File this under data points of interest, but AAWP reader Andrew Elliott had taken the time to shoot the same subject every ten minutes or so through a UK summer evening, giving a chance to see how well the Lumia 950 does - OIS, 1/2.4" sensor, f/1.9 aperture, and so on. The results are subjective in that only the 950 was tested, but the chance to look at an interesting scene as the sun sets proved too tempting. It's a novel way to test low light performance from a camera phone and i thought you might be interested too.

Of course, the Achilles heel of the PDAF (Phase Detection Auto-Focus) in the Lumia 950 is that, like traditional contrast-based focussing, it's not brilliant in low light and a few of Andrew's images have slightly indistinct focus. But the tests were still worthwhile.

Here's the overall scene, sized for the web here, in late evening light:

So light was already very low when Andrew started his Lumia 950 shooting spree. Credit to him for sticking with it.

And, to show the progressively decreasing light and the way the Lumia 950 camera coped, I've mashed his 11 shots (over 100 minutes) into one 4K video, embedded here. The shots aren't perfectly framed, but they're darned close. Doing sets of test photos like this is very hard work - you just try it sometime. Something always goes wrong, whether weather or forgetfulness or a rogue photo or a busybody neighbour, or whatever. Something.

Of course, you may not have the equipment to be able to see the full 4K resolution (roughly corresponding to the 8MP photos being captured), but see what you think anyway:

Andrew was impressed overall by the 950's camera and so was I. Let's look in more detail, right down at the 1:1 pixel level, taking a small portion of the frame above (the right edge of the roof). The 'slices' here are presented in time order as the light reduced further, showing the passage of time and the slight increase in noise levels:

Given that it was almost pitch dark at the end, the final slices are pretty impressive. Although the changing colours are notable, it's impossible to say how accurate they are without having been there, i.e. the reflected setting sun would have an impact.

If you're interested in doing your own analysis, the photos are here (sans location info) as:

1. http://mediafiles.allaboutwindowsphone.com/elliott/house1957.jpg
   
2. http://mediafiles.allaboutwindowsphone.com/elliott/house2019.jpg
   
3. http://mediafiles.allaboutwindowsphone.com/elliott/house2030.jpg
   
4. http://mediafiles.allaboutwindowsphone.com/elliott/house2043.jpg
   
5. http://mediafiles.allaboutwindowsphone.com/elliott/house2053.jpg
   
6. http://mediafiles.allaboutwindowsphone.com/elliott/house2103.jpg
   
7. http://mediafiles.allaboutwindowsphone.com/elliott/house2112.jpg
   
8. http://mediafiles.allaboutwindowsphone.com/elliott/house2121.jpg
   
9. http://mediafiles.allaboutwindowsphone.com/elliott/house2131.jpg
   
10. http://mediafiles.allaboutwindowsphone.com/elliott/house2141.jpg
    
11. http://mediafiles.allaboutwindowsphone.com/elliott/house2153.jpg
    

Part of what makes the Lumia 950 images so good at the pixel level is the PureView oversampling. It's dramatically less impressive than on the old Lumia 1020 (which used something like an 7-to-1 oversampling algorithm - on the 950 we're only talking about 3-to-1 (the exact details of the pattern algorithm used are proprietary). We can look in detail at this in action, or at least try, thanks to Andrew including a 16MP shot of one of the darker scenes above as well as the 8MP original. Note that he/we cheated slightly in shooting these on different days, but light levels were very similar, in terms of minutes after sun-down.

On the top, a 1:1 crop from the 16MP version of the house image, on the bottom a 1:1 crop from the 8MP oversampled version:

In practice, although oversampling benefits are relatively small on the Lumia 950 and 950 XL, there are certainly still there, you can see that the crop below, though smaller, is also slightly 'purer' and less digitally noisy. 

Plus shooting at 8MP means that you can use around 1.5x lossless zoom and you typically end up with 2MB JPGs to share rather than 5MB files. Which saves everyone data in the long run. For all of these reasons I leave my own Lumia 950 and 950 XL firmly in 8MP mode for daily use.

Comments welcome. Maybe Andrew's tests will inspire you to come up with an interesting image sequence of your own - if so, then please to get in touch!

PS. See also my camera head to heads with the likes of the Nexus 6P, iPhone 6s/SE and the Galaxy S7. The 950/XL came out on top each time.