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Lens Blur in the new Google Camera app

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Re: Lens Blur in the new Google Camera app

#41

Post by jawns »

grecy wrote: post #12

We had an interesting discussion about this a few nights ago at a Photojournalism talk. In that field, digital edits are seriously banned, to the point multiple very well known photo journalists have been fired for one little use of the clone tool [1] and other minor edits. It's interesting to think I can throw an f/1.8 lens on my DSLR and take a very shallow depth of field photo, which is OK, even though it's not ve…

When you say "digital edits are seriously banned," I think that's overreaching. I'm a former newspaper editor, and "digital edits" in the form of adjusting levels, color correction, etc., are performed on every single photo.

What's not allowed, as you allude to, is retouching a photo.

So does introducing blur after the photo was taken count as retouching, or does it fall into the same category as color correction? It's an interesting question. On the one hand, it has the potential to obscure elements of the picture, which seems like retouching, but on the other hand, you could just as easily achieve the same effect with a DSLR and there would be no outcry.

Re: Lens Blur in the new Google Camera app

#42

Post by aray »

theoh wrote: post #31
mcescalante wrote: post #20

I may be wrong because I don't know much about image based algorithms, but this seems to be a pretty successful new approach to achieving this effect. Are there any other existing "lens blur" or depth of field tricks that phone makers or apps are using? I'd love to see their code open sourced.

SynthCam is one, free but not open source. You might be interested in the various bits of lightfield rendering code released by Stanford: http://lightfield.stanford.edu/

Synthetic aperture-like algorithms are also common at SIGGRAPH if you go through the past two decades.

A quick search didn't unearth any, but there is open source software to do parallax depth inferencing, and you could just apply proportional gaussian blur kernels to each depth segment to get a very similar effect.

Re: Lens Blur in the new Google Camera app

#43

Post by gtremper »

frenchman_in_ny wrote: post #8

Does this pretty much blow Lytro out of the water, and mean that you no longer need dedicated hardware to do this?

This doesn't capture the whole light field, which is the advantage of a light field camera. Changing the focus is just a fun application if you have access to the whole light field. http://en.wikipedia.org/wiki/Light_field

Re: Lens Blur in the new Google Camera app

#44

Post by kbrower »

sib wrote: post #18

If only they had not confused shallow depth of field with Bokeh (which is not the shallowness of the depth of field, but, rather, how out-of-focus areas are rendered), this writeup would have been much better. http://en.wikipedia.org/wiki/Bokeh Cool technology, though.

Compare HTC's bokeh or any other attempt at this vs Google's and you will see that there is definitely a difference in how the out-of-focus areas are rendered.

Re: Lens Blur in the new Google Camera app

#45

Post by sp332 »

frenchman_in_ny wrote: post #8

Does this pretty much blow Lytro out of the water, and mean that you no longer need dedicated hardware to do this?

The Lytro images have a lot more data in them (although probably fewer pixels). You can move around slightly in a Lytro photo because it samples light from all directions. Also, Google's version doesn't seem to use the multiple exposures in the final photo. It only uses them to determine which pixels to blur in the first photo, and uses normal gaussian blur instead of simulating a lens.

Re: Lens Blur in the new Google Camera app

#46

Post by ISL »

apu wrote: post #21
ISL wrote: post #15

Earlier quoted context omitted.

The difference is that Lytro actually does it, instead of simulating it. It'd be fun to play around with the software to see in which cases it breaks (perhaps taking a photo of a framed landscape photo with another landscape behind, for example)

Lytro is also "just" simulating it, but with slightly more/different data. They capture a light field but that doesn't magically give them depth values; they have to estimate them using an optimization, and then render the final image using a very similar algorithm.

Edit: Whoops: I mis-read the article; 'Lens Blur' uses multiple frames. That lets you get a lot more information.

Re: Lens Blur in the new Google Camera app

#47

Post by JTon »

zippergz wrote: post #14
themgt wrote: post #10

Is looking at the examples giving anyone else a headache? It's like the software blur falls into some kind of uncanny valley for reality.

It doesn't give me a headache, but to my eyes it isn't remotely convincing. There's no way I'd look at any of those example pictures and not realize the blurring was done with postprocessing.

I'm a photography layman and I really can't tell it was done with postprocessing. What gives it away for you?

Re: Lens Blur in the new Google Camera app

#48

Post by nostromo »

I sure wish you could buy a DSLR that just plugs into your iPhone. I don't want any of that terrible DSLR software -- just the hardware.

I think many devices should become BYOD (bring your own device) soon, including big things like cars.

edit: I don't just want my pictures to be saved on my phone. I'd like the phone to have full control of the camera's features -- so I can use apps (like timelapse, hdr, etc.) directly within the camera.

Re: Lens Blur in the new Google Camera app

#50

Post by darkmighty »

aray wrote: post #25
theoh wrote: post #22

Earlier quoted context omitted.

I don't know for sure but the code may be derived from or related to Marc Levoy's SynthCam: https://sites.google.com/site/marclevoy/ It does similar things, and in fact I could believe it if the Google app was just a dumbed down version of the functionality intended to be usable by a wider audience.

There have been multiple implementations of this class of algorithm (collectively "synthetic aperture") using different techniques. Edit: below mentions the HTC "double camera" phones, and in fact it's also possible to create synthetic aperture photography with multiple cameras instead of moving a single camera to multiple positions. Then you have the added advantage of not needing to assume a static scene! But a sin…

It looks like this isn't creating a synthetic aperture, it's just creating a depth map and applying a depth-dependent blur to a single frame.
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