1D X and 5D MK3 sensors..... when will canon have backlight sensors?

[Astro]

if im not completely wrong the new canon sensors are still not using the backlight technology that sony uses for it´s EXMOR R sensors.

is there any official statement form canon that they are working on backlight sensors for their DSLR cameras?

i know there are some problems for larger sensors... but problems can be fixed right.

i mean today everthing is about gathering light, so more light hits the photosites and not some circuits on the sensor. canon is advertising new microlens design, gapless microlenses etc. with every new sensor.

but the backlight design should improve the sensor more then going from microlenses with a gap to a gapless design.. or not?

or is the backlight design not as efficient on a bigger sensor?
somewere i read that on bigger sensors the circuits occupie a smaller percentage then on small sensors.

so is there any info from canon about this?

 

[dr croubie]

Maybe I should just google this and not ask it here, but what's the point of backlit sensors?
If it's all about getting the photons into the sensor-diodes ("photon-buckets"), then aren't gapless microlenses enough? If the microlenses cover the entire surface area of the sensor, and if they're focussed correctly* to direct all light onto their individual photosites, then there's no light being wasted as it is. Thinning the sensor (as they claim to have done with the 5D3) should mean less far-corner vignetting too (at the expense of dynamic range? Depends on if the photon-buckets have the same overall capacity).

So what is a backlight going to do?
(and more importantly, who has the patent? there's a reason we never saw DX-cropping on canon bodies, or they'd be paying Nikon for it...)

(*of course, the definition of "focussed correctly" will vary, Leica has the patent on angling the microlenses to avoid vignetting at the extreme corners, but their problem is worse with the shorter flange distance of the M-mount)

 

[Astro]

Maybe I should just google this and not ask it here, but what's the point of backlit sensors?

in short.... you remove the circuits from the top layer so more light hits the photosites.

If it's all about getting the photons into the sensor-diodes ("photon-buckets"), then aren't gapless microlenses enough?

that´s a good question.
but with higher and higher resolutions i guess it would be better to increase the bucket instead of the funnel. as well capacity etc. must be effected too.

 

[dr croubie]

OK, so all the wiring is underneath the photosites and not around them?
That will make the photosite "wider", so yes, they will collect more photons. Your photosite can be as small as you want, but as long as your microlenses are gapless and 'focussed correctly', all your photons will be making it into the photon-buckets anyway.

Biggest advantage I can see is not in light capturing/wasting, but bigger photosites and less wiring in between just means a larger "full-well" capacity. That means more DR, and that's something canoners are screaming for (at least on this forum).

Do Nikony use microlenses? Gapless or not? If they own the patent for the backlit sensors, and canon own the patent on gapless microlenses, that could explain their various paths of sensor development. In a perfect world, we'd have a sensor with both (and the anti-vignetting leica microlenses too for good measure), that would be sweet...

 

[Astro]

Biggest advantage I can see is not in light capturing/wasting, but bigger photosites and less wiring in between just means a larger "full-well" capacity. That means more DR, and that's something canoners are screaming for (at least on this forum).

exactly my idea... i added that to my original posting while your where typing.

 

[nitelife2]

see here for more info:

http://www.cameratechnica.com/2011/06/23/technology-demystified-backside-illuminated-sensors/

 

[ippikiokami]

Did some research and it really does seem like backlit cmos is a Sony thing. (correction.. seems like a company called Omnivision has them too?)_

Even the p&s that Canon have that are backlist cmos use a Sony sensor. Doesn't mean that they are the end all of sensors though.

 

[Astro]

Did some research and it really does seem like backlit cmos is a Sony thing. (correction.. seems like a company called Omnivision has them too?)_

afaik sony has one patent for the EXMOR R sensors technology.
but that does not mean nobody except sony can produce backlight sensors.

 

[Bennymiata]

I might be wrong, but I think it was actually Fuji that first used BSI sensors for its higher end bridge cameras a few years ago.

I think it has more advantages with small sensors, as you can pack them more densly, and its advantages diminish as the sensors get larger.

 

[traveller]

There's a difference between patenting a way of achieving backlit sensors and being able to patent the concept, but even Sony doesn't use back side illumination for their larger sensors.

I think the main reason for not having large backlit sensors in the expense of using this technique versus the returns that you get from it. For a small CMOS sensor, where the associated on-sensor electronics take up a proportionately larger area of the imaging chip (for a given technology level), it is obviously worth the increased manufacturing cost to do this.

For an APS-C or a full frame sensor, you don't get the same advantage because the imaging 'sensels' take up a larger proportion of the real estate compared to on (for example) a 1/2.3" sensor. Back side illumination would still probably increase the cost of manufacture by the same percentage as on a smaller chip, but because total manufacturing cost of a large sensor is exponentially larger, it would result in quite a substantial impact upon final camera cost whilst not giving the same percentage increase in performance.

This probably explains why Sony uses BSI on their compact cameras, but not on their DSLR, DSLT, or CSC ('mirrorless') camera sensors.

 

[PhotoCat]

I really don't know if Canon is using a backlit sensor in 5D2. If not, I would say Canon's sensor technology is really not that bad, considering D700 is using a Sony backlit sensor. DXOmark suggests that D700 has only about 1/3 stop ISO advantage over 5d2 when viewing a 8x10 print at 300dpi.

Love to know if Canon really has backlit sensor technology.