Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×
Technology

Camera Lets You Shift Focus After Shooting 155

Posted by samzenpus from the we-can-focus-later dept.
Zothecula writes "For those of us who grew up with film cameras, even the most basic digital cameras can still seem a little bit magical. The ability to instantly see how your shots turned out, then delete the ones you don't want and manipulate the ones you like, is something we would have killed for. Well, light field cameras could be to today's digital cameras, what digital was to film. Among other things, they allow users to selectively shift focus between various objects in a picture, after it's been taken. While the technology has so far been inaccessible to most of us, that is set to change, with the upcoming release of Lytro's consumer light field camera."
This discussion has been archived. No new comments can be posted.

Camera Lets You Shift Focus After Shooting More

Camera Lets You Shift Focus After Shooting

Comments Filter:

  • fitrsrsitf (Score:2, Funny)

    by Anonymous Coward

    if you refocus that comment it reads as "first".

    • This was already done years ago in a different manner by Ren Ng (I believe was his name) who used an extra digital sensor and it's not a holocam it's a standard digital camera modified to enable changing of focus after the fact.

  • omg! (Score:4, Funny)

    by Tolkien ( 664315 ) on Wednesday June 22, 2011 @03:59PM (#36534732) Journal
    Enhance.

    • Re: (Score:1)

      by Anonymous Coward

      CSI's magical license plates are now possible!

      • The license plate on the black car didn't look like it was any clearer when zoomed in. Nor the writing on the signs. It seems more like it is taken with an extreme depth of field and then the system selectively focuses/defocuses areas of the picture. I very likely could be wrong, but that is how it seems to me from just this small demo.

    • Re: (Score:2)

      by tedgyz ( 515156 ) *

      Enhance.

      This is too funny! As soon as I read your comment, I realized Bladerunner was WAY ahead of it's time. It is still one of the best renditions of a future dystopia on film. We all wish it were like Star Trek, but the truth is far more grim.

      The real question is, are we already living in a dystopia? The world is pretty F'ed up.

      • The real question is, are we already living in a dystopia?

        Yeah, Satan is the ruler of this system of things. But a new king is coming; be awake and be ready.

        • Re: (Score:2)

          by Jeremi ( 14640 )

          Yeah, Satan is the ruler of this system of things. But a new king is coming; be awake and be ready.

          Damn straight. And Cthulu's reign of terror is going to make Satan's era look like the good old days...

  • For all the data it collects, does it do full spectrum or just 3 colors of light? Polarization after the fact? I wonder how long this will be "at least a year away." If it is the real, I can think of lots of scientific applications more useful than a consumer camera.

    • Re: (Score:2)

      by Relyx ( 52619 )

      The underlying concept and algorithms are real, and no doubt there are many proofs-of-concept in existence. Whether the technology can be commercialised in a year though seems a bit of stretch. I am willing to be proved wrong, of course - sounds very cool!

    • Re: (Score:2)

      by Relyx ( 52619 )

      I would hazard a guess that it records just three colours of light. After all, the underlying digital sensor is based on existing technology found in modern cameras.

    • Re: (Score:2)

      by Kenoli ( 934612 )

      I wonder how long this will be "at least a year away."

      According to the video in the article, the company is releasing "a competitively priced consumer camera" in 2011, ie no more than six months from now.

    • Well, it's a lot easier to commercialize something we already have [wikipedia.org]...

    • Re:Interesting. (Score:4, Informative)

      by marcansoft ( 727665 ) <hector@marcansoft.cDEBIANom minus distro> on Wednesday June 22, 2011 @04:32PM (#36535166) Homepage

      It's called a Plenoptic Camera [wikipedia.org]. You put a bunch of microlenses on top of a regular sensor. Each lens is the equivalent of a single 2D image pixel, but the many sensor pixels under it capture several variations of that pixel in the light field. Then you can apply different mapping algorithms to go from that sub-array to the final pixel, refocusing the image, changing the perspective slightly, etc. So color-wise it's just a regular camera. What you get is an extra two spatial dimensions (the image contains 4 dimensions of information instead of 2).

