Poser – Page 10 – aRtBee's Missing Manuals

What’s the Diffuse component intended for?

For short: Diffusion is equivalent to Object Color. This is the place to turn an object simply green, and/or to assign an image to it for a detailed coloring of the surface. The color swatch then works as a filter: when I assign an image as well as turn the swatch to green, it’s like I’m looking at the image through green glasses or through a sheet of green transparent plastic. A white swatch means: no filtering, and is generally recommended when images are used.

makes

Clicking the larger area opens the Texture Manager, which offers the option to import an image.

More in detail

In nature, objects get their color by scattering back some of the light that falls upon them, and do so in a color-filtered way. So white light shining on a plants leaf will make it look green because the leaf scatters back the green portion out of the white light, at the place and time the light hits the leaf. When the light is pure red without any green in it, then the leaf cannot scatter anything back and hence will look black instead. This “scattering back” is called Diffusion, not to be confused with Reflection.

The amount of light which is received by a “unit of surface” (say 1 cm² or in²) depends on the angle the light makes with the surface. Perpendicular lighting makes high intensities, skew angles make low intensities as the same amount of light has to shine on a larger area.

Also, the diffuse response to light usually will not be equal in all directions: the response perpendicular to the surface might be stronger than that parallel to it, making objects look darker at skew angles towards the camera. That is: at their edges.

Both effects are referred to as: shading, in contrast to shadowing which includes blocking the light by other objects, or other parts of the same object. In Poser all this is understood in the Diffuse part of the material definition.

Intermediate

The Advanced interface into Poser Material Room offers a Diffuse_Color which makes it the equivalent of Simple interface, and offers a Diffuse_Value next to it which acts as an extra filter. Intensities are reduced by that factor, and it can be driven by a (greyscale) image map as well. This way one can easily make dark stains on a surface. See the various articles on how both Simple and Advanced interfaces relate, and on the way Colors and Values work together.

Recommendations:

To prevent artefacts in rendering when applying the Gamma mechanism (recommended, available in PoserPro and Poser 10 and up) the Value setting should be kept to 1.0 only (or 0.0 but no intermediate values).
To prevent overlighting when combined with other aspects of lighting and material definitions, it’s recommended not to exceed 80% brightness in the Color-swatch and maps (or in the Value setting when not applying Gamma).

As said, in nature the diffuse response to light usually will not be equal in all directions. This was already investigated upon by the mathematician J.H. Lambert (about 1750). In Poser, this “Lambert diffusion” is embedded in the Diffuse part of the material definition (Simple and Advanced interface), as well as implemented in the diffuse node (Advanced interface only). See the various articles on more background on Lambert, on details about the Diffuse node, and on assigning either an image or a movie respectively to the Diffuse slot(s).

Anyway, the diffuse light is scattered outward, that is: with following the surface normal, which is a vector perpendicular to the surface which generally should be pointing outward. For various reasons the latter is not always the case, depending on the way the object is made and imported into Poser. If not, it can make the scattering go in the wrong direction, causing black spots in the render. The solution is to force Poser to reconsider the surface normals, and I can make it doing so by ticking the Normals Forward checkbox. It’s in the node, as well as at the bottom end of the PoserSurface definition itself. It’s not available in the Simple interface.

That aside, the results from the “Lambert approximation” do not look utterly realistic for organic, porous surfaces. Therefore, Poser offers alternatives to the Diffuse component, like the Alternate_Diffuse part of the material definition, plus a Clay node with enhanced properties.

On top of all this: in nature, non-metallic objects get their color from diffusion, while metals get theirs from reflection. Especially when I’m into photorealism, it will be good to understand – and to implement – this difference. Metals don’t diffuse, they reflect.

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Poser Materials II Simple Surface Definitions

The articles in this section discuss material definitions for object surfaces, which can be handled through the Simple Interface, and do not require a deep understanding of Material Room principles. Each article however also presents an Intermediate approach as well, using the Advanced interface for the same purpose. This is to avoid multiple articles answering the same question.

Next subsections present similar articles on an (III) Intermediate and (IV) Advanced level, as well as on defining the properties of (V) Non-objects (atmosphere, background, lights) as far as these are handled through the Material Room interface. The Appendix lists all Material Room nodes and relevant Render Settings, and their availability in the various Poser versions.

