Caught in the Tuna Net

They change the Renderosity Staff Picks on Sundays and three of us from the Virile Noir thread got in this week! Actually, we show up a fair amount. Do go see it! We have images from Kfox, LT Roberts, and myself there.

Today I answered a post, here, that said of a rendered image:

Playing around with depth of field and sort of liked the effect?  Too much?

If you haven’t gone to look at it, it was a figure against a blurred background, basically. The background was barely distinguishable as light and dark objects. (Really, the background is too contrasty and draws attention from the figure, which is its main problem, not the blur.)

You can read all about what depth of field (DOF) is in Wikipedia, here. But I mainly wanted to make a couple of minor notes about why one would use it in rendered art. For you who do not use Poser, the program has the option to simulate camera DOF give an focus object and an “f-stop” numerical value. I talked about simulated DOF in a previous post, here.

Whether it’s too much depends on what you wanted to do.    Not helpful, I know. But here’s something to keep in mind: DOF provides realism as well as focus to your image. Your background doesn’t seem all that far away, but it’s massively blurry–as if your camera were rather nearsighted.  If you don’t really want a background–if the background were distracting–you might consider a bokeh effect, or just putting a bokeh background in post, the way I did in this image:

Adrian - Bokeh background

And that’s an artistic, not a technical judgment you have to make.

Realism is not synonymous with photorealism, as my painting teacher would say. When human eyes focus on a subject, the rest of the ground blurs away and otherwise loses detail. We don’t *see* the way cameras do, with uniform clarity–it’s just that we’re used to looking at photographs.  So, realism is a painterly quality.  DOF can add to that, when combined with an interesting set.

Does your setting also play a necessary part in the image? If it only needed to be suggested, then you achieved your goal. Otherwise, you went a little too heavy. Also, if setting is important and you want it included, it’s a touch more effective if your character is in the middle ground, not the foreground, so that you have a blur on the foreground and background both, and a gradient of blur on planes leading up to and away from the subject.

I’ve been asked about my references to alpha masks and z-depth (or depth cue) with regard to creating renders in Poser, so here’s my run at explaining that. First, an image: This is from the Advanced Render Settings product in the RuntimeDNA store, and is so perfect I could not improve upon it as a visual example. Look at the last two images on the bottom row.

A normal render has a number of aspects combined in the image that we are used to seeing: shadows, ambient occlusion, specular highlights, diffuse color, displacement, and so on. In addition to that, to achieve additional effects, we may need extra render passes. In Poser, I use Semidieu’s Advanced Render Settings product (mentioned above) to do these.

The alpha mat pass generates a black and white silhouette of the selected figure or actor or material, usually a white figure against a black ground. You can bring this rendered result directly into Photoshop as a channel that can then be used to create a selection to assis in your digital painting. I usually generate alpha mats for the human figures (and their clothing and jewelry) in my scenes so that I can more easily paint hair for them, and use the selection generated by the alpha as a guide to erasing stray marks.

The Z-depth or depth cue render pass is also used in post-work, but is a little more complex. This grayscale pass colors the elements closest to the camera white, and in layers going away from the camer, increasingly dark until the furthest (or background) elements are black. I also load this render into a channel in my Photoshop file for the picture and I use it in creating a depth-of-field effect using the Lens Blur command. I do this instead of using the depth of field option in a render because it allows me a lot more control over the result. I do depth of field in images where there really is a lot of distance between the foreground and background as it adds realism to the picture and helps focus (pardon the expression) attention on the important elements of the scene.

For you students of humanity: I saw this interesting little article from AP today: Ivory sculpture in Germany could be world’s oldest. So, 35,000 years of pinups. Well, the anscestors didn’t have the Internet or magazines, and until they could invent those, they had to make do with what they had in the way of erotica. Suddenly, I feel so…classical.