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Messages - jrista

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31
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 12, 2015, 12:42:11 AM »
Well the guys testing it are obviously seeing some sort of not insignificant improvement, but of course if they release any RAW files and get caught that would be the end of their cozy relationship with Canon.  I'm hoping they will be allowed sooner than later to show some samples but knowing Canon, they will play it close to the vest.   I'm sure there will be more tweaks between now and June. Even that makes me wonder if they are pushing the release that far back as a red herring to Sony and Nikon to make them show their cards. I'm not betting on it, but I wouldn't be surprised if we see this camera show up a little earlier than they are suggesting right now.


There is perception and fact. I think a lot of the "significant improvement" will ultimately pan out to be feelings about how the files perform in an editor. They are also likely biased by each tester's tolerance for noise in the past. Banding certainly cut into people's tolerance levels in the past, so some people wouldn't do even as much shadow pushing as I have (and I don't do all that much with Canon files). The 5Ds is bound to have lower banding than the 5D III...which may mean these testers are more willing to push shadows than they have in the past. That wouldn't necessarily mean they had more DR, though.


The real test will be direct head-to-head comparisons with images that actually are 13.8 stops. I think in relative terms, the 5Ds probably won't exhibit anything quite so significant as a 1.5-2 stop improvement. In raw testing, I could see it getting a quarter to a third stop higher dynamic range measure, barring some cool new innovation or much lower read noise than the 7D II. If it DOES have much lower read noise, then we've simply been given bad information in regards to the 5Ds having the same DR as the 5D III (and I'd be happy to see that be the case!)

32
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 12, 2015, 12:25:40 AM »
Well if the new sensor design is already operating at significantly lower temps then I wouldn't think any additional ventilation or heat sinking would be necessary.


I think the reason it's operating at lower temps is due to some kind of active cooling. Canon was working on that a while ago, and it seems they may have finally put the technology to use. Especially of "significantly" means at or below ambient...for that to be the case, some kind of active cooling (best thing that comes to mind is heat pipes) would definitely be necessary. If the sensor maintains a below ambient temperature, something like a peltier would have to be used...but that draws a LOT of power (they aren't very efficient, just very effective)...
f

I guess I'm wondering if cutting out extra amplification needed for high ISOs didn't just itself eliminate the heat.  If it's not being produced to begin with...   That said you put a much funnier picture in my head of an NItros Oxide forced induction system on the body.  Little blue NOS tank and a ram air scoop  ;D


I don't think the elimination of high ISO options is going to affect temperature. I am pretty sure the reason they did that is because of the stronger CFA, which reduces EQE. Most of the DR discussion has to do with using the camera at ISO 100, so high ISO wouldn't factor into the picture anyway.


If the sensor is "significantly" cooler, though, that seems to me to imply that Canon has either employed or devised some way of actively removing heat from the sensor, to at the very least bring it within the realm of ambient. Maybe they designed something to bring it below ambient without the poor efficiency of a peltier. If they did, that would certainly help with the dark current...but, if the 5Ds has the same low dark current as the 7D II...I don't really know what that would do. The 7D II has such low dark current that you wouldn't get any noise from dark current at all under normal conditions unless temperatures were extremely high. The only other time the 7D II has any issues with dark current is when doing long exposures, but most photography is sub-second exposure.


That once again brings us back around to: read noise. :\ I really hope they reduced it by a very significant amount...but even if it's still 6.5e- (half what I'm predicting), that would bring us to 12.2 stops of DR, which is a stop improvement. (It would also entirely invalidate the "same DR as the 5D III unless you use special sauce measurements" claim...)

33
Landscape / Re: Deep Sky Astrophotography
« on: February 11, 2015, 11:50:29 PM »
EXCELLENT images, Cazza! Your modded 6D sucks out far more Ha than my unmodded 5D III does...really amazing. I'm amazed these are all tracked using the AstroTrac...that little thing must handle the weight very well.


Looks like you have access to more southerly skies. The Carina Nebula is something I can't see, but I find it fascinating. Love your wide field of the area, truly excellent.


