably most common pick for general use, but you'll hear people suggesting anything from 120-180mm as their personal favourite. I use a 150, and it's pretty versatile.
Long lenses give a narrower field of view, allowing you to be selective and focus attention on part of the landscape. In LF you just can't get the extreme lenses you may have enjoyed in 35mm- to achieve the kind of striking compression you get from (say) a 400mm on a 35mm camera you'd need a monstrous 1200mm lens. My longest lens in 5x4 is a 360mm, which equates to maybe something like a 100-120 in 35mm.
Also- your LF camera is limited by the extension of it's bellows. Hence the value of Tele lenses: a 360 Tele need less extension that a Non-Tele 360, allowing you to focus closer on the same camera.
Wides? Yes, wide lenses take in a view which emphasises foreground and diminishes distant objects. The wider the lens the more exaggerated the effect, but in LF you have another trick. I have a 90mm which is moderately wide, but you can tilt the rear standard to modify the image. LF allows you control over 'distortion' of all kinds (and focus) through movements you don't get in 35mm.
If you're new to LF I would really suggest starting with a single lens and stciking with it until camera control becomes routine to you before adding longer lenses. Wides need a bit of practice to manage well.
Best of luck in LF.

Pfsor
18-Sep-2018, 02:01
Expanding your comment, these are the coverage angles, so perhaps we should say Maximum Angle of View that can be obtained with a Rodenstock Apo Sironar S is 78°, in the diagonal, and if format and bellows_draw exhaust all the circle, the maximum Hor/Vert view angles would be smaller (if not vigneting in the corners).


There you're right, Pere. Bob simply mistakes an angle of coverage for the angle of view. This thread starts to be crazy with other mistakes served as well...

Pere Casals
18-Sep-2018, 02:43
There you're right, Pere. Bob simply mistakes an angle of coverage for the angle of view. This thread starts to be crazy with other mistakes served as well...

Professor, Bob does not mistakes about AOV vs AOC, he knows very well what it's what, he had explained a number of times why there is some confusion about that, coming from bad translations from German to English.

IMHO that was just an effective answer with deliberated loose wording to make it understand somebody that AOC limits potential AOV. Because that I said that I was "expanding" that answer, rather correcting it.

Pfsor
18-Sep-2018, 04:38
Professor, Bob does not mistakes about AOV vs AOC, he knows very well what it's what, he had explained a number of times why there is some confusion about that, coming from bad translations from German to English.

IMHO that was just an effective answer with deliberated loose wording to make it understand somebody that AOC limits potential AOV. Because that I said that I was "expanding" that answer, rather correcting it.

I see, it's just all clear to somebody, like mud. Deliberate loose wording to make the mud clear, at least it's now very clear. :)

Pere Casals
18-Sep-2018, 05:06
Pfsor, AOC and AOV are very straight concepts, but there has been a lot of confusion about the naming. If somebody uses the wrong naming perhaps you communicate faster by using also the wrong naming.

Think that very smart people has been using the wrong naming convention... That wrong naming has had a legion of practitioners !

The right naming convention is well known by opticians and well explained in The Camera (AA), but it also makes some sense saying that coverage angle is also the view angle of "the lens", but not the viewing angle of the camera with that lens.

Also a Wide Angle can be a lens with a wide coverage angle or a short focal for the format...

This is not a problem in a conversation between people that know about what they are speaking, but all that has been generating a remarkable degree of confusion to learners like me.

You may find threads around in other sites where they conclude that the wrong naming is the right one !!!

Pfsor
18-Sep-2018, 06:17
That's why those who want to speak with some professional authority here should use the correct nomenclature in the first place. Otherwise learners get just great confusion from reading. This forum has gone down in its level at a nosediving speed, unfortunately.

6x6TLL
18-Sep-2018, 06:37
To all who've replied, thank you for the lesson(s) and information.

To be honest I lost track of the AOV/FOV discussion between Pfsor, Pere and Bob, but I'm sure there will be some sort of summary at some point. Maybe.

