GTA15/PyraPhone


levi

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You don't get any more resolution if you remove the static colour filter on a conventional colour camera. The maths they use to predict the actual colour is at a lower resolution (1/2 for green and 1/4 for red and blue) but if you're producing JPEGs anyway that's quite a good fit as those drop the colour resolution by similar amounts anyway as I recall. But they have an intensity for each site and thus they tend to produce a pixel for each sensor site.

To be brutally honest, I'm rather impressed with the sorts of shots I see in phone reviews these days, which beat the pound of glass and metal I tend to carry around when I want to take a shot. The only thing they can't do well is limited DoF out of the box, which is why they've been working on faking that via software in the past few years. I don't know how they got rid of the terrible noise small sensors used to have.
 

Elw3

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Its all software magic. Somehing we should be able to dominate...
 

Wally

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My iPhone is still working quite well, i'll probably be updating it when 5G becomes a thing, although I am working on un-ravelling myself from a singular ecosystem and working towards stuff that works across all ecosystems (iOS / Windows / Linux / macOS), it's an interesting project with interesting results. I'll post it sometime :)
 

Binky

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Quite the opposite, this lenses are extremely bright for photographic standards.
Its rather that the sensor is too small with too many pixels on that tiny space giving too much noise.
No-no-no, elephants are like tree-trunks, not snakes!

The amount of light a camera can use to form an image is directly related to the exposed area of the objective lens, and the exposure time, for any given scene. Less light --> less information --> worse results.

If you have fewer, larger sensor-pixels, you'll get less noise, but you won't get more information about any given point in the scene.

I suspect a sequential-colour camera as you describe would end up performing very similarly to a normal colour sensor exposed for the same total time.
 

Elw3

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The amount of light a camera can use to form an image is directly related to the exposed area of the objective lens
No idea what you want to say with that. I can only assume that you mix up total amount of light with area amount. Think of the needed image cycle.

The point of a filter turrent camera is not to get better color shots but to be able to shoot monochrome which simply WILL be better.
The result of the color shots appears to be a tad better than normal sensors, but i am not that impressed either.
http://largesense.com/blog/2017/10/recent-photos-including-color/
 

levi

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The point of a filter turrent camera is not to get better color shots but to be able to shoot monochrome which simply WILL be better.
I think that's been true since colour film came into being. But everyone normal was happy to trade a little sharpness and noise for being able to see that the sky is blue.
 

Binky

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No idea what you want to say with that. I can only assume that you mix up total amount of light with area amount. Think of the needed image cycle.
I meant that light that does not fall into the lens of the camera during the exposure period cannot possibly contribute to the final image. Light reflected off the scene travels in all directions, but the more of it you can 'catch' with the camera, the more reliable the measurements you make of it will be.

Any real measuring device (like a pixel in a camera sensor) will be influenced by sources of noise, in addition to the signal you're attempting to measure (light, in this case)
The confidence you can have in your measurement is determined by the relative influences of the real signal and of the noise on your measurement. The SNR.
If you increase the strength of the signal, by collecting more photons emanating from that small. distant region, the absolute magnitude of the noise will increase slightly too, but nowhere near in proportion to the increase in signal strength. The SNR improves.

Therefore, I say that for a camera with a fixed field of view, and a fixed resolution, where each pixel represents a fixed area at a fixed distance, the best way to improve SNR is to allow more photons (a greater total radiated energy) to contribute to the image.

That could be achieved by:
  • Stronger illumination of the scene (with a flash, say)
  • A bigger objective lens, into which more light will fall
  • A longer exposure time, waiting for more photons to arrive
To imagine an extreme case, a camera with a lens diameter so small, an exposure so short, and a scene so dim that no photons at all make it onto the sensor (!) will be entirely unable to record any information about the scene. The photograph would be 100% noise!
 

Elw3

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Lens diameter has little to do with light output. A bottle cap sized lens is usually brighter than a bottle sized one.
 

Binky

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Lens diameter has little to do with light output. A bottle cap sized lens is usually brighter than a bottle sized one.
What exactly do you mean by "brighter"? It's hardly as though lenses themselves emit light!

I realise that what I've been calling "lens diameter" isn't quite right - since many cameras have an iris to effectively reduce it. I should probably say "iris diameter".

To be honest, I'm not entirely au-fait with the various uses of "aperture" in photography circles.
I think of it as the ratio of iris diameter to focal distance - which is tangentially* related to the range of incident angles over which the camera gathers light. That must affect depth-of-field.
Clearly, a camera with a greater aperture (in the sense of a diameter:distance ratio), and the same focal distance, will have to have a greater iris diameter and will collect more light. Furthermore, a camera with a wide aperture (diameter:distance ratio) achieved by making the entire optical assembly small in all dimensions will perform very poorly when compared to a geometrically similar unit on a larger scale.