Material Room Simple and Advanced interface – how do these relate?

The Advanced interface to Material Room offers access to some more properties of the same material on one hand, and offers access to far more ways to define the details of all properties in the other hand. Creating and managing materials through the Advanced interface is considered Intermediate to Advanced level. While working from the Simple interface, one might wonder: “what do I miss?”.

Intermediate

The following features are / are not supported in the Simple interface:

Supported: Diffuse, Specular and Ambient Color, plus an eventual Image_Map or Movie node from which the Image_Source and the Texture_Strength properties are supported. For Specular, the Highlight_Size property is supported.
Not supported: Neither the Diffuse/Specular/Ambient-Value properties, nor the Alt_Diffuse/Specular properties, nor any other node beside Image_Map and Movie are supported in the Simple interface. No Clay, no Subsurface Scattering (translucency). Translucency from the Advanced interface is not supported in any way.
.
Supported: For Reflection, the Image_Map node as well as the Reflect (raytrace) node are supported, including the Color. Also the Light color and Object color multiplicators (Reflection Lite Mult and Reflection Kd Mult checkboxes) are supported.
Not supported: Neither the Reflection Value property nor any other nodes beside Image_Map and Movie are supported.
.
Supported: Transparency, with an eventual Image_Map, and including Edge and Falloff, is supported.
Not supported: Refraction, Fresnel nodes and similar are not supported.
.
Supported: Bump / Displacement, with a required Image_Map (no map, no effect), plus the Amount option are supported.
But: the checkbox in the Simple interface forces me to choose between either Bump or Displacement, I cannot have it both.
.
Not supported: Features like Gradient Bump/Mode which give access to Normal maps, and like ToonID and Custom Output for advanced render pass handling, are not available in the Simple interface. The Custom_Outputs are available in Poser Pro only, by the way.

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Material Room offers a Simple interface. What do I miss?

When using the Simple interface, I miss:

About anything more advanced than assigning color and an eventual image map to any feature. As a result, my render will keep that artificial, hard plastic-like feel.
The option to have Bump and Displacement both in one surface definition, and the option to use Normal maps. As a result, I cannot distinguish large scale (displacement) from small scale (bump) surface variations. And I can’t use Normal maps, which are common in shading game characters and objects.
Access to more real-life optical effects like Translucency and Refraction. As a result, creating believable glass and fluids will remain an issue.
Access to the Preview / Diffuse / Specular split in direct light properties As a result, I’ll keep on having issues with handling Indirect Lighting (IDL) in an appropriate way, in preview as well as in rendering.
Access to advanced render features (Custom_output) Honestly, these are hardly used anyway and can be considered high-end pro stuff.

Intermediate

Generally, all features which remain unsupported by the Simple interface, will also go unsupported when exporting Poser scenes and objects to other formats or programs. Exporting to OBJ, integrating Poser with LuxRender, Octane, Vue or you name it, all tend to lose the material properties which are not supported in the Simple interface. And even some of those might get lost in translation. In other words: when Poser is just my scene building and posing tool but not my final renderer, I consider the Material Room Simple interface as the recommended one. The question: what do I miss, can be inverted to : what elements from the Advanced interface go (un)supported by the Simple interface. This is addressed in the next article.

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How do I access a Material?

The straightforward way is to use the Material tab to enter the Material Room. An object or part of it already can have been selected, or can be selected from within the room itself. The Material Room offers a Simple User Interface, as well as an Advanced one.

Intermediate

Next to that, there are some additional ways into Material Room, for the ‘material properties’ of Lights, Atmospheres, Backgrounds, and for some specific surface properties:

1) When a Light is selected, its Properties tab offers an [Advanced material properties] button which brings me into the Material Room, for the coloring properties of that light.

2) With menus File > Import > Background Picture or … > Background Footage,

and with the Shadow Color picker just right/below the Document window one affects the contents of the background material.

