February 28, 2015, 08:10:31 PM

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Messages - jrista

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46
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 11, 2015, 01:39:00 PM »
What I've not married up Jon, and maybe you have, is I use light to focus the viewer in pictures. If there's too much range in the shot, is there not a chance that it impacts the effectiveness of the shot? Some increase in DR, good. Too much ie 20 stops? Not so sure.


I'm not sure what your getting at... I don't see how more dynamic range could ever be a problem. Certainly not for focusing. Hell, if you had 20 stops, and an in-camera stretching function, you could lift the shadows by orders of magnitude to check focus there as well. Or pull down ultra bright highlights and check focus there. How could that possibly be bad?

47
Animal Kingdom / Re: Show your Bird Portraits
« on: February 10, 2015, 10:08:43 PM »
Woot! 500 pages! :D


Great photos, everyone. Northbid, that owl photo is ex-qui-site!

48
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 10, 2015, 08:45:18 PM »
This is making me think of Horsepower and Torque measurements on cars. In advertising we are quoted the power to the wheels but behind that is a pure power reading straight from the engine before it hits the transmission and drive shafts where some degree of HP is lost. Same true here. Sensor (engine) delivers A given HP before some of it is lost through the signal path and ADC (transmission and drive shaft).   If i want to boost my output to the wheels  I can either get more out of the engine or make my drive train a more efficient machine.... Or both.  canon perhaps did one or the other somewhere in the mix to boost the final horsepower to the wheels.


If they did indeed do that, then it would be entirely illogical to state the camera has the same DR as the 5D III. If they reduced noise and maintained FWC, that would increase DR, and thus, the 5Ds would have more than the 5D III. Why is no one saying that?


It's all very fishy. Word mincing in the extreme. We have a freakin smorgasbord of words right now.  ::)


The only thing that is going to matter in the end is actual FWC and RN measurements. I could care less what DXO says about DR when they downsample the monster file to 8mp. I care about the per-pixel DR...and I really don't think it's going to top 12 stops, let alone hit 13.8.

49
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 10, 2015, 08:41:07 PM »
For me the next breakthrough will be a 100 Megapixel camera (or 200, anywhere up to 500 is good).

DR is great, but not a game changer for me (it would be for those who think it is, but for me it's as good as 100+MP is for them).

Bigger sensors are an inevitability. The EOS mount is even big enough for a 50mm sensor as-is, if you remove the mirror.
All Canon has to do is make the sensors, and be able to sell a pro-mirrorless body.

If they make a new mount and forget about backward compatibility, I hope the sensor is at least 4x3" or at the very least IMAX (70.41x52.63mm).
I'm sick of seeing these puny 55-60mm sensors that provide barely any increase in surface area being called "Medium Format".


Umm, a 60mm wide, 45mm tall medium format sensor (same size as 6x4.5cm large format film) has 3.125x the surface area of a 35mm sensor. How can you possibly call that "barely" any increase in surface area? Even a 44x33mm medium format is twice the surface area, which is significant. Twice the surface area, twice the light gathering capacity. A 35mm FF sensor is is just a bit more than twice the light gathering capacity of APS-C...and look at how much that improves performance right there. Imagine having four times the light gathering capacity of APS-C...or with a 6x4.5 a whopping 6.25x the light gathering capacity.


As for IMAX-size medium format. Where are you going to get lenses that perform optimally across that entire surface area? How are you going to afford such lenses? The "normal" lens for such a sensor would be a 90-100mm lens. That would make a 300mm equivalent lens on IMAX a 540mm lens. At f/4, such a lens would still require a minimum 135mm objective...which is pretty huge. That's larger than a 300 f/2.8, it's even larger than a 500 f/4, for 35mm FF!!


Medium format cameras are expensive for a reason, and they are rare for a reason. :P I'd be surprised if Canon came out with a 44x33mm camera, let alone 60x45 or 72x53mm. Such a niche product...

50
Landscape / Re: Moon photos
« on: February 10, 2015, 06:47:32 PM »
Hand held with IS on.  300 2.8L IS II with 2xiii extender and 7d mark ii


Wow, nice work for handheld...yowz!

