My Oasis has splotchier lighting than any early Paperwhite or Voyage I've seen.

[Cinisajoy]

Originally Posted by disconnected

The short answer is I'm an idiot. I hate to return things so I managed to convince myself that I could get used to it. Predictably enough, I was wrong. It may not totally be the fault of the Voyage. My eyesight isn't great, I need a brighter than average screen, and I wear progressive lenses, all of which probably contributed to the illusion that the text near the top of the screen was swimming away from me.

I never managed to read comfortably on an unlit ereader; before they were lit I kept going back to reading on my phone.

I'm really pleased that my Oasis is much better for me.

Curiosity are you near-sighted or far-sighted?
And I am glad you are liking the Oasis.

[disconnected]

Originally Posted by Cinisajoy

Curiosity are you near-sighted or far-sighted?
And I am glad you are liking the Oasis.

Nearsighted.

[krazy4katz]

Originally Posted by NullNix

Hm. The rainbow effect on sapphire is a diffraction effect (as is the varying colouration on beetle cases and the heads of mallards, as it happens). I would expect any such effect to be caused by the diffraction grating, not the glass. Glass *can* diffract, but the effect should be minimal, particularly with small thicknesses of glass as in the Kindle. (But perhaps the 'gorilla' part of gorilla glass has additives which increase diffraction? You'd think Amazon would have taken a lot of care with that, with a diffraction grating already in the mix...). If this was the case, i'd also expect you to see *strong* rainbowing when the frontlight was off and the Kindle was lit only by the Sun (which is, after all, passing through a double-thickness of the same thing before it reaches your eyes).

I'm wondering if anyone knows how monochromatic the light from the LEDs is? It can't be completely monochromatic, surely, since the diffraction grating has to send the light in divergent directions at each point, and AIUI this requires multiple wavelengths so the waveguide can split them off one by one out of the screen. I'm not sure if it's optically possible for the wavelength to be completely invariant across the screen whle retaining a waveguide, though they could probably apply yet another variable coating to absorb the varying light and re-emit it at a constant wavelength -- but this would likely also scatter the light, which would be disastrous for clarity.

Can anyone who actually understands optics answer this?

My impression is that the LEDs are white (approximately). White light is a mixture of colors. There is no wavelength that is white. There is no wavelength that is black. Black is when all light is absorbed. White is when "all colors" are reflected. I don't know what colors would need to be combined to reflect white light. However, if diffraction is possible, then it can happen with white light. I say this even though I don't have this problem. I am happy with my Voyage (as I have said before and before and…)

[Barty]

Originally Posted by shalym

Ok...so you're saying that the Voyage and the Oasis have the problem, but the Paperwhites don't? So it must be the flush screen?

Shari

I had a PW1 and it was pretty colorful. Kind of pretty, like eyes that change colors depending on the light. The PW2 fixed the colors, more boring but better to read on. Still got the gray splotches, perhaps unavoidable. Doesn't bother me enough to go back to unlit e-ink.

[jbjb]

Originally Posted by NullNix

Some of the work the visual cortex does involves making really quite radical adjustments to perceived colour and contrast levels: these adjustments are optimized for making sense of objects in the real world, not for observing the levels of colour and intensity across a piece of paper or e-ink screen or for observing what is "really there". For instance, one adjustment made very early in the visual cortex is to use both sharp and gradual colour and intensity changes in an apparently continuous object as a clue to the 3D shape of an object with constant colour that is partially in shadow

An excellent illustration of the amount of adjustment the brain makes is the well-known checkerboard illusion:



The squares marked A & B are actually the same shade of grey.

/JB

[pagepack]

If its the camera that emphasises coning and colour shift, can anyone care to explain why these two Oasis's next to each other at the same light level look so different?



I can only assume terrible quality control.

[Josieb1]

I posted a picture somewhere in this thread of a Kobo Glo HD I've since returned to Kobo. It had four yellow lines running vertically up from the bottom between the led lights. The rest of the screen was white. I struggled to take a photo that actually showed the problem, yet with my naked eye it was obvious and in the end quite distracting. I don't care what colour screen an ereader is, yellow or white, as long as it's even.

[cme]

Originally Posted by pagepack

If its the camera that emphasises coning and colour shift, can anyone care to explain why these two Oasis's next to each other at the same light level look so different?



I can only assume terrible quality control.

Because the one on the right is obviously faulty. One half of the LEDs is much brighter than the other half.

[cerem0ny]

Originally Posted by pagepack

If its the camera that emphasises coning and colour shift, can anyone care to explain why these two Oasis's next to each other at the same light level look so different?



I can only assume terrible quality control.

Those cones on the right make me sad

[howyoudoin]

Originally Posted by cme

Because the one on the right is obviously faulty. One half of the LEDs is much brighter than the other half.

You sure it isn't just CCDs and hypersensitive eyes and agendas like it is being vehemently claimed in this thread?

[HarryT]

Originally Posted by pagepack

If its the camera that emphasises coning and colour shift, can anyone care to explain why these two Oasis's next to each other at the same light level look so different?

The fact that the a camera emphasises contrast differences (which is undoubtedly true) does not mean that there are not also faulty devices out there. They are unrelated things.

[NullNix]

Originally Posted by disconnected

Nearsighted.

I'm crazily nearsighted (-10.5 dioptres) but the text never swam at all.

I'm wondering if what you're seeing is uncorrected astigmatism, which often comes with nearsightedness. Before I got a prescription that corrected for that, too, moving my head laterally or rotating it would cause text to swim in exactly the way you describe (differently in each eye, too).

[NullNix]

Originally Posted by cme

Because the one on the right is obviously faulty. One half of the LEDs is much brighter than the other half.

I suspect one half of the LEDs in that model is simply not being powered at all. Perhaps the LEDs are connected in two parallel circuits, every other LED being powered from the same power line or something, and one line in that Kindle is detached or faulty.

[tovare]

Originally Posted by HarryT

The fact that the a camera emphasises contrast differences (which is undoubtedly true) does not mean that there are not also faulty devices out there. They are unrelated things.

Yeah, 5 lights when there should be 10 obviously isn't right :-)

But it confuses the discussion about how many slip through quality control at the factory, since it's entirely possible to look in from the side and see that the kindle is indeed edge-lit on a perfectly manufactured unit.

Then there's the third category of debaters who do have a perfect unit, but have some issues with it anyway. Which is fair ... everyone has their own preferences.

[Blossom]

Originally Posted by NullNix

I'm crazily nearsighted (-10.5 dioptres) but the text never swam at all.

I'm wondering if what you're seeing is uncorrected astigmatism, which often comes with nearsightedness. Before I got a prescription that corrected for that, too, moving my head laterally or rotating it would cause text to swim in exactly the way you describe (differently in each eye, too).

Dancing text can also mean Dyslexia. There are so many varying degrees of it most goes undiagnosed. It wasn't till I got a eReader that cause symptoms to worsen because I was reading so much did I get diagnosed. Switching fonts really help. Some fonts I just can't use. Amasis with weight added is what I use most but fonts that I can read comfortably and do not struggle with would be Trebuchet, Lucida. Fonts on the Kindle are a bit hard to use. Condense Caecilia is what I try to use but it's not as comfortable as I like. The new Ember font looks like it might be nice to try some of the letters from the pics I've seen look like Trebuchet.

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