WaltFrench

Lives in United States United States
Joined on Nov 25, 2009

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Total: 39, showing: 1 – 20
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<i>“However, currently low light performance is still bad enough for many users to happily sacrifice some resolution for better image quality in dim conditions.”</i>

I've yet to see any evidence that high pixel counts sacrifice more than a little bit of signal/noise ratio. More pixels means overhead circuitry inadvertently blocks a higher fraction of photons from being usefully recorded, but that should be a small fraction.

The real issue is how many photons the sensor can capture during the 1/100 of a second or whatever, and the rumored 1/2" size is approximately 32% bigger, which should more than offset a higher pixel count.

More likely, we aren't seeing small 50MP sensors is that the lenses don't really resolve enough detail to make the quadrupled file size and cost/processing time worthwhile. No sense trying to record detail that's just not there.

Link | Posted on Nov 5, 2015 at 20:09 UTC as 19th comment | 2 replies
In reply to:

Mister Roboto: Cross your fingers that they will put sensor bigger than a pinhead otherwise this will be another setback for iPhone. You can buy a $50 camera and it is far better than what iPhones have nowadays.

Yes, sensor size matters. But a bigger sensor has a wider view, lousy for many purposes, unless the camera is ALSO a lot thicker.

That's why P&S cameras, despite advantages in image quality, aren't selling: they're not as pocketable and not enough better quality.

SLR—higher quality—cameras have ALSO come down in sales, but they still take ENOUGH better pix, especially in dim light or high-speed sports shots, that pros keep buying them.

No reason to worry, I'd say: image quality is important to Apple. Whether they continue the pretty-much-standard sensor size, or have some magic multi-sensor or multi-snap software, nobody expects a regression.

Link | Posted on Jun 29, 2015 at 22:01 UTC
On article Sony debuts 21MP stacked CMOS sensor for smartphones (94 comments in total)
In reply to:

RichRMA: You can't bend the laws of physics. Sensors can be made any which way, but the small ones will never, ever match the larger ones. Back illuminated, electron-multiplying, it doesn't matter. They are modest enhancements that produce a slightly better product, but a 1/2.3" sensor will never be a m4/3, APS, etc.

But that's the point of this advance…by putting circuitry behind the sensor, rather than taking up area that should be capturing photons, you get an all-else-equal bigger sensor.

Then, there's the constant improvement in the physics of converting photons that impinge on a chip, into electrons. And optical improvements that get more photons onto the chip.

Lots of improvements here, and ahead. Hardware. Haven't even touched smart software.

Link | Posted on Jun 18, 2015 at 19:45 UTC
In reply to:

Lhermine: Very interesting article ! Thanks very much DPR.

As many people here, I was wondering if the number of photons can be so low that shot noise would be significant.

Based on the so-called "sunny 16 rule", I've found that for a proper exposition on a 24 MPix FF sensor, around 50,000 photons should hit each pixel. This lead to a shot noise with an amplitude of 1.4 %.

This kind of noise amplitude should to small to be noticed. However, in darker conditions, you may have to increase the ISO speed let's say for instance 6400. It means that you have fewer photons. The corresponding shot noise amplitude will be around 3.5 %. We reach up to 14 % for ISO 100,000!

And that's the bad news: 1,000,000 ISO speed will never be as good as 100 ISO whatever the quality of the sensor because of the shot noise.

So bad...

(for those who are interseted in the computation, please mail me, you may point out some mistakes ;-) )

I can't confirm/deny your calculations but I *WILL* note that it assumes 100% efficiency of capturing incoming photons. That's way too high.

I'm not the expert to describe the percentage that are captured, but in many sensors, a good fraction of photons fall on support electronics that are insensitive, and lost. More importantly, the fraction that hits the sensitive parts may fail to be recorded for a variety of reasons.

Using a SWAG (scientific, wild-assed guess) of 5% detection efficiency, your 1.4% noise rises to 6.3% (the square root of 1/.05). This doesn't seem unlikely for a well-exposed scene.

Note that RAW conversion techniques essentially ALWAYS employ noise-reduction. For example, a green pixel might take the average of the 4 nearest green pixels; this would smush fine details, but reduce the noise by half (again, the square root). In areas with lower signal, the RAW conversion might spread the average further, hoping to create a more acceptable image.

Link | Posted on May 13, 2015 at 19:57 UTC
On article Apple buys camera-technology company LinX (74 comments in total)

Think of the Very Large Array of multiple radio telescopes that are now state-of-the-art. Separate sensors covering a wider radius, so able—with some not-actually-horrible computations—to get the equivalent of a big sensor/lens w/o the depth that others here aptly note.