      Of course, the drawback is that you lose a lot of spatial resolution since you're dividing down the sensor resolution by a constant. I doubt they can do anything interesting with less than 6x5 pixels per lens, so a 25 megapixel camera suddenly takes 1 megapixel images at best. The Wiki article does mention a new trick that overcomes this to some extent though, so I'm not sure what the final product will be capable of.

  • What I want to know is, if they can focus at any point in the picture - and it looks as though they can, the interactive graphic is amazing - then why not just have the whole thing in focus at once. Infinite depth of field. If you wanted a shallow depth of field for artistic purposes, you could presumably add that later too. Neat.

    • Re: (Score:2)

      by Relyx ( 52619 )

      I think the depth of field in the demo is just there to accentuate the idea that you can focus on different areas. As you say, I am sure you could produce a version with a very deep depth of field if so desired.

    • Have you ever tried to reduce depth of field (DOF) to a photo that has too much (for artistic purposes) DOF? It's not easy at all. If you had a pair or more of images, of the same subject, from a slightly different viewpoint (i.e. of the kind you'd take for "stereoscopic" photography) it might be easier because at least then you had some additional cues as to distance from the imaging plane of various objects within the scene, and using that it should be possible to create software to uses those cues to ref

      • Re:I want it all (Score:5, Informative)

        by pjt33 ( 739471 ) on Wednesday June 22, 2011 @04:28PM (#36535138)

        The website about the camera doesn't have enough details, either, but this paper [stanford.edu] does give a reasonable idea of what's going on.

        • Thank you! And I was just going to post a reply to my own message wondering aloud if they manipulated the light using at the microlens level. Seem that this is exactly what they're doing

          [quote]This is achieved by inserting a microlens array between the sensor and main lens, creating a plenoptic camera.[/quote]

          That would still only give several (two, maybe three depending on the array) planes of focus, though, and at a sacrifice of resolution. Still, pretty cool idea.

          • Re:I want it all (Score:5, Insightful)

            by jrumney ( 197329 ) on Wednesday June 22, 2011 @08:02PM (#36537124)
            The sacrifice of resolution isn't really that big a concern. Consumer cameras have far more resolution than they need these days, as the almighty megapixel has been used as a marketing ploy even though increasing pixel density on the CCDs has led to lower image quality overall. My 10 year old 2Mpx Canon still takes better pictures than any of my wife's last 3 compact cameras (4, 5 and 8Mpx Nikon and Canons), especially in low light. I would go so far as to say it doesn't make sense to have go beyond much more than 4Mpx with lenses the size of compact cameras, as details will be lost due to lens quality long before the pixel count causes loss of detail.

            • The sacrifice of resolution isn't really that big a concern. Consumer cameras have far more resolution than they need these days, as the almighty megapixel has been used as a marketing ploy even though increasing pixel density on the CCDs has led to lower image quality overall. My 10 year old 2Mpx Canon still takes better pictures than any of my wife's last 3 compact cameras (4, 5 and 8Mpx Nikon and Canons), especially in low light. I would go so far as to say it doesn't make sense to have go beyond much more than 4Mpx with lenses the size of compact cameras, as details will be lost due to lens quality long before the pixel count causes loss of detail.

              I would beg to differ. Your 2 megapixel camera may produce higher quality pictures than your wife's compacts, but that likely has nothing to do with the relative resolutions. The dot pitch on decent CCDs is relatively small, so increasing the number of mega-"pixels" from 2 to 4 is going to have a negligible impact on the amount of light gathered. At best you're going to have increased resolution and sharpness that can be further used by improved processing chips. At worst you're going to reach a point w

      • Re: (Score:2)

        by tlhIngan ( 30335 )

        Back to the article, I actually don't understand how the process reported could work. To record light the recording medium (e.g. CCD or CMOS sensor) has to have the light fall on it and this implies focus. Possibly it somehow also records the direction of light to allow focus manipulation post-capture. Or possibly it takes multiple shallow DOF images at once. I wish the "article" had more details.

        ISTR a little ago there was a demonstration of a camera that basically used a honeycomb lens like that of a fly.

      • Re: (Score:3)

        by vlm ( 69642 )

        Have you ever tried to reduce depth of field (DOF) to a photo that has too much (for artistic purposes) DOF? It's not easy at all

        Bonus! Artiste types love to brag/complain about how difficult/expensive their work was to make.

