October 21, 2014, 05:35:48 AM

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Messages - dgatwood

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1
EOS Bodies - For Video / Re: 6D video for sports
« on: October 18, 2014, 09:40:11 PM »
Also, since the 6D doesn't have the AA filter there is tons of moire. Honestly, it makes a lot of footage look like crap  :-\

Unfortunately, you're wrong - the 6d does have an aa filter that also makes still shots softer, the moire is the result that downscaling to hd resolution cannot use "pixel binning" like on the 22mp 5d3 but needs to interpolate some of the 20mp lines - and the 6d is very bad at doing this.

They could just as easily do exact pixel binning on the 6D.  They would just have to crop the image first.

  • At 720p, the sensor is 4.275 pixels per output pixel, so you could throw away the outer pixels (use a 1.07x crop factor) and then scale 4:1.
  • At 1080p, that approach would be more problematic, because the ratio is 2.85:1.  Making it 2:1 would be a 1.43x crop factor, making it almost like shooting video on a crop body in terms of what it does to your field of view, but it still might be worth it if the results had less moiré.

With that said, it isn't just a question of binning.  If you just bin a bunch of pixels together, you'll get more moiré, not less.  You have to do the binning in combination with a digital low-pass filter that effectively does the low-res video equivalent of what the antialiasing filter does for stills.  The real question is whether the 6D has the CPU power to do the low-pass filtering.  If it doesn't, then binning won't help.  And if it does, then someone could probably come up with a better algorithm for non-integer downsampling than whatever the 6D currently uses, resulting in video that is comparable to what you'd get with binning, but without the field-of-view change.

2
I'd much rather see Canon bake the continuous gyroscope data into the EXIF tags and leave the processing to computers that actually have the CPU power to handle it.  Ideally, they'd downsample the video footage and compress it at somewhere around 1280p instead of 1080p, leaving a nice margin so that when you process the footage, you'd still have 1080p, and they would show you the center portion of that footage so that in the absence of massive correction, what you see would be the final, cropped output.

That scheme would also have the advantage of being able to correct more robustly by virtue of being able to look at the entire set of data rather than trying to guess whether that was a shake or a deliberate pan.  And when compensating for a particular shake would cause a black border, if you're working with the data all at once, you can retroactively adjust the center of previous frames to avoid the problem, or at least smooth it out in ways that you cannot accomplish in real time.

And just to clarify, lens IS does do this, but it isn't really designed for video; it is designed for holding the image dead still.  For video, it is suboptimal, because that usually isn't what you want.  You want motion to be smoothed out, not eliminated.  Otherwise, when you hit the limit of its range, you get a nasty jerk in the picture.

As for "no downsampling", you're downsampling anyway.  Just about nobody shoots RAW video.  And with the 16:9 aspect ratio, you're throwing away pixels on the top and bottom no matter what, even after downsampling, because you don't use the full height of the sensor.  Those pixels could be made available for post-processing... essentially for free, without even needing to crop, though you would probably want to crop a little bit to accommodate horizontal shake.  And because vertical shake usually has the highest amplitude, that's a real win.

3
I don't think people get offended, they just disagree and want to say why they disagree. Nothing wrong with that.

I think some of the posts on this website go a little beyond simply disagreement.

Name calling, personal insults, and ad Hominem attacks are not disagreements.  ;)

Also, just because someone publishes somethign that I disagree with, does not mean that I have to respond.   I disagree with a lot of stuff in life and I don't respond.  ;D

But... but... but...



(xkcd #386)

4
Lenses / Re: Why are Cine Lenses so expensive?
« on: October 15, 2014, 03:10:18 PM »
Another reason Cine lenses are more expensive: Calibration.

Roger Cicala of lensrentals.com in another post (not the one quoted earlier in the thread) was writing about sample variation and how shocked the average photographer would be at the differences between even high end pro lenses right out of the box.    Since as part of their business, they routinely re-align elements and test the lenses very carefully, he pondered how much effort would go in to making sure every lens is perfectly tweaked before it leaves the factory.

He reckoned it'd about triple the cost of the lens.  Which, he noted, is about what Cine lenses go for...

That might be true if you have a person do it.  If you design an automated calibration rig that tunes each lens precisely before final assembly, it would be a fixed equipment cost that, amortized over millions of lenses, should have minimal impact on the cost of the lens.