Combining the separate images is a bit trickier than for radio telescopes due to the much more challenging depth of field issues. Note that clever as Lytros was, the images never had the fine resolution that people increasingly expect from even snapshot cameras.

Link | Posted on Apr 17, 2015 at 00:59 UTC as 14th comment | 1 reply
In reply to:

makofoto: The iPhone6 optics are already pretty flat ... and impressive

@makofoto wrote, “iPhone6 optics are already pretty flat… and impressive”

That they are… but the lens DOES protrude from the back of the case, in the most un-Apple-like feature I've seen.

A shallower lens would allow Apple, or ANY smartphone maker, to have a good, not-just-fisheye lens AND a decently large sensor for better quality images. (Getting a “normal” focal length now would require an even thicker lens or a much smaller sensor and higher resultant noise.)

This one is worth watching. There are one or two things danced around (“…greatly improves its efficiency” suggests “not as much light goes where it should”) but that could come.

Link | Posted on Mar 11, 2015 at 00:45 UTC
On article Apple iPhone 6 Plus camera review (206 comments in total)
In reply to:

Fredy Ross: I guess I will stick with galaxy note. Very convenient to have a stylus.

Yes, very important in shooting pictures. Highly relevant to DPR readers.

Link | Posted on Oct 23, 2014 at 10:24 UTC
On article Accessory Review: Drobo Mini RAID (149 comments in total)

I don't understand the claim that the “Dual Disk Redundancy” feature saved your bacon.

Any (common) RAID setup continues working if one disk dies or is removed. I recently migrated from one NAS to another by buying 4 higher-capacity disks, replacing the old ones one at a time. True to claims, the new disks held the identical info (and the old ones went into a second (identical brand) NAS box, giving me two copies of my files as of that time.

I use that NAS as my Time Machine target. A week ago, my laptop's boot disk (a 240GB SSD) failed suddenly while I was traveling. As it was only 2 years old, the vendor replaced it gratis (even cross-shipping), and a couple hours after I got home, the Apple software had re-created the failed laptop disk. (The work I did while traveling stayed on the spinner, which was easily NOT restored, as Apple made it easy to separately restore partitions.)

RAID seems a valuable feature in smart backup/storage. You get 3/4 of the nominal space—a better value.

Link | Posted on Aug 20, 2014 at 19:08 UTC as 6th comment
On article Apple patents bayonet mount for mobile devices (72 comments in total)
In reply to:

NK777: It is joke?

You didn't read the patent, did you?

A hell of a lot more work went into this mechanism than your cheap shot joke.

Link | Posted on Apr 10, 2014 at 22:00 UTC
On article Apple patents bayonet mount for mobile devices (72 comments in total)
In reply to:

nawknai: I truly cannot tell if this is a joke.

It sounds like an April Fools thing, but then I see a link to the Patent Office, and unless the US Patent office, which I'm sure is a barrel of laughs, has put up an April Fools prank, then this may be the dumbest patent I've seen in a long time.

You may think the magnet idea is better, but that's for buyers, not the patent office, to decide. This approach is interesting… novel… in the best tradition of mechanical patents for innovation. And if nobody wants the extra precision or security of a similar mount to what real cameras insist on, why then it has cost nobody a penny.

Link | Posted on Apr 10, 2014 at 21:59 UTC
On article Apple patents bayonet mount for mobile devices (72 comments in total)
In reply to:

LensBeginner: Haha, was about to fall for it, then looked at the date...

You know what would be REAL nice? Is if some of you people who claim this idea is obvious or not innovative, could describe how it actually works.

Go ahead and show us that you have the mechanical engineering chops to understand it, rather than act as Boffo the Clown.

Link | Posted on Apr 10, 2014 at 21:56 UTC
On article Apple patents bayonet mount for mobile devices (72 comments in total)
In reply to:

Dr_Jon: Looks a lot like the Moment Kickstarter project (which is lenses and a Bayonet mount adapter):
https://www.kickstarter.com/projects/584288471/moment-amazing-lenses-for-mobile-photography

Let's be clear: the patentable part of the invention is for a bayonet mechanism that locks, but ALSO pops loose in response to sufficient pressure.

Right now, the Moment page shows a nice bayonet type design, but NOT one that even locks in place (still iterating) OR pops loose in a controlled manner.

Yes, the *idea* of a detachable lens is the same. Patents are never granted for ideas, only the specific implementations.

Link | Posted on Apr 10, 2014 at 21:53 UTC
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