Tagged with sensor - Personal View Talks https://personal-view.com/talks/discussions/tagged/sensor/p1/feed.rss Sun, 28 Apr 24 06:03:27 +0000 Tagged with sensor - Personal View Talks en-CA Sensor wars https://personal-view.com/talks/discussion/23400/sensor-wars- Mon, 20 Jan 2020 10:10:27 +0000 Eno 23400@/talks/discussions Omnivision Aims to Close the Gap with Sony and Samsung and Lead the Market in 1 Year.

"In the past, our gap [with Sony and Samsung has been,] may be, about one year. Last year, we were half a year behind, and our goal is to achieve new products to be leveled this year, and to achieve a lead next year," says Wu Xiaodong.

https://image-sensors-world.blogspot.com/2020/01/omnivision-aims-to-close-gap-with-sony.html

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Olympus E-M1 Mk II topic https://personal-view.com/talks/discussion/13959/olympus-e-m1-mk-ii-topic Mon, 19 Oct 2015 08:16:35 +0000 duartix 13959@/talks/discussions image

Specifications

  • 20Mp Sony m43 sensor
  • 4K30 and 4K24 Cine video modes, no crop, up to 237Mpix
  • Improved 5-axis stabilizer, up to 6.5 stops
  • Additional digital stabilization, adds 8% crop
  • 121 Phase AF points
  • TruePic VIII 4 core LSI
  • Articulating touch screen
  • 3 or 5 microphones for 3D audio (ala Panasonic or Sony camcorders)
  • 18fps burst with AF, 60fps (1 second) with fixed focus, both are with electronic shutter
  • 10fps burst with AF, 15fps with fixed focus with mechanical shutter
  • Improved EVF with 120fps refresh (before shooting starts, obviously)
  • 14 frames preshoot buffer upon half press
  • 50Mp sensor shift mode (still not working without tripod!)
  • Dual SD cards slot
  • HDMI 422 10-bit output
  • $1999 body at https://www.amazon.com/Olympus-V207060BU000-Dynamic-Thirds-Digital/dp/B01M4MB3DK/

More info at http://www.getolympus.com/digitalcameras/omd/e-m1-mark-ii.html

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Foveon x3 for video? https://personal-view.com/talks/discussion/4903/foveon-x3-for-video Mon, 15 Oct 2012 17:42:52 +0000 pletta 4903@/talks/discussions Hello,

So i've been reading about image sensors (much of it is way over my head) but I'm doing my best to learn and I'm curious about foveon x3 image sensors or at least the concept with regard to video. From what I've read (and much of that is written by foveon or sigma itself so it's hard to know for sure) this sensor or technology seems like it might provide some real benefits. They "say" that it records more color information than regular sensors that don't utilize their stacked pixel sensors as it captures light at different wavelenghts with the use of different layers of silicon within the sensor itself and thereby captures "full color" at each pixel location. This all sounds really good to me but I've looked and haven't really seen any extremely positive reviews of either the sensor or cameras using the sensors. My main question is whether this sensor or concept might make a ripple in video imaging technology or if there are limitations that keep this from being a serious option for sensors in video.

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How to Clean Sensor on GH2 https://personal-view.com/talks/discussion/5348/how-to-clean-sensor-on-gh2 Sat, 01 Dec 2012 18:46:33 +0000 matt_gh2 5348@/talks/discussions Need to clean my GH2 sensor (I'm seeing a green dot in the middle of my footage, and when looking at monitor of footage shot with lens cap on, I saw a bunch of white dots...assuming/hoping it's just dust on the sensor). So my question is this - I bought the Giottos Rocket Air Blower, but how to do I get the mirror(or is it shutter?) to lock open so I can blow air on it? Any and all tips much appreciated.

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Used GH2, sensor streaking or flaring https://personal-view.com/talks/discussion/23748/used-gh2-sensor-streaking-or-flaring Mon, 06 Apr 2020 18:05:57 +0000 TreyM 23748@/talks/discussions Hello all,

I just bought a used GH2 from eBay. When I got the camera, I quickly noticed some horizontal magenta sensor flaring/streaking when pointing at a bright light over a dark background. I tested the same lens on a GH4 and the issue was not present, so I am certain this is from the sensor. I sent the following video to the seller and he refunded me and told me to keep the camera. Is the behavior in the video below known behavior for the GH2, or is it indeed faulty? This is the only lighting scenario where the camera does this. It is otherwise perfectly fine and usable. Admittedly, the ISO is really high at 3200, but I'm hoping it's not normal GH2 behavior.

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Super cheap 4K video camera with Panasonic sensor https://personal-view.com/talks/discussion/22173/super-cheap-4k-video-camera-with-panasonic-sensor Thu, 13 Jun 2019 20:38:52 +0000 DrDave 22173@/talks/discussions There's a bunch of these that all look very similar. Claims to have 24p and a Panasonic 34110 sensor. Anyone ever see one in real life? $100.
https://www.aliexpress.com/item/Andoer-4K-Ultra-HD-3-0-LCD-Touchscreen-WiFi-Digital-Video-Camera-Camcorder-DV-Recorder-16X/32956355679.html

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GH2 to super-8 cinema format https://personal-view.com/talks/discussion/21676/gh2-to-super-8-cinema-format Thu, 07 Mar 2019 06:39:56 +0000 agaraster 21676@/talks/discussions I'm trying to setup a patch to make the GH2 as similar as possible to a super-8 cinema camera. On the hardware side I have mounted an angenieux 8-68 f1.9 and it's all good with the ex tele mode.

