I feel this is something that is really taken for granted in blender. Depth Of Field, it's overdone, or not used at all. Both of which can make your scene or render look really fake if you're not using it correctly. So after the break, I've put up a new video, that goes into the settings of the virtual camera to make you take a look at the depth of field you're using in your scene.
In photography, depth of field is affected by two major factors; Focal Length, and Aperture Size. Both of which you can control in blender. Of course, aperture size in real life, is generally affected by the amount of light in your scene. Depth of field is also affected by the focal point (focus), or distance (in blender), which it appears that blender does take this effect into consideration when rendering.
To think about focal length, is fairly simple, think of a zoom lens on a camera. The more zoom in a lens, the higher the focal length. This is a fairly high focal length render.
|Focal Length: 63, Aperture: 0.03|
|Focal Length: 16, Aperture: 0.03|
|Focal Length: 32, Aperture: 0.03|
But what I'm really trying to touch on here is how to use depth of field correctly in a scene. The aperture setting in blender really changes how this effect is brought out.
When working with a real lens, for example, a zoom lens will have a shallow depth of field. The aperture is set to 0.06 in this next render to show this shallow depth of field, which is double that of the previous.
|Focal Length: 32, Aperature: 0.06|
But a wide angle lens would have a deeper depth of field, bringing nearly everything into focus. This is exaggerated in this render, with an aperture of 0.001, everything is in focus.
|Focal Length: 32, Aperture: 0.001|
When working with scenes of things in the distance, like mountain ranges, the focal length needs to be also taken into consideration. If you're trying to zoom into the mountains a shallow depth of field and high focal length will really emphasize this. The mountains are cut off, but you can see them in focus, while the nearer objects are out of focus.
|Focal Length: 63, Aperture: 0.03|
A wide angle would normally keep the distant objects more in focus, and generally has a deeper depth of field, but here I have the depth of field still pretty shallow, although it still emphasizes the effect, I think this is fairly accurate.
|Focal Length: 8, Aperture: 0.03|
I also wanted to touch on some other settings in blender:
First is the exposure setting. This isn't really relative to exposure of a real camera, in fact all this is, is a multiplier applied to all the emitters. Which can brighten your scene, but can create hot spots from world textures, and other already bright emitters.
Gaussian blur; is a setting that is really tough to get a defining point that is perfect. I use 0.7 to 1.0 for general lens blurring. 0.3 to 0.5 if an image is intended to be really sharp and appear computer generated. 1.1 to 1.3 is to give a heavy blur as if the lens is just pretty bad. This can help remove or accentuate pixel lines, caused by computer rendering.
And one final thing that I wanted to save for last!
I love panoramas, I can't deny it. This render is designed for a spherical panorama, which is different than panos that we normally take with photographs (cylindrical). Some software can use this final render to give an "explore" or "world" view into your 3D scene.
Panorama mode, removes focal length and aperture, and just takes a spherical projected view of the scene into the frame. Basically everything is in focus. Where you can see the edges of the materials in my scene.
This can also be used if you're wanting to work with the sky and generate world skies in blender, that you can save for later use in other software or other renders.
I'll go into detail on how I did this sky effect, later this week. It's fairly simple, but a great effect, that you don't have to rely on your own photos, or paying for high definition world skies.
But if you do want real world skies, you can get some good quality ones from the great folks at http://www.cgskies.com
I hope this explained how to use focus and depth of field in blender, so you can accurately create a good render with proper focus, for your scene.
Remember these tips:
Zoomed Lenses = High Focal Length + Shallow Depth of Field
Wider Angle Lenses = Low Focal Length + Deep Depth of Field
Average Lens = Medium Focal Length (closer to the Sensor Size) + Depth of Field is dependent on light.
Dark Scenes, normally are deeper in depth of field.
Brighter Scenes, can have a shallower depth of field.
If you have any questions, or if I missed something let me know.