PureView: Phase Two

[False Morel]

The initial PureView model focused on the problem of digital zoom and perfect details. Phase two of development focuses on low light performance, and adds more practical features that will allow more camera phone users to take better pictures.

The number one camera phone annoyance – fixed

Low light performance has been improved through two particular measures.

First, the sensor type has been changed. A next-generation Back-Side Illuminated sensor is fitted that places the photosensitive area directly beneath the lens, without wires or metal between, as is the case with Front-Side Illuminated sensors. More light reaches the plate, in other words. That’s of critical importance when there isn’t much light around.



Image captured with a Nokia Lumia 920



Image captured with a Samsung GSIII

Second, we’ve adopted a massive f/2.0 aperture – in layman’s terms, it’s a bigger hole, and so it lets in more light from the start when you’re using it indoors. Both these measures mean a lower sensor size is needed in order to get great results when you’re working in low light.

Ready, steady, snap

These advances are complemented by Optical Image Stabilization (OIS). Your pictures and videos won’t blur when your hands are shaking, or when you are on the move. Again, it’ll help in low-light conditions where exposure times can get significantly longer.



Image captured with a Lumia 920



Image captured with a competing high-end smartphone

The OIS technology isn’t a digital algorithm, like you may have experienced previously. Crucially the rear-end of the camera is caged with a gyroscope to move the whole optical assembly to compensate unintended camera movement. Enough explanation: this video tells the story best.



This is a simulation of OIS technology.

As a self-confessed terrible photographer, thanks to genetically inherited shaky hands, it’s this part of the story that interests me the most.

But there’s more…

The Nokia Lumia 920 packs a new generation of LED flash. This can be used as a continuous light for video and – for the first time – a pulse burst flash. The technology behind LED flash has improved significantly over a period of mere months, to be able to accurately freeze subjects under many more conditions than used to be the case.

Next, the image processing algorithms on the Lumia 920 significantly outshine any found on previous camera phones. In particular, the ‘denoise’ algorithm for reducing any visual noise from images is brand new and better than ever. These advanced algorithms compensate for not having the oversampling technology used in the previous generation of PureView.

Once more, we’d urge the true camera-fanatics to take a look at the white paper for more in-depth information. Even if you’re not, there’s a ton of information there that’s just plain fascinating for anyone with an interest in photography.

White Paper
Source

[False Morel]

[False Morel]

So as I mentioned in the other thread, I had some photos with my DSLR for that set up Nokia had to test the 920's low light imaging.

What I tried to do is go as close as possible to the Lumia's setting, first to have an idea of an estimation of what slow SSs it's capable of, and also compare the overall quality to that of a high-end DSLR.

For the Lumia 920, we know it has an equivalent of 26mm focal length, F2.0, and won't be shooting high ISO similar to N8 and 808 due to much smaller sensor. Despite the fact that the new BSI sensor is new and tech has moved on from two years ago when the N8 came out. But still size does matter in this situation.
So regarding ISO, I doubt Nokia would go over 400 ISO on automatic setting.
Let's suppose they use ISO 200 since they're using longer SS for correct exposures and also minimize noise levels.

On my DSLR, my lens was wide enough to match the 26mm wide angle, but not the F2.0 as it has a max of F3.5 aperture. The other lens is capable of F1.8 but it's a fixed 50mm equivalent lens so no good. Although focal length is not that important here but still such a big difference could skew the results.

So I had to settle for F4 for the 26mm equivalent, and had to boost up the ISO to compensate for the lost stops.
F4 to F2 is two full stops. That means I have to double the ISO two times: 200*2*2 = 800 ISO for my DSLR.

The mistake I did is I forgot to shoot one photo in complete Auto mode. And one photo in Aperture mode where I fix the aperture to F4 and ISO to 800 and let the camera decide for the SS..

I may I go one more time on Sunday. I will then take these photos.

Anyway, forward to the pics:



This one is taken with the 52mm equivalent lens. Hence the narrower view angle.
The cam was P mode. ISO set to Auto. The camera went for F1.8 (max aperture) and 6400 ISO (max ISO before one jumps into High Mode), and 1/25s SS..
Interesting part is actually the cam could have went a stop down with the ISO and halved the SS to 1/13s..

Should have tried full Auto mode with this lens too, but sometimes I forget I have this mode on the camera..



Jumped to the zoom lens here. Manual mode.
This one is at 1/2sec SS, F4, and ISO 800. Although the lens features VRII, latest OIS from Nikon, I couldn't manage to avoid the blur!!
And it's underexposed too! Which is weird as well!! This tells how dark that set up is!! (that combination actually add up to a relatively high EV)



So here I jumped to 1 second SS, and the aperture third stop lower at F3.8. Exposure good but no OIS can handle this!

So actually I'm left with more questions than answers. How did the 920 achieved that exposure at relatively low ISO?!!
The Nokia rep told me 920's OIS is capable of compensating up to 3 to 4 stops!

Nikon claims VRII could do 4 stops! Nokia did claim that their OIS is 50% more effective than high-end SLRs! 50% more means 6 stops!! I find this hard to believe!
If they achieved it, then it answers the raised questions and would be a marvelous achievement. 6 stops!! But I won't believe it for now!

Anyway, my testing was a bit rubbish too. The place was crowded. Had to bend awkwardly to get the camera to the opening of that set up, and also had little time to think of my calculations and missed some points.