The big cost of Cine lenses is lack of amortization.  All of the design is spread across a much smaller number of lenses, because most people don't demand parfocal lenses for still photography (even though they really should).  If Canon designed every lens to be parfocal, the impact of parfocal designs on the cost of lenses should also be pretty small.  The same goes for other design decisions, such as lack of focus breathing.

So basically, they're expensive because not many people buy them, and not many people buy them because they're expensive.  The day someone new enters the market and decides to make all their general-purpose lenses be up to Cine lens standards, Canon will suddenly find ways to bring the cost down.

5
EOS Bodies / Re: EOS 6D Mark II to Move Upmarket? [CR1]
« on: October 14, 2014, 06:46:42 PM »
The 6D, while completely capable of capturing beautiful images, has some serious limitations for certain types of photography. That is not to say it is a bad camera, just better suited to other types of photography.
Sure, a better AF system would be better for sports, but I'd hardly call it seriously limited.  I've used a 6D to shoot sports (basketball), birds in flight, landscapes, panos, portrait work, etc., and it did a reasonably good job at all of them.
I didn't say the AF system was a serious limitation. Why would you interpreted my comment as referring to the AF system?

I can only think of two aspects of the 6D that qualify as limitations: the AF system and the frame rate.  The frame rate might not be 1DX speed, but it is fast enough to be usable to get great shots, even for sports.


Anyway, since you brought it up sports photography, why would a professional sports photographer choose the 1D-X to shoot at the Olympics rather than the 6D?

The question is not which one is better.  There's no question that the 6D is outclassed by the 5D Mark III and the 1D X.  The question was whether it has serious limitations—that is, if there are aspects of it that would prevent someone who knew how to use it from being able to get decent shots.  Personally, I don't think so.

6
As for Samsung, I think you're right.  Why not go with them?  They've integrated the Android OS into some of their cameras.  You can shoot an image, run your favorite mobile processing app, and share it all in the span of a few moments right from the "camera".  Time barriers to creativity collapse.

IMO, Samsung entering the interchangeable lens camera market is a recipe for disaster.  I have very little faith in their ability to pull it off, because it is too completely different from any market in which they've ever had the slightest bit of success.

The big problem is that Samsung has a long history of building cheap consumer crap that doesn't last very long, with buggy firmware that never gets fixed.  They have no need to design for the long term, because consumers throw everything out after two or three years anyway.

Contrast this with the harsh reality of photography—that glass (good glass, anyway) is expensive.  It is a long-term investment.  It has to be done right the first time, it has to last for the long haul, and it has to be forward-compatible with future hardware for many years, or else people feel ripped off.

Samsung has not shown the ability to design for the long haul, and worse, has shown plenty of evidence that they are completely unable to do so.  Just take a look at all the horror stories from people whose Samsung refrigerators have exhibited repeated hardware failures under warranty, in which the electronic brain crashes and all of their food spoils.  And this is a company that you think will build lenses that people will still be using in twenty years?

That's not to say that they couldn't cheat—build bodies that are electrically compatible with a more competent company's lenses—but I can't see them ever being a serious player in the high-end camera market, because they have so epically failed at every attempt to build high-end products of any kind every time they've tried..

7
EOS Bodies / Re: EOS 6D Mark II to Move Upmarket? [CR1]
« on: October 14, 2014, 04:52:38 PM »
The 6D, while completely capable of capturing beautiful images, has some serious limitations for certain types of photography. That is not to say it is a bad camera, just better suited to other types of photography.

Sure, a better AF system would be better for sports, but I'd hardly call it seriously limited.  I've used a 6D to shoot sports (basketball), birds in flight, landscapes, panos, portrait work, etc., and it did a reasonably good job at all of them.

8
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 13, 2014, 03:22:27 PM »
Quote from: dgatwood link=topic=2316channel 1932#msg4channelste=1413081039
It would also be a tremendous amount of data, and a lot more data to be factored into image processing. Five layers at 25megapixels is 125megaphotodiodes. At 14-bit, that's around 235-245 megabytes per image. RAW editors would also have to add the right kind of support to utilize those extra layers.

