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Messages - jrista

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31
Animal Kingdom / Re: Show your Bird Portraits
« on: January 05, 2015, 12:45:25 AM »
Thanks, Rpt. :)


Heh, I didn't notice it before, but all the birds are facing the same direction. One guess what's in that direction.... :D

32
Lenses / Re: Lens 'resolving power' vs sensors.
« on: January 05, 2015, 12:44:44 AM »
Happy to help. :) It's just a hobby, really...well, a hobby that assists me in my other hobby, really. :D I like to know everything about what I do, so as a photographer, well, I had to know how sensors and lenses worked. So I researched it.

33
Animal Kingdom / Re: Show your Bird Portraits
« on: January 05, 2015, 12:35:18 AM »
Winter Songbirds

Just a few songbirds from the past couple of months. Haven't been doing as much bird photography...not as much photography in general, rally...the last six months or so. Other things to do, and a lot of my time is spent on astrophotography (after you get the data, then you gotta make something of it...and THAT is where all the time goes. ;) )


Anyway, finches, chickadee, and a junco. The winter staples. All natural perches this time. I had a setup, but there were actually so many birds crawling all over it at once that the good opportunities were on all the branches where the other birds were waiting. ;P


Canon EOS 5D Mark III
Canon EF 600mm f/4 L II + 2x TC III
Handheld & Gitzo GT3532LS w/ Jobu Pro 2


















34
EOS Bodies / Re: Canon Confirms Development of High Megapixel Camera
« on: January 01, 2015, 11:10:02 PM »
Sometimes I think applying figures and statistics to an otherwise organic subject can be a bit confounding.

There's much talk about resolution and the ability of a lens to resolve it but from practical experience I can wholeheartedly say it's a load of crap.

I've had a Pentax 645z on loan for a few weeks. I've got 30 year old glass on it and it resolves just as well, if not better than any of my Canon glass with little or no distortion or CA when wide open. I've always maintained that beyond a certain point of development and design the importance of super duper statistically perfect glass falls away.

It's just my opinion, but it's always been about the sensor for me. Sure, the mk1 version on the 24-70 was a bit of a dog compared to the mkii. But we're now at a point where the lenses are pretty much bang on.

I struggle to get over the image quality from small sensors with a high mp count on. Really I do. I bet you that if Canon does dump a 52mp 35mm Canon designed sensor on us (The Sony MF sensor is 51.9mp btw) then I say dollars to donuts the majority will rip it to shreds on here because it'll be noisy and have poor dynamic range.

That's unless they've really come up with something special. It's now mostly about the sensor size and the quality of the pixels on it. There's nothing wrong with having a 35mm sensor but the pixels have to be good ones not just an all you can eat buffet with as many as possible on.


Regarding the quality of a lens, I'd be curious to know what aperture you shoot at. Beyond a certain aperture, pretty much every lens is going to produce similar results, because they are all diffraction limited. If you shoot every lens at f/16, regardless of format, your circle of confusion is (barring a particularly bad lens) going to be wholly diffraction limited.


I do agree that for the most part, modern lenses, from almost any manufacturer these days, are more than good enough. Most people won't have any problem with most lenses.


For the discerning photographer, the improvements in recent Canon and Zeiss lenses offer meaningful benefits, and further improvements could be realized that some photographers (who knows how many, but I'd say enough to warrant continued improvements) will recognize. One of the biggest improvements that can still be realized is corner and edge performance. Lenses perform superbly in the center, not all lenses perform well in the peripheries. A lot of improvements in lens quality, from Canon, Zeiss, even Sigma, in recent lens releases have had to do with corner performance. Prior generations had HORRIBLE CA and blurring in the corners, while the new generations perform quite well to exceptionally well (i.e. Otus) in the corners.


Sure, most lenses are good enough for a majority of photographers. However, there are nuances and complexities when it comes to lens design that will continue to warrant improvement in lenses for years to come. Canon's wider angle lenses, particularly their zooms, were (and really still are in some cases) in desperate need of an update, not for resolving power in the center, but for overall IQ and resolving power at the periphery. I think Canon has been succeeding immensely in that area, with the 24-70 IIs, the 16-35 f/4, etc. The Zeiss Otus line is utterly incredible, and should be the icon of lens quality for a decade or more to come. Every manufacturer should strive over the long term to approach the quality of the Otus line.

35
Landscape / Re: Deep Sky Astrophotography
« on: January 01, 2015, 03:42:27 PM »
No artifacts in the stars this time.  Lens okay?