3) From within Material Room some buttons on the right affect the object surface material at hand:

Add Reflection and Add Refraction
Add Skin Subsurface Scattering
Setup Shadow Catcher and Setup Toon Render

The [Create Atmosphere] button however affects the Atmosphere material, while the next buttons

Setup Light Style
Setup Ambient Occlusion
IBL

affect the various coloring properties for Lights.

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What’s a material, a shader, a texture, a map?

In real life, a material is the stuff something is made of. Rock, brick, sand, knitted red wool, thin leaded glass, anything. Real life materials not only have a look, they also have a feel, a smell, and a response to our actions determined by a weight, flexibility, and the like.

In virtual life, like a Poser scene, a shader refers to a set of object (surface) properties that mimics the looks of a real life material, when rendered. So we can have a rock shader, a knitted red wool shader, etcetera. Shaders do not have a feel, or a smell, they’re inside the computer. But since everyone can tell real life from virtual, the word “material” is also used in these cases, at least in some software communities. So, in Poser one has a Material Room, to make a “brick material” and to assign it to a wall in the Poser scene. In Poser communities, “shader” is rarely used.

In real life, texture relates to the feel of the thing at hand. The surface roughness of the brick when I rub it with my hand, the structure of the fish I feel with my tongue when tasting it. In virtual life however, texture usually refers to the colors of an object surface. A texture then is an image used to assign such colors to elements in my Poser scene. However, since people are somewhat relaxed in their choice of words, they’re happy to assign a “brick texture” to a wall; not only implying color but roughness and reflectivity as well. So in those cases texture means material means shader.

While texture usually refers to an image which is used to assign colors to a surface(property), a map refers to an image which is used to vary the amount of something. A bump map to vary the amount of roughness, a transparency map to vary the opaqueness, and so on. Maps in those cases tend to be black & white, which refer to 0% .. 100% and have greyscales for everything in between.

On the other hand, mapping (as in: UV-mapping) is the term for assigning images in general to an object surface whether it’s for coloring or for determining roughness or reflectivity. So some people might use “map” while referring to the image driving the coloring process too. Fortunately, there is some method in this madness: as shader is hardly used in the Poser community, material or texture is used instead. The people using material for the whole thing tend to use texture for the coloring images. The people using texture for the whole thing tend to use texture-map for the images. But be aware; without context or background info, “brick texture” still might mean either the whole thing or just the color-driving image.

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Poser Materials I – Introduction

The articles in this section discuss some terminology, and the various interfaces to the materials definitions:

Next subsections present articles on defining the surface properties of objects, on a (II) Simple , (III) Intermediate and (IV) Advanced level, as well as on defining the properties of (V) Non-objects (atmosphere, background, lights) as far as these are handled through the Material Room interface. The Appendix lists all Material Room nodes and relevant Render Settings, and their availability in the various Poser versions.

Poser Material Concepts & Elements

The content of this entire section can be downloaded in two versions

FULL version, PDF 8.7Mb covering it all
BASIC version, PDF 0.8Mb covering only subsections I and II, for starting Poser users

This Concepts & Elements section discusses to some extent the buzzwords, the interactions with Poser Lighting and with the Poser Firefly renderer, and the way things work (together), all as far as the Poser Material Room is concerned. It discusses intensively the technical details of all elements that build the shader definitions within the Material Room.

That’s quite a lot, and for that reason the information is presented in various subsections:

I Introduction

The articles in this section discuss some terminology, and the various interfaces to the materials definitions:

II Simple Surface Definitions

The articles in this section discuss material definitions for object surfaces, which can be handled through the Simple Interface, and do not require a deep understanding of Material Room principles. Each article however also presents the Intermediate approach, using the Advanced interface for the same subject at hand. This is to avoid multiple articles answering the same question.

III Intermediate Surface Definitions

The articles in this section discuss some material definitions for object surfaces (the PoserSurface), which are handled through the Advanced Interface: the nodes from the Lighting group, and the nodes on image-maps and movies. It also discusses some principles on dealing with the PoserSurface root node.