Even three layers would be unworkable uncompressed at 25 megapixels per layer.  It's hard enough to deal with 25–30 megabyte image files, much less four times that.  They're clearly going to have to come up with a good lossless compression algorithm.  A lossless scheme similar to PNG should get you about 2.7:1 compression, which means about 81 MB with all five layers included, or 49 MB with only three layers.  But I think it is possible to do better than 2.7:1.  After all, the high order bits of nearby pixels are likely to be fairly similar except near high-contrast edges, and the more bit depth you have, the more identical bits you'll probably have.

Storage space probably isn't nearly as big a concern, as yes, you can compress the files. However when your working on them, you need the full pixel data. It's like opening a large 16-bit or 32-bit TIFF in Photoshop...if you look at the memory usage, it is usually several hundred megs.

So what?  When you're working in Lightroom or Camera Raw you're working on demosaiced data anyway at 16 bits per channel for four channeks.  The size is 8 bytes * pixel count.

I doubt they maintain an alpha channel during processing; it would always be 1.0f/65535.

Either way, jrista is correct that when you process the data, you'll need more working space, because every time you edit the IR/UV handling, you'd have to redo the computation where you collapse the five channels into three.  (I'm not going to call it demosaicing because it isn't mosaiced in the first place.)  With that said, outside of cell phones, the difference between 50 megabytes (25 megapixels at two bytes each) and 250 megabytes is IMO mostly noise compared with all the other memory usage in these sorts of apps.

It also requires more CPU power to read three or five 16-bit values than one; effectively, each destination pixel in a traditional debayer algorithm requires reading on average one new subpixel value that hasn't been read before, so assuming your algorithm achieves maximum reuse of values (which it won't), a multilayer sensor would be 3–5 times as CPU-intensive.  In practice, it is probably closer to a factor of two, though, and I'm pretty sure the debayer algorithm is a small percentage of the total processing, so I doubt this will be a serious problem.

Basically, if your computer is barely tolerable now, it might be intolerable with a multilayer sensor.  In practice, though, the apps will probably evolve to take better advantage of multiple cores, and this will probably make the difference moot.

9
Speedlites, Printers, Accessories / Re: CF Cards Vs SD Cards
« on: October 13, 2014, 12:09:36 AM »
Using 1d4 and 5d3 its simple: I prefer the CF cards due to the slow SD interface
In my Sony or Fuji the SD shine with speed.....

7d2 supports finally the UHS protocol- wow. Canon, the late adopter.

The 6D supported UHS-I (2009), too.  Too bad Canon still hasn't adopted UHS-II (mid-2011).  :/

10
Canon General / Re: Financial Times - "Digital cameras: out of focus"
« on: October 12, 2014, 11:19:26 PM »
Hi,
   IMHO, yes, smartphone will kill the low end compact camera market, but also might increase high end compact and DSLR sales. Those user using smartphone camera most probably are not interested in photography in the first place, but once they shoot more with smartphone, they might be interested in photography and once they are interested in photography, they might buy a DSLR. Camera manufacturer should actually target those smartphone shooter by showing the different in quality and speed between a smartphone and a high end compact and DSLR.

   Have a nice day.

Smart Phone Photos have won World Press Awards :) iPhone photos have been published on the front page of the New York Times :) iPhone photos have been published in Sports Illustrated :) The Stock Photo Agencies are seeing a demand for photos shot with Smart Phones (because of their Authentic look) :)

Check-out this article in the NYTimes  http://www.nytimes.com/2014/10/02/technology/personaltech/smartphone-photography-evolves-with-camera-apps-and-related-tools.html

Eventually Smart Phone will kill DSLRs for many (not all) uses. BIF photographers and Professional Sports shooters will still need DSLRs and Long Lenses.

No, they really won't.  There's a real feasibility problem with building zoom lenses in such a small package, so cell phones are generally limited to digital zooms.  As long as that is the case, they'll never compete with DSLRs.  A cell phone is like shooting with a fairly wide-angle prime all the time.  Can you imagine gluing a 30mm prime lens to the front of your DSLR?  50mm, maybe, assuming you don't care about landscapes, but not 30mm.

Besides the painful lack of flexibility in composition inherent in a fixed-focal-length camera, you'll never have any real depth of field with a lens that wide and a sensor that small (excepting possible simulation thereof), and more importantly, you'll never be able to get usable shots of anything more than a few feet in front of you unless your subjects are very large (e.g. landscapes).