Colin, Bob, Leigh, Jim, thank you for being practical and specific.

I haven't shot 35mm in about 25 years, been MF only for a very long time. I use a Rollei TLR as my travel/snapshot camera, and a big System 6000 setup with several lenses for more "serious" work, or when I don't mind carrying the weight and bulk (I think it was around 15kg or more last I checked). My favorite lens in general is a little bit longer than normal, but with macro. When I was doing 35mm, I used a 35mm and 50mm lens most often, an 85 for portraits, sometimes something wider for fun (24mm - 28mm) and a telephoto (150-200mm or so) for birds, animals, etc.

My very first MF kit was a Bronica SQ-A, I rented one along with a Hassy 500CM, took a bunch of film and a tripod and spent a weekend shooting all over. Had the slides developed and together with the staff at the lab looked at the pics under a loupe. None of us could tell the difference in resolution, sharpness, contrast, etc, so I went for the Bronica at 1/3rd the price of the Hasselblad. It performed flawlessly for years and was well worth the money. Sold it later and moved to Rollei. I do see a difference with the Schneider lenses there, and the ergonomics and modern features are much nicer.

My favorite lens on the SQ was a 110mm Macro, on the Rollei it's the 90mm APO Macro (although I've strongly considered picking up the Zeiss 120mm Macro Planar).

I also have and use a 40mm Super Angulon, 150mm Tele-Xenar and 80mm Xenar (f2, great for low light shots). Since I am a hobby photographer, I'm not as focused as I could be when it comes to subject matter, and tend to go for hikes or walks with the camera hoping to find something interesting, although I do take trips specifically to take pictures (wildflowers blooming in California, sunset beach pics, downtown by night, etc).

When I got my first MF kit, I bought one lens and stuck to it for a year before buying another one (it helped that I was a starving student at the time, lol). Just to really get to know it inside and out, understand what I could and couldn't shoot effectively with it, how it reacted to different lighting situations, etc. I'm a believer in knowing your tools. (apropos my other thread). Then I rented a 40mm and a 50mm for a trip to Egypt to figure out which I preferred, and went with the 40mm. And so on.

I may do the same if I do decide to go LF. Probably get a 150mm APO Sironar-S or Nikkor-W to start with as they seem to be solid performers in a reasonable attractive size and weight. Then something for portraits, 210-300mm or so, and something wide, 75-90mm, and I should be pretty well set.

I've figured out that if the gear is too big/bulky, or heavy, I won't bother taking it, meaning it will sit in a closet instead of being used. So I'm aiming to keep this no heavier (lighter if possible) than my MF rig.

As I understand it, macro is something one can do with any standard/normal lens, but it requires additional bellows draw to get close? I can always start another thread for that topic, so we keep this one on topic.

Leigh
18-Sep-2018, 07:51
As I understand it, macro is something one can do with any standard/normal lens, but it requires additional bellows draw to get close? I can always start another thread for that topic, so we keep this one on topic.Hi 6x6TLL,

That's correct. You can do macros with any lens.

The only difference is that the optical design of a Macro lens is optimized for close work, while the design of regular lenses is optimized for more distant subjects. The difference in the image quality on film will vary from slight to not significant at all.

The bellows extension from infinity focus to full-size (1:1) image on the film equals the lens focal length, for all lenses regardless of design or type.

- Leigh

Pere Casals
18-Sep-2018, 09:46
To be honest I lost track of the AOV/FOV discussion between Pfsor, Pere and Bob, but I'm sure there will be some sort of summary at some point. Maybe.


This is straight:

https://en.wikipedia.org/wiki/Field_of_view
Field of view (FoV) is the extent of the observable world that is seen at any given moment, so we are not speaking about angles but about crops of planet earth, but some can speak about the angle that has our Field of View, saying FoV for the Angle of View, but this is loose.


https://en.wikipedia.org/wiki/Angle_of_view
Angle of view (AOV) describes the angular extent of a given scene that is imaged by a camera.
It is important to distinguish the angle of view from the angle of coverage(AOC), which describes the angle range that a lens can image.

