domingo, 6 de abril de 2014

HDR Photo Camera gets a 3MP upgrade, focussing, still underwhelms

Version 2.4.04 of HDR Photo Camera has arrived in the Nokia Store and addresses two specifiv deficiencies in the early version:

  • You can now take HDR shots at around 3 megapixels (c.f. 0.5MP)
  • You can now focus properly, meaning that you can take HDR photos of objects that aren't necessarily far away

In addition, there's

  • a facility to shoot in 'Fast HDR mode', using two images, rather than three.

Although it's great to see HDR Photo Camera being updated still, I'm still rather underwhelmed. Each HDR bracketed shot takes around a second to capture, meaning that you absolutely have to use a tripod or rest the phone on something solid - try a HDR photo handheld and the results are disastrous:

HDR shot gone wrong!

Overall colour processing is unspectacular still, here's another shot from the new version, captured on the N8, with the phone solidly resting on a fence, so there was zero movement. I chose the shot (in the absence of sun here in the UK) as there were dark patches in the greenery, with bright background in the distance. First of all, the image from HDR Photo Camera (click it to download the 3MP version if you're so inclined):

HDR example, click to download full version

And now the unedited photo from the N8's native camera application:

N8 version

Yes, the HDR version includes a little of the background beyond the woody glade, showing that the combination of shots is working, but I still prefer the colours and contrast of the N8 original image. I'm convinced this is something that the developers of HDR Photo Camera should look at - something's going horribly awry in the contrast handling. I did see that in 'Advanced settings' it's possible to alter the contrast (plus saturation and 'exposedness') from the defaults, but I'm concerned that most users will never find these settings - either the defaults should be different or the algorithms should be a heck of a lot better.

I did experiment with upping both contrast and saturation to their midpoints (5 of 10), but then this messes with the HDR algorithms, producing patches of grey, as shown below. And the colours are still nowhere near what they should be.

50 shades of grey!

The other problem is the length of processing time for each 3MP shot - up to three minutes per image. Contrast this to the way the same task can be accomplished in a second by the iPhone 4S's GPU and it's clear that coding HDR for a main processor just doesn't make sense. On a photo walk, you effectively only get one HDR shot per scene, because it will take most of the walk to the next scene in order to process the images from the previous one.

Partially addressing this is the option in HDR Photo Camera to not try fusing the images at the point of capture, i.e. you can do this later, when back home, with the 'Fuse images' function - but then if you're back home and are interested in HDR, why would you not take some properly bracketed N8 original 12MP images (for example) and then use a more powerful desktop OS-based HDR utility?

I'll keep an eye on HDR Photo Camera over the next year, but I have to say that it's still not something I'd consider using for a second in its current form.

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