Cell phones are not particularly practical even in the portrait world.  Outside that world, they're a disaster and a half.  It's not just long zooms; you can't get a decent shot of much of anything with a cell phone unless you're right there.  This mostly precludes any serious use of cell phones for capturing concerts, plays, weddings, sports, birds in flight, locations with even moderately bad light—basically any of the sorts of things people commonly use high-end cameras for, with the possible exception of landscapes shot in the daytime.

And that's why I carry a 6D with 16–35L II, 24–105L, and 70–300L lenses when I go on vacation, travel with groups, etc.  Sure, with a cell phone, I'd be able to capture a few of the shots that I want to capture (along with a lot of badly smudged shots), but with a DSLR, I can get all the shots I want, without the need to rent a crane or a helicopter to get me close enough, along with a Lowel lighting kit or a nuclear warhead (depending on distance) to provide enough illumination.  A cell phone simply cannot match the "keeper" rate of even a low-end DSLR from ten years ago, much less the DSLRs on the market today, and without changing the laws of physics or covering the back of the camera with a giant lens array and doing some really bizarre image processing, it never will.

11
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 11, 2014, 10:30:39 PM »
It would also be a tremendous amount of data, and a lot more data to be factored into image processing. Five layers at 25megapixels is 125megaphotodiodes. At 14-bit, that's around 235-245 megabytes per image. RAW editors would also have to add the right kind of support to utilize those extra layers.

Even three layers would be unworkable uncompressed at 25 megapixels per layer.  It's hard enough to deal with 25–30 megabyte image files, much less four times that.  They're clearly going to have to come up with a good lossless compression algorithm.  A lossless scheme similar to PNG should get you about 2.7:1 compression, which means about 81 MB with all five layers included, or 49 MB with only three layers.  But I think it is possible to do better than 2.7:1.  After all, the high order bits of nearby pixels are likely to be fairly similar except near high-contrast edges, and the more bit depth you have, the more identical bits you'll probably have.

12
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 11, 2014, 09:42:46 PM »
Will Canon use more than 3 layer?

What does the patents say?

From what I can gather from the poor japanese translation, the UV and IR layers are only for blemish removal. They are not used for output pixel generation...that still only uses the RGB layers...however those layers are modified by the blemish removal logic before demosaicing (at least, as I understood it...and I'm honestly not sure if that is just for JPEG, or includes RAW or not...I kind of think it's only JPEG.)

I would expect the extra information to be included in RAW files as a separate data layer, so that post-processing tools could benefit from it in the same way.  That would also have the rather sizable advantage of making it possible to do IR photography with an unmodified camera just by changing the way that you combine the various layers in post-processing, which would be really cool.

Incidentally, there shouldn't be any demosaicing with a multilayer sensor.  That's the whole point of having spatially coincident subpixels.

13
EOS Bodies / Re: Upgrade Path Advice...
« on: October 11, 2014, 09:37:22 PM »
As far as the Canon line up is concerned you have got a choice between the NEW KING of crop in the fully featured 7D or the entry level and aging Full Frame 6D which lacks a few refinements of the 7d (eg  AF, Burst Rate, 1/8000 SS , weather sealed etc) but gains a couple of others ( eg GPS, FF sensor, ?) So it really does come down to  a choice between sensor sizes and the advantages of each. Have a look at the imaging resource comparometer images and you will see that the 7D2 loses little in IQ relative to the 6D IMHO.

Both the 7D Mark II and the 6D have GPS.  Wi-Fi is the feature that is exclusive to the 6D (and the 70D).

14
EOS Bodies / Re: Wifi on 5D MK IV?
« on: October 11, 2014, 04:49:58 PM »
Looking at that brick got me thinking... maybe they should just integrate Wifi into the next generation battery grips.  The Wifi in the 6D and 70D does not add significant weight or bulk to those cameras so presumably it could easily fit in a battery grip. Then there is also a synergistic relationship between a battery grip's additional energy capacity and Wifi's lust for power.

Most folks turn the camera's Wi-Fi on right before they use it and turn it off again afterwards, so aside from exceptional circumstances where you're controlling a long shoot over Wi-Fi, the battery life issue should be largely moot.

15
There is a reason the guys who shoot NFL/Olympics/etc. use top gear. They would have a worse takes if they all shot it with the original Rebel and a 75-300 IS.

They should be so lucky.  Imagine shooting with an original Digital Rebel and a 75-300 non-IS:)

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