September 30, 2014, 08:00:01 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - Don Haines

Pages: 1 ... 15 16 [17] 18 19 ... 216
241
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 26, 2014, 10:25:17 PM »
Yeah Canon may eventually add 4k. That just shows Canon is no longer an innovator, just a  follower.
Sometimes when you are following someone and they go off a cliff, it's a good thing that you had time to stop.....

242
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 26, 2014, 07:23:31 PM »
Most buyers will be looking for integrated imaging devices, not specialized stills or video cameras.

Indeed.  That explains why everyone has one of these:



I cringe when I see those. It is a tool that does nothing well and usually leaves a mess behind....

243
EOS Bodies / Re: Do Sensors Make the Camera?
« on: August 26, 2014, 04:37:42 PM »
and that means the split pixels it does not improve the file quality.

That's not what he was getting at. He's saying (I believe) they already have a finer process, and citing DPAF as proof, even though they currently are using it for something other than IQ.

Well, to be fair, he is still speculating about the 70D being made with a 180nm process. The 70D has only a few extra gates to handle the ability to read the two separate photodiodes in each pixel separately, as well as to bin them for a full pixel read. There isn't even a 10% increase in pixel FWC...if they had moved to 180nm, that means the border of wiring and transistors around each pixel would shrink by 320nm each side. That would lead to an increase in photodiode area of nearly 43%. Even assuming the independent read and binning logic takes up more space, I would still have expected more than a 9% increase in FWC if the 70D had moved to a 180nm process.
If they had done DPAF on the 500nM process, I would have expected the FWC to have dropped... yet, as you point out, it has slightly gone up...

of course, all this is speculation..... I have no inside information and am just guessing at a possible scenario....

244
EOS Bodies / Re: Do Sensors Make the Camera?
« on: August 26, 2014, 04:32:55 PM »
and that means the split pixels it does not improve the file quality.

That's not what he was getting at. He's saying (I believe) they already have a finer process, and citing DPAF as proof, even though they currently are using it for something other than IQ.
Yes!
With the available space on the die, I believe that there is not enough space to build the circuitry required for DPAF for the 70D using the 500nM process...

245
EOS Bodies / Re: Do Sensors Make the Camera?
« on: August 26, 2014, 03:09:54 PM »
Why is a cooperation like Canon not making a new sensor fabrication?

A new CMOS production line worth at least twenty million dollars. Without enough motivation, a old school cooperation is very unlikely to spend this kind of money on things like that. Therefore, the company decided to work the engineers' buds off to push the limit for the old 500nm sensor because it is cheaper.

The best reason that I can think of as to why they are not buying a new CMOS production line is because with the downturn in P/S camera sales, production capacity is opening up on their existing production line for small sensors, which is a finer line than that used for FF and APS-C (Non DPAF) sensors.

The second point to make is that the complexity of circuitry required to make a DPAF 70D sensor is beyond that which can be fabricated on the 500nM line... therefore, it must be fabricated on something else and that means the existing fabrication line for P/S sensors.... This means that they are now in the process of switching over to a finer line and when that is done, they can shut down the 500nM line and save money..... because it costs more to keep 2 lines running than 1 line.

246
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 26, 2014, 02:33:19 PM »
Concerning heat dissipation, why not a Peltier unit affixed to the sensor assembly?

Extremely power hungry, you have to get the heat out somewhere (often a finned heat sink with a fan), very expensive.

For example:


http://www.atik-cameras.com/products/info/atik-4000

A peltier device adds heat to the system. It moves heat from one location to the other, and that takes energy. In a closed system, like a sealed camera, that's bad! You will just make things hotter. In most devices that use them there is either a big heat sink on the outside of the unit, or a fan to blow air across the peltier device to get rid of the excess heat... I suppose you could use the bottom of the camera as the heat sink and then use a metal tripod to help conduct it away, but most of the time that isn't an option.... and as mentioned above, you would drain the battery very fast.

247
You can find these folks in Yellowstone standing within ten feet of bison with their 18-55's and iPads.
and inside grizzly and polar bears.....

248
Animal Kingdom / Re: A few wildlife images
« on: August 26, 2014, 11:26:30 AM »
Here's a few wildlife favs..
#2, the fox out mouse hunting.... That is absolutely perfect timing! Congratulations!

249
Animal Kingdom / Re: Your best animal shots!
« on: August 26, 2014, 11:25:18 AM »
Hi,

my name is Stefan and I am from germany.

I'd like to show you, 3 of my all-time-fav pics:


I REALLY! like the first one.....

250
I've been waiting for it for years but have given up hope that Canon actually listens to their user base  :(

you can only wonder how they manage to still sell the most DSLRs.....
it seems canon knows better what the majority of the silent userbase will.

im waiting too but the repeating of the above statement doesn´t make it true.

i bet canon has more inside information about what the users want than what is written on geek websites with a few thousand members at most.
Unfortunately, the masses seem to want a $300 crop camera left in automatic mode, with an 18-250 or 300 mm all-in-one zoom lens.....

251
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 26, 2014, 11:16:02 AM »
snip

You of course are correct. I was fixating on the number of possible entries, not the entries themselves. This is why we don't drink and post. Carry on.

