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It would be great to have a high resolution camera for jolla phone.If it's possible to upgrade the present one even better.

It would be great to have a high resolution camera for jolla phone.If it's possible to upgrade the present one even better.

It would be great to have a high resolution camera for jolla phone.If it's possible to upgrade the present one even better.

It would be great to have a high resolution camera for jolla phone.If it's possible to upgrade the present one even better.

Edit: 16.03.2015 (by MikErk)

I have done some measurements with the camera to determine the real resolution of the imaging system. I used the slanted edge method which is described in the next link. As test chart I used the ISO12233 printed on A4. I took a photo of this A4-chart with the Jolla and cropped into a slanted edge (pretty in the middle of the image):

http://carlesmitja.net/2011/02/06/image-quality-of-photographic-cameras/

Some results from that:

1. The Edge spread function shows pretty strong over and undershooting (see https://en.wikipedia.org./wiki/Gibbs_phenomenon). This is probably due to an over-sharpening in post-processing. The slope of the edge itself seems pretty flat. This can be a artefact of a low resolution test chart or some other thing which I will have look on.

2. The line spread function looks like a triangle function with a spread of about 5pixels. So by the camera a perfect line (f.e. only one black pixel line) is smeared out over some 2-3 pixels.

3. Due to the over-sharpenening the MTF shows an overshooting for low frequencies. The 50%-MTF lies only at around 0.25 Cycles per Pixel. Note that an ideal system would be at 0.5 Cycles per Pixel. So the camera shows only a resolution of about half its nominal one.

Further things to do:

1. Make a better measurement with averaging many frames and eventually using a better target

2. Make measurements with other smartphones or even DSLRs and compare the results

It would be great to have a high resolution camera for jolla phone.If it's possible to upgrade the present one even better.

Edit: 16.03.2015 (by MikErk)

I have done some measurements with the camera to determine the real resolution of the imaging system. I used the slanted edge method which is described in the next link. As test chart I used the ISO12233 printed on A4. I took a photo of this A4-chart with the Jolla and cropped into a slanted edge (pretty in the middle of the image):

http://carlesmitja.net/2011/02/06/image-quality-of-photographic-cameras/

Some results from that:

1. The Edge spread function shows pretty strong over and undershooting (see https://en.wikipedia.org./wiki/Gibbs_phenomenon). This is probably due to an over-sharpening in post-processing. The slope of the edge itself seems pretty flat. This can be a artefact of a low resolution test chart or some other thing which I will have look on.

2. The line spread function looks like a triangle function with a spread of about 5pixels. So by the camera a perfect line (f.e. only one black pixel line) is smeared out over some 2-3 pixels.

3. Due to the over-sharpenening the MTF shows an overshooting for low frequencies. The 50%-MTF lies only at around 0.25 Cycles per Pixel. Note that an ideal system would be at 0.5 Cycles per Pixel. So the camera shows only a resolution of about half its nominal one.

Further things to do:

1. Make a better measurement with averaging many frames and eventually using a better target

2. Make measurements with other smartphones or even DSLRs and compare the results

Some conclusions:

• The optical system can't resolve the 8MP from the sensor. Effectively we have way less resolution.

• The image processing software is already trying to compensate for the bad resolution and makes it worse by over-sharpening the image. It A little less might give some better results.