From here on, articles discuss the workings of the PoserSurface root node in general.
From here on, articles discuss some elaborate details of components available in the Simple interface: diffuse shading, reflection details, render settings.
From here on, articles discuss the additional components of the PoserSurface node, like Translucency, Refraction, ToonID and the like.
From here on, articles discuss Alternate_Diffuse, Alternate_Specular and all the nodes from the Lighting > Diffuse and Lighting > Specular groups.
From here on, articles discuss the nodes from the Lighting > Special group, like Scatter and Hair. In this article the various scatter nodes are compared.
From here on, articles discuss the nodes from the Lighting > Raytrace group. In this article their complex relationship with Transparency is dealt with.
From here on, articles discuss spherical mapping, image maps and movie-based textures.

IV Advanced Surface Definitions

The articles in this section discuss all Material Room nodes required for either procedural textures, and the ones explicitly aimed at node-tree building.

A procedural texture is not derived from an (eventually color filtered) external image or movie still, but is mathematically generated internally from surface or spatial coordinates. The nodes to accomplish such textures can be found in the 2D Textures and 3D Textures groups.

Materials are applied to objects, objects parts and more precise: to specific Material Zones within those objects and parts. This article discusses the details.

Material Room supports the creation of quite elaborate node-trees, like a programming language into material definitions. This section will not address the art of such programming itself, but will present and discuss the building blocks alone. These can be found in the Variables and Math groups.

V Materials for Non-Objects

The articles in this section discuss properties for Scene Atmosphere, Scene/render Background and Lights Coloring. These are not objects with a surface, but do have properties which are handled in Material Room. These properties can be accessed via the Object selector.

Most of those topics are considered Intermediate level, although various configurations can be setup via Material Room menus, and can be managed through the Simple interface. On the other hand, managing the details of a scene Atmosphere requires the use of nodes from the 3D Texture group, which by itself is considered Advanced.

This section concludes with some varied, advanced topics like mapping for IBL , Gamma Correction (GC) and GC on Transparency. The Appendix lists all Material Room nodes and relevant Render Settings, and their availability in the various Poser versions.

Managing Poser Scenes (02. Camera Intro)

The Poser camera is my eye into the virtual world. There are various kinds of special purpose cameras available, and (via menu Object \ Create Camera) I can add new ones.

The Left / Right, Bottom / Top, Front / Back cameras are “orthogonal” or “2D”. This means that an object keeps its apparent size independent of the distance to the camera, which is bad for believable images but great for aligning objects and body parts. These cameras help me positioning props and figures in the scene.

All other cameras are “perspective” or “3D” ones which mean that objects at a larger distance appear smaller.

Two objects with some distance

As seen by the Left (2D) camera

As seen by the Main (3D) camera

The Posing, Left/Right-hand and Face cameras are constrained to the selected figure, and meant to support the posing of body and hands, facial expressions and the precise positioning of hair and jewelry. These cameras help me creating figures the right way. This implies that when I change figure in the scene, the Posing, Hand or Face camera will show something different immediately.

The Shadow Cams help me aiming spotlights. The camera looks through the lamp into the scene which gives me a fine way positioning those lights. For Infinite lights and Point-lights such an aid is far less relevant.

Camera type

Poser gives me, in each new scene, three cameras to walk through the scene, perform inspections, and take other points of view and everything. These are the Main cam, the Aux-cam (both of the Revolving kind) and the Dolly cam (of the Dolly kind).

Revolving cameras live in Poser space. They rotate around the center (0,0,0) and around the Poser X,Y,Z axes through that center. The angles are called x-, y- and zOrbit. They move according to their own local axes, so when such a camera looks down, an Y-translation makes it move sideways, not up or down. More precise: the camera origin rotates as stated and the camera itself translates against that origin. This is very satisfying from a computational point of view, but very confusing for us, humble human users.

Dolly cameras live in their own space, rotate around their own center and their own axes, like any other regular object. Roll means rotating around the forward axes, like a plane taking a turn. Pitch means rotating around the local left-right axes, making the nose of a ship (or plane) going up and down. Yaw means rotating around the local up-down axis, which is what makes people seasick. They move according to the Poser X,Y and Z axes so if I alter the DollyY value they just move up or down, whatever they’re looking at.

Main and Aux represent nearby and away director overview cams, fixed to the studio. The photographers’ camera, moving through the scene, even animated maybe, and shooting at various angles at will, is best represented by a Dolly camera. So when I create a new, I choose the Dolly kind. Their transform parameters (move, rotate) are easier to understand and especially their animation curves are easier to interpret.

