DOF and Motion Blur: how do I control these in Render Settings?



  • I am experimenting with both of these FX in Superfly for the first time. I never tried them in Firefly because I was comping my renders and doing everything in post.
    But is there a way to set them so that I can control the angle and amount of motion blur, or the DOF amount and what it affects?



  • @rokketman If I recall correctly, because it's been a while since I actually used it, DOF is controlled with the Focal control parameter on a camera. When setting it, you will see a cross hair appear on the screen. After that it's basically just trial and error using little area renders to give you an idea of what the finished render will look like.



  • @eclark1849 Thanks. I'll give that a try.



  • Like I said, though. Take what I say with a grain of salt. It's been awhile since I've even used it.



  • @rokketman generally speaking, and there are oodles of photographic enthusiast web sites out there with excellent explanations, you would choose a camera focal length and position first, to frame your scene as you require. Then you need to ensure that your main object or figure of interest is in sharp focus. This is done by adjusting the focus distance control of the camera, during which the Focus Distance Guide object will appear (ball, circle and diagonal crosshairs, though @bagginsbill has an excellent grid replacement, which I find far more useful to tell where the plane of sharp focus cuts your figure).

    Once you have your subject in focus, adjusting the fStop will vary the Depth Of Field, i.e. how much remains in focus in front of and behind the plane of sharp focus. There are scripts around which can set the hither and yon clipping planes to match the extents of objects in focus. There is also a useful algorithm to calculate maximum depth of field, which returns the fStop at which everything from half the focus distance to infinity is in focus, only foreground objects will be out of focus.



  • @anomalaus That's a lot to take in. I'll have to spend a little time experimenting.

    What I am more interested in though, is controlling the motion blur. I'll post an example of what I am working on in a bit, but basically, I want to be able to control the amount and angle of the blur without resorting to comping and doing it in post.



  • As you can see here, she is dropping out of the sky from right to left and downward. The motion blur is all over the place. I think I accidentally added in the DOF too. So what I want to do is control the blur so that her descent looks natural.
    0_1538284958388_Roxie in the sky.png



  • I figured it out for my own scene, eventually - used my own camera settings.

    Working scene
    1_1538292445933_FinallyFiguredItOut-Unrendered.jpg

    Superfly rendered scene
    0_1538292445933_FinallyFiguredItOut.jpg

    In the working scene, I had to switch on IBL. In the rendered scene, I switched off all lights and used only the HDRi procedural shader on the Background material ofThe Construct.



  • @ibr_remote

    0_1538293020381_DoF_camera.jpg

    These are my Main Camera settingsw, which I used to render the scene.



  • @ibr_remote
    0_1538293106219_DoFrendersettings.jpg
    These are my very rough render settings for the scene - I am sure that a higher pixel sample number is needed for a human figure - I am only using Mannie in this case !



  • 0_1538302537746_the angel.png
    Here is what I have so far. I really only want to adjust the motion blur...



  • @rokketman though I haven't played with motion blur for a long time, before I gave up, I did read here recently that the blur for a render of the current frame is calculated against movement to the next frame, not from the previous frame, if that helps.

    It appears from your render that the figure and wings have no movement between the frames, so the motion blur is only affecting the background. Are you changing the focal length or distance of the camera between frames, as that kind of perspective change is the only thing I can think of that would give that kind of angle change the blur presents from one side of the render to the other. Have you tried a straight camera move (like just using the posing camera unanimated) to give straight, parallel line blur of the background between two frames?

    Oh, it just occurred to me that if you're using an environment sphere, it may not be possible to get straight line motion blur, as the perspective calculations won't work for a background with no depth information.



  • @rokketman Okay, I'm giving out a lot of advice for something I just don't use, so if what I tell you is wrong, I'm sure someone will point it out. But from my understanding of the manual, you apply motion blur to the document AFTER you render it. There's a good chance I'm misunderstanding that, but to apply Motion Blur you check it under the animation menu.



  • @eclark1849 Actually, it is one of the options on the SF render menu
    0_1538312444633_render.png



  • @anomalaus I am using an environment sphere, and I am not sure what else you are referring to with regard to the frames, as I posed the figure in frame 15 and ran the cloth sim. I am not animating this, so it's only the product of the final frame I am trying to capture in a still frame



  • 0_1538312814943_the angel.png



  • @rokketman
    If you only render a still then motion blur will not do anything.
    It mimes the effect of items in the scene moving relative to the camera or otherwise changing while the shutter is open.
    The cameras have a setting of shutter open time.
    I never used it but I expect that Poser then makes multiple renders and uses the weighted sum of the results.
    Not behind my system now. Maybe the manual gives some examples?



  • Just a little tip for folks when using DOF blur: The larger the lens, the larger the FStop. If you don't follow this rule you'll end up with an image that looks like it's miniature. I don't know any of the math behind it but this is what it looks like.
    0_1538324199470_FStop Manipulation.jpg



  • Back when Poser 6 came out and for the first time had a useable DoF setting, I made a DoF for beginners-tutorial.

    Still works in PP11 ;)
    http://trekkiegrrrl.dk/DOFtut1.htm



  • @trekkiegrrrl
    yup.principles did not change.
    It mimes physical events, and these do not change over time. It has been well over 200 years since Archimedes had his Eureka! moment and all the ships on the sea still go by what he said back then.