        The non-artsy types don't really care about technical quality or anything other than getting a tolerably viewable "subject standing next to cultural item"

        • you speak as if there's no middle ground.

          like somebody wanting to take a picture that looks good, but who does not wish to place themselves on a pedestal.

    • Re: (Score:3)

      by cruff ( 171569 )

      ... then why not just have the whole thing in focus at once. Infinite depth of field.

      I watched the video and I believe the guy being interviewed said you can do just that.

    • They can - and he does in the video.
  • I have a small point and shoot camera, and I rarely ever have the problem that my photos are out of focus. Blurry photos on evening and night shots is the most common problem I have. Not to say this technology sucks, but I doubt that you can get the average consumer to pay double the price for this feature. However, there are probably tons of other uses that this technology might have (in more profitable areas). Maybe for security cameras, or unmanned vehicles.

    • Re: (Score:2)

      by Relyx ( 52619 )

      The smaller sensor, the greater the depth of field and therefore the easier it is to get sharp images. I would imagine your point and shoot has a pretty small sensor. A professional DSLR on the other hand has a much larger chip.

      • Exactly. I shoot motorsports with a canon DSLR (D20) and a 400mm lens. Not the same thing as pulling out a little point and shoot and pressing the button ;)

      • Re: (Score:2)

        by afidel ( 530433 )
        And it's not just sensor size, the larger the magnification of the lens the shallower the DOF (generally). The DOF on my 150-500 at 400-500mm is really shallow making shots of anything moving in less than perfect sunlight fairly difficult.

    • Re: (Score:2)

      by lahvak ( 69490 )

      Small point and shoot cameras have very small sensor and a lens with a small focal distance. That combination means that they have very large depth of field, which means that on a typical picture, everything or almost everything is in focus. That can be an advantage, but it can also be a disadvantage if you want to for example "isolate" an object by focusing on it, and having it show sharp and focused against blurry background.

    • It seems to me this might eventually be cheaper than a conventional focus, because it doesn't require any moving parts. Obviously it's not cheaper yet, but usually solid state electronics end up being cheaper than complex mechanical assemblies (pop open an old tape walkman sometime and check out the choreography of moving parts as you push "play").

      Assuming the microarray isn't part of the lens, you could seemingly reduce the cost and complexity of big telephoto lenses by a lot, which are the most expensi

      • Re: (Score:2)

        by aug24 ( 38229 )

        Effectively, we've reached the point where it's easier and cheaper and better to move electrons around nuclei, than to move nuclei around other nuclei.

        That really brings that 'living in the future' line into... focus.

    • when most people do not need the 12MP photos they take now; cam makers can offer this or similar features based upon the micro camera feature to sell greater MP sensors for images that are no larger than 12MP. Initially, I'd imagine they'd want a work around for when they do not want to use this feature so they can sell you a 18MP camera but the new mode outputs "small" images which are still plenty large for sharing online.

  • Conceptually, its a little like focus stacking http://prometheus.med.utah.edu/~bwjones/2009/03/focus-stacking/ [utah.edu] only with a compound lens that does all the exposures at once. More examples of focus stacking here: http://prometheus.med.utah.edu/~bwjones/tag/focus-stacking/ [utah.edu]

    • Re: (Score:2)

      by lahvak ( 69490 )

      I did not read the details, but the example pictures they provided did seem to have several distinct planes of focus that you could choose. With the size of the pictures, I couldn't tell whether the focus changes if you select two objects that are actually fairly close to each other, but it didn't seem so to me.

    • I use focus stacking for my microscopy, however does (or could) this method "scale up" to objects, or parts of objects, that span a much greater distance (i.e. beyond the mm or sub-mm range I have experience with (you're in a better position to answer this than me I think, judging from your post history). I'm asking because I know when I stack say 50 images each with a depth of field of 0.5mm to create an image with ~25mm (just as an example) alignment problems become problematic (I'm not talking about stac

      • Just adding to my above comment, those numbers I used as an example are not typical. More often than not the final DOF I am after is probably 1mm maximum and each photo in the stack has way less than 0.5mm DOF.

        • This system could well work for that, but as has been pointed out, you either use resolution or you scale up to a large, expensive sensor (16 MP sensor giving roughly a 1 MP image). Depending on the various tradeoffs it might be something Zeiss or Nikon would kick out (for a nice chunk of change, of course).