Oh, there are artifacts. I just stopped down to f/4.5, which creates the starburst diffraction effect, which hides the wedges. Look closely, though...and you can still see the wedge. My lens element is definitely tilted, which you can tell from the heavily elongated stars in the upper left (see the astrobin version.)


I like the starburst effect, so I usually stop down to f/4.5. I just forgot to with the Orion Nebula image.

36
Landscape / Re: Deep Sky Astrophotography
« on: January 01, 2015, 03:41:10 PM »
Hi Jon,

Just now looking back through this thread, nice work! I have one question for you. You have really nice red in the North American and Pelican nebulas and in some of the stars in the double cluster. I think I read that you're using Deep Sky Stacker to stack images, is that right? I took a few one minute subs of the double cluster a few nights ago with a 70D, and the individual frames show red stars but when I stack in DSS the red mostly disappears, and I can't seem to get it back when processing in Photoshop. I have had similar problems with the North American and Pelican nebulas. I know that the 70D cuts out a lot of the H alpha, but as I said I'm losing red in stars between the individual frames and the stacked result, so that can't be the explanation. And even with an unmodded 5D you're getting good red in the nebulas. What settings are you using in DSS (if you're still using DSS).
Thanks,
Glenn


I think you would be surprised how much Ha you can get with modern DSLRs. All of my cameras are UNmodded...look at the Ha I'm picking up. ;) I get a lot. Personally, I like the amount I get...any more, an I think the Horsehead image would have been overpowered by Ha, which would have hidden the very faint blue reflection that's all over the place. (I think I have more blue reflection in my image than any other image of Horsehead I've ever seen...which I'm pretty happy about. :P)


I used to use DSS to integrate. Now I use PixInsight. I've learned some things about Canon RAW files lately. I've NEVER liked how Lightroom demosaiced my CR2 files, not for years. It always results in pretty blotchy data, lots of red color noise, soft detail in the shadows, etc. DSS has always done the same. I've learned that LR/ACR, DSS, and a good number of other RAW editors use the AHD form of demosaicing, Adaptive Homogeneity-Directed demosaicing. I don't think AHD is ideal for Canon data.


I recently trialed Capture One 8, an alternative RAW editor to LR. I had a 60 day trial, and throughout that time, I definitely felt as though it was doing a better job with Canon CR2 files. It resulted in a finer grained noise, much lower color noise characteristic, less blotching, etc. Overall, I was pretty impressed with COne 8, and if anyone is looking to maximize their daytime photography quality, you should look into it. I let my trial lapse, and I've stuck with LR for now...simply because COne is a very different program, and has a tenth the camera compatibility, not to mention the fact that it does not work seamlessly with PS. I'm hoping that someday soon, Adobe may switch to the algorithm COne 8 uses.


Which brings me to PixInsight. PixInsight is an astrophotography editing tool, specially designed with tools to make the most out of ultra low SNR astro data. Unlike ACR/LR and most other RAW editors, it uses VNG (variable number of gradients) demosaicing. The VNG demosaicing of PI is very similar to the demosaicing of COne 8. I suspect they are both based on the same core VNG algorithm, with different tweaks to optimize results for their intended use case. Anyway, VNG results in VASTLY superior results from Canon CR2 files. I don't now why, but the noise is clean, usually an order of magnitude lower STDev, very low color noise, practically no color blotch. I use the PixInsight BatchPreprocessing script to calibrate and integrate my images now, as it just does a better job. Not just with the demosaicing either, it is far superior at star registration and rejecting out-of-sigma pixel data (hot pixels, aircraft/satellite/asteroid trails, etc.)


Anyway...PixInsight is not free. If you can afford the couple hundred bucks or so for it, I say go for it. You'll want it anyway if you really get into astrophotography...it's an essential tool, and WELL worth the money. If you use the BPP script, you shouldn't have too many problems with getting good results.


If you want to stick with DSS for now, then my advice is, register, calibrate, integrate...then just save off the data to a 16-bit TIFF file. Do NOT apply adjustments (checkbox in the save dialog), and do all of your processing in Photoshop. DSS does not render the integrated data well, and your just seeing it's poor rendering. Search the web for video tutorials on how to stretch your integrations with Photoshop, and go from there.