51
Landscape / Re: Deep Sky Astrophotography
« on: February 10, 2015, 06:46:15 PM »
So I broke down and ordered a camranger.  Mostly so I could use my ipad for micro focus in the field.  Anyone else use a camranger for astrophotography and does it provide useful features?

I had been using a laptop for microfocus but I dreaded dragging that off to the midwest when I would have my tablet anyway.


I know a bird photographer who uses one. He uses it to get difficult shots, like Kingfishers. I don't know of anyone who uses one for astro...but if it helps you focus, I say more power to you.

52
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 10, 2015, 06:45:14 PM »
And As always Jon, thank you for the technical explination.


I'm hoping I'm wrong...it would be nice to see Canon blow my mind with a truly radical IQ improvement for a change.

53
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 10, 2015, 06:18:04 PM »
I want to throw away my nd grads. They suck. So more dynamic range and iso 12.

Bad news Im afraid even at 20 stops of DR their will be situations where people will want to use ND grads, forget how many stops unless something drastically changes your need polarizing filters and to get creamy water extended exposures with filters (up to 20 stops is possible, the Big Stopper is 10 stops). Ive always seen filters as an artistic tool not a hindrance if they were so I doubt the worlds greatest Landscape Photographers would use them. Unless CMOS sensor design changes IRNDs for 2/4K video are also here to stay.


A solid ND filter like the big stopper is different than an ND grad. You could use that fine on a camera with unlimited dynamic range, as it has nothing to do with dynamic range. It has to do with allowing you to expose for longer (much longer) than you normally would...blurring motion.


A camera with 20 stops of DR would pretty much eliminate the need for graduated nd filters. That is a LOT of dynamic range. Remember, every stop DOUBLES the range of the previous. Going from 11 to 12 stops DOUBLES the range of light your camera is simultaneously sensitive to. Going from 12 to 13 stops DOUBLES the range again. Going from 13 to 14 stops DOUBLES it again. Double it six more times, and you finally reach 20 stops.


That is a truly massive amount of dynamic range. About the only thing you couldn't do with that much dynamic range would be imaging the sun setting behind a mountain well enough to pick out sunspots and flares, while simultaneously pulling out full detail in the deepest shadows of that mountain. There are a couple of celestial objects that could probably use that kind of dynamic range as well...say Orion Nebula or Andromeda Galaxy...both of those are extremely high dynamic range objects, with ultra bright cores and ultra faint outer regions.




54
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 10, 2015, 06:02:44 PM »

I still think people are mincing words here. The 5D III does not have 14 stops of DR. The 5D III has 11 stops of DR. You cannot ignore the read noise, and people seem to be trying to do that with these funky explanations of why the 5Ds "has the same DR as the 5D III, but also has more DR than the 5D III". None of it makes sense.

It's possible (although not likely) they're discussing about two different things. The dynamic range of each pixel is related to its capacity versus noise, and the dynamic range of the output is limited by the bit-depth of the ADC and file structure.


Aye, I think that's mincing. The output is all we have. We can't get the raw sensor signal pre-ADC. According to Roger Clark, the 5D III sensor itself is capable of over 15 stops of DR (ratio of ISO 100 FWC and lowest recorded read noise.) But, that's entirely moot and meaningless, because you cannot get the signal out of the camera without running it through the ADC. The dynamic range of a camera IS the dynamic range of the output.




If I took a sensor like a Newton 920 with 94dB DR but ran it through an 12-bit ADC and store export 8-bit JPEGs, which would be the appropriate DR to quote?


That would depend on the context. If your just selling the sensor, then 94dB (15.67 stops) is certainly the only number you could quote. However, once you stick that sensor in a camera with a 12-bit ADC, the CAMERA can only deliver, at absolute best, 12 stops of DR. It'll likely deliver less, possibly a couple of bits less depending on the quality of the ADC unit, because of the added read noise. In the case of the CAMERA (vs. the SENSOR), the appropriate DR number to quote would be the one derived from FWC/RN ratio for that particular camera.