So often a LF lens has a way larger circle than it's needed to cover the format, this allows rise-shift movements for perspective control.

Every lens projects a cone of light to the film, that projection on the film is the image circle, this cone has an angle that's named angle of coverage, for the same focal (and same magnification) that cone can have a greater or smaller angle, allowing more or less "translational movements".

It can happen that a 120mm has a larger image circle than a 300mm, for example Nikon SW 120 covers 8x10 while many 300mm for 4x5 lenses won't cover 8x10.

All that it's clear.

Confusion arised long time ago because many people started calling angle of view to angle of coverage, and that confusion still reached our days.

To clarify, all lenses with the same focal have the same magnification of the scene on the projection, but lenses with the same focal can have a greater or smaller circle showing more or less scene on the film plane, the circle size and the focal determines the angle of coverage of the lens, while the focal and the format size determines the angle of view of the camera with that focal (if the lens is able to cover that format).


Finally we have to distinguish the illumination circle (or illumination angle) from the image circle (or coverage angle), some lenses project a light circle that's not sharp in the boundaries, so the image circle we consider is smaller than the light disc.

The illumination disc excess can be useful sometimes, if we have a subject in focus in the center and corners are out of focus anyway we can cover a superior format with a lens that's intended for smaller formats.

MAubrey
18-Sep-2018, 09:48
No, portraits are usually taken at about the same distances, regardless of format. If you are using lenses appropriate for portraiture for each format.
You want to be close enough to the subject to direct them and relate to them. Except for some environmental distant portraits.

I don't know who you're talking to, but you're not talking to me.

Bob Salomon
18-Sep-2018, 09:55
“So often a LF lens has a way larger circle than it's needed to cover the format, this allows rise-shift movements for perspective control.”

No!!!

Perspective is controlled by the angle of the camera to the subject.

Direct displacements do not control perspective.

consummate_fritterer
18-Sep-2018, 09:57
I'm only repeating what others have written but maybe this is a little easier to understand.

Foreshortening (many call this perspective distortion) is affected by subject to camera/lens distance. Short (wide) lenses include more of the periphery whereas long lenses magnify the center of the subject at the film plane.

Consider taking a close head shot of a person. On 135 format the person's face size on film will be greatly reduced from real life size. But on 11x14 film their face will be approximately life size, or 1:1 reproduction.

To achieve 1:1 reproduction of a subject on film requires approximately double the focal length of the lens. When a lens is extended to double its focal length, its effective focal length is doubled.

So, on 135 format a 135mm lens is a good focal length for a close face portrait and because the image on film is tiny and the lens is only focus outward a little bit, the focal length only increases a little bit, say it's effectively 150mm (approx).

However, on 11x14, with the lens extended to double its focal length to fill the film with the subject's face, its effective focal length is doubled. So, for this format a 'normal' lens (450mm) or a very 'slightly' longer lens is a better option if the goal is to match the perspective of the same subject shot on 135 format. Of course, the depth of field is vastly different due to the great difference in lens focal lengths but that's a separate issue.

The effect increases as film size increases. The difference in effect between 135 and medium format is relatively negligible. The difference in effect between 6x6cm and 4x5 inch is more noticeable but not extreme, as it is between 135 and 11x14.

Bob Salomon
18-Sep-2018, 10:07
I'm only repeating what others have written but maybe this is a little easier to understand.

Foreshortening (many call this perspective distortion) is affected by subject to camera/lens distance. Short (wide) lenses include more of the periphery whereas long lenses magnify the center of the subject at the film plane.

Consider taking a close head shot of a person. On 135 format the person's face size on film will be greatly reduced from real life size. But on 11x14 film their face will be approximately life size, or 1:1 reproduction.