Regarding getting the deep red. A lot of my images from summer suffered from wicked-high dark current noise. A lot of the red in those images is false...blotchy color noise from Canon's heavily red-weighted color read noise. There is some Ha data in my images (less now during winter, with temps that hover around 0°C and ultra low dark current), but not a ton. What Ha data I have, I attribute to the power of PixInsight in helping me bring out. You might be able to bring out Ha data with Photoshop, but if you really want to get the most out of your images, PixInsight is a very worthwhile investment. It's a perpetual license, so once you buy it, you get updates until the next major version (which, at the current rate, is probably not going to be for another five to ten years at least. :P)

37
Landscape / Re: Deep Sky Astrophotography
« on: January 01, 2015, 03:28:24 PM »
Wow jrista, those shots are incredible. Unbelievable detail.

I've been making a few attempts at astrophotography lately. Unfortunately I live in a "white" zone for light pollution (right next to a large city). Here is a shot of Orion I took a few days ago. The cumulative exposure time was about 20 minutes, and was stacked in Deep Sky Stacker from forty 30sec exposures. No darks, flats, or bias frames. Taken with a 7D Mark II and EF 100-400L II.

To be honest I am very happy with the result, considering the light pollution in my area. Aside from shooting from darker locations, do you have any recommendations for improving the image, or dealing with light pollution in general? Will simply increasing the number of shots help?


Very nice! For heavily light polluted skies, without any LP filter, and without any calibration at all, that is VERY well done! Once you calibrate with bias, darks, and flats, you should be able to get a lot more detail out of that.


As for improving your images. You have two options. Find a dark site that's close enough to get to on a regular basis, or invest in an LP filter. If you are using an APS-C, you could get either the Astronomik CLS clip-in or the IDAS clip-in. If you are using an FF, then I do NOT recommend getting the Astronomik CLS-XL clip-in for Canon FF dslrs...the design of that filter is flawed, and it causes more problems than it's worth. You should get the IDAS LPS-V4 screw-on filter instead, which can be threaded 48mm for use with standard 2" T-adapters that attach DSLRs to telescopes, or if you are using one of Canon's great white lenses, you can get it in 52mm threaded for use with the drop in filter holder.


Personally, I say find a dark site. Use this map to find one:


http://www.lightpollutionmap.info/#zoom=4&lat=6156149.93155&lon=-11229480.6837&layers=0BTFFFTT


38
Landscape / Re: Deep Sky Astrophotography
« on: January 01, 2015, 05:05:11 AM »
Here is another one. My last image of 2014. Same equipment, same dark site, as the Orion's Sword image:





Managed to capture a number of galaxies in this one as well, maybe around a dozen or so. I highlighted the largest here:






39
EOS Bodies / Re: Canon Confirms Development of High Megapixel Camera
« on: January 01, 2015, 05:02:49 AM »
Yup. I am even more convinced now than ever before that I've bought my last Canon DSLR. Pity.


I'm not saying I'm done with Canon, nor that I've bought my last Canon DSLR or lens. It's more that I'm no longer interested in locking myself into a single brand. It's more likely that I'll by a different brand's camera next time I do, unless Canon has stepped up their game and provided me with the things I want (primarily, more DR...I don't really care if they do it at ~20mp or ~50mp, resolution isn't as important to me as more DR, preferably LOTS more DR, like 16 stops DR; I'll take more resolution, but I want lower noise, across the board, less noise in every respect) by the time I'm ready to buy another DSLR.


Personally, Canon now has some time with me. I'll be investing in more astrophotography equipment this year, including at least one new OTA, a mono CCD and a bunch of filters (some of which might cost as much as a grand each), and possibly a higher end mount. That will likely set me back for a couple years, so here's to hoping Canon puts the time to good use and releases something extremely compelling by year end (yes, it is now 2015, pplz!! Happy new year!)

40
EOS Bodies / Re: Canon Confirms Development of High Megapixel Camera
« on: January 01, 2015, 01:24:35 AM »
So then my next question would be "Can Canon not employ a similar design?  Is such a design patented by Sony?"  "If they can, what's stopping them from doing this if a solution has already be discovered?  Would putting the ADC right on the chip be some radically expensive redesign?"


The real question is, why hasn't Canon employed technology they already own?

<snip>

Why aren't they employing this amazing technology in their consumer products? While Sony, which has many similar patents for many very similar technologies, IS employing it all, and continues to employ new innovations as they are made? Same thing goes for Samsung...similar patents, similar technologies, and they are employing those technologies in consumer products.

I think we can make a good guess at the answers to these questions: it's because they haven't had to.  It costs money to re-tool for innovative new tech, and that cuts into both profits and R&D.  Sony and Nikon have had to push out their best efforts to remain competitive; Samsung needs to put out their best to get into competition.

