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Revolutionary "Light Field" camera tech - shoot-first, focus-later

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Re: Revolutionary "Light Field" camera tech - shoot-first, focus-later

#51

Post by snarf »

sbierwagen wrote: post #17

The downsides, which, of course, this press release doesn't mention: - Greatly, greatly reduced image resolution. Great big dedicated-camera sized lens and image sensor, cellphone-camera sized pictures. 1680×1050, at most. (1.76MP) - Color aberration. The microlenses have to be small, of course, so they're going to be made of single physical elements, rather than doublets.[1] - Various amusing aliasing problems. (not…

The NYTimes also has an article on Lytro which suggests that they have solved the resolution problem. From http://www.nytimes.com/2011/06/22/technology/22camera.html?_... :

"The picture resolution, he added, was indistinguishable from that of his other point-and-shoots, a Canon and a Nikon. Eliminating any loss of resolution in a camera like Lytro’s, which is capturing light data from many angles, is a real advance, said Shree Nayar, a professor at Columbia University and an expert in computer vision."

Re: Revolutionary "Light Field" camera tech - shoot-first, focus-later

#53

Post by awarzzkktsyfj »

ricardobeat wrote: post #35

I remember seeing this "news" years ago... edit: here's the article from 2005 http://graphics.stanford.edu/papers/lfcamera/ The company that flourished from this research in 2008: http://www.crunchbase.com/company/refocus-imaging And another startup already doing this for mobile phones: http://dvice.com/archives/2011/02/pelican-imaging.php

The article is about a company named Lytro. 'Refocus Imaging' is the previous name of Lytro.

Re: Revolutionary "Light Field" camera tech - shoot-first, focus-later

#54

Post by humanfromearth »

Doesn't Magic Lantern already do this? I mean the Focus Bracketing shoots 3 (or maybe more) pictures as fast as the camera is able to do it at different focal distances. You just make sure the depth of field is wide enough to cover the distances between those points and you should have a similar effect.

Re: Revolutionary "Light Field" camera tech - shoot-first, focus-later

#55

Post by revorad »

This sounds very exciting. To play the devil's advocate however, on most of the example photos on Lytro's site, you really only need two points of focus - roughly near and far. Clicking on those two shows you everything there is to see in a picture.

If someone comes up with software to allow refocusing on two distance points with existing photos, they could eat Lytro's lunch. Can Picasa do something like this?

Re: Revolutionary "Light Field" camera tech - shoot-first, focus-later

#58

Post by gjm11 »

bad_user wrote: post #46
hristov wrote: post #44

Earlier quoted context omitted.

Focusing with point and shoots should not be a problem. They all have a huge depth of field due to their small sensors, so you have to try really hard to put something out of focus. Smudged pictures on point and shoots are usually not a result of lack of focus, but something else (e.g. shaky camera). Even with DSLRs you usually only need one focus point. You can focus at the center and re-frame. It is very simple to…

You cannot re-frame when shooting moving subjects - kids playing, sports, birds, cars, motorcycles, boats - there's all kinds of instances in which your subject doesn't stand still and even has unpredictable moving patterns, so keeping your subject in the center of the frame and/or re-framing is in many instances not feasible. Nikon DSLRs have this 3D tracking feature in which you select an object to keep in focus an…

> under 6MP a camera is only usable for publishing on Facebook.

2560x1600 pixels is 4.1MP. At 1:1 that will completely fill the most monstrous computer monitors one can get for under about $10k. At 300 pixels per linear inch (a very reasonable resolution for photos; about the same as the iPhone 4 "retina" display) it will give you a picture with 10" diagonal.

Unless you're making posters or big prints for photographic competitions or something, even at 4MP raw pixel count is not going to be your problem. It's completely untrue that below 6MP your pictures will be useless for anything beyond Facebook.

(Of course pixel count starts to matter more if, e.g., you're taking pictures of distant birds or distant celebrities with a not-especially-long lens and you need to crop heavily. Most photographers, most of the time, are not doing that.)

Re: Revolutionary "Light Field" camera tech - shoot-first, focus-later

#59

Post by stan_rogers »

hristov wrote: post #44
bad_user wrote: post #40

Earlier quoted context omitted.

You can just produce a composite image that's sharp all over… – but what fun is that? With DSLRs that have huge lenses with large aperture sizes, the depth of field varies a lot and those lenses also have a sweetspot in focal-length / aperture for which images produced are the sharpest. Lowering the aperture size increases the depth of field, but then you've got another problem as the shutter speed also has to be adj…

Focusing with point and shoots should not be a problem. They all have a huge depth of field due to their small sensors, so you have to try really hard to put something out of focus. Smudged pictures on point and shoots are usually not a result of lack of focus, but something else (e.g. shaky camera). Even with DSLRs you usually only need one focus point. You can focus at the center and re-frame. It is very simple to…

Focusing with the center AF sensor only and recomposing will generally put the plane of focus behind the intended subject (assuming the lens does not have an extraordinary degree of field curvature). The geometry is easy to see if you remember that your focus distance is the distance from the sensor/film plane to the subject, not the distance from the lens to the subject. The problem is more noticeable with a wider lens, a larger aperture setting and a closer subject, but it's always there. That's why Hasselblad (who only offer one AF point in the H4D camera system) has incorporated positional sensors and focus correction in their latest models.

If your camera offers the option, choose a focusing composition that will put your subject as close as possible to its final position in the picture and use the focus point closest to that position.

Re: Revolutionary "Light Field" camera tech - shoot-first, focus-later

#60

Post by rakkhi »

bad_user wrote: post #46
hristov wrote: post #44

Earlier quoted context omitted.

Focusing with point and shoots should not be a problem. They all have a huge depth of field due to their small sensors, so you have to try really hard to put something out of focus. Smudged pictures on point and shoots are usually not a result of lack of focus, but something else (e.g. shaky camera). Even with DSLRs you usually only need one focus point. You can focus at the center and re-frame. It is very simple to…

You cannot re-frame when shooting moving subjects - kids playing, sports, birds, cars, motorcycles, boats - there's all kinds of instances in which your subject doesn't stand still and even has unpredictable moving patterns, so keeping your subject in the center of the frame and/or re-framing is in many instances not feasible. Nikon DSLRs have this 3D tracking feature in which you select an object to keep in focus an…

I find the higher mega-pixel really helps on cropping. Especially when photographic wildlife like a dragonfly its nice to be able to crop a photo to just focus on that while still maintaining resolution. For me 10MP minimum is for this purpose rather than large prints. 2c this looks like a really cool technology, I would love to see it built into phones.
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