Plus, as we approach a problem/question from different backgrounds, we see things differently.... It often helps when we try to explain ourselves and show examples. Many times we are saying the same thing with different words.... A pleasant and professional discussion helps everyone out.

252
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 26, 2014, 08:16:47 AM »

0-16384 (14 bit ADC) is infinity?  ???



16,384 = 2^14.

The lowest value the sensor records, however, isn't 0.

It's 2^0. Were it zero, any increase would be infinite on a percentage basis.

But it isn't.

1-2-4-8-...2^bitdepth

The range is from 0 to (2^N)-1
it is 0 to 16383

I think what 3kramd5 was getting at was that no system has zero noise. When we convert the voltage of a pixel into an ADU with the ADC, we cannot convert a fraction of an ADU. If RN is 3e- and FWC is 60ke-, then 3e- RN, although in floating point precision is 0.8192, ADUs are integer (at least, they are in todays sensors...maybe at some point we'll have cameras that can convert directly into 32-bit float RAW. :D) Since ADUs are integer, you cannot convert any non-zero charge to zero...the minimum ADU is 1, or 2^0.

DSP (Digital Signal Processing) 101......

A N bit D/A converter is capable of resolving 2^N states. A 4 bit D/A can resolve 16 states, an 8 bit D/A can resolve 256 states, and a 14 bit D/A can resolve 16,384 states. I think we can all agree on this.

So with a 14 bit D/A there are 16,384 states. These states are represented as binary 00 0000 0000 0000 to 11 1111 1111 1111, or 0 to 16,383 in decimal.

The signal that we wish to measure is typically fed through an amplifier (or attenuator for large signals) so that it's maximum value will be scaled to the input range of the A/D converter. For example, lets say we have an 8 bit D/A converter that works from 0-15VDC.... if we are using it to measure a signal from 0 to 1VDC then we only get the last 4 bits of resolution toggling and we have thrown away the accuracy of the system. Scale the input signal up by 15X and now you get all bits toggling. In this system the state 0000 0000 does not represent 0 volts, it represents from 0 volts to less than 15Volts/256 (0.0586 volts). Likewise, the state 1111 1111 does not represent 15 volts, it represents from 14.9414 volts to 15 volts. Each state represents a range, not an absolute value. The state 1111 1111 is special, it also represents the overload condition where an input signal is high enough to saturate the converter.

So back to our Canon 14 bit A/D....
It's lowest possible reading is 0, it's highest possible reading is 16,383. In any circuit there is the noise floor... the lowest level of signal found in the input signal. In a well designed circuit, the resolution of the A/D converter will be less that the noise floor. What this results in is the last few bits of the A/D converter toggling almost at random. The noise comes from our amplifier, from our converter, from fluctuations in our reference voltage on the A/D converter, and from outside. When we get rid of our least significant digits that are toggling randomly, we are left with the "significant digits".

My suspicion is that Canon does not use 14 bit A/D converters, but uses 16 bit or even 20 bit A/D and throws away all but the most significant 14 bits.

253
Canon General / Re: Advice sought on travel to Cuba
« on: August 26, 2014, 12:17:25 AM »
There are lots of tours run out of Canada... I have no idea how they would comply with US laws...

254
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 26, 2014, 12:05:21 AM »

0-16384 (14 bit ADC) is infinity?  ???



16,384 = 2^14.

The lowest value the sensor records, however, isn't 0.

It's 2^0. Were it zero, any increase would be infinite on a percentage basis.

But it isn't.

1-2-4-8-...2^bitdepth

The range is from 0 to (2^N)-1
it is 0 to 16383

255
EOS Bodies / Re: Do Sensors sell the Camera?
« on: August 26, 2014, 12:01:12 AM »
I fully expect Sony/Nikon cameras to have 15, if not 16, bit ADCs in 4 years time.

I am amazed that they don't have them already...

The 7D has a full well charge of 24,800. you need 15 bits to properly read that.... and in the last 5 years full well charges have increased, particularly with FF. Only having 14 bits is a choke point.

The full well charge on the full-frame bodies won't even fit into 16 bits.  In an ideal world, they'd dispose of the downstream amplifier and go to at least a 17-bit DAC (or cut costs and use an off-the-shelf 18-bit DAC).

With that said, given that we're talking about an analog voltage level, they'd probably be better off using a higher-precision DAC even though strictly speaking there are fewer discrete levels, if only because you'd expect some charge decay over the course of longer shots, and having a more precise measurement of the voltage would allow you to adjust for that in post processing.

Also, there's the issue of noise floor.  You want the digital floor to be way below the analog floor so that you guarantee that anything that qualifies as signal gets captured.  Right now, the digital floor is considerably above the analog floor (as you pointed out), which is bad.  Pushing it several bits below makes for a nice safety margin.

Personally, I don't really understand why all the camera manufacturers don't just standardize on a 20-bit DAC and be done with it.  Storage is cheap.  Quality is irreplaceable.  Why cut corners?
I know.... it's not like it's hard to do....
I can't think of anything at work that does not use at least 24 bit A/D and we have some test equipment that has 64 bit A/D and others that have 48 bit A/D running at 60Ghz sampling rates... I think that the last time I designed something with only 16 bit A/D was back in the 1980's....

Pages: 1 ... 15 16 [17] 18 19 ... 216