My hope (though not my rational expectation) is that Canon will push far enough ahead in their next retool to last for several iterations of the product cycle.  Maybe that's what will be at work with the new high-MP camera: the megapixel count could be an opportunity to take it out of competition with the 1-series so they can put in the new sensor tech.

Let's hope Sony, Nikon and Samsung put more pressure on Canon.

Happy New Year to all.  Go out and take some pictures!


Your probably dead on. The bummer about Canon doing that is it pushes out any real competitive sensor IQ tech out another three years. So, if they just slide by again in 2015, maybe reemploying the evolutionary improvements in the 7D II in a high MP FF sensor...then it's probably going to be 2018 before we see a layered sensor. If they skip the layered sensor (or any other competitive new sensor tech) in 2018, it'll be 2021 before we see something truly new. Despite the lower dark current of the 7D II, it still "feels" like the last time Canon really did something amazing with their sensor technology was with the 5D II. I just hope I don't feel the same way in 2018 or 2021. :P Canon IS my preferred brand...but it's getting old "getting old" waiting for them to stop being...old. :D

41
EOS Bodies / Re: Canon Confirms Development of High Megapixel Camera
« on: December 31, 2014, 11:50:25 PM »
So then my next question would be "Can Canon not employ a similar design?  Is such a design patented by Sony?"  "If they can, what's stopping them from doing this if a solution has already be discovered?  Would putting the ADC right on the chip be some radically expensive redesign?"


Both Canon and Sony have patents for column-parallel ADC implementations. Canon filed for a Dual-Scale CP-ADC patent a couple of years ago, and quite probably had functional prototype (i.e. 120mp APS-H) sensors years before that (based on Canon's descriptions of the technology used in that sensor prototype.) Both Canon and Sony have patents for a variety of hardware level noise prevention concepts.

The real question is, why hasn't Canon employed technology they already own? Canon achieved high speed 9.5fps readout from a ONE HUNDRED AND TWENTY MEGAPIXEL APS-H sensor...YEARS ago. They have patents for backside illuminated five layer full frame sensors (as well as a host of additional patented innovations to improve the sensitivity and reduce light loss in such a sensor, something critical to a layered sensor's success against bayer designs). They have patents that should reduce dark current to obscenely low levels. They have demonstrated some of the most sensitive sensors on the planet. Why aren't they employing this amazing technology in their consumer products? While Sony, which has many similar patents for many very similar technologies, IS employing it all, and continues to employ new innovations as they are made? Same thing goes for Samsung...similar patents, similar technologies, and they are employing those technologies in consumer products.

That's the one thing about Canon I really don't understand. They aren't any innovative slouch...they are one of the most innovative companies in the world. They just don't seem to employ a LOT of the innovations they create. Canon sits on awesome technology, letting it rot away in some R&D corner of the company somewhere. I just hope 2015 is a year of radical change for Canon...I hope we SEE that layered BSI sensor in an actual product. If 2015 closes out without a hint of any truly ground breaking new sensor technology from Canon, I'll be pretty bummed. And confused...it makes no sense for a company to innovate and never actually employ the technology they own.

42
EOS Bodies / Re: Canon Confirms Development of High Megapixel Camera
« on: December 31, 2014, 07:50:03 PM »
Ok now I'm even more perplex.  The blog mentions "taking advantage of the full 14 stops of DR the sensor IS CAPABLE of"   So now I gotta ask....if the sensor is CAPABLE of it....what the hell are we talking about with bad DR?  Granted the base Canon firmware doesn't allow for dual ISO HDR single shooting... but it seems the sensor CAN produce it given the right tweak.  I guess I'm wondering if the DR issue is really a sensor issue...or a Canon firmware issue?  I need people way better versed on this than I am to help me. Glad ya'll are here LOL


Most SENSORs these days are not that noisy in the grand scheme of things. If Roger Clark's data is anything to go by, Canon sensor DR is anywhere from 14.3 to 15.7 stops. Canon's most significant problem is the introduction of noise from downstream (off-die) electronics. Primarily, read noise introduced by their high frequency ADC units, of which there are four, eight or sixteen separate units on the PCB board, between the sensor and the DIGIC processor(s). It's that electronics that adds some quantity of noise to every single image read off the sensor.