Your Lovejoy is superb as well!


Welcome to the forums!

Thanks jrista!

I live on the Sunshine Coast (about 26deg S) - just north of Brisbane, Australia - so I am lucky to have a full view of the many goodies in the southern sky.

Yes, the full spectrum modification does make a huge difference - like about 400%+ increase in Ha sensitivity. A visible+Ha band pass filter that cuts infrared is essential. The FS 6D is also very handy for daytime (and night time) IR work.


Yeah, once you get rid of Canon's stock IR/UV cutoff filter, things improve dramatically for astro. I've resisted doing that with my 5D III, as I don't want to mess with it's existing IQ for my birds and wildlife, and am planning to get a mono CCD with filter wheel and narrow band filters soon here anyway.


The 5D III definitely struggles to get any Ha though.


The Astrotrac does pretty well, but can be fiddly to get right. I usually spend about 45min drift aligning before shooting. And you have to keep the center of gravity of the camera and lens close to the center of rotation of the Astrotrac. If I'm lucky, on a good night, I can get 4min subs with a 400mm FL.


Thanks for the insights. It is possible to use PHD to do very rapid drift align. I am not sure if that would be possible on the astrotrac, PHD has compatibility with certain guide cameras and may not work with a DSLR. I can dial in a PA error of about 30 arcseconds or less in about 10 minutes or so using the technique I describe here, though:


http://www.cloudynights.com/topic/472874-drift-alignment-with-phd2-the-bookmark-technique/


If you can figure a way to make it work, it might get you dialed in much faster.

34
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 11, 2015, 11:45:11 PM »
Well if the new sensor design is already operating at significantly lower temps then I wouldn't think any additional ventilation or heat sinking would be necessary.


I think the reason it's operating at lower temps is due to some kind of active cooling. Canon was working on that a while ago, and it seems they may have finally put the technology to use. Especially of "significantly" means at or below ambient...for that to be the case, some kind of active cooling (best thing that comes to mind is heat pipes) would definitely be necessary. If the sensor maintains a below ambient temperature, something like a peltier would have to be used...but that draws a LOT of power (they aren't very efficient, just very effective)...

35
Lenses / Re: Canon 85 1.2L USM II for only $10!?
« on: February 11, 2015, 10:49:27 PM »
My guess is the price was supposed to be $1000, and some quirk of how you enter numbers ended up adding an unexpected decimal.

36
Landscape / Re: Deep Sky Astrophotography
« on: February 11, 2015, 10:43:37 PM »
EXCELLENT images, Cazza! Your modded 6D sucks out far more Ha than my unmodded 5D III does...really amazing. I'm amazed these are all tracked using the AstroTrac...that little thing must handle the weight very well.


Looks like you have access to more southerly skies. The Carina Nebula is something I can't see, but I find it fascinating. Love your wide field of the area, truly excellent.


Your Lovejoy is superb as well!


Welcome to the forums!

37
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 11, 2015, 10:03:03 PM »
Now you might, if you have a brain, realise that my position is within a gnats hair of being the same as jrista's, what I don't do is wrap up the obvious in 1,600 of repetitive verbage. We have been told two things by Canon, DR is the same, and the noise floor is lower so editing latitude is higher. There are growing reports from non techs that the second is true.


You write that as though being verbose is some kind of atrocity. If you like to be terse, more power to ya. You guys are pedantic about everything, so I've learned to be as verbose and explicit as possible, and even then, it doesn't matter.


The reason I'm writing what I am writing is Canon has said one thing, but they haven't said another thing, and both things are important to improving DR. Lowering the read noise floor is meaningless in the context of a smaller pixel if they did not also increase the amount of charge each pixel can hold. Lower read noise + lower FWC != more editing latitude. Lower read noise with a smaller pixel AND a larger charge capacity would, then, mean more editing latitude...maybe Canon has done that. However if they did, then the statement that the 5Ds has the same dynamic range as the 5D III would be false. Something doesn't add up.


