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July 24, 2012

The iCamera (Nokia 808 Pureview) Part II: In the studio ;)

A still image taken in the studio by the Nokia 808 Pureview mobile phone
-- Please, click onto the image to access the uncropped full 38.4 megapixel image --


First of all, I'd like to clarify that this article isn't meant seriously. The Nokia 808 Pureview (808PV) isn't a studio camera. Medium format cameras and the Nikon D800E play in their own league when it comes to work in the studio. And they better do as the 808PV is positioned as a mobile phone ...

But just for the sake of having some fun, we can ask the question of how close the Nokia 808 Pureview (808PV) is actually being able to get to true studio cameras. And so we did :)

Above, you see "Young Fruits" in the studio, shot by the 808PV. I ordered some other young fruit but without going into to much detail, "Plan B" turned out to be it ;) You can click the above image to access the full resolution image. It isn't the JPG out of camera. It is the JPG after doing some post processing in Lightroom (no, the 808PV doesn't write RAW but this isn't a big problem for Lightroom). I basically improved contrast and adjusted colors a bit. I personally consider such things arbitrary as you can change settings in camera too. The image's EXIF data reads: 8.016 mm f/2.4, 1/100s, ISO 50. The image's physical size is 7.5 x 10.0 mm^2 (crop 3.45), i.e., the 35mm-equivalent EXIF data reads: 27.7 mm f/8.3, 1/100s, ISO 600.
It isn't actually simple to use the 808PV in the studio. This is the procedure I was going to follow:
  1. To save you a few hours of frustration:
    Do not use CameraPro, use the 808PV native camera app!
  2. Set the 808PV into creative mode, full resolution with 4:3 aspect ratio, super fine JPG, -1EV exposure compensation, sunlight white balance, ISO 50.
  3. The tricky part: Set flash to "Red eye reduction"
  4. Configure your studio flashes into slave mode.
  5. Focus with the Xenon flash allowed to act as focus assist, or with an external focus assist light source.
  6. Fire with 808PV Xenon flash:
    - either covered by paper to remove its effect from the photograph
    - or from a few meters distance where it appears darker
    - or alternatively enforce the ND filter which makes the Xenon flash appear darker too.
    The studio must be dark enough to make the 808PV use the flash at all. Because the "Red eye reduction" setting doesn't enforce flash in turn. The paper cover must not be too dark to hide it to the slave flashes though.
  7. Another tricky part: Your studio flashes need to be powered for f/2.4 ISO 50 (which is low power) or 3 stops higher power when using the ND filter (which is a bit above normal power, as would be used by ISO 100 f/9.6). But at the same time, the power must be low enough for your studio flashes to discharge twice within a fraction of a second. In my case, this required the flashes to stay at 1/2 power or below. Which I am perfectly happy with.
Following this procedure, the 808PV will fire the flash three times: a preflash to determine exposure, a first flash to make the eyes close and soon after, the final flash for the exposure which will have studio flash support again. The second flash will come too soon after the preflash to trigger the slaves. Some slave flashes can be configured with a trigger count. You can then use "2" and don't need the "Red eye reduction" setting. CameraPro seems to do the Red eye flash manually which implies that a second preflash is fired and synchronization fails. I had no problems to get the 808V to use anything between 1/100s and 1s exposure time. If you obtain faster than 1/100s or 1/200s exposure times though, you can dial in less than -1EV exposure compensation.

The 808PV has an ND8 filter which you can see with your naked eye when looking at the lens: there first is a protective glass, then a motorized protection shutter, then a motorized ND8 filter glass, and eventually there is the fixed aperture lens with focus motor (you can see the lens move forth and back). I wanted to make sure that the ND filter doesn't negatively effect image quality, so the image above has been made without ND filter. However, I have seen little or no negative impact of the ND filter on image quality. So, the above procedure may be easier to follow with enforced ND filter and I recommend to do so (if your studio flashes recharge quickly enough).