I would like to change the sensor coverage of the MJPG mode, but it's hard for me to find a way.

The patch i'm starting with is flowmotion 2. Sensor coverage is great on ex-tele combined with both "cinema 24P mode" and "HBR" mode. On MJPG and 720p the sensor coverage is smaller than the above, and this is what i'd like to fix.

What I'm trying to achieve, at the end, is a final result of film 3:2 aspect ratio 1920x1280 frame, possibly @24p or 25p.

Any suggestion?

thanks in advance

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Recording a sensor feed directly from chip lines? https://personal-view.com/talks/discussion/21423/recording-a-sensor-feed-directly-from-chip-lines Tue, 29 Jan 2019 05:27:05 +0000 mei 21423@/talks/discussions Hi. I saw years ago, projects to directly tap sensor image data from a camera chip output lines and record it. Does anybody know where these are now?

You could convert a normal camera direct output.

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Speculations on the Future: Panasonic GH6, Sony A7000 and others... https://personal-view.com/talks/discussion/17707/speculations-on-the-future-panasonic-gh6-sony-a7000-and-others... Sat, 09 Sep 2017 10:54:36 +0000 apefos 17707@/talks/discussions Do you think Panasonic will implement 8k video in the upcoming GH6 camera?

Will it have a new organic sensor with more dynamic range?

What about Sony? Will they release a 8k mirrorless?

What will be the future of Sony Sensors?

It seems Nikon is entering the mirrorless full frame game. What to expect?

Share your thoughts...

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Sensor Cleaning https://personal-view.com/talks/discussion/10684/sensor-cleaning- Sat, 28 Jun 2014 17:29:07 +0000 Azo 10684@/talks/discussions I was looking into an easier way to clean the sensor on my cameras and found the sensor gel stick. I have a sensor loop and have cleaned the sensor's with the wet method and it is a pain in the ass. Every time I do the wet method there seems to be streaks from the kit that I use. Lensrentals.com also seems to use a type of dry cleaning method with the butterfly and a different type of sensor gel stick. Check out the videos below.

I will buy one of these to try out seems a lot easier then the wet method and the streaks are really a pain in the ass to clean. If you don't have a sensor loop you will not see the streaks, also they did not show up in the test images that I have shot. However I know that the streaks are there so I always try to get all the streaks out which is a time consuming process. My sensors end up clean as a whistle but the effort and time that it takes is too long. So moving forward this product along with the arctic butterfly will be my method for cleaning sensors.

The other great thing about this method is that usually you have to buy a kit that is specifically made for each camera sensor size. So for example if you have a FX, DX and M/43 cameras you need to have 3 different kits to clean your sensors. So this is another benefit to using this system as opposed to the traditional wet cleaning method.

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High Speed 10 bit RAW 2.5K camera with a 1 inch sensor, $1600 https://personal-view.com/talks/discussion/11662/high-speed-10-bit-raw-2.5k-camera-with-a-1-inch-sensor-1600 Tue, 28 Oct 2014 14:39:06 +0000 Brian202020 11662@/talks/discussions The FPS1000 looks promising, at least the Gold and Platinum models. There are 8 days left of the Kickstarter. The 290fps 720p sprinkler video from the "Gold" model looks nice. The 200 fps 1080p video from the "Platinum" model looks like something may have gone wrong when uploading to the web. There is a weird banding thing going on in the footage. I'm personally waiting for better 1080p footage before I buy. Anyway many stretch goal were reached and there is now going to be an internal battery, better case, 3D option, and a high speed expansion port for a future high speed media module or to connect to a PC for longer takes.

Kickstarter page: https://www.kickstarter.com/projects/1623255426/fps1000-the-low-cost-high-frame-rate-camera

290fps 720p sprinkler footage: https://vimeo.com/user33535663/review/109492168/ff84853146

290fps 720p sprinkler footage with added sharpening: https://vimeo.com/user33535663/review/109518150/7df49dccbf

200fps 1080p flower/water video: https://vimeo.com/user33535663/review/110201175/34ae6f752c

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Discussion on lenses and perception across camera systems. https://personal-view.com/talks/discussion/6453/discussion-on-lenses-and-perception-across-camera-systems. Wed, 20 Mar 2013 18:05:22 +0000 RRRR 6453@/talks/discussions This is not a thread to debate or explain physics. This is a thread which hopefully can become a resource for lens selection for so called crop sensors.

The other day I was involved in a discussion about "85mm" lenses, and the differences between the characteristics of a certain FOV lens on "full frame", compared to how it looks on a crop sensor. A "native" lens can be designed to perform just like it´s other sized sibling, but when one is into vintage lenses / lenses that can be used on multiple systems it gets far more complicated! Lately I´ve been thinking a lot about lenses that work across different camera systems and the different qualities that are exhibited, depending on the size of the sensor. I´m not thinking so much about the obvious depth of field related changes as to how the overall feel of the image and subtle optical imperfections alter the image with the same lens used on different systems. I´d like to think of aps-c or s35 as base sensor / imager size over "full frame", at least for us who have video as the main area of camera usage, however, many lenses where designed for "full frame" and although the differences on s35 and aps-c can be rather small, I find the differences increase exponentially the smaller imager you put it on.