To achieve 1:1 reproduction of a subject on film requires approximately double the focal length of the lens. When a lens is extended to double its focal length, its effective focal length is doubled.

So, on 135 format a 135mm lens is a good focal length for a close face portrait and because the image on film is tiny and the lens is only focus outward a little bit, the focal length only increases a little bit, say it's effectively 150mm (approx).

However, on 11x14, with the lens extended to double its focal length to fill the film with the subject's face, its effective focal length is doubled. So, for this format a 'normal' lens (450mm) or a very 'slightly' longer lens is a better option if the goal is to match the perspective of the same subject shot on 135 format. Of course, the depth of field is vastly different due to the great difference in lens focal lengths but that's a separate issue.

The effect increases as film size increases. The difference in effect between 135 and medium format is relatively negligible. The difference in effect between 6x6cm and 4x5 inch is more noticeable but not extreme, as it is between 135 and 11x14.

Let’s start all over, and wipe your mind clear of what you read!

Foreshortening means that things closer to the lens reproduce larger then things further from the lens.

The wider, or shorter, the lens the greater the effect is.

Long lenses minimize foreshortening, wide lenses maximize it.

That is why portraits are usually done with lenses longer then normal focal lengths.

consummate_fritterer
18-Sep-2018, 10:11
Yes, we do indeed need to cull through misinformation.

Pere Casals
18-Sep-2018, 11:30
“So often a LF lens has a way larger circle than it's needed to cover the format, this allows rise-shift movements for perspective control.”

No!!!

Perspective is controlled by the angle of the camera to the subject.

Direct displacements do not control perspective.

Bob, lenses that are suitable for architecture (the perspective control realm) sport a really large circle to perform step c in this procedure:
182564

If a large circle is not necessary for perspective control then why architectural lenses have mastodontic circles ?

It is true that we can also shift the circle with a front tilt, but we also require a large circle.

Dan Fromm
18-Sep-2018, 11:40
Papi, converging verticals as are eliminated by leveling the camera and using front rise or rear fall to adjust the framing have nothing to do with what most of us think of as perspective.

Pere Casals
18-Sep-2018, 11:55
Papi, converging verticals as are eliminated by leveling the camera and using front rise or rear fall to adjust the framing have nothing to do with what most of us think of as perspective.

Dan I was referring this kind of perspective control:

https://en.wikipedia.org/wiki/Perspective_control

I'd say this used widely in photography, even in small formats, as in Nikon PC-E lenses, sporting a rise, PC stands for perspective control.

https://upload.wikimedia.org/wikipedia/commons/5/5a/Nikkor-PC-E.jpg

What do you understand for "Perspective Control" ?

Bob Salomon
18-Sep-2018, 12:02
Bob, lenses that are suitable for architecture (the perspective control realm) sport a really large circle to perform step c in this procedure:
182564

If a large circle is not necessary for perspective control then why architectural lenses have mastodontic circles ?

View cameras use either direct movements, rise/fall/shift, or indirect movements, tilt/swing.

For things that will show keystoning - buildings for instance.

First level the camera. Then with direct movements, raise the front and lower the back until the building is framed properly.

For indirect movements, level the camera, tilt the front till the building is positioned as desired then tilt the back the same degree.

Not enough direct movement available, then combine them with indirect movements.

Linhof, for one, monorail cameras have exceptionally large direct movements and many models, from the B up, accept accessory 3.5” extensions to add front or rear rise. So Linhof used direct movements primarily as they are faster and easier then indirect movements.

Other systems with limited direct movements rely primarily on indirect movements.

To take complete advantage of direct movements lenses with large image circles have to be used.

The end result is the same with either type of movements.

One point of warning. If the building is reproduced with perfectly parallel sides it will appear to some viewers that it is leaning backwards.

It is true that we can also shift the circle with a front tilt, but we also require a large circle.

cowanw
18-Sep-2018, 12:36
Are mastodontic circles the opposite of crop circles?

