[hatts]

I've noticed that Maxwell is extremely good at rendering a believable depth of field blur effect. Most rendering engines seem to get this catastrophically wrong. Post processing results seem to be hit or miss.

Does anyone know if there is some fundamental difference in the way MW's handles DOF?

[tom]

It's just not faked, nor an additional effect and that's why. DOF comes from real camera optics and Maxwell doesn't really do anything special about it.

[bograt]

I was just thinking about DOF.... Maxwell does a great job but it would be great to see support for some more effects such as: http://www.dofpro.com/technology.htm
Custom aperture and photometric burnout in particular

By the way, DOF PRO does a great job but crashed non-stop when I tested it.

[Polyxo]

I was just thinking about DOF.... Maxwell does a great job but it would be great to see support for some more effects such as: http://www.dofpro.com/technology.htm
Custom aperture and photometric burnout in particular.

Yup. Maxwell Dof may be accurate but I find it far from spectacular. It's no bashing to say that it can not seriously compare with
the creamy Bokeh of good lenses. In fact it is a world of a difference. I've asked for additional controls before in the Wishlist...
It was so cool if we could dial in our favorite Lens Profiles and was fantastic means to add some extra Pop.

Holger

[Bubbaloo]

Lens profiles or not, good (real camera) lens bokeh is infused with distortions influenced by imperfections in the lens, so I think it's not something Maxwell can do until you have a modeled imperfect lens in front of the Maxwell camera. I think that's why Maxwell's bokeh is passable, because it's "real", but it's perfect, which makes it less than real.

[dmeyer]

Lens profiles or not, good (real camera) lens bokeh is infused with distortions influenced by imperfections in the lens, so I think it's not something Maxwell can do until you have a modeled imperfect lens in front of the Maxwell camera. I think that's why Maxwell's bokeh is passable, because it's "real", but it's perfect, which makes it less than real.

So it is, at once, real and not real.

[Bubbaloo]

Lens profiles or not, good (real camera) lens bokeh is infused with distortions influenced by imperfections in the lens, so I think it's not something Maxwell can do until you have a modeled imperfect lens in front of the Maxwell camera. I think that's why Maxwell's bokeh is passable, because it's "real", but it's perfect, which makes it less than real.

So it is, at once, real and not real.

Well, seeing as how we're all living inside a simulation anyway... yeah.

[Polyxo]

Lens profiles or not, good (real camera) lens bokeh is infused with distortions influenced by imperfections in the lens

I don't think this is correct.
Distortions like bulging or also or chromatic aberation qualify solely as errors while Bokeh is a property which gets very carefully designed by Camera Manufacturers.
The Blur quality is one of the most important aspects of the look of certain lenses and one of their selling points.

Concerning acurately simulating aspects the physical lens properties so that the blades appear in bloom...
I personally could live with additional controls as well implemented and fast post effect which works in conjunctions with a Zbuffer Channel.
Don't forget that we already have some other post effects as well. One would manipulate the appearance of fractions of the image which are very
heavily out of focus anyway. Maybe here one could relax a tiny bit in terms of physical accuracy and rather give us users some interactive styling options
as available in Photoshop Plugins like Focal Point.

[polynurb]

let's not forget we have: http://support.nextlimit.com/display/ma ... phic+Bokeh

I was quickly having a look, but i could not find any way to "reverse apply" the lens profiles in lightroom (or such).
in theory this should be possible
Concerning distortions and vignetting, this would be a good solution, if for some reason one finds the rendered image to "perfect", or needs to match an unaltered backplate.

concerning the additional Bokeh control in question here, this lense would be the comparable analog counterpart:

http://slrgear.com/reviews/showproduct.php/product/101
(if you click on the thumbnail with the mannequin, an applet starts where you can interactively view the changes)




and something like this, i could well imagine in a future version of maxwell

[Mihai]

Yup. Maxwell Dof may be accurate but I find it far from spectacular. It's no bashing to say that it can not seriously compare with
the creamy Bokeh of good lenses.

What kind of look do you mean more specifically? Because in fact it is due to lenses not having a perfect surface that you see some uneven lightness in bokeh - it does magnify scattering problems in the lens and thus gives it its personality. They hardly start from a perfect glass surface when dealing with a commercial lens.

http://fc08.deviantart.net/fs51/f/2009/ ... linger.jpg
http://infocusdaily.files.wordpress.com ... 3-5345.jpg
http://www.photoforum.com/forum/attachm ... odifie.jpg

[Polyxo]

Hi Mihai,
what I am after is not primarily that circular bloom but a certain soft luminous quality of the unsharp (but noise-free!) portions of the image
which I have not seen in non postprocessed digital renderings yet (regardless of engine). It appears most pronounced on shots with very shallow depth of field.
I'm not on my work machine currently but I attach some of Toras Bird-images and some other samples I just found through Google.
Something like that is relatively easy to set up (at least on static objects) with a good camera and lens but a nut I could not crack through rendering yet.

Maybe such happened at SL48?

[eric nixon]

That last image looks the way it does because of motion blur (camera is zooming out I think) + the DOF. Maxwell can render all these images if the scene is built properly.

Also sl15, rather than 48, will be fine most of the time.. given correct materials and lighting.

Its not the software that creates beautiful images its the user.

[Polyxo]

No, that last image was made as a still with a Nikon SLR see here.
I have created images with similar appearance too.

Also sl15, rather than 48, will be fine most of the time.. given correct materials and lighting.

Just go ahead an show me an example which even comes close.

[eric nixon]

Are you implying that what I said is not true? If so what isnt true, clean images of complex scenes by sl15 or the concept that you need to work harder to get the rich detail you see in photos?
Personally I am not a fan of soft focus, but I managed to find one render which has some bokeh in it. As it happens I dont really like this render but the bokeh looks fine.





I dont know what sl that butterfly is but this mini render is sl 14/15 with Motion Blur, Personally I havent seen any noise since using maxwell 2.7 even at low sl's. So the point is, if you get noise, dont render to sl48, fix the scene, fix that emitter which intersects or that additive material which uses more than 100%. The colour of the noise and its location should help you pinpoint the error.

Some people say avoid using high values in color chips, but that advice is out of date since MW2, avoid 255 ofcourse, but 253 can be fine.. it depends, for an interior wall maybe 242 is a good maximum. Remember that the effective value outputted will be somewhat less if there are other bsdf's in the mix.

[Mihai]

I think these ones come fairly close...








but it would be interesting to run some tests and get a better view, or this talking will be for nothing. Bokeh is always nice to look at I would guess there are so many complex light interactions that go on inside a lens between glass, and glass+coating that it's not realistic to expect a "lens profile" to mimic your favorite lens. But I wouldn't say either that it doesn't even come close to what bokeh looks like from a real lens.