Hence I have come to search for vintage full frame lenses which will exhibit appealing qualities on a gh2 or a blackmagic design cinema camera. Now, what is appealing to me might not be appealing to you, but I will try to define my own criteria and I hope you can supply yours and add to this thread.

I have been building two main sets of vintage still lenses after ditching my canon fd´s (they were not getting the use to justify having them). For one, I have been buying c/y zeiss optics and I have been adding m42 mount lenses as I have come across them or found some interesting aspect which could fit in with the rest. The c/y´s will no doubt be a mainstay in my arsenale for years, however the ultimate reason why I pulled the trigger on the full set was the advent of the metabones speedbooster – I much prefer how they look on a slightly bigger sensor over a smaller one and I have high hopes for the speedbooster. The reasons for the preferred vicinity to "native sensor size" are:

  1. less pronounced CA. I have become a bit allergic to aberrations of late.
  2. nicer transition to OOF areas, wide open or stopped down.
  3. More obvious contrast/microcontrast "sweet spot". (I think this is down to a slightly larger FOV)
  4. Usability wide open, much in line with the criteria above. A lens which looks sharp in the center on full frame or aps-c might just look soft on a smaller sensor because there´s less contrast between edge and center.

With the m42´s it´s different. I like very much how they look on the gh2 AND f.i. the fs700 or BMD, so I find them extremely useful for video, across systems. So what is it I´ve been looking for?

  1. Low(ish) contrast
  2. Pleasing (sort of neutral) OOF and bokeh, also when stopped down.
  3. good price / performance ratio.
  4. great CA control
  5. reasonable color match
  6. good distortion control / flat focal field

I have mainly been searching through lens databases (on possible candidates), comparing sample images.

Now, this set consists today of the following lenses:

20mm flektogon f2.8 29mm meyer optik, pentacon f2.8 37mm Mir-1b f2.8 50mm Pancolar f1.8 58mm Helios f2 135mm meyer optik orestor f2.8 200mm meyer optik orestegor f4

I´m still looking to add a few but for the ones I have / I´ve had I can say the following:

20mm flektogon - I prefer the f4, as it´s tack sharp wide open. (f2.8 needs to be stopped down to 4-5.6) 29mm Meyer optik is sharper / has less blooming (coma) than the pentacon wide open.. maybe half a stop brighter as well - otherwise they are remarkably similar - both useful wide open. Bokeh can be both expressive and sort of neutral depending on where you place the focal field / subject and f-stop. 37mm Mir is a great "normal" lens on the gh2. Too slow? No. Just right. I want to add a macro ring to help out close focusing. Great value for money and beautiful OOF transitions thanks to the 10 blade aperture. 50mm pancolar - a bit too low in contrast to fit the others well. Not a fan of it´s bokeh. 58mm helios f2 - rock´n roll short tele on the gh2. Wonderful out of focus rendition and also nice transitions thanks to the round aperture. 135mm meyer optik - beautiful and tack sharp tele. Notoriously nice OOF / Bokeh rendition. Low in contrast and needs a push in post to match most of the other lenses. 200mm meyer ... - used it very sparingly so far. Not super sharp wide open. Not a preferred lens on gh2 sensor.

In general, I´ve had some issues with mechanics in cold conditions (needed to clean out and lubricate some helicoids) but they have been put to very good use already. I traded away a 35mm flektogon which I felt was a tad harsh in contrast in comparison to the others anyway (great lens tho). Another thing which is down to physics - the wider the lens, the more restless / harsher the bokeh is. The performance of a certain FOV does not quite match what you´d get on a larger sensor but this will only be a problem in case you are looking for really wide lenses in which case you are better off with native lenses anyway. The difference is mainly where you place the camera. (between different sensor sizes).

Note: I believe it´s difficult to switch lenses with acute focal fields between different sized imagers and not get very differing results.. For my m42 set I´d normally not use all for one production but choose a few depending on priority, like f.i. one or two wides, one or two tele´s to contain the slight differences in coatings, color e.t.c. However, they match remarkably well despite transgressing manufacturers and brands. I´d guess it´s because they are in the vicinity of one lineage of optics manufacturing.

Samples to follow.

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Which CCTV lens for wide angle fisheye use ? https://personal-view.com/talks/discussion/7609/which-cctv-lens-for-wide-angle-fisheye-use- Fri, 26 Jul 2013 05:31:26 +0000 TruHype 7609@/talks/discussions Hello everyone,

I've recently started to get interested in C mount (CCTV) lens, for they are fast, wide, and cheap. So I wondered, is there any CCTV lens that I could use as a Fisheye (and get the same effect as the Panasonic 8mm f3.5, but faster) ? Here's a few lens I've found looking on the internet :

  • Rainbow 3.5mm 1.6

  • Tamron 4-12mm 1.2

  • Pentax 6mm 1.2 (+ wide conversion lens x0.45)

Wanted effect :

The GH2 exact m4/3 sensor crop is x1.86.