To add some artistic words on camera angle:

* I keep the horizon straight, especially in landscapes, unless I’ve good artistic and dramatic reasons not to. The reason is that my audience looking at my image will have a problem identifying themselves with the photographer when they have to twist their neck. In Poser camera terms: don’t Roll.
* I shoot straight, in Poser camera terms: I don’t Pitch either. This is interesting because most people tend to take pictures while standing upright and have the camera angle being determined by the position and size of the object. Animals, kids and flowers tend to be shot downwards while basketball players, flags and church bells tend to be shot upwards. So boring, so predictable: we see things in that perspective every day.

Focal length

Now let me put the camera at some distance of the scene or the subject. Depending on what I want to accomplish in my image, I have to zoom in or out by adjusting the focal length. The “normal” focal length for modern digital consumer cameras is 35mm, for analog cameras it was 50mm, and for current Hasselblads it’s 80mm. So, 50mm is considered wide angle for Hasselblad, normal for outdated analog and mild zoom for consumer digital. Poser follows the route of consumer digital. The 55mm initial setting for the Main camera is good for groups and studio work but needs zooming for portraying. The Dolly camera initially reads 35mm, the Aux camera reads 25mm which fits to its overviewing role. New cameras are set to 25mm initially and do need adjustment.

Perhaps you’ve noticed that in real life the modern consumer digital cameras are quite smaller, and especially quite thinner, than the older analog ones. You may know – otherwise: have a look at the hasselblad.com – that pro cameras are bigger. And yes indeed, there is a simple proportional relationship between camera size and its normal focal length. Poser supports this relationship to some extend: take the Main camera, and increase the Scale to 150%. You will see it is zooming out, while keeping the same value for its focal length.

Scale 100%, F=75mm

Scale 150%, F=75mm

A larger camera needs a larger focal length to establish the same amount of zoom. But Poser is cheating a bit, which can be seen when I use the Aux camera to watch the behavior of the Main Cam. When scaling up the Main cam, it not only grows but it also moves back from the scene, while keeping its DollyX,Y,Z intact.

Scale 100%

Scale 150%

This is because a Poser Main or Aux camera is the whole thing from 0,0,0 to the view plane capturing the image, and it’s that whole thing which is scaling.

A camera which moves back while the DollyX,Y,Z values remain intact should ring a bell: apparently things are measured in “camera units” which are scaling as well. And indeed: the Focal Distance changes too. Try it:

Just Andy, just the Main cam, and you’ll find Andy at 11,7 (mtr).
Scale the Main cam to 150%, and you’ll find Andy’s Focal Distance at 7,8 (mtr) = 11,7 / 150%.

So while the camera retracts the focal distance DEcreases. Sometimes, Poser is black magic.

Another magical thing: some Poser cameras can scale, others cannot. Main, Aux, Dolly and even Posing cams can scale, but L/R-hand and all user added cams cannot. To some extent, this is a good thing because from the above we learn to watch camera scale as it might present more problems and unexpected results than is does any good. Since I take the habit of shooting my final renders with my own cam, instead of a build in Poser one, I don’t run this risk.

On top of that, cameras show a Focal and a Perspective parameter. Actually, the orthogonal Left/Right etc cameras show a Perspective setting only and go berserk when I try to change it. Other cameras, like the Dolly cam, show the Focal parameter only. Other cams, user added ones included, show both, and both parameters consistently show the same value. So, what’s up?

Perspective

Have a look at this simple scene, where I enlarge the focal length while walking backwards so Blue Andy remains about the same size in the shot.

20mm (scale 100% fStop=5.6):

35mm:	55mm:
80mm:	120mm:

As you can see, zooming in not only gives a smaller (narrowed) portion of the scene, it also brings the background forward. In other words: zooming flattens the image.

