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Bokehlicious Selfies

rahulrav.com

51–53 of 53 posts

Re: Bokehlicious Selfies

#51
post #12

Earlier quoted context omitted.

Yeah. I don’t see anything here that couldn’t be done in Photoshop with a bit of masking work. Here’s an example [1] of how bokeh really looks, using a high quality fast lens on a decent camera. We’ve got a long way to go. [1] https://upload.wikimedia.org/wikipedia/commons/8/8a/Josefina...

So it’s a “find bright spots, bloom them into circles or hexagons or some such, then make 2-4 offset less opaque circle clones and overlay them offset by position”?

There’s a bit more to it than that. Look near the edges of the frame vs the middle. Also note that the effect is not binary. It’s dependent on depth as well as angle. One of the reasons the example from the original article looks so unrealistic is that the flowers are not at a great depth so they really shouldn’t be blurry unless the subject is also out of focus.

Additionally: finding true bright spots (vs regular objects that happen to be white) is difficult with a typical low dynamic range photograph. You’d have a much easier time with an HDR photo. It still wouldn’t give you any depth or angle information though.

Re: Bokehlicious Selfies

#52

To make the Gaussian blur look better, it needs to be applied to linear lightness, not to gamma-encoded colors, as it is done here. In reality, the blur is induced by the lens, on linear lightness, and only gamma-encoded afterwards. The effect being that blurred colors mix wrongly, as you can see where the red from the flower mixes with the green. The transition looks wrong, and not how a lens would render it.

Shallow depth of field blur is not a Gaussian blur though. Attempts at faking shallow depth of field with that filter will not result with true bokeh.

True, but Gaussian or not, convolutional filtering should be performed in linear light space!

Re: Bokehlicious Selfies

#53

Earlier quoted context omitted.

I agree. My goal here was to get something that look like bokeh if you squinted at it. I just wanted to see how far I could take this idea.

FYI, the web page seems entirely unusable on my iPad Pro. It goes blank at the first example, and without a scroll indicator I have no idea what’s going on. I was able to scroll to the bottom footer, but I can’t scroll back to the top, so there’s literally nothing but a blank page now except for the footer.

Thanks for the feedback. Let me fix that.
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