Page 2 of 2

Re: cam calculator

PostPosted: Thu Jan 29, 2015 3:20 am
by linvanchene
abstrax wrote:During the discussion in viewtopic.php?f=9&t=44522 I realized that the aperture calculation was incorrect, since it calculated the aperture diameter instead of the aperture radius which is what the aperture pin actually specifies. I fixed the script in the opening post.

For fun and out of curiosity I did a little experiment to see how closely the Octane DOF matches a real world photo. So I set up a simple scene with a black pen in front of a white wall and have the wall in focus. I measured the various dimensions and distances and then roughly recreated the scene in Octane via C4D.

This is photo taken with a Canon EOS 550D (sensor size is is 22.3mm x 14.9mm) and a Tamron lens set to a focal length of 50mm and the aperture set to f/2.8 and processed in Lightroom:

And this is the approximated scene rendered in Octane:

In the image above, I set the "aperture edge" in the camera node to 0.8, but it's hard to get the bokeh into the same ball park, especially since Lightroom also applies some fancy non-linear response and the Tamron is certainly not the lens with the smoothest bokeh on this plant. But yeah, it's pretty close I would say.

This is how it looks like with an aperture edge of 0.5:

This is the scene to render the above image:

Thank you a lot for this update.

And special thanks for pointing out the "Aperture Edge" functionality in the camera node!
In the plugin I use this feature is called "Bokeh sharpness" so I kept overlooking it in the standalone.
Guess now I will hopefully finally remember. :oops:

Great idea with the pen example! It is impressive what can be achieved when knowing how to work with the standalone.

Re: cam calculator [fixed]

PostPosted: Thu Jan 29, 2015 6:08 am
by glimpse
great, now I can try convert some of my old scenes to see what "real-world" parameters I was working with..I though these fields meant different things (my bad), but I felt something was not right when trying to setup DOF..let's see.

Thanks for taking time not only to change things, but also explain them! In the end for some that will stick!

Re: cam calculator [fixed]

PostPosted: Thu Jan 29, 2015 9:53 am
by martincarlson
Yeah, thanks!