I honestly don't see how you could quote anything else. What can you actually USE when you bring that RAW file up in an editor? Can you use the 15.67 stops the sensor itself is capable of? Of course not...so why would you use that number when marketing your camera? You wouldn't, simple as that. (Well, maybe you would...guess it would depend on how honest a business man you were. :P)

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The 5D line uses 14-bit ADCs and 14-bit files, and thus the output is bounded at 14-stops, for all 5D cameras.
The 5Ds sensors may have lower noise (and similar FWCs) to previous 5D cameras, and thus have greater flexibility to lift shadows. Again, I don't think it's likely, but whatever, 12-ish stops is generally plenty.


Personally, I think whether 12-ish stops is "plenty" is entirely subjective and contextual. There are those of us who could use 16 stops, 20 stops, if we had it. In some contexts, 12 stops is woefully inadequate.


Subjectivity and feelings vs. objectivity and facts. I'm trying to stick to the latter. ;)

55
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 10, 2015, 05:53:52 PM »
Jrista, why do you even shoot with Canon? You seem to bash them so much. The d810a was just announced. Maybe you should just make the switch. Sounds like you'd be a lot happier than you are here.


First, I don't "bash" Canon. I am annoyed with Canon for ignoring the sole issue they have for so long, but I don't bash them. Not anywhere remotely close to how some past members have, not by a long shot. I think Canon can do better. I KNOW Canon has patented technology that would allow them to do better. It's annoying that they just sit on the technology, rather than employing it...and I call them out for that. But that's different than raw, unmitigated Canon hate (of which there are plenty of members here who do just that...hate Canon regardless.)


I'm simply delivering simple facts here. This is simple math. It's objective truths. This has nothing to do with bashing Canon...it's just the facts. DR is DR...it's not complicated, it's not quirky...it's just a ratio. Unless Canon has magically pulled an Exmor out of their conservative hat...I believe the evidence is strongly stacked against the notion that Canon is suddenly going to get 13+ stops of DR on a 500nm process with their high read noise and tiny pixels.



BTW, I don't shoot with Canon for landscapes. I use them for my high ISO stuff, where they perform perfectly well. I also own a $13,000 600mm f/4 Canon lens (and it's the best of it's class, across brands, so I'm not complaining), but because of that lens I am kind of stuck with Canon over the long term for high ISO regardless. High ISO is more physics bound, and Canon doesn't have much in the way of problems there, so it's not an issue.


However, I don't use Canon for landscapes. I gave up on shooting landscapes, at least the kinds of landscapes I really like, once I realized how bad Canon's read noise is in my 5D III, and having seen little improvement in the 6D, 70D, 7D II. I don't have much time for landscapes...I certainly can't go driving all about the Colorado Rockies all the time to find amazing vistas, and it's even more difficult to find them with good light. On top of that, I'm putting all my resources into astrophotography these days. With astro, you have no option but to dig way deep into your signal data...and once you do, there is simply no denying the fundamental and radical differences in data quality between Canon...and the rest.


Canon has stuck with their old technology. From a business standpoint, I understand...but it's still put them well behind the curve when it comes to core image quality. Objective image quality, measurable image quality...I'm not talking about my own personal subjective perceptions of how I "feel" when I see a Canon image or a Nikon image. Again, this is simple, objective, mathematical stuff here. Cold, hard facts...not feelings. I'm not proclaiming from the walls that everyone should "jump ship or die" or anything like that...I'm just delivering some simple facts. If you choose to get emotional over that...that's your deal.


Otherwise...take it for what it is...realism. Unless Canon is truly hiding some phenomenal technological improvements (and if they are...wtf, why?!?!), the cold, hard facts indicate that your very likely not going to be getting 14 stops of DR out of your 5Ds. (Not without Magic Lantern, anyway. ;) )

56
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 10, 2015, 05:31:56 PM »
Oh, BTW, the DR formula:


Code: [Select]
DRstops = 20 * log(FWC/RN) / 6

57
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 10, 2015, 05:20:46 PM »
There seems to be more fuel to this fire.  More than 1 NL source telling them this...  I really hope it's true.   