Canon HAS stated that the dynamic range of the 5Ds is the same as the 5D III. I also don't believe in any kind of alternative means of measuring dynamic range...it is what it is, and if you want apples-to-apples comparisons, you gotta measure the same way. I'm not going to give out any special treatment here. Given that, the only logical conclusion I can come to is that the FWC has not been increased for the given size of pixel. That means that in order to protect the highlights, you have to shift exposure down to keep those highlights from clipping, which pushes more information into the read noise floor. Same as with any other camera...hence the reason a lower read noise floor rapidly leads to more dynamic range.


Dynamic range is agnostic of any of these nuances...dynamic range is dynamic range. If it's the same as the 5D III, but has the low banding of the 7D II, it's going to have about the same shadow pushing ability as the 7D II. Which is marginally improved over prior Canon cameras, but nothing anywhere remotely close to what you can do with something that actually has 13.8 stops of DR.


There is a logical disconnect between "lower read noise" and "same DR as 5D III" and "more editing latitude"...one of those can't be true if the other two are true. Lower Read Noise + More Editing Latitude != Same DR as 5D III; Lower Read Noise + Same DR as 5D III != More Editing Latitude; More Editing Latitude + Same DR as 5D III != Lower Read Noise. That final one could also be stated this way:  More Editing Latitude + Same DR as 5D III != Lower Read Noise + Higher FWC. Lower RN+Higher FWC != Same DR as 5D III, therefor editing latitude must still be the same, or the camera has more dynamic range than the 5D III.

Alright, I've stuck you on my ignore list. Goodbye.

38
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 11, 2015, 09:30:53 PM »
There is something I've said a lot, and somehow it doesn't seem to sink in. That's ok, I'm probably just not explaining it well enough. But here goes again:


Noise affects the entire signal.

When people hear read noise, they first think: shadows. Sure, read noise has the most significant impact on the shadows, but the shadows are not the only thing it impacts. The midtones are impacted as well. The tones halfway between an 18% gray midtone and the shadows are affected. The highlights are affected. Every single tonal level in the image is affected. It isn't just the shadows. I'll see if I can create a graphic to demonstrate, maybe that will explain better than words can (they do say a picture is the embodiment of 1000 words...)


So, for a camera like the 1D X, with over 38e- read noise at ISO 100...could it's image quality be improved? Are we assuming that just because the 1D X has big pixels and a big FWC that it is already delivering the best IQ possible?


The 1D X has an FWC around 91ke-. With 38e- read noise, it's got around 11.26 stops of dynamic range. What happens if Canon could reduce that read noise to 3e-? Dynamic range jumps to 14.94 stops. FOURTEEN POINT NINE FOUR STOPS.


Ever looked at the OOF background blur of a bird photo taken with the 1D X? A wildlife image? Ever looked at the boke in a macro photo taken with the 1D X? Ever compared that background with the background of similar photos taken with the D800? Big difference....especially on a normalized basis. HUGE difference on a normalized basis. Creamy smooth, clean, practically noise-free OOF backgrounds from the D800, D810, D600, D750, A7r, A7s, etc. But even the mighty 1D X has visible noise in OOF backgrounds...


I don't deny that there are a lot of other things Canon could improve. I look at it this way, though. Canon has no problem with their AF system. Their AF systems are awesome...well designed, highly capable, top of the line in terms of frame coverage, very fast, and now meter-linked which allows even more advanced features. Canon has no problem with their metering. It's now (in the models that matter) a full color RGB meter with high resolution sensor, and advanced algorithms are hooked into the metering subsystem to enhance it's effectiveness. Canon has no problem with their ergonomics, nor their button placements (they are sublime, if I do say so myself!) Canon has few problems with their lenses (wide angles suffered a bit in the past, but Canon certainly seems to be remedying that problem.) Canon now currently holds the title for highest resolution camera...certainly no problems there.