So I would like to get the same widness as the Panasonic 8mm or any 8mm Fisheye (Samyang, Peleng, Rokinon...) :

Panasonic 8mm : 8 x 1.86 = 14.88mm equivalent (no need for ETC mode)

Rainbow 3.5mm : 3.5 x 1.86 = 6.51 -> 6.51 x 2 = 13mm equivalent

Pentax 6mm : 6 x 1.86 = 11.16 -> 11.6 x 2 = 23.2mm equivalent -> 23.2 x 0.45 = 10.44mm equivalent

x 1.86 : GH2 Sensor Crop

x 2 : ETC tele conversion mode crop (to cover vignetting)

x 0.45 : Wide convversion lens

Does that mean we could use any CCTV c mount lens instead of the Panasonic lens to get the wide fisheye effect ?

A few videos :

Lenses :

C mount lens (1/2") work well on the GH2, but I heard that the CS mount lens (1/3") would still have really heavy vignetting because even with the ETC mode it would not cover entirely the GH2 sensor. Is that true ?

Interesting CS mount lens, but 1/3 inch : http://www.ebay.fr/itm/TAMRON-Manual-Iris-CCTV-Lens-3-0-8mm-1-1-0-ASPHERICAL-C-Mount-3-Mega-Pixel-/261248954560?pt=UK_CCTV&hash=item3cd3a6b0c0

I would use the fisheye to film Skateboarding.

Thank you.

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Quantum Film - new sensor technology https://personal-view.com/talks/discussion/14067/quantum-film-new-sensor-technology Mon, 16 Nov 2015 07:11:50 +0000 cas1 14067@/talks/discussions From DPreview I found this video explaining the new Quantum Film technology. In essence the traditional silicon layer is replaced by a thinner new material layer, that allows for a bigger dynamic range and global shutter.

Will this scale to larger sensor sizes? Will it allow a higher Iso?

I'm looking forward to seeing some ungraded shots.

Source: http://www.dpreview.com/articles/1365289912/invisage-brings-long-promised-quantum-film-smartphone-sensor-to-market

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Is my sensor broken? https://personal-view.com/talks/discussion/14058/is-my-sensor-broken Thu, 12 Nov 2015 03:50:20 +0000 jrhager84 14058@/talks/discussions I've searched through pages and pages of hits, and can't seem to find an answer to this. I'll attach an image of what my sensor is showing me in live view. Have you ever seen anything like this before? My mother-in-law dropped the camera, and now it has this weird banding effect. I'm not sure it it was there before but more subtle, as I applied the hack after the drop, but rolling to a stock firmware doesn't help, so I don't think it's that. Help!

http://imgur.com/KrFc0tK

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Lensless Ultra-Miniature CMOS Computational Imagers and Sensors https://personal-view.com/talks/discussion/10531/lensless-ultra-miniature-cmos-computational-imagers-and-sensors Tue, 03 Jun 2014 14:56:28 +0000 karl 10531@/talks/discussions Rambus published an interesting paper on cheap, tiny camera sensors that work without lenses.

Given that those sensors are said to cost only cents in production, I wonder whether one could combine a large amount of them to gain more than just a low-resolution image.

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Why M4/3 is special size sensor https://personal-view.com/talks/discussion/12860/why-m43-is-special-size-sensor Thu, 23 Apr 2015 01:29:50 +0000 endotoxic 12860@/talks/discussions MFT format sensor.

first size and cost and weight. No one can beat size performance. shape 4:3 perfect for multiaspect.

the shutter 40 for 24p. it was all about cadence and motion blur. To properly emulate certain texture and movement. those topics are already understood and well documented.

But the theory i have is more from the optical/sensor perspective. I said in a previous thread that m4/3 sensors are special for the human eye. You see, the usable human retina is about 21mm diagonal in diameter in a standard adult, The size of the retina is very similar to the m4/3 format sensor which is 22mm diagonal.

For me this is very important, since the lens you use will behave very similar to your eye, if there was a lenses in front of it. there is something about from f2.8 to f3.5 that you can position your self when you use the EVF and connect only one eye to camera and immerse in video mode on your head. The characteristics of this size sensor and the way it behaves on camera is quiet similar on how you see on day to day.

Yes Yes, each focal length at different apertures on different sensors can achieve similar effect. But no the one m4/3 does.

is like the old battle from full frame to smaller sensor, there is some big bokeh to achieve on 5DMKIII or D800 that m4/3 would have to make a trick to achieve but the other way is also doable, but on each part the result always are not only different (they can look similar) but the characteristics are different. The behaviour is the key.

So for me is a special sensor size, maybe i cant explain it very well, but for narrative purpose this format works for me better than super 35mm sensor.

maybe im crazy, but super 16, super 35 look grate full frame excellent, but m4/3 its more real. human retina sensor size and optic characteristics brings an special look and feel not possible withe smaller or bigger sensors.

for me sweet spot.

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C mount Fujinon E6x14AM f/1.6 14-84mm : Conversion help & Sensor size https://personal-view.com/talks/discussion/12513/c-mount-fujinon-e6x14am-f1.6-14-84mm-conversion-help-sensor-size Tue, 03 Mar 2015 10:52:28 +0000 Fujinonner 12513@/talks/discussions Hi all,

So I have a Fujinon E6X14AM f/1.6 14-84mm TV Zoom lens that's C mount. What I'm trying to understand is what sensor sizes this lens will be compatible with for conversion. Can anyone help me out?

Also, I wanted to know if someone could link me to a site/document that explains which dimensions on the rear mount of a lens determine which sensor sizes it will cover.