If the sensor starts out with 14-15 stops of DR, it's the introduction of read noise from other non-sensor electronics that is basically "eating away" at dynamic range. Canon's off-die electronics, given that their sensors usually have around 11 stops of DR, are apparently reducing dynamic range by 3-4 stops! Canon's problem isn't necessarily their sensors (not explicitly)...it's the way they read the sensor signal out. The solution to Canon's problem is to reduce the operating frequency of readout electronics, and reduce trace paths along which pixel data is transferrred. The best way to do that IS to improve their sensors...by moving ADC units onto the sensor die, by increasing ADC parallelism, and by employing other technologies allowed by CMOS sensor designs to increase Q.E. and reduce sources of additional noise (outside of the amplifiers in each pixel themselves.)


That's what Sony did...they moved all the readout electronics onto the sensor, hyperparallelized the ADC units (one per column), and employed a number of other techniques to reduce noise futher (i.e. moving high frequency components, such as the clock, to remote areas of the die so they don't risk injecting additional noise into the pixel data as it's read out, use of digital CDS, use of per-column tuning in each ADC unit to eliminate vertical banding, etc.)

43
Landscape / Re: Deep Sky Astrophotography
« on: December 30, 2014, 02:17:15 PM »
Very nice. I am always amazed at the clarity of you images. I find it hard enough to get any clear nights with light pollution I can't imagine needing 2 or 3 times as many without . Orion is in the perfect location for me right now, but we only have had one clear night in the last month and that was Christmas eve.


You need many times more clear nights imaging the same target WITH light pollution. You can get away with imaging for much less time WITHOUT light pollution.


Why? Because LP is additive to the object signal. If I'm imaging from my back yard, red zone light pollution, for every single object photon I get from a nebula, I get anywhere from 10 to 100 photons from light pollution (depends on transparency). To get 10 object photons, I have to collect 1000 light pollution photons. For 20 object photons, I've collected 2000 light pollution photons. Light pollution is something we ultimately subtract from our images...we correct a bit of it with flats, then we offset the rest. That leaves behind whatever object signal that was collected. If I offset by 2000, my object signal would still be 20. That is VERY low.

So, if my goal is to expose to about 1500-2000 e- at ISO 800, with a gain of say 0.6e-/ADU, then my image level in 16-bit integer would be something like 2000-3333 ADU. After correcting with flats and offsetting for the light pollution level, I end up with an object signal of 15-33. I could expose for longer, but because LP is compounding in the signal so much faster than the object, even if I doubled my exposure again, 4000 photons or 6666 ADU, my object signal is still only 66 ADU. Problem is, at ISO 800, 4000 e- is already getting close to the saturation point of an APS-C sensor, and is likely over half the saturation point of an FF sensor. That's too much exposure, your stars are guaranteed to be heavily clipped. Light pollution thus limits your object exposure depth by making your images "skyfog limited" very quickly.

Now, contrast this with a dark site. For every object photon gathered, I might gather 0.5 or 0.3 photons for skyfog (from light pollution, or at a truly dark site with 21.5mg/sq" or darker, from airglow). Then for every 2 or 3 object photons I gather, I get one skyfog photon. I can expose for much longer, or maybe just expose at a higher ISO for a similar amount of time (not generally recommended unless your imaging something REALLY dim, like the dust in my Orion Sword image.) For 100 object photons, I'd have 33-50 skyfog photons. Maybe even less (if airglow limited, you might expect about 0.1 skyfog photons for each object photon, meaning you can expose your object signal ten times stronger than skyfog.) Therefor, at a dark site, you are freed to expose for much longer, potentially as long as you want, before you become "skyfog limited"...which may be 10 to 1000 times longer or more than when imaging under light polluted skies.

If your goal is to expose to 2000e-, in a backyard with a ratio of 100:1 skyfog vs. a dark site with a ratio of 1:5 skyfog, you would have to expose 80 times longer in your backyard to gather the same number of object photons as you would at a dark site. Your gathering 20 photons per sub in the backyard, but 1600 photons per sub at the dark site. So, 1600/20, or 80x. If your goal is to expose 5 hours worth of total object integration at ~1600 photons per pixel per sub, your subs are 4 minutes (240 seconds) long, then your gathering 6-7 object photons per pixel per second at a dark site. You'll gather a total of 120,600 photons per pixel over five hours. Conversely, to get the same number of object photons from your back yard, you would be gathering 0.083 photons per pixel per second. To gather the same 120,600 photons...you would need to image for a whopping 403 hours under light polluted skies!!! Assuming you take the same 240 second subs, your still gathering 2000e-, however most of that signal is skyfog. So you would need over 6050 subs to get the same signal from your backyard as at a dark site.

