Lytro Camera: Understanding Focus After Image Acquisition

In summary, a company released a camera that allows for changes in focus *after* the image was acquired. This technology is very innovative and has the potential to revolutionize the way we take pictures. However, there are some limitations in terms of resolution at this point.
  • #1
Andy Resnick
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For those who don't know, a company (Lytro) just released a camera that allows for changes in focus *after* the image was acquired. Now that's it's been released as an actual product, I'm intensely curious to understand how it works.

Their website has a cutaway image, and the 'lightfield sensor' looks (or is described very similarly) as a Shack-Hartmann wavefront sensor.

http://en.wikipedia.org/wiki/Shack–Hartmann_wavefront_sensor
http://www.mpia.de/AO/INSTRUMENTS/FPRAKT/HistoryOfShackHartmann.pdf

Oh- the CEO's dissertation is posted on their site... whoa. This is pretty cool.

http://eces.colorado.edu/~pavani/Plenoptic.pdf [Broken]
 
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  • #2


The idea is extremely cool. Don't hold your breath for hi-res pictures, though.

You need a 2D image sensor (CCD, CMOS or other) behind each lenslet. So if each small CCD is, say, 30x30 pixels, then the lenslet has to cover the area of 30x30 pixels in a conventional digital camera. A camera with a total of 9 MPixels would have an effective resolution of only 0.1MP. So an in-phone focus-everywhere-at-the-same-time lightfield camera is not quite ready for the market yet.

The possible specialist applications where the overall size of the camera does not matter so much, however, are rather sexy. Think large format or medium format backs for existing cameras.
 
  • #3


I would LOVE this camera. I've been following its development for some time. Sadly it is not available outside of the US yet :frown:
 
  • #5
Here are interactive images in which you can change focus simply by clicking on a part of the field.

http://www.pcmag.com/article2/0,2817,2401039,00.asp

Looks like $400-500, depending on how much internal memory you want. You can buy one here. https://www.lytro.com/camera
 
  • #6


turbo said:
Here are interactive images in which you can change focus simply by clicking on a part of the field.

http://www.pcmag.com/article2/0,2817,2401039,00.asp

Looks like $400-500, depending on how much internal memory you want.

Great link turbo! That is very slick! The camera looks clunky. This technology can't be rolled into a DSLR or point and shoot?
 
  • #7


Greg Bernhardt said:
Great link turbo! That is very slick! The camera looks clunky. This technology can't be rolled into a DSLR or point and shoot?
I think they need all that depth to layer the sensors to allow re-focusing. I haven't seen a cut-away yet, but that seems to be a reasonable explanation for the length of the camera.
 
  • #8


fyi, a retired staff member works for Lytro. I'll see if I can get him in here to give us the scoop :)
 
  • #9


Greg Bernhardt said:
fyi, a retired staff member works for Lytro. I'll see if I can get him in here to give us the scoop :)
That would be nice. BTW, scroll back up to post #5. I edited after or during your subsequent post, to add the Lytro page with the "buy now" buttons. Apparently, you buy directly from them. I tried the usual suspects (Amazon, etc) and they don't carry this gadget.
 
  • #13


I think one of the real highlights of this camera is speed at which it captures images and the lack of moving parts. Also, I think there may be potential to have a limitless (or near-limitless) focus for these pictures.

Anyway, a very neat concept. In it's infancy there are certainyl some drawbacks (resolution, namely), but there is a lot of potential. I fear the need for them to make this stand out from the traditional camera did lead them to design what appears to be a brightly coloured wooden block.
 
  • #14


Greg Bernhardt said:
Great link turbo! That is very slick! The camera looks clunky. This technology can't be rolled into a DSLR or point and shoot?

I don't think it looks that clunky, at least not compared to a DSLR. The shape is needed because of the way the lenses need to work down the length of the camera. I bugged that retired staff member with a bunch of questions when it first hit the news last Fall. At least at the time, the limitation from my view is in the post processing software, but he assured me they're busy working on software to do what I want to do, which is to focus on more than one area of the photo at once, or get it all in focus, and to export as something other than jpeg. Right now, it's best if you do a lot of online photo sharing. It's really fun playing with the photos it takes. :biggrin:
 
  • #15


Moonbear said:
I don't think it looks that clunky, at least not compared to a DSLR. The shape is needed because of the way the lenses need to work down the length of the camera. I bugged that retired staff member with a bunch of questions when it first hit the news last Fall. At least at the time, the limitation from my view is in the post processing software, but he assured me they're busy working on software to do what I want to do, which is to focus on more than one area of the photo at once, or get it all in focus, and to export as something other than jpeg. Right now, it's best if you do a lot of online photo sharing. It's really fun playing with the photos it takes. :biggrin:
Yay! Let's see what happens.
 
  • #16


Mech_Engineer said:
I find its ergonomics to be lacking.
I thought that at first but I've since changed my mind (perhaps I'll change again if I ever get one in my hands). It's nice and compact so could easily fit in a bag or jacket pocket without worry and seems quick to be able to grab, point and shoot. The advantage of course being that it doesn't matter if your pic is out of focus.
 
  • #17


The DPReview commentary is spot-on, in my opinion. Keep in mind that the first digital cameras 15 years ago had crappy resolitions like 1.2MP. This is a technology to watch, but it is not quite ready for the mass market yet. Can't wait to get in-browser support for dynamical refocussing on photo sites like Flickr.
 
  • #18


Something I can't figure out is if the processing will work with volume scatterers- rain, fog, inclusions in a glass object, (ahem) shower curtains... can it be used to remove atmospheric turbulence?
 
  • #19


Good question. How do you focus a random wave front?

In telescopes they can do that because they know the object is far far away, therefore the "corrected" wave front has to be flat.

I guess if you knew at what distance to focus you could calculate the curvature the wave front should have and correct for that. So you might be able to get a sharp image of a point source in fog. If you have several sources in the fog that give overlapping wave fronts on the camera's sensor... good luck.
 

1. What is a Lytro camera?

A Lytro camera is a specialized type of camera that captures a "light field" image instead of a traditional photograph. This means that the camera records not only the color and intensity of light, but also the direction and angle of light rays. This allows the user to adjust the focus of the image after it has been taken.

2. How does a Lytro camera work?

A Lytro camera uses a complex array of lenses and sensors to capture the light field data. The data is then processed using specialized software, allowing the user to refocus the image after it has been taken by manipulating the light rays in the scene.

3. Can I change the focus of a Lytro image on any device?

Yes, as long as you have access to the Lytro software, you can refocus the image on any device. The Lytro software is available for computers, tablets, and smartphones.

4. Are there any limitations to using a Lytro camera?

One limitation of using a Lytro camera is that the final image quality may not be as high as traditional cameras, as the light field data must be compressed in order to be viewed on devices. Additionally, Lytro cameras are not suitable for capturing fast-moving objects or action shots.

5. Can a Lytro camera be used for professional photography?

While some professional photographers have experimented with using Lytro cameras for certain types of photography, they are not yet widely used in professional settings. The technology is still relatively new and may not have all the capabilities and features that professional photographers require.

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