Could canon make improvements in those areas? Probably...they have, even. The 7D II increased the resolution of the iTR meter sensor. It also expanded the AF point count a little bit above and beyond even the great 1D X. But, how much do those improvements actually matter? Outside of a tiny bit of jitter in a couple cases, I've never even had problems with my 5D III AF/meter system, and it doesn't even have the iTR system. The biggest focus issue I have is that the lens hunts forward first, rather than outward first, when I try to photograph BIF (would love to have a little switch on the lens for that, but that's a small thing.)


The single biggest gain for Canon, given that they already excel in every other area, would be to address the one area they don't excel at: read noise. Change that one thing, and the 1D X could skyrocket from delivering a mediocre 11.26 stops of DR, to delivering 14.94 stops of DR. Bam. Suddenly they actually have a NEED for a 16-bit ADC, because they can actually use the bit depth offered by it. Suddenly they rocket forward as the premier camera model with the highest dynamic range...but not only that, it's also paired with all the other excellent technology I just mentioned above. Who could possibly complain about that! :P


I see Canon as having one single weak area. As far as I am concerned, they don't NEED to "fix" anything else, because nothing else is broken. Canon needs to improve their read noise issues, though...because, well at least in my own personal opinion, it's the one single thing that Canon really sucks at.  ;D

39
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 11, 2015, 07:54:02 PM »
I totally understand what you are saying. Here are some of the things I do know.

1. Canon themselves have blamed part of the decline in DSLR sales on lagging technological improvements
2. A couple years ago financials from Nikon indicated that they had gained a significant amount of DSLR growth thanks to their improved technology (can't say what technology specifically, the documents don't say), in significant part due to the D600 and D800 as well as some of their mirrorless cameras (the latter seems to have fallen off, honestly not sure about the others as there have not been more recent financial reports that state similar information)
3. Canon already has a 180nm fab, so they would not need to invest in a new one

Given the above, particularly given #3, why would Canon "go under" in five years by working on improving their dynamic range? It's even simpler than that. Canon already has patents for many of the same kinds of technology that Sony used to improve DR in their Exmor sensors. The big one was going to CP-ADC, but Sony also upsells their digital CDS as well. At the very least, since Canon already has a newer and more advanced fab (this very low cost to just start using it), and since they already have patents for the kinds of technology that would improve dynamic range, the cost barrier seems very low, for the gains it could provide.


As you can see with the math, reductions in read noise are the best way to rapidly gain more DR. Increases in FWC can help as well, but that is a lot more physics-bound...small pixels have small capacities unless you do something much more drastic (like embed CCDs into each pixel that can expand the charge capacity, called multibucketing...but that requires smaller transistors, too! :P)


When the D800 came out, Nikon benefited from it, according to their financial papers from the following fiscal cycle. Canon openly acknowledged that lagging technological advancements (generally speaking, they did not call out sensors specifically, but sensors are a key technology area in digital imaging) was a part of their growth problem. If Nikon, a much smaller company with more schizophrenic marketing and model naming (well...I donno about the marketing...Canon has had some STRANGE marketing lately....  :o), could make gains of 45% in a single fiscal cycle thanks in significant part to the D600 and D800...why couldn't Canon, a company that has a history of excellent execution?



Something else I know:

4. Sony is making big waves in many markets.

I used to be snugly engulfed in bird and wildlife photography. Lot of photographers there are long-time Canon users, and there is solid brand loyalty. That said, I have been seeing an increasing number of bird photographers using the D800. For certain kinds of birds...say chickadees, or common loons...birds with extremely high color contrast (deep black and bright white all on the same bird, as the case with these two), the D800 up through ISO 400 performs significantly better than the 5D III or 1D X. I was amazed at the quality of some ISO 200 Loon images from one particular professional bird photographer...very fine detail in both the bright white feathers as well as the deep black feathers on the shaded side of the bird. The lighting on the bird was more "non-standard" in that it wasn't lit broadside like usual...the light came more from the side, and the bird was angled towards the photographer...very difficult situation which usually blows the DR limit of a 5D III or 1D X.

