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0 pointsdgacmu7y ago0 comments

Sorry, but no - stacking is as much about dynamic range adaptation as noise, and that's why I'm arguing against your terming it a "ghetto version of a long exposure". It's not. A long exposure has a fundamental problem with saturation, as well as noise. It's not just about lack of stabilization, there's also the motion of the subject. Computational approaches can compensate for subject motion - long exposures cannot. Computational approaches can do dynamic range adaptation to avoid blow-out due to CCD pixel saturation. Long exposures cannot.

If you read the slides from the Levoy talk I cited, you'll note that they explicitly choose to under-expose the individual exposures to minimize motion blur and blowout.

(Marc is now at Google continuing his work on computational photography, and his group contributes to many of the cool things you see on the Pixel series.)

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endorphone7y ago

"Computational approaches can compensate for subject motion"

But they don't. They don't in this example. Moving subjects are a blur. As an aside, of course stacked photo frames are underexposed because it wouldn't make much sense otherwise.

Computational photography can do interesting things and holds a tremendous amount of promise. However every single example that I can find of this mode -- across the many astroturfed pages -- show a longer exposure than what the stock app normally allows. And with that the requisite blurring of any moving subject.

hug7y ago

Are you arguing that EIS over a series of burst photos is incapable of making things better?

Everything I can see you saying -- much if it agreeable, like the fact that long-exposure OIS makes a lot of what this technology currently does possible without it -- is simply handwaving away the fact that EIS-over-burst with OIS can achieve things that OIS cannot by itself.

It seems to me that it's patently true that EIS has some benefits, and those benefits can be realised over the top of OIS.

There's obviously still a fair limit to OIS. I have somewhat shaky hands and even using something like Olympus' top range 5-axis IBIS, which is the best I've ever seen, I can still only shoot at 1/10". What can EIS do with a burst of 3x 1/20" exposures? Probably counter for my shaking a bit, at least. (If not for subject movement, yet.)

I simply do not see why you're discounting this so heavily.

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ricardobeat7y ago

> But they don't. They don't in this example. Moving subjects are a blur.

If you stack the original exposures together, you'll get ghosting and not a blur. The natural-looking blur is a result of computation.

> of course stacked photo frames are underexposed, wouldn't make sense otherwise

Except it does make sense if you want to capture more shadow detail, this is how HDR images are made.

You're severely underestimating the amount of computation involved in getting these shots. These are all handheld, and as @dgacmu mentions can benefit from exposure bracketing which gives much better results than a single long exposure.

Of course you could already get similar shots from a good camera and technique - the fact these are handheld shots coming from a mobile device, and straight out with the camera is the impressive part.

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