I would have to think it is.  Step back a moment and look at the big picture. 5D3 has 14 stops but only 11-12 usable by reasonable measure due to read noise.  5DS has "equivalent DR of 5D3" (14 stops).  Brunhill adds to this "more ability to pull up shadows with lower noise floor" (paraphrasing).  We know Canon "tuned this for Low ISO" which I'm not sure what else that could really mean other than lower noise and more DR along with this better CFA.  In order to get usable images at higher ISO, I imagine you have to sacrifice SOME level of capability at the lower end, so now they have eliminated that trade off by foregoing higher ISOs for the intended audience of this camera.  Here's what else makes sense. All this talk about Canon having to remake their fab lines or greatly alter the process to get the AD on the Sensor like Sony.... Canon (if this is all correct, which I have no reason to suspect not at this point) has found a way to keep making sensors just as they have been with separate AD blocks (minimizing new capital expenditures to re tool manufacturing) but making the sensor itself operate at much lower temps (as per Northlight sources) because it's not worried about 3200 and beyond sensitivity...thus creating far less potential for noise creation.  This to me appears to be a perfect trade off between making a new product and keeping the company financials happy.  I think my logic there is sound, but I'm happy to hear debate.


I still think people are mincing words here. The 5D III does not have 14 stops of DR. The 5D III has 11 stops of DR. You cannot ignore the read noise, and people seem to be trying to do that with these funky explanations of why the 5Ds "has the same DR as the 5D III, but also has more DR than the 5D III". None of it makes sense.


Dynamic range is a very simple concept. It is the ratio between the FWC and the noise floor. Many things can affect the noise floor...including shot noise in the signal itself. I haven't actually heard anyone from Canon officially state that this camera has more dynamic range...they just keep talking about the "noise floor". The 7D II, which nearly the same pixel size, has lower read noise. It has lower read noise because it has small pixels (something about how Canon designs sensors leads to this scaling of read noise with pixel size...not all sensors are that way). The 5Ds has the same small pixels...so, it stands to reason that the sensor will have lower read noise.


The KEY here is that...for the 5Ds to have more dynamic range, it MUST ALSO have a higher FWC than the 7D II does at ISO 100. If it has, say, 13e- RN per pixel at ISO 100, and still has a 29455e- FWC...well, it'll actually have slightly less DR than the 7D II (which has 12.9e- RN per pixel with ever so slightly smaller pixels.) The 5Ds, at 13e- RN, would certainly have less read noise than the 5D III, the 6D, the 1D X, etc. But with a 30ke- FWC, it's got less than half the FWC of a 6D!!! It wouldn't have more DR...it would have the same DR as all Canon cameras have...around 11 stops and change.


If the 5Ds has 13e- RN and say a 45ke- FWC, alright, now we're talking. That is 11.8 stops of DR...half a stop to a stop better DR than other Canon cameras. If it has a 60ke- FWC (double the 7D II...eh, I don't think that's possible with 4.14 micron pixels, especially not on a 500nm process, but let's go with it), then you have 12.2 stops of DR. Hmm...a solid stop better than any other Canon camera...but still not comparable to the 13.8 stops of a D810. So...let's just go all out and say the thing has 75ke- FWC (same as the 6D). It'll have 12.6 stops of DR...eh. For this camera to get 13.8 stops of DR at 13e- RN, it would need an FWC of 180ke-. Not gonna happen...not with 4.14 micron pixels and a 500nm process.


Let's go the other way here. Let's reduce read noise. Let's say it has 6e- RN and a 30ke- FWC. That's 12.3 stops right there. What about at 3e- RN? Bam, 13.3 stops of DR. Let's say it has a higher FWC than the 7D II...say 40ke-, and that same 3e- RN. Voila! 13.75 stops of DR.


Canon needs to reduce their read noise to Exmor levels. There is no way they are going to get enough well capacity in a 4.14 micron pixel to support more than MAYBE a stop more DR at similar RN levels to the 7D II. There are certainly things Canon could have done to reduce read noise to 3e- at ISO 100...however it would be THE unprecedented move they have needed to make for oh so, so long. To actually achieve it, Canon would have had to have moved to a newer, better process (180nm at least, smaller better), and moved all the core image processing logic (amp, CDS, ADC) onto the sensor die, and go CP-ADC (thus reducing ADC frequency considerably). Just doing that wasn't even enough for Sony to achieve the ultra low level of 3e- RN...they had to use additional innovations. They added a digital CDS stage to the readout pipeline. They also moved the clock generator to a special remote area of the sensor die to prevent it from adding uneven noise to whatever ADC units were closest to it. Finally, they designed ADC/DCDS units which adapt themselves to each pixel column, eliminating vertical banding.