I am now also engulfed in the astrophotography world. The D810, D810a, A7s and A7II are all making big waves in the astrophotography world lately. I'm friends with a modder, a guy who opens up these cameras (well, Sony and Canon cameras) and mods them for higher hydrogen alpha sensitivity. He has been modding A7s and A7IIs lately, and he routinely remarks about the higher build quality of the Sony cameras vs. Canon cameras, their tighter construction. Feature-wise that doesn't say anything...there are still some functional limitations on the A7 series of cameras that don't compete with Canon cameras...but it is very interesting to me the comments he makes about the superior build construction and quality of the innards of Sony cameras vs. Canon cameras (and he's taking those things apart, modding them, and rebuilding them all the time, it's one of his businesses, how he makes part of his living.)

The D800 and D810 have been regularly demonstrated to produce much lower noise across the board, even at higher ISO, than the 5D III and 6D. This is largely thanks to lower dark current, but many users are shooting at wider fields, and using lower ISOs like 200, where they also have lower read noise. Nikon cameras have much better color discernment than Canon cameras, and also have higher natural Ha sensitivity, and tend to produce more richly colored subs right out of the camera.

Old, used Canon Rebels used to be THE go-to camera for beginner astrophotographers. That paradigm, which has been in place for near a decade, is rapidly shifting. The D5100, 5200, and particularly the D5300 have become the new darlings of the novice. They can be picked up for similar used prices as Canon Rebels, but they have significantly lower dark current (for all except the 7D II), have very low read noise (the D5200 in particular, as it uses the Toshiba sensor and has some of the lowest high ISO dark current I've ever seen), and have absolutely no banding or blotchiness of any kind.

I know this is all anecdotes...but, it's things I've observed. I've been observing little things like this for years now. The trend keeps spreading as the years go on. I used to recommend Canon Rebels or DSLRs in general for new astrophotographers, as Canon used to take the cake on signal linearity. Today, Nikon and Sony cameras are significantly more linear. Nikon has even stopped using black point clipping in their newest models, and are now using a small bias offset of 600 natively. The Exmor sensors had very good linearity to start, but both Nikon and Sony were black point clipping. Removal of the black point clipping results in even better linearity, and consistent linearity across ISO settings (something that Canon is actually fairly poor at...there are one or two thresholds where increasing Canon ISO results in key changes in signal linearity in Canon cameras, probably due to the secondary amplifier kicking in.)

Bill Claff recently generated new plots on his charts from some Samsung NX1 data. The NX1 has some of the best linearity I've ever seen, besting even the D810. The NX1 has one of the most advanced sensors on the market, and is the first APS-C camera to get a BSI sensor design. It's got an extremely compelling featureset that directly competes with the 7D II (and the key features have nothing to do with DR)...Canon may well be losing a 7D II sale to me, as I am pretty sure I'll go with an NX1 instead.

I notice these things as I continue expanding my knowledge of photography and cameras. I also notice that I'm not the only one noticing them. I hear a lot more in recent months people questioning why Canon does the things they do. Those questions are even more significant when they come from modders who are actually in the guts of these cameras on a regular basis, seeing the differences in design and construction.

I think Canon is right in their assessment that lax technological improvement has, in part, hurt sales. It's certainly making me hold back, consider other options. It's also certainly made me recommend cameras from different brands.

Has any of this impacted Canon's bottom line? Well, tough to say. I do know that I've recommended the D5100 or D5300 to many new astrophotographers who took the advice. I would say those are at least some sales that at the very least did not go to Canon (not sure that's a "lost" sale to Canon...but Canon did not get the sale.) I know a number of skilled astrophotographers who rave about the D800/810 for anyone looking to buy a 6D...bit of a price dichotomy, but the D600 is just as good, and priced much more like the 6D (and that's often my recommendation, for them to get the D600 instead.) Not everyone takes that advice, the 6D is one of the best astro cameras Canon currently offers, but some people do indeed take it. More sales that Canon did not get.