Your help is much appreciated.

Thanks!

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Sensors: Global shutter https://personal-view.com/talks/discussion/2923/sensors-global-shutter Wed, 18 Apr 2012 09:10:02 +0000 Vitaliy_Kiselev 2923@/talks/discussions To conform to early TV system architectures and other mediums that transmitted data serially, the earliest image sensing technology utilized an electronic shutter mechanism known as a rolling shutter. With this long history, the rolling shutter and its associated columnparallel readout architectures, in which pixels of the same row are readout simultaneously, was also the natural choice for performing shutter operations within CMOS image sensors.


The global shutter pixel technology typically found on charge-coupled device (CCD) image sensors can offer significant benefits such as the elimination of rolling shutter artifacts through simultaneous image capture of the entire frame. However, the use of global shutter pixel requires the addition of a pixel-level memory – one of the barriers to widespread global shutter adoption. As CMOS image sensors have grown in popularity and as machine vision, movie production, industrial, automotive, and scanning applications increasingly place high priority on the ability to capture fast-moving objects with high image quality, image sensor vendors have worked to solve the technical challenges involved with the utilization of global shutter pixel technology on CMOS image sensors -- sensors that were instrumental in making advanced machine vision, scanning, and the filming of movies like Titanic, The Matrix and Avatar1 possible. Further, with significant CMOS processing technology advancements, transistors can be made much smaller; this, together with improved micro-lens technology, is better enabling image sensor vendors to cost-effectively integrate the memory required for a global shutter.

Today, CMOS image sensor providers are closing the performance gap between rolling and global shutter alternatives by addressing several technical challenges -- fill factor/quantum efficiency (QE), global shutter efficiency (GSE), and dark current. In overcoming these challenges, CMOS image sensor vendors are delivering global shutter pixel technology with smaller pixel size, larger fill factor, higher GSE, lower dark current ,and lower noise, better positioning CMOS image sensors to replace CCD at an accelerating rate.

Rolling Shutter Overview

Also known as focal-plane shutter, a rolling shutter utilizes two scans – reset and readout – to control the exposure time. A shutter pulse that resets a row scans the pixel array prior to readout scanning (Figure 1). The interval between the shutter and the readout pulses determines the exposure time. However, since exposure times of different rows are shifted when a rolling shutter sensor is used, still images of fast-moving objects become distorted, rendering the rolling shutter unsuitable for applications like barcode scanning, machine vision, or automated inspection systems, which require the imaging of rapidly moving objects.

image

Often found on some film cameras as well as digital still and video cameras using CMOS image sensors, a rolling shutter does not record each frame at a single point in time, but rather captures sequential strips of the image from a vertical or horizontal scan across the frame. The advantage of a rolling shutter method is that the image sensor can continue to gather photons during the acquisition process, thus increasing sensitivity. The disadvantages of rolling shutter - predictable distortion of fast-moving objects or flashes of light, or rolling shutter artifacts - are most noticeable when imaging in extreme conditions of motion or light. The use of rolling shutter technology can also result in other motion artifacts, such as smear, skew, wobble, and partial exposure. A shift from rolling to global shutter has been explored in the past. At the time, CMOS image sensor vendors found that adding an additional memory element would sacrifice too much of the photodiode area, negatively impacting quantum efficiency. Further, with existing semiconductor processing technology, application requirements, market demands, cost, and other considerations, it was not justified to push ahead.

Global Shutter Overview

CCD image sensors, which require analog memory for their operation, naturally lend themselves to operation with a global shutter; as a result CCD cameras with global shutter have become more prevalent. The global shutter pixel technology typically found on CCD image sensors used in video cameras eliminates the rolling shutter artifact through simultaneous image capture of the entire frame (Figure 2).

image

However, for CMOS image sensors, the implementation of a global shutter has the primary disadvantage of requiring the addition of a pixel-level memory, making this an expensive alternative for some applications (Figures 3 and 4). For cost-sensitive mobile applications, in particular, the need for additional pixel-level memory has historically made global shutter undesirable as these applications do not place as high a priority on image quality or the mitigation of rolling shutter artifacts as do other applications, rather for cell phones cost is paramount.

image

Other drawbacks associated with global shutters include the reduction in pixel fill factor, which results in a decrease in quantum efficiency. To compensate for this effect, a global shutter pixel generally has a larger size than a rolling shutter pixel, as shown in Figure 5.

image

Another issue of concern is dark current at the memory node. Dark current refers to the small current generated in a pixel even when the pixel is in complete darkness. Typical regions of dark current generation include depletion regions of PN junctions and silicon surfaces. Dark current is one of the main contributors to pixel noise and is more severe in a global shutter pixel than in a rolling shutter pixel.

Finally, it is important to note that, when implementing global shutter in backside illumination (BSI), quantum efficiency is higher than with its front side illumination (FSI) counterpart as there is neither metal nor transistors in the optical path. However, it is this lack of metal that leads to a significant disadvantage for a BSI global shutter. With no metal layer to protect the memory node from light, global shutter efficiency (GSE) is typically degraded. A possible solution is to deposit metal on the backside, but the problem with this is that the resulting stack height is so high that stray light would still be able to contaminate signals stored there. This issue remains an open problem though the industry is exploring it. In the absence of an electronic global shutter, a mechanical shutter can always be used. However, the addition of a mechanical shutter not only increases system cost, but it may be difficult to practically implement in some applications, such as mobile products. Another alternative approach would be to use digital correction of the rolling shutter artifacts; however, this approach would increase power consumption, cost, and may introduce reconstruction artifacts.