Pere Casals
18-Sep-2018, 12:47
Are mastodontic circles the opposite of crop circles?

:) yes, of course, a nikon sw 120 in a 45 camera is a mastodon !!!

Pfsor
18-Sep-2018, 12:50
Dan I was referring this kind of perspective control:

https://en.wikipedia.org/wiki/Perspective_control

I'd say this used widely in photography, even in small formats, as in Nikon PC-E lenses, sporting a rise, PC stands for perspective control.

What do you understand for "Perspective Control" ?

Me too I'm curious about what he understands by perspective control, especially when he speaks about most of us... The PC on the small cameras PC lenses had only one meaning, as far as I can remember.

Pere Casals
18-Sep-2018, 12:52
View cameras use either direct movements, rise/fall/shift, or indirect movements, tilt/swing.

For things that will show keystoning - buildings for instance.

First level the camera. Then with direct movements, raise the front and lower the back until the building is framed properly.

For indirect movements, level the camera, tilt the front till the building is positioned as desired then tilt the back the same degree.

Not enough direct movement available, then combine them with indirect movements.

Linhof, for one, monorail cameras have exceptionally large direct movements and many models, from the B up, accept accessory 3.5” extensions to add front or rear rise. So Linhof used direct movements primarily as they are faster and easier then indirect movements.

Other systems with limited direct movements rely primarily on indirect movements.

To take complete advantage of direct movements lenses with large image circles have to be used.

The end result is the same with either type of movements.

One point of warning. If the building is reproduced with perfectly parallel sides it will appear to some viewers that it is leaning backwards.



Bob, this is a very well sumarized procedure

Also I'll remember that point of warning... I always end learning something from you, I was not aware of that



Me too I'm curious about what he understands by perspective control,

I'd say that "perspective control" it has a very direct meaning in the architecture context, if we speak about the control of the perspective in general, then I guess that we are speaking about the focal we use and the distance to the main subject.

Pfsor
18-Sep-2018, 13:24
I'd say that "perspective control" it has a very direct meaning in the architecture context, if we speak about the control of the perspective in general, then I guess that we are speaking about the focal we use and the distance to the main subject.

I remember, that whenever there was a bigger discussion about perspective on this forum, it always ended in different definitions of the word and big disputes thereafter...

Pere Casals
18-Sep-2018, 13:52
I remember, that whenever there was a bigger discussion about perspective on this forum, it always ended in different definitions of the word and big disputes thereafter...

IMHO any dispute about the subject is futile: this is perspective: https://en.wikipedia.org/wiki/Perspective_(graphical)

And in LF photography we can work it in these two ways:

1) https://en.wikipedia.org/wiki/Perspective_control
2) https://en.wikipedia.org/wiki/Perspective_distortion_(photography)

I don't guess what more can be said about it !

Bob Salomon
18-Sep-2018, 14:41
IMHO any dispute about the subject is futile: this is perspective: https://en.wikipedia.org/wiki/Perspective_(graphical)

And in LF photography we can work it in these two ways:

1) https://en.wikipedia.org/wiki/Perspective_control
2) https://en.wikipedia.org/wiki/Perspective_distortion_(photography)

I don't guess what more can be said about it !

Why not get the definition from a photographic source?

Pere Casals
18-Sep-2018, 15:38
Why not get the definition from a photographic source?

My view is that perspective is an universal concept that does not require at all photography to be explained, in fact it has an underlying math.

And the ways we have to adjust perspective in photography are pretty well kown,

ic-racer
18-Sep-2018, 19:29
if I want to foreshorten the distance between a subject, the midground and background, I know that I can use a telephoto lens

That has nothing to do with lens or format. Increasing camera to subject distance will do that with any lens or format.

Pere Casals
19-Sep-2018, 04:40
That has nothing to do with lens or format. Increasing camera to subject distance will do that with any lens or format.

...but when we determine a distance for our perspective we need a certain focal that, for our format, it renders our subject with the size we want in the framing.

