This page exists within the Old ArtZone Wiki section of this site. Read the information presented on the linked page to better understand the significance of this fact.
When you want to take a picture of your Cousin Ned, you would probably use a normal 50 mm lens (for a 35mm film camera) and be within a few feet of him when you take his picture. But in order to get the picture of the blue bird perched on the bird bath, you have to keep your distance (so you don't scare the subject away) and need a long lens (100 to 400 mm).
Both subjects will fill the image area to produce a normal size picture. But there are advantages of using different lenses.
In DAZ|Studio, you use the Focal Length Parameter to simulate changing lenses. The default setting is 65mm.
To see how this works in Studio, we'll set up a scene with a couple of objects.
For this scene we'll use a couple of free models available from DAZ. Put these into a new scene.
Emotiguy (http://www.daz3d.com/i/3d-models/free-3d-models/emotiguy?item=3101&cat=382&_m=d) Scale him down to 50% so that he doesn't overpower the scene. Feel free to dress him up and pose as you see fit.
DM Garden Corner (http://free.daz3d.com/free_weekly/detail.php?free_id=219)
Use the wall and floor tile for the Garden Corner. Look through the top view camera (zoom out until you see the complete grid) and adjust the X scale until the floor is just a bit wider than the Garden Corner (50% works well). Then adjust the Z-Scale until the now narrowed floor covers the grid (342.4% does the job).
(Note: this article will suggest you look at your scene from the top view camera in the work space and then set various objects into scenes. Also, the suggestion will be that you do not look at the normal (Default) camera until told to do so. The reason is to let you see the view a bit more dramatically.)
In the following set ups, the coordinates will be for the translational coordinates of X; Y; Z.
Using the top view, select the wall translate coordinates to 0, 0, -1874. Select Emotiguy and set him to the same translation coordinates.
Still in the top view, select the Default camera from Scene Tab and translate it along the Z-axis down to the bottom of the grid (translate factors 0; 105; 2001).
You might want to save this scene so that you have a 'playground' for further experimentation on your own with other settings and positions.
Let's use this scene to see the main aspect of the focal length parameter.
Use the Default Camera in the view port and look at the scene. The default focal length in Studio 3 is 65 mm
Emotiguy and the wall are a bit far away and should look a lot like this rendered scene:
Make sure the Default Camera is still selected and change the Focal Length (in mm) to 35mm. You are increasing the field of view (seeing more of the sides) which makes our character look further away from the camera.
Change the Focal Length to 600mm and you have 'zoomed in' on our friendly face.
Well, you could since Emotiguy isn't camera shy. But, there's another phenomena that occurs with telephoto (long) lenses.
It's called by some, foreshortening, others say compression. In essence, the foreground and the distance between the objects appear compressed. This comes from the fact that you reduce the field of view as the image is magnified.
To illustrate this, create a new scene.
Use three primitives; cylinders will work well. Use Height= 1 m; Diameter= 0.5 m; Segments=1 Sides=12.
Locate the objects as follows:
Object 1: at -100; 0; -125;
Object 2: at 29; 0; -740;
Object 3: at 102; 0; -1500.
As before, you may want to save this scene as a different file. Then you can change various settings and move the camera around to experiment with different view points and focal lengths and return to your base scene.
When you look through the Default Camera lens at 65mm in its default position, you see a normal perspective view as in the screen-shot below.
Note the grid (only visible in your view port and not in a render) compresses as it disappears towards the horizon and the objects appear smaller as they recede into the background.
Now change the camera to the following coordinates: 20.00; 90.00; 11500.00. The objects suddenly appear far away. To change that perspective, change the Focal Length to 2000mm. Your scene should look like this screen-shot.
Notice that the grid is nearly non-existent because of the compression. Also see that the objects appear to be about the same size and the same distance apart. This is foreshortening though admittedly quite exaggerated. You have filled the view port with all your objects and changed the perspective for the person viewing the image.
The effect is called 'forced perspective' - a photographic technique where objects appear farther or closer, larger or smaller, than they really are. You've probably seen pictures of an adult standing in the palm of a child, or someone holding a monument in their hand. And as a side note, in many movies when you see the hero surrounded by flames, chances are he or she stands far away from the actual flames and a long lens is used to make the danger look real.
You can use this compression to your advantage and compose a scene without having to move the camera a lot and without having to rescale the objects. Since the objects are further apart in your virtual space, you can light each one separately.
Let's compose one more scene to illustrate that point. You might want to position the objects using the top view for this exercise…it's a bit more fun when you see the outcome.
For this image we'll use Emotiguy placed at: 0; 0; 1980. (Leave him at 100% size this time).
Add a vicious, ferocious, large creature (I will use Allosaurus) at: 0; 0; -1997.
You may want to add a ground plane primitive to give the characters something to stand on.
Place the default camera at: 195; 160; 3150.
Look through the Default Camera view and you'll see that our little buddy has nothing to worry about; the bad old dinosaur is WAAAYYY back there.
Switch back to the top view and change the Default Camera's coordinates to: 350; 134; 16942. Use rotational settings of X=0.31; Y=1.04; and Z=0. Set the Focal Length parameter to 1200mm.
Now, look through the Default viewer and you'll see a completely different story.
Add dynamic posing and lighting to each element and you tell a story.
By moving the camera away from the scene and applying a long lens, you can foreshorten the distance between objects (forced perspective) and add a dramatic flair to your composition. The virtual distance also gives flexibility in lighting each object in the scene.