CMOS Image Sensors with Global Shutter Technology

In 2000-2001, it became clear to CMOS image sensor purveyors that global shutter technology could offer significant advantages, but the implementation needed to be carefully considered. The most popular approach that has resulted is “memory-in-pixel,” in which each pixel, in addition to a photodiode and readout circuitry, contains an extra memory element to temporarily store photo-generated charges. In this scheme, every row of the sensor starts an exposure at the same time. At the end of the exposure, photo-generated charges are globally transferred from photo diodes to pixellevel memories and then read out row-by-row via readout scanning. Essentially, the additional pixel-level memory allows photo-generated charge accumulation and readout operation to be performed at each individual pixel, thus eliminating the need for rolling shutter pulses. This approach is similar to that of an Interline-Transfer CCD (IT-CCD) shown in Figure 6, where a line buffer located next to each column of the pixel array serves the same purpose as the in-pixel memory. Since the exposure starts at the same instant for every row, the rolling shutter artifact is not present in this approach. Taking this one step further, by pipelining the accumulation and readout operations, the next exposure can start before finishing the current readout, enabling extremely high frame rates to be achieved.

image

Fill Factor and Quantum Efficiency

The addition of a memory node in a global shutter pixel causes its fill factor to always be smaller than that of its rolling shutter counterpart. To mitigate reduction in quantum efficiency, such a memory element should occupy as small an area as possible. On the other hand, its charge storage capacity has to be large enough to hold all charge transferred from the photodiode. Ideally, the storage capacity of the memory node should be engineered to be the same as that of the photodiode so that full well of the pixel is not limited by the memory node. Additionally, microlenses should be optimized such that the entire incident light will be collected by the photodiode.

Global Shutter Efficiency

GSE, an important figure-of-merit for a global shutter pixel, is a measure of how well signal charge can be stored in the memory node without being contaminated by parasitic light. GSE measures how well the memory node protects stored signal from parasitic light contamination. Various sources contribute to such a contamination. For example, incident light can never be 100 percent focused onto the photodiode in practice and some may fall onto the memory node due to mechanisms like diffraction and scattering. Figure 7 shows how photo leakage from a bright light hitting the pixel memory during the storage time can affect the stored signal, causing smear-like and shading artifacts.

image

As shown in Figure 8, the memory node acts as a parasitic photodiode that generates electron-hole pairs in response to incident stray light, thus contaminating the signal originally stored there. In addition, electrons generated deep inside the silicon can diffuse into the memory node and act as a second source of signal contamination. To maximize GSE, a metal light shield covering the memory node needs to be used. Additionally, the metal light shield should be as close to the memory node as possible so that the node is protected from stray light arriving at a wide angle. Doping and potential profiles inside the silicon need to be carefully engineered so that stray electrons generated inside the silicon are directed to the photodiode instead of the memory node. Additionally, lenses should be designed such that light is focused as much as possible to the photodiode instead of to the memory node.

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Dark Current

With a rolling shutter pixel, charges are accumulated and stored in a low-dark current, surface-pinned photodiode until the pixel is read out. In contrast, a global shutter pixel has to store accumulated charges in a memory node commonly implemented in silicon. For example, in a 2003 study by Krymski and Tu2, the floating diffusion of a pixel was used as a memory node. Similar to a 3-T photodiode, there is a large leakage current associated with the surface even though the pixel is in complete darkness. Additionally, the fact that the floating diffusion needs to be a heavily doped junction results in a large PN junction leakage current which acts as another source of dark current. This highly undesirable dark current contaminates the signal stored in the memory node. To mitigate this, a process should be developed to passivate or pin the surface of the memory node. Instead of using a floating diffusion as a memory element, Aptina has utilized a surface-pinned storage node in the pixel to address dark current challenges. Available in its newest global shutter sensor, the MT9M031, the storage node also enables using a true correlated double sampling technique to reduce readout noise to four electrons, resulting in excellent low-light performance. The combination of the effective use of an anti-reflective metal light shield in close proximity to the memory node and careful doping and potentialprofile design results in a high GSE. Charge storage capacities of the photodiode and the memory node are also balanced, and when taken together with the use of a two-way shared pixel architecture, the impact of the memory node on fill factor and QE is minimized. The combination of all these engineering innovations is a 3.75 micron global shutter pixel that enables high performance without rolling-shutter artifacts.

Via: http://www.aptina.com/products/technology/Aptina_Global-Shutter-WhitePaper.pdf

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Could a GH4 hack allow full sensor capture (16:9)? https://personal-view.com/talks/discussion/10834/could-a-gh4-hack-allow-full-sensor-capture-169 Sat, 19 Jul 2014 03:28:27 +0000 Adinan 10834@/talks/discussions Hey guys, sorry if anyone's mentioned this already but I didn't find any topics on this.

I've been researching this camera for a while now before I decide to buy it, and a personal problem for me is wider angles, given how the widest I can go is 2.24x with C4k. I'd read a wishlist of ideas for a GH4 hack allowing full sensor width capture at 4608x1920 (2.4:1), which would be awesome. Although, this raised the question for me as to whether or note a full sensor readout of 4608x2592 (16:9) is possible?