Given that, on average, there are only 7 hours of total dark each night (a little more during winter, a little less during summer), it would take you 58 days to gather enough subs from a light polluted site. Assuming you started imaging an object as soon as it started rising high enough over horizon haze in the east, and continued until it was finally setting into the horizon haze in the west, you MIGHT have enough time in a single season to get enough subs to produce the same kind of signal from a light polluted yard as at a dark site. ;P (And, note, in reality, most places have a handful of clear nights a month to image, between cloudcover and the moon, so in a three-four month period of time you MIGHT get 15-20 clear nights tops...to get 6000+ subs on a single target, you would actually need YEARS to get all 57 full nights worth of imaging done.)

If your really interested in astrophotography, I highly recommend finding a close dark site. You might be surprised to find that, pointing either east or west, you have one closer than you think. There are a lot of light pollution maps on the web, but most are based on the bortle scale, which is a tool for visually gauging how dark your skies are, which involves how well you can see city light bubbles on the horizons. A "true or exceptionally dark" site on the bortle scale requires that LP bubbles NOT be visible on the horizons. That isn't necessarily required for imaging, you can often find skies with an SQM reading (sky quality) of >21 within 30-60 minutes from the middle of a downtown city area. Just image in the part of the sky that is dark, and in a few hours you might be able to gather enough "dark site" data that would be comparable to imaging for months from a back yard. You can use this site, which measures direct light levels from overhead, to find potential sites that might be dark enough to image from (anything blue or darker is good enough):


http://www.lightpollutionmap.info/#zoom=4&lat=4838950.03614&lon=-9735847.10785&layers=0BTFFFTT

The other option is to use a monochrome camera and narrow band (NB) filtration. Mono NB imaging blocks out 99% or more of the light, passing only very narrow bands of emission. You can image under LP, even when the moon is half or larger. The kicker here is you need a mono camera with a filter wheel and nice, very narrow band filters. A decent mono CCD is going to cost a couple grand, a filter wheel another grand, and the filters themselves could be anywhere from $400 to $1200 a piece. Expensive...but, if you don't have the ability to drive to a dark site all the time, it is the best alternative. Atik has some decent cameras and a nice filter wheel for pretty good prices, and Baader has some narrow band filters (little wider bands, but still narrow enough to be useful) for good prices. You might be able to get away with a mono CCD camera setup for about $3500 or so.

44
EOS Bodies / Re: Canon Confirms Development of High Megapixel Camera
« on: December 30, 2014, 01:44:41 PM »
Quote
There is no problem of pixel size.

<physics>There is. </physics>

Yeah...let's talk about that.

I decided to calculate diffraction-limited resolution.  Here are the assumptions:  Green light (550nm), Bayer full-frame sensor, AA filter, MTF10 cutoff.  Here are the results:

f-stop Maximum MP count
1.4     8,333
2.0     4,167
2.8     2,083
4.0     1,042
5.7     521
8.0     260
11.3   130
16.0   65
22.6   33
32.0  16

So, does that seem like a problem to you for the foreseeable future?


your calculations seem off. For FF at f/4.0 a 115 Mp sensor would be diffraction limit.
see
http://www.luminous-landscape.com/tutorials/resolution.shtml


He is probably using Rayleigh (MTF9) rather than MTF50. At Rayleigh you can resolve more detail, but it is at ultra low contrast, so fine differences in detail require intense scritinization to detect with the human eye. Personally I prefer using MTF50, as that's the standard contrast level for the very, very vast majority of photographic systems testing, and has been for years.


That said, neither case is wrong...so long as your clear about what MTF contrast level your basing your numbers on. In Lee Jays's numbers, it's all MTF9 (or maybe MTF0, sometimes he uses that as well...although that is entirely irrelevant for regular daytime photography, the only time it really applies is when analyzing multiple star diffraction patterns at excessively high magnification). In your case, I'm guessing it's MTF50.

45
EOS Bodies / Re: Canon Confirms Development of High Megapixel Camera
« on: December 29, 2014, 07:02:41 PM »
Heh, this thread is absolutely hilarious. The debate about immeasurable differences in "critical sharpness" is beyond inane. All of these photos are critically sharp, ppl!! Your making mountains out of grains of sand. The mole hills are off to the left...why not at least make a mountain out of a mole hill, if you must make a mountain out of something pointless.


 ???

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