There's also equivalent aperture, which Wikipedia describes as:
...the 35mm-equivalent aperture range is sometimes considered to be more important than the actual f-number. Equivalent aperture is the f-number adjusted to correspond to the f-number of the same size absolute aperture diameter on a lens with a 35mm equivalent focal length.
Despite the great potential for confusion here, I maintain that in principle, a camera that can gather a greater absolute quantity of light from a given region of the scene, will make a more accurate and reliable measurement of the colour of that region. (Other considerations being equal)

I also maintain that for a given scene, exposure time and lighting conditions, the amount of light gathered will be proportional to the area of the iris aperture.

Please explain why that's wrong!

*In a trigonometric sense, literally!
 

Elw3

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Wikipedia contradicts itself in a few points there anyway. Disregard all parts where they talk about equivalent, its bullshit. Basically just made up by the camera industry for common consumers who dont know what an angle is.

Furthermore, a camera with a wide aperture (diameter:distance ratio) achieved by making the entire optical assembly small in all dimensions will perform very poorly when compared to a geometrically similar unit on a larger scale.
This is where you are wrong. It will simply shring the image cycle but not alter the quality of the projected image.
The interesting part is the opposide, if you try to make a phone lens bigger you will get a rather good lens that would be expensive to produce.
This is why phone lenes are of good quality, they cost nothing to produce in that size.

You are looking at photography from the eyes of a physicist whereas in my head it keeps pondering "what about the image cycle?" and "Its not about getting much light!".
Brightness is indeed just the brightness of the projected image, normally you take only a slice of it for you sensor and throw the rest away. What you propose here is to use all of it, that is called speedboosting. Basically the opposide of enlarging an image, shrink it down to increase the light density.
Yes you can do that, but it is not a normal lens design and i have no idea how the result behaves. Most likely its worse than just using a proper sized sensor or else everyone would do it.

For normal lens designs it simply makes no sense to use a larger apperature because the focal plane gets too thin. Say you create a phone lens with f/1 then you can shoot the tip of you nose but not the eyes behind it, let alone that you have a hard time to even focus on said tip.
Or in other words, sure you can get more light by just removing everything and expose the sensor directly, but that wont make a picture.
 

levi

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I haven't seen the numbers but compact cameras often have what in the conventional world of 35mm film lenses and their digital descendants would be very expensive maximum apertures to have, because as the sensor size goes down the focal length of the lens also goes down, and therefore wide lenses in terms of their aperture numbers (which are the ratio between physical aperture and the focal length) are similarly smaller than they would be in larger lenses on larger sensors. On a 50mm (standard) 35mm lens a f/1.5 aperture would need to be 23 and a bit mm wide, which leaves very little space in the typical lens barrel for any of the mechanical bits needed to form the aperture hole, let alone anything else. On a hypothetical 5mm phone sensor where a 7.2mm lens should give the same fov, f/1.5 represents a less than 5mm diameter hole which is easier to manufacture.

Also, depth of field is mostly influenced by focal length also. With a tiny sensor you're approaching a pin hole camera where by definition everything's in focus.
 

Askarus

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There are 2 things the Pyra is missing:
1. Camera
2. NFC

If it had that it would be a modern device.
Not it can not replace my Phone completely.
 

ThinkPad

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Dec 21, 2012
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It will be pain in the ass to use Pyra as a phone,
The LTE modem is a great feature for mobile INTERNET data on this pocket computer but making calls on Pyra ? COME ON!


You guys don't understand, the mobile smart phone is a essential TOOL this days especially in the business and corporate environment,
So tell me why I should cripple my productivity with a Pyra phone, or worst - getting Pyra and use it as my main phone ?

Librem 5 is the only close to reality FSF endorsed smart phone which will be an actual and useful product.
Pyra phone is a MEME, and using Pyra as a phone is also MEME.
 

Silent-Hunter

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May 29, 2010
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Why would I cripple my productivity using something without a keyboard? Android absolutely sucks for productivity tasks. And using an external keyboard is clunky and irritating, especially if it's wireless and I have to worry about charging it.

I understand the Pyra may not be for everyone, but there's no need to be angry and insulting to the people who want to use one.

Of course this PyraPhone thing hasn't got a real keyboard either, but at least it won't have Android.
 

LoopStar

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Dec 10, 2006
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Let's hope they are aware that they need to place the order for the phone's case at least 5 years upfront... :D because I don't think even the hardcore-linux-fans will buy a smartphone that is so open that it comes without a case. xD
 

rygD

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Don't they already have a case for their/his previous smartphone they can try to squeeze it into?
 
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