Tobias Key
19-Sep-2018, 06:31
To actually answer the question of the OP, I have found that same foreshortening exists in LF but a shallower depth of field can exaggerate familiar portrait effects you'd be familiar with in MF. On top of this there is some extra difficulty in using lenses on the longer and shorter end of the 'common' focal lengths. This means that portraits are more commonly made with lenses that are slightly shorter than those you would use in medium format. I would guess that most portraits in 4x5 are shot with a 210mm which is around the 70mm mark in 35mm terms. This is because if you used a 300mm, you'd need more bellows extension than a lot of field cameras have, be stuck with a 1/125 max shutter speed with a copal 3 shutter, the lens would most likely take 100mm filters and its weight would strain the front standard of many lighter cameras. At the shorter end (say 75mm) the lenses are often in a recessed board which is fiddly and the ground glass is dim in the corners.

So practicalities and ease of use influence lens choice more than they would in smaller formats.

Leigh
19-Sep-2018, 09:37
I would guess that most portraits in 4x5 are shot with a 210mm which is around the 70mm mark in 35mm terms. This is because if you used a 300mm...Tobias,

How did we get from 210mm to 300mm ? ? ?

I have 4x5 lenses in 240mm and 250mm.
Some of these take filters as small as 52mm.

- Leigh

Tobias Key
19-Sep-2018, 10:40
Tobias,

How did we get from 210mm to 300mm ? ? ?

I have 4x5 lenses in 240mm and 250mm.
Some of these take filters as small as 52mm.

- Leigh

Because 100mm is a common portrait length for 35mm and its equivalent is about 300mm in 4x5. If you are shooting portraits you'll probably want a f5.6 lens and modern plasmats are big. A 210mm plasmat is much easier to use on most cameras and is a much more common choice even though it is only 65-70 (depending on how you calculate it) in 35mm terms. Just trying to illustrate the point that lens selection is a bit more complicated in 4x5 because of the twin issues of bellows extension and weight. You really need a monorail to shoot fast long lenses in 4x5.

Bob Salomon
19-Sep-2018, 11:38
Because 100mm is a common portrait length for 35mm and its equivalent is about 300mm in 4x5. If you are shooting portraits you'll probably want a f5.6 lens and modern plasmats are big. A 210mm plasmat is much easier to use on most cameras and is a much more common choice even though it is only 65-70 (depending on how you calculate it) in 35mm terms. Just trying to illustrate the point that lens selection is a bit more complicated in 4x5 because of the twin issues of bellows extension and weight. You really need a monorail to shoot fast long lenses in 4x5.
You should also consider that 35mm produces a 1x1.5” negative which is a totally different proportion to 4x5”.

Leigh
19-Sep-2018, 11:52
Because 100mm is a common portrait length for 35mm...I've always considered 85mm as the standard portrait lens for 35mm.

But I've only been shooting those for 60+ years, so maybe I'm wrong.

- Leigh

Corran
19-Sep-2018, 11:58
Good Lord you guys

duff photographer
22-Sep-2018, 15:38
Good Lord you guys

Hah! I pulled up a sofa and ripped open a bag of crisps (chips). Need to get a soda before the next round starts.

;)

(I hope it hasn't put 6x6TLL off too much :D)

Willie
23-Sep-2018, 11:42
Another thing to consider is the Image Circle of the lens in use and what film size you are working with.

A lens that throws an image circle of 325mm just covers 8x10 film and can cause problems with smaller formats at times. The larger image circle may cause light bouncing off the inside of the bellows. Using a lens with a smaller image circle will generally see few problems with this. See the Fuji 210 lenses. One covers 8x10 while the newer versions throw a smaller image circle. Some have found light bounce problem with the bigger image circle, solved by moving to the newer lens with a smaller image circle. Possibly the newer coatings help as well?

Bob Salomon
23-Sep-2018, 12:18
Another thing to consider is the Image Circle of the lens in use and what film size you are working with.

