Thursday, 23 September 2010

Lumix 12.5mm 3D lens

Ok, so this lens has just been announced, and obviously I have not tried it. So this is based on what I have read about the lens so far.

Since writing this, I have made a review based on using the actual product.


Contrary to what some people say, I actually find this lens pretty interesting. Some say that Panasonic should rather spend the time developing "real" lenses. However, I think that this lens might have some real creative potential, and it also serves to bring more interest into the Micro Four Thirds system. So what's not to like?

Focal length

The lens is specified to have a focal length of 12.5mm. However, don't let that fool you into believing that this is a wide angle lens. Far from it. The two separate lenses project image circles that are smaller than the full sensor. Hence, there is an additional crop factor to take into consideration.

The field of view is comparable to a 65mm lens on traditional 35mm cameras, corresponding to 32.5mm on Four Thirds cameras. Hence, this is a long normal lens. Observing that 32.5 / 12.5 = 2.6, we can conclude that this lens has an additional crop factor of 2.6, beyond the crop factor of Four Thirds lenses, which is 2.

On the Panasonic Lumix GH2, the lens produces stereo images of 2048x1536 pixel resolution. With the GH2 having 4602x3456 pixels, this means that each of the two stereo images comprise 20% of the image sensor. Here is an illustration:



Aperture

With a fixed aperture of f/12, the lens gives a deep depth of focus. Which is good for a lot of applications. On the other hand, at f/12, you will need to push the ISO up unless being outside on a sunny day.

3D effect

Obviously, the 3D effect is achieved by having the two separate lenses seeing slightly different perspectives. The lenses appear to be very simple constructions, with four lens elements in three groups.

The stereo base, the offset between the two lenses, is 10mm, corresponding to about half of the sensor width. This looks like a very short distance, and I am unsure if any significant 3D effect can be achieved with this short lens offset. Perhaps the 3D effect can be boosted in post processing?

Usage on non-compatible cameras

When used with a 3D compatible Micro Four Thirds camera, you can probably use the lens in a seamless fashion. The viewfinder will probably not show a confusing picture like the illustration above, but rather one of the subsections, to make framing easier. Compatible cameras at the moment include Panasonic Lumix G2 and GH2.

With an older, non-compatible camera, like G1, GF1, etc, I'm guessing the lens can be used like all others, with the exception that the two lenses will not illuminate the whole sensor. You may need to set the autofocus point to somewhere off centre, for that reason. Perhaps you will also need to change the exposure mode, since parts of the sensor are not exposed.

Of course, if the lens is used with non-compatible camera, i.e., anything older than the G2 or GH2, then you must convert the image into 3D in post processing.

13 comments:

  1. FYI, according to Panasonic's 3D lens specs the stereo base is 10mm [ see: http://panasonic.net/avc/lumix/systemcamera/gms/lens/g_3dlens.html ]. I'm quite curious too as to its actual 3D effect capabilities.

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  2. Hi,
    If i use the 3D lens on my GH1, would i bew able to focus?

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  3. I guess you would. If you put the focus spot area inside one of the exposed circles.

    But using the lens on a non-compatible camera would not be very convenient. You would need to cut out the individual stereo images for further processing manually.

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  4. So, your recomendation will be to sell my GH1?

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  5. If you want to use the 3D lens, then it will certainly be more convenient to use a G2 or GH2, that's for sure.

    I've read that these cameras cannot record 3D movies with the lens. That may be worth noting.

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  6. G2 nor GH2 can't record 3D movies?!

    How about the Loreo 3D Lens?

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  7. You can certainly record movies with the Loreo lens attached. But to convert this into a 3D video that you can playback on a 3D tv, for example, is going to require post processing.

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  8. What do you think about the GH1 vs G2?

    Do you think is worth selling my GH1 to get a G2?

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  9. Depends on what you want to use it for. The GH1 is probably still a better camera than the G2 in terms of image and video quality. On the other hand, I like the ergonomic of the G2 better.

    So do you want to retain the better image quality, or do you want the updated ergonomics?

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  10. Great, thanks for your advice!
    Love your reviews

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  11. The lens is nearly useless for general 3D photography (too small stereo base) but becomes VERY interesting once modified for 3D macro photography (unscrew the 3 screws, insert washers (0.5-1 mm) so you can focus a close distance).
    You can also place a piece of tape on the lens contact (the first 6 are enough CW) so the lens will act as a dumb lens (anyway it's already fix-focus and fix-aperture). Then you can use the full sensor surface (taller images), use RAW or make videos.
    Full instructions (by DrT):
    http://3d-con.com/files/PANASONIC-3D-LENS-NSA2013.pdf

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    Replies
    1. Yes, regarding your idea to mask the contacts to use it as a dumb lens. I have tested that myself, and as you say, it is still rather poor for general 3D photography.

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