Slashdot Mirror
Wavy Lenses Extend Depth of Field in Digital Imaging
genegeek writes "On Feb 25 CDM Optics was awarded a patent for a new digital imaging system utilizing "Wavefront Coding" that produces images with 10-fold the depth of field of conventional lenses. The image itself is blurred until processed. Image examples are here."
Basically what this is saying is that if I go out and get a new whiz-bang camera with this funky new lens, I will be able to take a picture almost as good as the pictures I take with my 30 year old Cannon AE-1, and not have the leeway of doing photo processing tricks in the darkroom.
Personally, I will stick to analog photography.
You say you want a revolution....
Yes. Even with the new lenses, they didn't see the Slashdot Effect coming. :)
They did, but didn't have time to process it so it was too blurred to make out :)
Ah yes, I know this system well. I did my master's research in extended depth-of-field optics and came across this research which pretty much blew away what I was working on.
Here's a bit of background: in photography or laser scanning (point-by-point photography, basically), you always have a trade-off between depth-of-field and aperture size (as any photographer knows). Bigger aperture means shallow depth-of-field. However, a smaller aperture means lots of wasted light (imagine closing the aperture in your camera), and this means longer exposure times, and more importantly more NOISE in your images. This is true for digital, film, or photodetector.
So the "holy grail" is to keep the aperture open but still have high depth-of-field. This system depends on changing the phase of the light, instead of the amplitude (which is what you do when you stop down a lens to a smaller aperture). That way, no light energy is blocked and wasted.
Since the phase is changed, the resulting image on the CCD or film is fuzzy and has to be "decoded". You can think of it as "encoding" the wavefront in a special way that preserves the depth of field, capturing the image, and then "decoding" it into a sharp picture. It is really amazing. I hope it shows up in consumer cameras someday, it could completely change consumer photography since most "snapshot photographers" don't care about depth of field or all that stuff. It will also be great for medical and industrial imaging.
My system was sort of a hybrid between shading the aperture (instead of a sudden stopping of light, it gradually goes to black at the edge) and phase changes. Lots of people have been working on this problem over the years, but these guys really stripped the problem down to the essence and came up with a highly optimized solution.
Just because the base image quality may not be better (for 8x10 and larger from a 35mm sized camera, digital is so much better, but I like analog for 3X5 snapshots) doesn't mean the tricks and effects are neccessarily better.
Photoshop is great software, but no matter how much I try, basic manipulation (on b&w images particularly), especially brightness/contrast adjustment and dodging/burning, always gives me much better results under an enlarger. Same for exposure effects; Photoshop's solarize filter is good, but there's just some intangible warmth and...analog-ness to a well-solarized paper print. Maybe it's just the random scatter and size of the grain of film against the gridded regularity of the digital images, or the slight variation in quality across the print (not imperfect, but not...digitally homogenous), but for purely aesthetic ends, I have to go with film and paper.
Facts do not cease to exist because they are ignored. - Aldous Huxley
A story...on Slashdot...about a patent...that's legitimate?
I'm suprised, the USPTO actually managed to issue a patent for something new and innovative and unique, rather than for something thats been common practice for a few years.
If I have been able to see further than others, it is because I bought a pair of binoculars.
I don't get the sense that you've ever used a good digital camera.
I've blown 6MP images up to 20"x30". They look great. Good enough that people gush about how great they look when they buy them from us, at least. While I don't have access to an 11MP camera, I can't imagine that 30"x40" would be too much of a stretch.
Keep in mind that I'm talking about images from a $5000 camera, not a piece-o'-crap point-and-shoot.
ZFS: because love is never having to say fsck
There are at least two experienced photographers (Rob Galbraith and Michael Reichmann) who feel that the 11-megapixel Canon EOS-1Ds delivers images with detail exceeding that of 35mm and approaching (in some cases besting) medium format film. They've published some very interesting comparisons:
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http://www.robgalbraith.com/bins/content_page.a
http://www.luminous-landscape.com/reviews/camer
This may just change someone's opinon on how digital compares to film. I know it made me rethink the "conventional wisdom" that many more pixels are needed to reproduce film detail.
Cheers,
Jeremy
... and I can't find out because the site is /.'ed :-( :-) but some of us nature photographers do.
is this: Can this technology be used to control (not just increase, but also decrease) depth of field at image processing time? More specifically, can I get selective focus *after* creating the image? In criticizing my own work, I ususally wish I had openned up for *less* depth of field. I realize that sports photographers don't have this problem
Although Colorado University may never forgive me, this address has links to the research papers as well as more images: http://www.colorado.edu/isl/
There were two approaches:
1) Throw a shitload of light on the scene (This is what they did for the effects work on "Darby O'Gill and the Little People..Peter Jackson eat your heart out)
2) Use a diopter, a lense that changes focal length split down the middle, so that half the image is at 20mm, and the other half is at 120mm (for instance). This was a trick pioneered by Orson Wells, I beleive.
What were you expecting?
Slide film captures the colour exactly as it was, whereas digital rounds it to the nearest bit.
This is what we refer to as "argument by bizarre definition".
Slide film captures color via photochemicals that change in response to light. Digital cameras capture color via sensors that signal in response to light. Saying that one is better "by definition" is patently absurd.
If slide film is inherently perfect, why are there so many different slide films with different color responses? If slide film captures color "exactly as it was", why is Fuji Velvia widely known for producing great landscape shots but murdering skin-tones? Slide film has all the same color concerns that any other capture method has -- good red response but poor greens, or great blues but muddy purples, for instance. Nothing is perfect, especially when the only real way to judge them is using the also-imperfect human eye.
I'm not basing my "better color" assertion on a bizarre definition of the abstract ideal. It's just my opinion, but I hold that my professional digital SLR, with little or no post-processing, produces better color than anything the film world has to offer. "Good color" is a subjective thing, and while you may disagree with me about that (cite examples please!), I stand by my statement.
ZFS: because love is never having to say fsck
If anything, as other people posted, digital is closer to the "real thing".
One person mentioned that Fuji Velvia is great for landscapes but murders skin tones. This is because the sensitivity curve of a digital can be easily optimized, while it's very difficult to tweak the sensitivity and linearity of films based on chemical reactions.
As to rounding to the nearest bit - There's a lower limit in both electronic and film recording of the precision that a light level can be recorded which is distinguishable from noise. This is called the "noise floor" - Use enough bits, and then all the bit roundoffs will be well below the noise floor of even film media. (Which does indeed have a noise floor, just as digitals do. The nice thing about digitals is that with improved electronics and sensors, the noise floor of the sensor is dropping while film is staying the same. One of the things "pro" digitals are known for is having far less noise than lower-end digitals, and those improvements are constantly moving down to the consumer level.)
And for those that WANT the nonlinearities/quirks of film - All a camera manufacturer has to do is model the nonlinearities of major film types and then they can easily be emulated, just like guitar amps that use modeling techniques to emulate older units.
retrorocket.o not found, launch anyway?
http://www.economist.com/science/tq/displayStory.c fm?story_id=1476751