How long does it take for such small changes in purchasing decisions to become a big trend? I dunno, but Canon has seen falling DSLR sales. Too bad we can't get information about WHY each manufacturer is seeing falling sales... ;P What about Canon's mirrorless offerings? They repeatedly pale in comparison to the big players in that segment...such as Panasonic and Sony. Sony's A7 line is quite new to that market, but is still more highly regarded by far than any EOS-M option. The A7 series even made digital-converts out of many die hard large format film landscape photographers, the ones who said they would never, ever give up their Velvia 50 4x5. That's really saying something...

I can't say that Canon is "in fact" losing sales to the competition because they don't have more DR. What I can say is that I see people questioning what Canon is doing with their cameras, and I see many of them (a growing majority, even?) ultimately buying non-Canon. It isn't just a handful of pain in the ass nutcases here on CR bitching about Canon...people are actually making purchasing decisions based on information from people like myself, like my camera-modding friend Mike, etc. and most of that information is based on the core, fundamental technology. In the astro world, basically the only piece of technology that matters is the sensor, and how it's read out...which makes sensor technology the key deciding factor for many discerning astrophotographers (which, BTW, is a growth market. ;))

40
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 11, 2015, 06:24:18 PM »
Thanks for the response Jon. I can't say I've ever been in a situation where my camera was hot to touch. It probably doesn't get as hot here.

Now you've provided me with some interesting reading to think over. I'll have to do some research on dark current noise. Sounds like I'll be much happier with the 5dsr than the 5d2 if the 6d and 7d2 are already much better. Once again thanks for the response.


Welcome.


The 5D II without question has significantly more dark current than Canon's newer cameras. The 5D III still has more than the 6D, but it too is much lower. I would say that the bulk of the 5D II high ISO noise is from dark current, rather than actual read noise. I say that, because in comparisons between cameras done on astro forums, as the 5D II is cooled, it's high ISO performance improves significantly, although not to the point of the 5D III or other newer Canon cameras.


I would figure the 5Ds has to be a least as good as the 6D in that area, and the 6D is a highly regarded camera for astrophotography. The 7D II is about 10x better, but the 6D was no slouch.


The 5Ds R would have another advantage for astrophotography: no AA filter. With astro, you don't have anything that could cause moire, so an AA filter is just costing you resolution. The 5Ds R should make for a great wide field astro cam, and would even work quite well at moderate focal lengths up to around 800-1000mm, and should produce crisp, detailed results...more detailed than most cameras. I'd say the only thing better would be a D810 or the new D810a...they don't have AA filters either, and the new astro version has extremely high Ha (hydrogen alpha) sensitivity, which makes it a lot easier to bring out nebula.

41
EOS Bodies / Re: DR from 5Ds will be 2 stop better then 7D mk II
« on: February 11, 2015, 05:56:37 PM »
So anyway, wondering if anyone has an answer to this question. There's speculation that the sensor MIGHT run at a lower temperature and might have lower read noise. Would this affect long exposure noise in any way? The one thing I hate about my 5d2 is the long exposure noise. I can fix it mostly by combining 2 exposures (usually I only want the slow shutter speed for clouds or water) but I'd like to skip that step if possible. Does anyone know theoretically of course.


It is definitely possible. There was a rumor...at least a year ago now?...that indicated Canon was working on some kind of active cooling. My guess is there is a fan or heat pipe of some kind in the camera body that moves heat away from the sensor, possibly releasing it along the body.


If the 5Ds is based on the same technology as the 7D II, it should be starting out with significantly lower dark current noise. It's got slightly different pixels, though, so it may not gain the same benefits as the 7D II. Active cooling should certainly help, however if the camera has 0.6e-/s/px dark current at 33C, it's already ludicrously low, so cooling would have a marginal effect. If the dark current is the same as the 6D, then active cooling could help.


One area where it might help more than others is when shooting in sunlight. I've photographed birds on some hot days, and I remember my camera getting very hot to the touch. Some kinds of active cooling (i.e. TEC) could certainly help keep dark current lower in such situations. Heat pipe or fan should also help a little, as a warmed up sensor would still likely be hotter than ambient.