Actually, while zooming in I’ve got to walk backwards quite a lot, which might be undesirable in various cases. This is where the Perspective parameter comes into play. When changing the Perspective from 55 to 120 (218%), I will notice a change in camera size (scale 100 => 218%, zooming out) and a drop in the DollyX,Y,Z values (of 1/ 218%). The scaling enlarges the “camera distance unit” so this change in Dolly values actually makes me stay in the same position in the scene. At the same time the focal length goes up, zooming in. In order to keep Blue Andy about the same size in the image I still have to walk backwards, but far less. Simply, if I use the old 100% DollyXYZ numbers, I’m standing in the right place, Blue Andy has its original size but the perspective of the scene is that of the 120mm zoom lens.

Again: when I change the Perspective (instead of the focal length dial) and I keep the DollyZ etc values intact, then the foreground of the scene remains the same while the background comes forward, while I slowly moves backward myself, and so on. Even the focal distance can keep its value, as it’s measured in the same “camera distance units”.

If you keep standing in place and take the DollyZ as the Perspective dials presents to you, don’t forget to reduce the focal distance (in this example: with 1/218%, or from say 6 to say 3). This, for whatever reason, is not done by the Perspective dial.

Note: some Poser cameras (e.g. L/Rhand cam) have no Scale parameter, but I might change Perspective. This only changes focal length, so I just use that one instead. Scale remains at 100%. Some Poser cameras (e.g. Dolly cam) have no Perspective parameter, but I might change Scale by hand (and DollyX,Y). Some Poser cameras lack both, so I cannot use this Perspective feature at all. This is the case in user added cameras. When I use one of those for my final imaging I don’t have to bother on Scaling and Perspective tricks and troubles. I just cannot turn my digital consumer cam into a Hasselblad by spinning a dial.

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Managing Poser Scenes (03. Camera Blur & Parameters)

Like a real-life camera, the Poser camera presents us: Focal or Lens Blur (sharpness limits), Motion Blur (speed limits), Field of View (size limits) and even more limits.

Focal Blur

Focal Bur, or Depth of Field, is in reality the result of focal length, diaphragm (fStop) setting and shutter speed, while also fStop, shutter speed and film speed (ISO) are closely related. In Poser however, there is no such thing as film speed, and the Depth of Field is determined by the fStop setting only. Whatever the shutter speed, whatever the focal length, they won’t affect the focal blur.

20 mm, fStop 1.4:

120mm, fStop=1.4:

In a real camera, the change in focal length would have brought Pink Andy and the back wall in a sharp state as well. In Poser, the blur remains the same. And because the back end of the scene is brought forward when enlarging the focal length, the blur even looks like it’s increasing instead of the other way around.

Motion Blur

Shutter Open/Close both have values 0 .. 1, Close must be later that Open. The shutter time is measured in frame-time, so if my animation runs at 25 fps the frames start at 0.00; 0.04; 0.08; then Open=0.25 means the shutter opens at 0.01; 0.05; 0.09 or: 0.25 * 1/25 = 0.01 sec after frame start. Similarly, Close=0.75 means that the shutter closes at 0.03; 0.07; 0.11 or 0.75 * 1/25 = 0.03 sec after frame start and therefor 0.02 or 1/50 sec after Open. Contraring to real-life cameras, shutter time does not affect image quality like depth of field, it only affects motion blur or: 3D / spatial blur, in animation but in stills too.

So, a shutter speed of 1/1000 sec translates to a 0.030 value in a 30 fps animation as 0.030 / 30 = 0.001. For stills without motion blur, I just leave the defaults (0 and 0,5) alone. For anything with motion blur, I should not forget to switch on 3D Motion Blur in the Render Settings.

More parameters

The other two parameters: hither and yon, have no physical reference. They mark the clipping planes in OpenGL preview only. Everything less than the hither distance will be hidden, and everything beyond the yon distance will not show either. That is: in preview and in preview render, when OpenGL is selected as the delivery mechanism. Not when using Shreed (the software way of getting previews), not when rendering in sketch mode, not when using Firefly.

Hither = 1, Yon = 100

Hither = 10, Yon =20, near and far ends don’t show in preview. They do show in Firefly render.

This can have a surprising effect. When the camera is inside an object, but less than the hither distance away from the edge, you won’t notice it in the preview because the objects mesh is clipped out. But when you render, the camera is surrounded by the object and will catch no light. This gives the “my renders are black / white / … while I have the right image in preview” kind of complaints.

