Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-19-2013, 01:11 AM - 1 Like   #106
Veteran Member




Join Date: Oct 2007
Location: France
Photos: Albums
Posts: 804
QuoteOriginally posted by dosdan Quote
That used to be a problem in old designs. But with modern micro-lenses, the fill factor is quite large. FF can also be improved with a hexagonal sensel shape and staggered arrangement in the array. This has been done in the past.

Dan.
Right; The most modern design now is back illuminated sensor. You have a description here :
Back-illuminated sensor - Wikipedia, the free encyclopedia
Please note, that according to this source, 90 % of photons are gathered in this design. I don't think there is an application in APS-C sensor now, only for small sensors. Anyway with the presence of the bayer filters that select only one of the 3 primary colors, only 33 % of the light hit the detector.
And despite the fact that the light can be seen as a wave, Einstein has demonstrate that the power of the electromagnetic wave is transported by quantums of energy called photons. As I wrote, the best detector can only transform 1 photon into 1 electron, and this is the physical limit that will prevent performance improvement on high iso. Don't forget that moore law applies to microprocessors, not sensor. And even on microprocessors, when transistors will be so small that the will deal with a very limited number of electrons, moore law will not be applicable anymore.

04-19-2013, 03:21 AM   #107
Pentaxian
dosdan's Avatar

Join Date: Dec 2007
Location: Brisbane, Australia
Photos: Gallery | Albums
Posts: 1,699
QuoteOriginally posted by goubejp Quote
Right; The most modern design now is back illuminated sensor.

BSI is mainly useful for overcoming the sensel optical cross-talk & light loss caused by the narrow, deep stack depth occurring in a small-sensel sensor (e.g. high MP on small sensors like mobile phone cameras).

http://www.imagesensors.org/Past%20Workshops/2011%20Workshop/2011%20Papers/R...Comparison.pdf

At this stage is not worthwhile for the relatively large sensels of current DSLRs (3.9-7.2Ám). As well as mobile phones, it is used in some small-sensel (<2Ám) MILC's e.g. the Pentax Q & Q10, and some P&S cameras e.g. Canon SX260 HS. (Probably more - I'm a bit rusty with the current P&S scene.)

Dan.
04-19-2013, 03:25 AM   #108
Site Supporter
Aristophanes's Avatar

Join Date: Jul 2008
Location: Dartmouth, Nova Scotia
Photos: Albums
Posts: 3,922
QuoteOriginally posted by Sol Invictus Quote
I think this is a halo product. Sigma doesn't necessarily need to move a lot of units. It's there to draw attention to Sigma and display what their engineers are capable of.
Huge and expensive = Halo?!

It's like saying the other guy has a bigger urinal.
04-19-2013, 05:29 AM   #109
Veteran Member




Join Date: Oct 2007
Location: France
Photos: Albums
Posts: 804
QuoteOriginally posted by dosdan Quote
BSI is mainly useful for overcoming the sensel optical cross-talk & light loss caused by the narrow, deep stack depth occurring in a small-sensel sensor (e.g. high MP on small sensors like mobile phone cameras).

http://www.imagesensors.org/Past%20Workshops/2011%20Workshop/2011%20Papers/R...Comparison.pdf

At this stage is not worthwhile for the relatively large sensels of current DSLRs (3.9-7.2Ám). As well as mobile phones, it is used in some small-sensel (<2Ám) MILC's e.g. the Pentax Q & Q10, and some P&S cameras e.g. Canon SX260 HS. (Probably more - I'm a bit rusty with the current P&S scene.)

Dan.
I have understood that there are technical issues to produce large backlit sensors; but the principle of backlit sensor can be applied to aps-C and full frame too, as the principle is to avoid loosing incoming photons stopped by wiring, this is an issue also on aps-C sensor as pixel count increases. Have a look on this article :
How back-illuminated sensors work, and why they’re the future of digital photography | ExtremeTech
There is a recent rumour that canon has published a patent for large aps-c and ff backlit sensors Patent Publication No. 2012-15275
sensor

04-19-2013, 05:48 AM   #110
Veteran Member
jsherman999's Avatar

Join Date: Dec 2007
Photos: Gallery
Posts: 8,228
QuoteOriginally posted by Aristophanes Quote
Huge and expensive = Halo?!

.
Except you just described the 645D, which is considered a Halo product.
04-19-2013, 06:11 AM   #111
Site Supporter
Aristophanes's Avatar

Join Date: Jul 2008
Location: Dartmouth, Nova Scotia
Photos: Albums
Posts: 3,922
QuoteOriginally posted by jsherman999 Quote
Except you just described the 645D, which is considered a Halo product.
But the 645D uses a much larger sensor. This Sigma is an APS-C beast at FF size. Maybe Sigma's engineers pulled off the obvious, but marketing is on an illegal substance.

Halo is when Lexus made the first upscale SUV. This is more like the Pontiac Aztec of lenses...and no deal either.

04-19-2013, 06:50 AM   #112
Veteran Member
Sol Invictus's Avatar

Join Date: Aug 2011
Location: Calgary, Alberta
Photos: Gallery
Posts: 392
QuoteOriginally posted by Aristophanes Quote
But the 645D uses a much larger sensor. This Sigma is an APS-C beast at FF size. Maybe Sigma's engineers pulled off the obvious, but marketing is on an illegal substance.

Halo is when Lexus made the first upscale SUV. This is more like the Pontiac Aztec of lenses...and no deal either.
This is the first 1.8 constant aperture zoom ever! Something no one has bothered to do before. Not Canon, not Nikon and not Pentax. I have no idea if this will sell well but as someone upthread mentioned, it's roughly the size of the Sigma 85mm with the hood attached. Not everyone is obsessed with the absolute smallest size, especially dSLR shooters.