Result:

The results are pleasing. I invite you to click the image above to see the full size version. The quality is certainly good enough for most applications. And probably beats anything APS-C or FourThirds.

However, it isn't without quirks. First, enforcing ISO 50 is crucial. The pixels are small (1.4 ┬Ám) and therefore, the 35-mm equivalent sensitivity is ISO 600. I.e., the pixels aren't entirely noise-free and it doesn't help that they need some sharpening to get rid of diffraction blur. Moreover, the autofocus isn't fast and it isn't very reliable in studio modeling light (using the ND filter doesn't help either -- it is not switched off during AF ... ;) ). Therefore, the kind of studio work which would also use a tripod is quite feasible. But shooting is nowhere near as fast or reliable as with a dSLR.

Also, I had to ramp up the contrast a bit. It may be that the studio light from the sides create a little bit of stray light lowering contrast. Nothing serious though. And to be fair, the 808PV uses no lens hood :)

Look at the strawberry right to the peach, the bell pepper tip to its left, or the peach itself: IMHO, the level of detail is great.

However, before enthusiasm rises too high, I post the same subject shot with the Nikon D800E, for comparison:

A still image taken in the studio by the Nikon D800E 35mm digital SLR
-- Please, click onto the image to access the uncropped full 36.2 megapixel image --
While the level of detail in the image from the 808PV was great, it is simply stunning from the D800E. Just look at the peach'es hairs ...

So, while the 808PV delivers great results for static subjects in the studio which is good enough for professional use, it doesn't actually compete against the D800E or medium format. At least ;)

9 comments:

  1. Very informative article, as always.. thanks for sharing. Have you tried a studio shot with the 808 in PureView mode ? I like what it does in outdoor/landscape shots, but I curious how it would do in a studio setting.

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    1. Thanks for the reply and no, unfortunately I did not try it in Pureview mode here. I assumed that I have all freedom for downsampling in post-processing. But I may independently look at the Pureview scaler vs. known algorithms in another article. Thanks for the inspiration.

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    2. I dont think that pureview tech can be compared with dowsampling, otherwise they will just called 808 Downview :) . So a comparison 808 at 38mp vs 8mp PV will be nice

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    3. Nokia said that their pureview downsampler is AT LEAST as good as anything found in Photoshop. I doubt that but at the same time, my curiosity is limited about the subtle details which may exist. Personally, if I would have to guess, I would guess that they used a FIR filter.

      BTW, Nokia built a coprocessor dedicated to downsampling (called the scaler, able to process 1 billion pixels per second, part of the camera module) and I have reason to believe that its output compares well with downsampling. I may look at it when I look at video.

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  2. Tks for the test, D800 is still a bit better, but you can't call anyone with it, or get called. Maybe in a few years Nikon will include a phone in the D8000, :-). I use a NEX-7 and an S5Pro, by the way. I just have to buy a new cell phone those next days, mmmmhhhh .....

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  3. Great article. I particularly like your detailed explanations with tips on how to pull it off. Hopefully Nokia will pull together all these tips in a Pureview online booklet, because it would just make their product so much more powerful in the users' hands. Thank you again!

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  4. Related to item 6 in your procedure: I read somewhere that placing an exposed film in front of the master flash will block all the visible light but pass the frequency needed to trigger the slave... is that the case?
    Also, couldn't you place a small mirror in front of the master flash and direct the light away from the subject but towards one of the slave flashes?

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    Replies
    1. I am not sure about the exposed film trick. But thank you for the hint. And you're right of course about the mirror. But using any kind of master flash manipulation (paper cover, mirror etc.) is tedious because the 808's camera module is so tiny. I needed an assistant. So, in practice it would have to be taped to the camera. Which is why I think that just using the built-in ND filter is the easiest solution (where it works).

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  5. Thanks for the Article.
    But I think the fact of comparing Pureview to D800, Makes Pureview a hero since it`s smartphone.

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