I dunno. Maybe it's just me...but that sounds like much too big a leap. Especially given the rumors that the 5Ds is STILL manufactured on a 500nm process. Even more especially given that it's already been stated so many times that it has the DR of the 5D III. Yeah....just doesn't sound plausible to me. I don't think the 5Ds will have Exmor-level 13+ stops of DR. At best...I'd say 12.2 stops...with the faint hope that Canon will totally surprise me and prove me totally wrong with some truly amazing technology in the 5Ds.

58
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 10, 2015, 01:52:56 PM »
What's wrong with the 5D III's dynamic range?


Lots and lots of blotchy, blurry, scratchy, banded, hot-pixely & red-shifted noise in the shadows, and much less shadow pushing ability. It's a good two stops and change behind the competition these days. Back when the 5D III was released, that was disappointing but understandable. Three years on, it's entering the realm of unacceptable to many who would use this kind of camera for landscapes.


Despite the fewer megapixels, the D810 with it's 36.3 million pixels has a better signal in each and every one of them. If the 5Ds hits the streets with less than 13 stops of DR, personally I'd still take the D810 and a 14-24mm for landscape work.

59
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 10, 2015, 06:26:58 AM »
More DR.  :P ;D

60
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 09, 2015, 07:24:01 PM »
And right now, based on revenue forecast due to overall market shrinkage, Canon are not showing any sign of investing in a different process. Which for many people, won't matter. For some it may do, and they will weigh it up as to move or stay. In that respect, the 5Ds does not change Canon's position, it just offers a bunch of people who are happy with the DR of the current sensors a higher res sensor in a similar package to the MK III. I think expectations for the IV and X II should align similarly. Iteration of, modest improvements, no step change. Which again, will be enough for many people...


Aye, a shrinking market would certainly put a damper on investments, however Canon already has a 180nm fab. From what we do know, it was used to manufactuer their P&S sensors in high volume. The P&S market has crashed already, and Canon couldn't possibly be at full capacity on that second fab. They are clearly still investing some money (a billion and change or so?) in R&D on the photography side of things. Most of that seems to be going to lens innovations, but some has gone to sensor innovations. Canon should be able to move some fabrication off their ancient 500nm fab and onto their 180nm fab without actually having to invest a billion or so into a new fab.


Sounds like a win-win to me, and to some others...the curiosity is that they simply haven't done it. I cannot fathom why...but from Canon's own mouth, they stated that they see a big reason for the shrinking DSLR market being lack of technological innovation. Again, seems like a win-win for them to utilize freed up capacity on their 180nm fab (which is a 300mm wafer fab that can apparently produce sensors on a copper wiring process, which is competitive with what Sony is doing) to improve their technology.


Fortunately (?) there may not be any significant change in Sonikon sensors in 2015 either, but there will be a 50MP body from both of them....


I'd call it unfortunate myself. :P The more pressure other companies can put on Canon from a technological-through-IQ standpoint, the better. It's not so bad for SoNikon though, as they are already ahead of the curve when it comes to eeking out as much IQ as possible from their current sensor technology. I think Sony is in a much better position to create a 50mp body that gives closer to medium format class IQ than Canon is.


I am very interested to see if Canon has increased FWC while lowering read noise, or whether the lower read noise is simply a consequence of smaller pixels, and paired with a similarly smaller FWC. It seems read noise varies more linearly (not exactly, but more closely) with pixel size, while FWC varies with area. If we divide the 6D read noise of 26.4 by the 7D read noise of 12.9, we get 2.05. As far as FWC goes, the ratio of pixel areas between the 6D and 7D II is 2.513 (sqr(6.5)/sqr(4.1)), the FWC of the 6D is 74256e- and the FWC of the 7D II is 29544. Divide the FWC of the 6D by the area ratio, and you get 29,544.22.

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