Like I said previously, which product is going to draw more attention to Sigma? A 18-250 zoom from the old Sigma, or this new headline grabber? I've even seen this lens get press on some general tech sites that would never mention another Sigma lens.
04-19-2013, 07:09 AM   #113
Pentaxian
thibs's Avatar

Join Date: Jun 2007
Location: Belgium
Photos: Albums
Posts: 5,260
Moore's law is no law at all.

I know everybody uses the expression but this is so misleading...

04-19-2013, 08:17 AM   #114
Pentaxian
Edgar_in_Indy's Avatar

Join Date: May 2010
Location: Indiana, USA
Photos: Gallery
Posts: 2,636
QuoteOriginally posted by Aristophanes Quote
This is more like the Pontiac Aztec of lenses...
Now THAT's a low blow!

The Aztec was a useful vehicle that had the misfortune of being ugly. I could think of some Pentax lenses that could apply to, such as the Pentax FA 50mm 1.4. Call me fickle, but the ugly 80's styling of the 50mm 1.4 was enough to dissuade me from ever buying this otherwise useful lens.
04-19-2013, 08:34 AM   #115
Veteran Member




Join Date: Mar 2007
Location: Boston, PRofMA
Photos: Albums
Posts: 3,053
QuoteOriginally posted by Unsinkable II Quote
Only enthusiasts are going to buy this lens, because they want to go wide and fast.
Actually, I thought it would make a great video lens if they de-clicked it and the edges are sharp.
And yes, that's niche, but they seem to be willing to pay quite a bit. I'm guessing $1500 as well...it's something no one has done before.
04-19-2013, 08:39 AM   #116
Veteran Member




Join Date: Oct 2007
Location: France
Photos: Albums
Posts: 804
QuoteOriginally posted by thibs Quote
Moore's law is no law at all.

I know everybody uses the expression but this is so misleading...
The issue is also that some people mix pure logic equipments like computer microprocessors - that only has to deal with binary number, which are sequences of 0 and 1, so in an ideal case a single electron is sufficient - no electron = 0, electron = 1; with image processing which obviously need for each pixel a lot of different possible values in order to achieve good image tonality and dynamic. I'm not sure I'm really clear, english is not my mother language...
To say in a different manner, an ideal DRAM can use a single electron to store a binary value, moore law will apply until size of transistor is so small that it deal with a single electron. An image sensor need to collect for each pixel as many photons as desired levels of tonality; and the image sensor pixel density is already so high that at high iso only a small number of photons hit the detector.
04-19-2013, 08:40 AM   #117
Senior Member




Join Date: Feb 2013
Location: Albuquerque, NM
Posts: 136
"Hello Zach,
Unfortunately we have no plans at this time to produce the lens in the Pentax mount.
Yours Truly,
Paul Pizzano
Sigma Corporation of America"

Well there you go everyone. I asked the question and I got the answer and it blows. *sigh* Seems like Sigma doesn't care much about Pentax anymore. :\
04-19-2013, 08:47 AM   #118
Veteran Member
Smeggypants's Avatar

Join Date: Sep 2010
Posts: 1,536
QuoteOriginally posted by dosdan Quote
BSI is mainly useful for overcoming the sensel optical cross-talk & light loss caused by the narrow, deep stack depth occurring in a small-sensel sensor (e.g. high MP on small sensors like mobile phone cameras).

http://www.imagesensors.org/Past%20Workshops/2011%20Workshop/2011%20Papers/R...Comparison.pdf

At this stage is not worthwhile for the relatively large sensels of current DSLRs (3.9-7.2Ám). As well as mobile phones, it is used in some small-sensel (<2Ám) MILC's e.g. the Pentax Q & Q10, and some P&S cameras e.g. Canon SX260 HS. (Probably more - I'm a bit rusty with the current P&S scene.)

Dan.

Are you a sensor designer and also involved in the economic management of sensor production?
04-19-2013, 09:04 AM   #119
Veteran Member




Join Date: Oct 2007
Location: France
Photos: Albums
Posts: 804
I have found this nice publication that explain how sensor works and how many photons hit each sensor cell for a given illumination level
Photon Behaviour & Cameras
04-19-2013, 09:16 AM   #120
Veteran Member




Join Date: Nov 2009
Location: Hong Kong
Posts: 1,352
QuoteOriginally posted by zdwagner Quote
"Hello Zach,
Unfortunately we have no plans at this time to produce the lens in the Pentax mount.
Yours Truly,
Paul Pizzano
Sigma Corporation of America"

Well there you go everyone. I asked the question and I got the answer and it blows. *sigh* Seems like Sigma doesn't care much about Pentax anymore. :\
My guess is that Pentax/Ricoh (I should say Ricoh/Pentax) don't need Sigmaron in their business plan.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
18-35mm, 18-35mm f/1.8 dc, dc, dc hsm lens, f/1.8, f/1.8 dc hsm, hsm, lens, pentax news, pentax rumors, sigma, sigma 18-35mm f/1.8
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sigma 17-50mm f/2.8 EX DC OS HSM Lens Samples pop4 Lens Sample Photo Archive 12 09-08-2016 06:34 AM
For Sale - Sold: Sigma 18-50mm f/2.8-4.5 (DC HSM) Pentaxguy22 Sold Items 4 01-24-2013 06:39 AM
pentax 18-135mm wr lens vs sigma 18-125mm dc os hsm lens atg Pentax K-5 5 12-14-2012 08:24 AM
Sigma 17-70mm f/2.8-4 DC Macro OS HSM Lens infos Pentax SLR Lens Discussion 11 10-18-2012 09:03 PM



All times are GMT -7. The time now is 12:27 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top