Monday, April 18, 2011

EDoF vs AF Comparison

All About Symbian publishes a nice comparison of EDoF and AF camera phones. Nokia E52, E55, E5, E6, E7, C6-01, C7, and X7 phones are EDoF-based, while E72, X6, and N8 have AF cameras.


  1. interesting read.

    Which other phone manufacturers use EDoF other than Nokia?

  2. i believe palm used a stm/dxo part w/ edof. lots of people were shocked that it wasn't an ovt part after all the hype ovt disseminated about edof(wavefront coding) after buying cdm. and i've heard that samsung also has edof in some of its phones but never confirmed this.


  3. Long live EDOF!

  4. Edward Dowski of CDM Optics (part of OmniVision) has done a lot of work on this type of application (although they call it "wavefront coding"). Maybe they're making the camera modules for Nokia?

  5. I thought the illustrations in the article were good and showed the power and problems with EDOF. I think the extended depth of field was clearly shown in the sample pics. One cannot argue with data.

    But, the problems are (at least) three-fold.

    First, humans don't see the world with EDOF so that natural pictures with EDOF look a little strange - at least to my eyes. The girl in the pipe is a good example. It just looks wrong and unnatural. Interesting effect, however.

    Second, low light performance has always been a major metric for camera-phone manufacturers, Nokia especially. As far as I know, and as mentioned in the article (but for the wrong reasons, I think) EDOF does not work well in low light. I am not sure how well the story carries over, but I recall well when NASA/JPL launched the Hubble Space Telescope with perfect but out of focus optics. Image processing software could do a good job at fixing most of the focus problem but not all of it, especially when the SNR was weak. Eventually, many many millions of dollars were spent to fix the optics (actually, replacing the whole camera) via a Shuttle mission because one could not image-process-out the focus problem.

    Third, as the article also notes, AF is quite good for shooting printed documents with a camera phone but EDOF cannot do this, at least not yet.

    There are additional power issues associated with EDOF that trade against AF power issues but perhaps these are not as important.

    My information on EDOF v. AF is a little old - I haven't worried about this much since the Siimpel days (when we were making MEMS-based AF actuators and shutters). I wonder if someone who says EDOF is dead can explain their rationale based on the last 4 years? My thoughts from 4 years ago were that EDOF combined with AF might be pretty powerful.

  6. Most of the rants on EDOF is due to its inability to take clear photos of documents/food etc. This is largely a misconception. Similar EDOF provider for Bird handsets in china were already using EDOF that could do 15cm -> infinite.
    DXO latest EDOF + DOP7+ could do 10cm -> infinite.

  7. I spent quite a bit of time evaluating EDOF from several different suppliers. There definitely were image quality trade-offs including loss of resolution. For an image the size of a cell phone screen, you couldn't detect the loss of resolution, while the sharpening made the image look better. But if you zoomed in at all, EDOF was worse.

  8. Why to use EDoF to compete with AF?
    With EDoF, you can use large apture lens not only in order to improve low lux performance but also increase the FMT yield rate for AF modules...

    CDM and Tessera have similar methodology to implement EDoF while DXO chooses a simple way.

    Now who has mature EDoF modules? Surely STM, Toshiba and Sony. Samsung is still behind. OVT is never an EDoF player...

  9. if i wnat 2 buy a new phone for a good photography which one would be the best option between nokia asha 311 and c2-03..coz one has EDoF technology and one has plz u all kindly suggest ur reviews..!!!so dat i can make a better choice. :)


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