It should also be noted that studies done decades ago showed that cooling does not seem to have any significant impact on read noise, only dark current. So I wouldn't expect any active cooling system to reduce read noise, which would be the primary source of noise if DC was 0.6e-/s/px.

42
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 11, 2015, 05:49:47 PM »

I'd also love to know how much the average person would look at a picture and dismiss it because it only had 12 stops of DR. Clearly a side by side, you'd hope they notice....]


I figure I'll address this question first. Personally, I think about DR entirely differently than this...however, it seems that this is more how most people think about it. To put it simply, the answer is: no one. A little more complex than that: some people (mostly other photographers. :P )


That said, having more DR isn't about what the user who sees your final, processed image things. At least as far as I see it, having more DR is about making your life as a photographer easier, simpler, with less work. You already know one case for how that works: you could stop using GNDs! :P


I use GND filters myself...but I have a hard time with them. Not because they are hard to use, but because of how they are limited in the ways they can manage contrast in a scene. For one, they have a flat gradient, and as such, they only work best when you have a flat horizon. Say, a sunset photo on a beach, with a clear sky. THAT would basically be THE epitomy of ideal use case for a GND. The moment you add clouds...or have that nice big rock out a short ways from shore, or are photographing mountains with a deep valley between them, or are photographing a forest with an uneven boundary with the sky, etc....then the use of a GND filter breaks down. You end up having to make additional compromises, you either end up lightening the use of the GND, and thus are still DR-limited, or you heighten the use of the GND, and suffer funky dark shading across the top of your image (you've seen those landscape photos where the mountain peaks fade into pitch black at the top, silhouetted against a bright orange or pink sky...ugh.)


You can always do HDR, bracket your shots, blend in post. That also has limitations. Images don't always blend well, sometimes you have ghosting artifacts that are impossible to correct properly, some have funky artifacts in the shadows. HDR is less applicable when there is movement within the scene. HDR is also still additional work. Sometimes HDR is the only option, and even when you have high DR thanks to low read noise, if you still have a limited FWC, you might still need to use HDR anyway (because photon shot noise will still dominate the shadows.)


More dynamic range, the way I see it, is all about simplifying life for the photographer. Your viewers may not know the difference in the end...but you will know the difference, because the journey from point a (taking the photo) to point b (sharing the photo online/printing the photo) was quite different...simpler, faster, more efficient, more enjoyable, even?

Thanks for taking the time to explain further. I'm with you in the most, and perhaps using DR for the scene and S/N for the sensor might be indeed simpler, but without labouring the point. If portraying a scene, a landscape from your earlier example, I dont necessarily need 16 stops let along 20. That was my point. It's good to have a clean image ie S/N ratio, but just because a scene has 24 stops of range, doesn't mean I as a photographer require a sensor capable of capturing it. And that's what I was trying to say (albeit not as elonquent or succinctly as I should), technology advancement has to have a point. Wasn't the same said about hi-fi devices in the 80s which strived for the lowest THD and ended up being "too clinical / without soul" to some people?

Appreciate that every time I use a grad I'm acknowledging the scene is greater than the sensor. I guess I'm trying to figure out how much more the sensor needs to have. Is it 15 stops (based on using a 3 stop grad on a 12 stop sensor?).


There are a couple things here. First, no one would always need 16 stops of DR every time they took a photo. There are often times when I don't even need the 10.97 stops of DR my 5D III has...say when I am photographing a misty landscape under and overcast sky. Heh, I probably need a mere 6 stops tops for such scenes. Conversely, I could easily use several more stops of DR than I usually have when photographing wildlife in certain ways at certain times of day. Most of my birds and wildlife are shot head-on, light almost directly behind me, fully illuminating the subject. That leads to very flat contrast. It's easy to to get great photos up to as high as ISO 12800 that way, because DR is low...but, such photos are not really the most flattering or best. A lot of the time I would prefer to get at a more interesting angle to my subject...but doing so rapidly increases contrast between the shaded side of the subject and the illuminated side. My DR needs can jump several stops with only a few degrees change in angles between me, my subject, and the sun.