If I go again Sunday, I'll be ready this time.
Note that due to sensor's size, the optical performance will differ. But what we're looking after here is the exposure and blur due to long SSs..

[False Morel]

So here's the update from today:

This time I was a bit more cheeky trying to get some answers, and I did got some:
- Lumia 920 goes up to 1/3sec SS in auto mode, and up to 1 sec in night mode!!
- As to ISO, range is 100 to 800. On those low light photos, Lumia should be using ISO somewhere around 200.
- Not sure of the LED flash! I insisted to see a photo taken with flash on. One photo was good, one wasn't. And it wasn't as dark as in a bar for instance!! Now for normal paused photos one could use night mode without flash. But for capturing kids, or someone dancing, or doing any movement, one can't go for long shutter speed. Flash is needed.
- The rep said the Lumia is expected for a mid November release!! But he could just be playing it on the safe side. Phone should be released between 26th of Oct. and 3rd of November.
- Smartshoot and Cinemagraph Lenses are developed by the company Nokia recenlty bought! So these are not in-house all through project. Still nice hunt by Nokia.
- The rep today didn't know how to demo Smartshoot! I can't just take the phone from him and show him how it's done. But what he did is he thought Smartshoot works with your main subject moving! (He mixed between Cinemagraph and Smartshoot)
For instance, in a group photo, each member poses differently evrey one to two second. It doesn't work like that! Smartshoot mainly recognizes moving objects in order tends to remove them or manipulate parts of a non-moving object; for instance a changing face of a non-moving head, but not the head altogether or arms floating around or someone jumping in place! Not sure if final version or in future upgrades it would be able to go that far, but at the moment it can't.

But this doesn't take anything of this great feature! In group photos, everyone tends to freeze into position, but everyone smiles at different times! Could be less than a second between a smile and another. Here comes in smartshoot to ensure every smile is captured. You switch between face expressions (mostly eyes and smiles) of each person to choose the best, and go on to the next one and so on. It can also apply to single portrait even! And of course ability to remove surrounding moving objects/persons.

Anyway, further with my analysis, I took further shots:

Last time I forgot to shoot in auto mode, as well as in P mode for the 16-85 lens.
It turned out auto mode will trigger the flash and I can't do anything about it. So away with it, it seems it will stay unused forever.
So I took a shot in P mode this time. However, I ended up deleting the photo after I left the booth by mistake as I intended to delete another one shot directly after it. Coudn't retrieve it back with a dedicated software as well.
Anyway, it looks similar to the P mode photo above with the 35mm lens, only that it's shot at 24mm equivalent instead of 52mm, and as F3.5 was the max aperture it could go for instead of F1.8 on the other lens, it went for longer exposure at 1/2.5 sec to compensate for three stops lost! ISO remained at 6400. Saw it only on the camera display but the result was decent, similar to the above P mode but wider.



This one I also forgot to shoot last time: Aperture mode, F4, ISO 800, meant to see the SS the camera went for.
It went with 1/3 sec.. Same exposure the 920 goes for: 1/3sec SS, F2, ISO 200. So same SS as the 920's!!
It's not blurry. Acceptable. Too bad don't have the full resolution 920 photo to compare it with directly. But as far as the blur goes, both are good.



This one turned back to manual mode again: 1/2sec SS, F4.0, ISO 800.
There is a slight blur into it. But generally acceptable. Could be used.
I supported my hands a bit (but not the camera) to the opening of the box though.

Here's that set-up btw:




(Photos not shut by me)
t's ridiculously dark. The cameras at these shutter speeds, produce brighter images than the human eye can see!



This with 1/2sec SS, camera completely held in the air. Didn't work. Same as last time.



These are the camera modules of the 920 and 808 respectively.
The upper one is the 920's. It's significantly thicker, and in width and length, both are almost the same.
OIS does take a lot of space! I do think if Nokia wanted to go with the 808's module, they could have fitted it there.

And here's my take on the issue:
- Low light and video professional stabilization, though, fit the modern Lumia and current consumer demands more than a geeky 41MP oversampling technology that could only benefit those who want super clear high quality photos under good lighting.

- Lossless 3x zoom though is not geeky. But I'll take low light and video stabilization over it at any given time.

- Xenon is definitely not geeky too. And shame Nokia didn't go for it! Can't tell if size was the issue, power consumption, or as the lady (pictured above) told me due to LED's uses in video mode and as a flashlight! But they could have went for both really! Like in the 808. This is the biggest let down to me of the 920 actually!!

So the average users' needs dictated this move by Nokia. That's how I see it.

Anyway, it's confirmed that Nokia are working for a solution to combine both phases into one for future products. It's challenging, but should be doable.


Conclusion:

- So biggest conclusion of this is that the 920 is capable of hand-held 1/3 shutter speed; all due to its OIS which is on par with high-end professional products!
- At night mode, it can even go as far as 1 seconds, but as the rep told me, one needs to keep the hands as steady as possible. With alcohol or caffein effects, it might not work. Still, a big feat there. Chapeaux bas!
- Lack of Xenon is killing me! Hope they bring it back once and for all on future flagships! Or at least bring LED into a state where it's as capable as Xenon!
- Cinemagraph and Smartshoot are more than cool! They're capable tools!!

The Lumia 920 just can't arrive soon enough! And this is the biggest negative so far!