      • Re: (Score:2)

        by BWJones ( 18351 ) *

        Absolutely. The algorithms and principles are the same. The issue is that it tends to be more useful when your plane of focus (depth of field) is limited as it in in microscopy. You can experiment with this with an SLR camera by selecting an aperture wide open (f/1.2, 1.4 or 1.8 on a 50mm lens for instance). Take pictures of things close, mid and far away and stack the images. Works great.

        As for alignment, Photoshop CS5 contains algorithms that also automatically align your images. Very useful.

  • The first product will probably be a DSLR-sized sensor with mobile phone-type image sensor density. They are trading in a lot of pixels for this feature. You'll need 100 megapixel sensors to end up with usable image sizes as one microlens covers many sensor cells. It will be interesting to see how low light noise artifacts will look as there is bound to be a lot of them with such high sensor density.

    • I don't know how this technology works, but I can also imagine they may take several pictures with a normal CCD, with the lens going through a series of steps. Then in software, they may recombine the images, and compensate for the long shutter time by some kind of smart algorithm that tries to compensate for movement.

    • Re: (Score:3)

      by ka9dgx ( 72702 )

      Because a big sensor with a microlens array could be calibrated, you could use Richardson-Lucy deconvolution [wikipedia.org] to recover almost all of the raw resolution of the original sensor if the computing resources are available, in a given plane of focus.

  • useful for movies! (Score:3)

    by StripedCow ( 776465 ) on Wednesday June 22, 2011 @04:25PM (#36535084)

    For making movies, this would be very useful. Because when taking a movie, it is generally quite difficult to keep focus.

    • Re: (Score:2)

      by tibit ( 1762298 )

      Yes, but the way it'll be used is that synthetic focus will be applied during post production / editing, and it will end up as a "regular" film. IOW: nothing interactive about the end product, when used for movies.

      • It would be a huge time saver. Pulling focus gets complicated quickly. Not having to worry about it is one less thing to have go wrong. You can do less prep work, less takes, and require less staff. Save $$$ and now complicated things become more approachable for a lower budget film.

        Also, having that control after the fact in post production would be great. Got a poor performance from an extra in the background? Well, now there's a very simple way to make it less noticeable. A shot is too confusing and th

  • I've been doing this for a few years, with one camera taking many views, since I first found out about the research they were doing at Stanford. Here are some scenes around Chicago [flickr.com] which are composites of many photos to generate a synthetic focus. The idea is to capture the scene from many slightly different points of view, and to capture all of the parallax information, which then yields depth.

    I haven't be able to make it happen, but it should be possible to combine N pictures to get a bit less than N time

    • Re: (Score:2)

      by ceoyoyo ( 59147 )

      "I haven't be able to make it happen, but it should be possible to combine N pictures to get a bit less than N times the normal resolution. If you had 100 photos that were 8 megapixels each, you should be able to composite them into a 100 megapixel image with the right alignment and extrapolation algorithms."

      No, you can't. Using super-resolution and an expensive mount that can shift the picture by EXACTLY half a pixel (or a quarter, or an eighth), you can get better resolution out of multiple shots, but th

      • Re: (Score:2)

        by ka9dgx ( 72702 )

        Actually, with Richardson-Lucy deconvolution [wikipedia.org] it's possible to recover the information, as long as you have the positions of the pixels, and the diffusion function to enough precision.

        • Re: (Score:2)

          by ceoyoyo ( 59147 )

          No, it's not. You can do a little bit, provided you have enough precision moving the camera, but super resolution (no matter what deconvolution algorithm you use, and RL isn't exactly cutting edge) doesn't really buy you much. It's useful in a few niche areas, like microscopy, but other than that it's impractical.

          Yes, I did super resolution research a few years ago.

  • "hyper stereo" cameras (Score:5, Informative)

    by peter303 ( 12292 ) on Wednesday June 22, 2011 @04:35PM (#36535212)
    There has been a fair amount of computer science research over the last decade over what you could do if you took a picture with a plane of cameras instead of just one or two. The resulting dataset is called a "light field". You can re-composite the pixels to change depth of focus, look around or through occluding obstacles, dynamically change point of view, etc. As digital webcams became dirt cheap people started building these hyper-cameras and experimenting with them. people learned you could relatively interesting things with small arrays of 4 or 5 squared cameras. Later on they discovered you do this with one camera, with a multi-part lense, then reconfigure the output pixels in the computer in real time. I've seen all these systems demo'ed at SIGGRAPH over the years. Now someone appears to be commercializing one.