As far as I know, 4k writing speed had been clocked at 12.5mb/sec. Assuming the 4k (8.3mp) is written at 12.5mb/s, and C4k (8.85mp) at a slightly higher rate, how taxing would it really be for the camera to record at a full sensor 4608x2592 (12mp)? If we were to simply crunch the number in mp, full sensor 16:9 capture would be 1.44 times the file size, meaning it'd require an 18mb/s writing speed. Also, if that full width recording, 4608x1920 (8.85mp), was hacked for, it doesn't seem to me that it should be any more taxing on the camera and the cards.

I mostly bring this up because of the crop factor, though the increase in resolution for 16:9 would be sweet, frankly. Personally, I'm interested in the GH4 for shorts, so a 4608x1920 recording would still be a wet dream come true, but C4k suffices for the time being. My interest in 16:9 is for potential client work. These are just a few thoughts on possible hacks, custom/2.35 grid lines would be sweet.

Hope this doesn't arouse the ire of pressured hackers, just some thoughts. Thanks for reading :)

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Rating sensors readout speed https://personal-view.com/talks/discussion/9578/rating-sensors-readout-speed Sun, 09 Feb 2014 22:06:22 +0000 Ze_Cahue 9578@/talks/discussions After the GH4 release its becoming popular the sensor readout speed on the technical specification (50ms over 100ms GH3). Before that we was just guessing by comparing rolling shutter video tests between cameras.

The question: is out there a list of sensors readout speed rated in ms?
How fast is the Alexa readout in ms? How about Red, Sony and Canon cameras?

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Another take on RGBW sensors https://personal-view.com/talks/discussion/9377/another-take-on-rgbw-sensors Fri, 17 Jan 2014 10:24:18 +0000 Vitaliy_Kiselev 9377@/talks/discussions image

Fujifilm has filed a patent application, which describes the image sensor, markedly different from the existing ones. In the structure of the sensor into account peculiarities of the human visual sensitivity. As is known, the eye is most sensitive to the green portion of the spectrum and the noise easier to allocate the luma than color.In the diagram it is evident that the elements corresponding to the green and white channels have larger dimensions

http://egami.blog.so-net.ne.jp/2014-01-06

http://yournewsticker.com/2014/01/fujifilm-specialists-developed-image-sensor-rgbw-pixels-enlarged-green-white-channels.html

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New m43 Panasonic sensor with 4K support - MN34230PL https://personal-view.com/talks/discussion/8745/new-m43-panasonic-sensor-with-4k-support-mn34230pl Mon, 11 Nov 2013 16:17:46 +0000 Vitaliy_Kiselev 8745@/talks/discussions image

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Specs also have some explanation how 720 and 1080 modes work.

Also interesting is that 1920×1080×4 = 8 294 400 and 1270×720×9 = 8 229 600

http://www.semicon.panasonic.co.jp/ds8/c3/IS00006AE.pdf

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NHK shrinks its 8K camera to camcorder size https://personal-view.com/talks/discussion/3192/nhk-shrinks-its-8k-camera-to-camcorder-size Sat, 12 May 2012 17:05:09 +0000 Roberto 3192@/talks/discussions May 11th 2012 5:04AM

We may still be years away from watching the sweet, sweet 33MP resolution video promised by Super Hi-Vision in our own homes, but over in Japan, NHK engineers are slowly working out the various kinks keeping it from us. Their latest development is this camera seen above on the left, capable of recording 8K in a camera head that is smaller and lighter than the previous unit (the new one weighs 4kg, about 1/5th the weight) shown on the right, and is more comparable to the size of a standard HDTV camera. According to the NHK the savings were achieved by developing a new single plate color imaging mechanism and eliminating the need for a prism to separate the colors beforehand, so it's small enough to be used with standard SLR camera lenses. Sure, it's not quite ready to go on your next vacation, but if you're in Japan you can get a peek at it (and that 145-inch 8K Panasonic plasma) at the broadcaster's open house later this month.

From www.engadget.com/2012/05/11/nhk-smaller-8k-super-hi-vision-camcorder/

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GH3 sensor failure? https://personal-view.com/talks/discussion/8049/gh3-sensor-failure Mon, 09 Sep 2013 03:10:25 +0000 EspenB 8049@/talks/discussions I was taking some Pictures at Alexander platz in Berlin when my GH3 sensor literaly died from one shoot to the next. In an instant the image from the sensor is mostly rolling banding with a fainth unclear image of the subject. Se Attached file. The camera still takes Pictures if you press the shutter, but the recorded images are allmost as bad as the liveview on the LCD/viewfinder. The dislay Works ok during playback of previously recorded pictures. Have the sensor gone bad? I tried a different lens, but there was the same malfunction regardeless. Comments.

The camera is obviousl under guarantee, but the body have suffered some minor dents during use - but still worked perfectly until my Berlin trip. I have a slight worry the shop might try to blame the malfunction as a result of the minor dents.

Any comments on this strange malfunction?