A lens that throws an image circle of 325mm just covers 8x10 film and can cause problems with smaller formats at times. The larger image circle may cause light bouncing off the inside of the bellows. Using a lens with a smaller image circle will generally see few problems with this. See the Fuji 210 lenses. One covers 8x10 while the newer versions throw a smaller image circle. Some have found light bounce problem with the bigger image circle, solved by moving to the newer lens with a smaller image circle. Possibly the newer coatings help as well?

I started using LF in 1962. I have used an old Ansco, Sinar 45 to 810 and Linhof when I had my studio. I have sold Sinar as a rep for EPOI and was Product Manager and Sales Manager for Linhof from 1979 to 2015 and for Wista from 1990 to 2015 and for Rodenstock from 1986 to 2015.

In all that time, using, managing and selling LF your perceived problem never occurred. Not once!

The use of proper material to make a bellows and the pleats in the bellows and the proper finish inside the camera makes this a folk tale!

What is correct in your post is the image circle is of equal importance as fov and, if you use direct or indirect displacements, even more important!

Pere Casals
23-Sep-2018, 16:20
The use of proper material to make a bellows and the pleats in the bellows and the proper finish inside the camera makes this a folk tale!


Not always, but light bouncing in the bellows can add very significative flare in some conditions. For example when sun is not in the framing but it's in the image circle, or when bellows are compressed, in that case the internal bends are very good reflectors.

faberryman
23-Sep-2018, 16:22
duplicate

faberryman
23-Sep-2018, 16:24
Not always, but light bouncing in the bellows can add very significative flare in some conditions. For example when sun is not in the framing but it's in the image circle, or when bellows are compressed, in that case the internal bends are very good reflectors.

Theoretically. Have you ever experienced this problem in real life? This is like saying using a tripod is a problem because if a dog goes running by, your camera might get knocked over.

Pere Casals
23-Sep-2018, 16:56
Theoretically. Have you ever experienced this problem in real life?

No, because I use a compendium shade, but I made personal tests using ISO 18844 method

Bob Salomon
23-Sep-2018, 17:23
No, because I use a compendium shade, but I made personal tests using ISO 18844 method

Why? That is a digital camera standard, not a large format film standard!

faberryman
23-Sep-2018, 17:45
No, because I use a compendium shade...
You use a compendium shade to reduce the image circle?

Dan Fromm
23-Sep-2018, 17:52
You use a compendium shade to reduce the image circle?

The shade can vignette.

faberryman
23-Sep-2018, 18:02
The shade can vignette.

Obviously, which is why I asked if he uses his compendium shade to intentionally reduce the image circle to reduce minimize internal reflections.

Pere Casals
24-Sep-2018, 10:57
Obviously, which is why I asked if he uses his compendium shade to intentionally reduce the image circle to reduce minimize internal reflections.

It's the same, when the compendium shade trims the circle it effectively decreases the potential flare induced by reflections in the bellows.

It's also useful to avoid lens induced flare, specially if no multicoating there...



The shade can vignette.

Yes... the shade can provocate a sort of mechanical vigneting because partially blocking the off-axis rays going to the corners, provocating a penumbra in the trim, this not happens if the lens is quite stopped as the penumbra is very narrow in that case, but wide open we should retract a bit the shade (specially for the shorter focals) to avoid it, this is well seen in the ground glass...

I know three kinds of vigneting: natural (cos^4), mechanical and optical. I guess this one has to be mechanical.

Bob Salomon
24-Sep-2018, 11:00
It's the same, when the compendium shade trims the circle it effectively decreases the flare induced by reflections in the bellows.




Yes... the shade can provocate a sort of mechanical vigneting because partially blocking the off-axis rays going to the corners, provocating a penumbra in the trim, this not happens if the lens is quite stopped as then the penumbra is very narrow, but wide open we should retract a bit the shade to avoid it, this is well seen in the ground glass...