It sounds stupid: how can one land the camera inside an object? Well, my bets are that it will happen to you when you’re into animation. Smoothing the camera track will give you some blacked-out frames. Previewing the camera track through the Aux camera, and/or adding a ball object on top of the camera entry point (watch shadows!!) can help you to keep the view clear. Just setting the camera to Visible in the preview might not be enough.

Having said that, let’s have a look at the various camera properties.

* Focal (length) refers to zooming
* Focal Distance and fStop refer to focal blur, and requires Depth of Field to be switched ON in the render settings.
* Shutter Open/Close refer to motion blur, which requires 3D Motion Blur to be switched ON in the render settings.
* Hither and Yon set limits in the openGL preview.
*

Visible implies that I can see (and grab and move) the camera, when looking through another one. By default it’s ON.
* Animating implies that changes in position, focal length etc. are key framed. Great when following an object during animation, but annoying when I’m just trying to find a better camera position during an animation sequence. I tend to switch it OFF.
* And I can disable UNDO per camera. Well, fine.

Field of View

In order to determine the Field of View for a camera, I build a simple scene. Camera looking forward, and a row of colored pilons 1 mtr at the right of it, starting (red pylon) at 1 mtr forward. So this first pylon defined a FoV of 90°. The next pylon (green) was set another 1 mtr forward, and so on. Then I adjusted the focal length of the camera until that specific pylon was just at the edge of the image.

Pylon	Color	Focal(mm)	FoV (°)	Pylon	Color	Focal(mm)	FoV (°)
1	Red	11	90,0	9	Blue	115	12,6
2	Green	24	53,1	10	Red	127	11,3
3	Blue	36	36,8	11	Green	140	10,3
4	Red	49	28,0	12	Blue	155	9,4
5	Green	62	22,5	13	Red	166	8,7
6	Blue	75	18,8	14	Green	178	8,1
7	Red	87	16,2	15	Blue	192	7,6
8	Green	101	14,2

For simple and fast estimates, note that (pylon nr) * 12,5 = Focal(mm), like 6 * 12.5 = 75, where (pylon nr) is (meters forward) at one meter aside. As an estimate. I can use this for further calculations, e.g. on the size of a suitable background image.

Example 1

I use a 35mm lens, which gives me a 36-40° FoV, and my resulting render measures 2000 pixels wide. Then a complete 360° panorama as a background would require 2000 * 360/36 = 20.000 pixels at least, and preferably 40.000 (2px texture on 1 px result). With a 24mm lens the preferred panorama would require 2* 2000 * 360/53.1 = 27,120 pixels.

Example 2

In a 2000 pixel wide render, I want to fill the entire background with a billboard-like object. For quality reasons, it should have a texture of 3000 (at least) to 4000 (preferably) pixels. When using a 35mm lens, every 3 mtr forward sets the edge of the billboard 1 mtr left, and the other edge 1 mtr right. Or: for every 3 mtr distance from the camera, the board should be 2 meters wide. At 60 mtrs distance, the board should be 40 mtrs wide, left to right, and covered with the 4000 pixel image.

Non-Automatic

Modern real life cameras do have various modes of Automatic. Given two out of

sensitivity (ISO, film speed),
diaphragm (fStop) and
shutter speed (open time)

the camera adjusts the third one to the actual lighting conditions, to ensure a proper photo exposure.

Some 3D render programs do something similar, like the Automatic Exposure function in Vue.

Poser however, does not offer such a thing and requires exposure adjustment in post. For instance by using a Levels (Histogram) adjustment in Photoshop, ensuring a compete use of the full dynamic range for the image. Poser – the Pro versions – on the other hand, support high end (HDR/EXR) image formats which can survive adjustments like that without loss of information and detail.

The Poser camera is aware of shutter speed, but it’s used for determining motion blur only and does not affect image exposure. The camera is also aware of diaphragm opening, but it’s used for determining focal blur only and again, it does not affect image exposure. The camera is not aware of anything like film sensitivity, or ISO. It’s not ware of specific film characteristics either (render engines like LuxRender and Octane are). With this respect, the Poser camera is limited as a virtual one.

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