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Samsung ISOCELL https://personal-view.com/talks/discussion/8211/samsung-isocell Tue, 24 Sep 2013 06:14:28 +0000 Vitaliy_Kiselev 8211@/talks/discussions

Samsung Electronics announced its new advanced pixel technology for CMOS image sensors, ISOCELL. This new technology substantially increases light sensitivity and effectively controls the absorption of electrons, resulting in higher color fidelity even in poor lighting conditions. - See more at: http://global.samsungtomorrow.com/?p=28442#sthash.h9Spe5Hl.dpuf

The quality of an image sensor is determined by the amount of light that is accurately captured by the individual pixels within the sensor array. With the market pressure to increase camera resolution and image quality, without growing the camera size, the pixels have had to shrink, while improving their performance at the same time – a challenging task.

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To meet this challenge, previous sensor technology developments focused on improving the light absorption of each pixel, and have progressed pixel technology from FSI (Front Side Illumination) to BSI (Back Side Illumination) which places photodiode at the top to maximize photoelectric efficiency. While being very effective at the time, this BSI technology also faced limitations in improving image quality as pixel sizes continued to decrease.

ISOCELL technology forms a physical barrier between neighboring pixels – isolating the pixel. This isolation enables more photons to be collected from the micro-lens and absorbed into the correct pixel’s photodiode minimizing undesired electrical crosstalk between pixels and allowing expanded full well capacity (FWC).

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Compared to conventional BSI pixels, the ISOCELL pixels decrease the crosstalk by approximately 30 percent which results in higher color fidelity to reproduce the original color with sharpness and richness, and increase the full well capacity (FWC) by 30 percent which leads to greater dynamic range.

Additionally, an imager designed with ISOCELL can feature a 20 percent wider chief ray angle (CRA), reducing the height of the camera module. This makes it suitable for slim and small form factor mobile devices with challenging low z-height requirements.

http://global.samsungtomorrow.com/?p=28442

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Panasonic's new 4K sensor https://personal-view.com/talks/discussion/7806/panasonics-new-4k-sensor Fri, 16 Aug 2013 10:24:03 +0000 Manu4Vendetta 7806@/talks/discussions __.redsharknews.com/technology/item/852-panasonic-s-new-4k-sensor-camera-coming-soon

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Imec and Panasonic present 4K2K CMOS sensor https://personal-view.com/talks/discussion/7334/imec-and-panasonic-present-4k2k-cmos-sensor Sun, 23 Jun 2013 21:57:13 +0000 Manu4Vendetta 7334@/talks/discussions The co-developed imager sensor chip targets high speed, high resolution imaging applications such as next generation HDTV

Leuven, Belgium – June 18, 2013 – Imec presents a CMOS image sensor capable of capturing 12-bit 4,000x2,000pixel progressive images at 60 frames per second (fps). Based on a stagger-laced dual exposure, the image sensor developed with Panasonic, was processed using imec’s 130nm CMOS process on 200mm silicon wafers to deliver high-speed and high-quality imaging, at reduced output bit rate.

The number of pixels on image sensors in video and still cameras keeps increasing, along with the frame rate and bit resolution requirements of the images. 4K2K will be the next-generation broadcasting format, offering an increase by a factor of two in both horizontal and vertical resolution compared to current state-of-the-art High Definition TV.

The image sensor chip is a floating diffusion shared 4T pixel imager, with a pitch of 2.5 micron and a conversion gain of 70 μV/e-, which allows for both a classical rolling shutter or stagger-laced scanning mode. The 4K2K 60-fps imaging performance is realized by 12-bit column-based delta-sigma A/D converters. The stagger-laced scanning method improves imaging sensitivity and realizes a 50 percent reduction in output data rate by alternating the readout of two sets of horizontal pixel pairs arranged in two complementary checkerboard patterns. Additionally, the overall power consumption of the imager is less than two Watts.

“This is an important milestone for imec to demonstrate our capability to co-design, prototype and manufacture high performance CMOS image sensors in our 200 mm CMOS fab,” commented Rudi Cartuyvels, Senior Vice President Smart Systems & Energy Technologies at imec.

http://www2.imec.be/be_en/press/imec-news/imecpanasonic4k2kimager.html

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Improving sensor dynamic range https://personal-view.com/talks/discussion/7330/improving-sensor-dynamic-range Sat, 22 Jun 2013 23:29:30 +0000 Vitaliy_Kiselev 7330@/talks/discussions

We have shown that multi-bit temporal oversampling with conditional reset and variable duration of sampling intervals can be used to increase the dynamic range of image sensors by effectively extending the full well capacity. Conditional reset is necessary for good low-light sensitivity. A test chip was fabricated to implement the method, and the improvement in performance of 22dB in the case of the 3T based pixel and 23dB in the case of the 4T based pixel matches the simulation model. Our approach of pre-defined sampling intervals and conditional reset gives each pixel the optimal sampling sequence based on its light intensity without the need to add storage or decision circuits to each pixel. Since our measurements and model agree, we predict that we can achieve over 80dB dynamic range in a single shot capture with a 1.4um pixel.

Check full paper at http://www.rambus.com/assets/documents/events/2013/iisw-binary-image-sensors-vogelsang-paper.pdf

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Camera and Image Sensor Technology Fundamentals https://personal-view.com/talks/discussion/7329/camera-and-image-sensor-technology-fundamentals Sat, 22 Jun 2013 23:06:43 +0000 Vitaliy_Kiselev 7329@/talks/discussions

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