Wide open the circle of illumination is smaller then when stopped down. Is that what you are trying to say?

Pere Casals
24-Sep-2018, 11:18
Wide open the circle of illumination is smaller then when stopped down. Is that what you are trying to say?


Bob, no... what I want to say is that the (square) compendium shade casts an squared image in the film plane, rather than the regular circle. That square is smaller or larger depending on the shade extension, and the boundaries of that square have a wider or narrower penumbra band depending on lens aperture.

Bob Salomon
24-Sep-2018, 11:40
Bob, no... what I want to say is that the (square) compendium shade casts an squared image in the film plane, rather than the regular circle. That square is smaller or larger depending on the shade extension, and the boundaries of that square have a wider or narrower penumbra band depending on lens aperture.

If your film format is rectangular then why use a square compendium?

Pere Casals
24-Sep-2018, 12:11
If your film format is rectangular then why use a square compendium?

I would line this one:

182751

but regular ones are squared so you use it for both vertical and horizontal...

Anyway an squared one usually works perfectly, as it can be used to shade well the sky and direct sunlight, then if the earth side is not well trimmed this is not a tragedy, because the lower brightness.

Willie
24-Sep-2018, 13:04
I started using LF in 1962. I have used an old Ansco, Sinar 45 to 810 and Linhof when I had my studio. I have sold Sinar as a rep for EPOI and was Product Manager and Sales Manager for Linhof from 1979 to 2015 and for Wista from 1990 to 2015 and for Rodenstock from 1986 to 2015.

In all that time, using, managing and selling LF your perceived problem never occurred. Not once!

The use of proper material to make a bellows and the pleats in the bellows and the proper finish inside the camera makes this a folk tale!

What is correct in your post is the image circle is of equal importance as fov and, if you use direct or indirect displacements, even more important!

Bob, on this one I am speaking from experience. Some of the newer bellows are fairly shiny and almost polished. Using a 300mm Nikkor M on a 4x5 with new bellows(eBay) and I got the pleat pattern light reflection on the negative. Switched to a 360 Nikkor Tele and it went away. I was shooting Fuji Velvia and the odd reflections had me baffled. Checked with Fuji Tech folks in LA area and they helped me track it down. If I had not been on the West Coast and processed some film there on the trip I would probably still be wondering what the wierd pattern was.

Shining bright flashlights into the lens with the back off I could see the reflections. More when the light was way off center than near the center of a composition.

Have not run into it with the 8x10. But, that is an older camera with original bellows.

Leigh
24-Sep-2018, 13:33
Using a 300mm Nikkor M on a 4x5 with new bellows(eBay)...
Have not run into it with the 8x10. But, that is an older camera with original bellows.Willie,

I'm amazed that you fail to understand the problem.

It starts with 'e' and ends with 'y'.
Use proper components and you won't have that problem.

- Leigh

Bob Salomon
24-Sep-2018, 16:05
Bob, on this one I am speaking from experience. Some of the newer bellows are fairly shiny and almost polished. Using a 300mm Nikkor M on a 4x5 with new bellows(eBay) and I got the pleat pattern light reflection on the negative. Switched to a 360 Nikkor Tele and it went away. I was shooting Fuji Velvia and the odd reflections had me baffled. Checked with Fuji Tech folks in LA area and they helped me track it down. If I had not been on the West Coast and processed some film there on the trip I would probably still be wondering what the wierd pattern was.

Shining bright flashlights into the lens with the back off I could see the reflections. More when the light was way off center than near the center of a composition.

Have not run into it with the 8x10. But, that is an older camera with original bellows.

Willie, you get what you pay for, in this case, a cheaply made bellows!

Willie
25-Sep-2018, 07:56
Willie, you get what you pay for, in this case, a cheaply made bellows!

You are right about that one, Bob. Bought the 4x5 at auction and it had the bellows on it. I prefer Custom Bellows in the UK. They do a nice job.