I do believe it is entirely appropriate to say that a camera has dynamic range. I was saying before that images don't really have DR...they have a contrast ratio. The camera, though, does have dynamic range, as it has a maximum allowed signal and a relatively fixed amount of electronic noise. So, scenes and cameras have dynamic range...images have contrast. One might be able to make the argument that a RAW image has dynamic range...I guess what I'm getting at is once the image signal in the sensor is digitized, you are locked into what you have, and can no longer get any more out of what the camera may have to offer (i.e. you couldn't overexpose, without clipping the highlights, more than you did to preserve more shadow detail...once you have the RAW, you can lift the shadows, recover the highlights...but they are what they are, they have the noise they have, you cannot change that.)


My question is...if you periodically DO need  (or, maybe less controversially...periodically "could make full use of") 15 or 16 stops of DR, would you settle for a camera that had only 12?

43
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 11, 2015, 05:22:52 PM »
Hey look, jrista !

This has been made especially for you !


Yeah, that's making some waves on astro forums. It's got significantly more Hydrogen alpha sensitivity than any other DSLR on the market...significantly more than even the 60Da. The long exposure modes are nice as well.


The price seems out of touch, unless it can also double as a landscape camera, though. An extremely good mono CCD camera with filter wheel and filters is only a couple hundred bucks more.

44
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 11, 2015, 04:27:03 PM »
Maybe I am indeed getting confused. The Dynamic Range of a scene is surely the difference between the lightest and darkest point. The DR of a sensor would then be it's ability to capture the scene as close to the live scene as possible. Noise in the camera's various systems as you describe limit the sensors' ability to capture it completely. Remove those limitations, and I may sometimes end up with more DR than I desire (I have to reduce post-capture).

And that's what your maths is demonstrating, how you can improve the tonal ranges you can record through the ability to capture more photons, or have less noise. All good, thank you for taking the effort.

But if I don't need 16 stops, let alone 20, and my sensor can capture say 15 - and thus the tonal range required, then I'm not sure I appreciate why I need the other 5?


Well, now your getting into personal need. I honestly cannot speak to that. :P


In a scene, dynamic range is the range of tone from brightest to darkest. In hardware, dynamic range is the range of tone from the brightest that can be captured before clipping, to the amount of read noise in an image entirely devoid of light. In a photo, dynamic range is really not a thing...I think it's better to call it contrast ratio or tonality or something like that, since an actual image has a signal to noise ratio. If you don't utilize all of the dynamic range your camera has to offer, you can still have a good S/N.


As for not needing DR...well, if you don't need it, it's really pretty much as simple as attenuating your contrast curve more. That's all it really takes to discard parts of a signal you do not need or did not use.

45
EOS Bodies / Re: After a 50MP camera what is the next breakthrough?
« on: February 11, 2015, 04:23:37 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...

sorry, I was mixing formats and actually talking about the 44 by 33 millimeter sensors that you mentioned.

At wost Full Frame is 2.58x bigger than the Canon APS-C sensor, and 44×33 is at best 1.7x bigger than Full Frame.
I call that incremental.


Ok, I can understand that a little better. I still think gathering 170% more light is meaningful, but it certainly isn't as big as gathering several hundred percent more light with something more like 6x4.5cm size.


Even with a 44x33mm sensor, though, the optics are going to become significantly more expensive if you want corner to corner performance. I think that is where the major value in 35mm format is...you can get excellent optics at relatively reasonable prices. The larger the sensor gets, finding excellent optics at even relatively reasonable prices, let alone affordable prices, becomes exponentially more difficult.


If you have the funds for medium format, I say go for it. There are some excellent and "relatively affordable" options out there right now. It wouldn't be any different than Canon doing it, since Canon would need a new mount anyway.




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