    I think the infamous bullet-dodging scene in the first Matrix movie was a type of hyper-stereo camera, a row of them albeit. The output lightfield was reconfigured expand point-of-view into time.
    • So basically what you're saying is you take an array of pinhole cameras, interpolate the array of images further, use the differences to generate depth, and then apply a post process? Or is it actually doing some resampling... like using the array of cameras as "film"? I was skeptical at first on hearing about this (they make it seem like a single camera), but now it makes sense. Clever.

      • Re: (Score:2)

        by peter303 ( 12292 )
        A desired output image may be (1) just one of the cameras, (2) a mathematical operation on a subset of cameras, or (3) a mathematical operation on all the cameras. I recall changing the focus is an weighted integral of all the cameras with the weighting kernal a function of depth and camera position. I'd have have to google "synthetic aperture" and "Marc Levoy" of Stanford for the paper. His research summery lists many of the light field algorithms with references to other work.

    • Re: (Score:2)

      by hitmark ( 640295 )

      Likely not even close, but the first thought that came to mind was the photo stuff from Blade Runner.

    • Re: (Score:2)

      by AmiMoJo ( 196126 )

      There was a story on /. a year or two back about un-blurring images, but I can't find it now. Basically all the information is there in the image, but what would be one pixel if it were in focus is actually spread over several pixels. Some software was able to gather all the info and bring blurred objects into focus. It wasn't perfect but still very useful.

  • Lots of red flags, little tech (Score:3)

    by erice ( 13380 ) on Wednesday June 22, 2011 @04:43PM (#36535296) Homepage

    All the information is about the implications but not about how it actually works or the trade offs required to get there. They also seems to going directly to the consumer. There are only two reasons to bypass big spending pros and prosumers when introducing new technology:

    • 1) The technology is useless for those who know was they are doing (face recognition) or
    • 2) The quality of the result is significantly lower than existing tech without compelling advantages for those who know what they are doing.

    My guess is #2. Exploding the pixel count of the sensor would make the product outrageously expensive. Clearly they are not doing that. So that means the quality suffers as finely adjustable optical focus is replaced by coarse digital focus achievable from the available sensors. We are probably getting camera phone level results. Good enough for Facebook but not something you want to print.

    • Look at page 4 of this: http://www.lytro.com/science_inside. You can read the founder's Ph.D. dissertation and I guarantee you'll get your geek on if you can follow it. It's a really excellent piece of work, and at the same time it is written in such a pleasant style that it keeps you curious and interested.

    • what this really means is that they know where the real market is. Good enough for Facebook is probably good enough for 90% of the people shopping for cameras.

      Don't get me wrong, I've got the whole DSLR thing and still have my medium format film gear, but sometimes I just want to whip out a small camera to get a shot of the kids and it would be nice to know that no matter what, I'll have an in focus shot now or in post processing.

    • Re: (Score:2)

      by brunes69 ( 86786 )

      Or #3... the product is cheap to make so they know the product will appeal to the mass market and want to make a metric shitton of money.

      The reason most tech goes to the pros and prosumer first is simply because new tech. is usually expensive to produce, so only pros and prosumers can afford it. These early adopters then drive the prices down for everyone else.

      If, on the other hand, the tech is cheap enough for the mass market in the first place, there is literally ZERO reason for a company to target the pr

    • I second jet_silver's recommendation that you look at the dissertation, which discusses the tradeoffs and is quite well written. You are correct that to achieving professional quality with this technology requires a huge number of pixels, though the cells themselves do not need to be very large. Such sensors are possible today but until now, there hasn't been much reason to produce them. If the company finds some success in the consumer market, perhaps it can then invest in the additional development nee

  • Now I hope when I watch a 3D movie, the focus of the picture follows what my eyes are focusing! That would makes 3D movie much more enjoyable.

Slashdot Top Deals

Statistics are no substitute for judgement. -- Henry Clay

Close