October 31, 2014, 05:56:09 AM

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Messages - Don Haines

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61
Equivalence is a lot like a car in the US can be driven 30 miles on a gallon of gas. The same car in Canada can only go for 12.7 kilometers on a litre of fuel.... and then someone says that as their car crosses the border it magically changes from 30 miles per gallon to 30 miles per litre....

62
Yes an f2.8 is an f2.8, but the term equivalent was used and if you do that for focal length it is disingenuous to not also do it for aperture, after all the focal length doesn't change either.
+1

It's a ratio.... A/B = C :) You can't change A without changing B if you are keeping C a constant ...

If the equivalent length is 200mm then the equivalent F is 7.6.....

but to really be accurate, the focal length is 8.8 to 73.3mm and the F stop is 2.8.... period... the optical properties are what the are and short of Harry Potter magic, will remain so..... and the sensor has much tinier pixels than FF so it samples much more densely over a smaller area... and people will forever be confused with "equivalence" :)  Did I mention that people will forever be confused with equivalence?

63
An F 2.8 lens is a 2.8 lens regardless of the sensor size, the amount of light it lets in doesn't change by changing the size of the sensor. This camera is equivalent to 24-200mm in 35mm terms and the only thing that is different is the depth of field.

Oh, just the DoF is different?  Well, that's ok then...I mean, it's not like DoF matters for pictures, or like photographers care about DoF or anything like that, right??  It's a smaller sensor, so is noise or anything like that different?  Or is that something else that doesn't matter?

If you say 8.8-73.3mm f/2.8, that's fine.  Saying it gives a field of view equivalent to 24-200mm on FF/35mm is fine.   Calling it 24-200mm f/2.8 is a lie, since f/number is focal length / iris diaphragm diameter.  Calling it equivalent to 24-200mm f/2.8 on FF/35mm is also a lie, the DoF for equivalent framing is different, which means they can't be equivalent.  It might be done commonly, but it's still a lie.  People exceed the posted speed limit all the time, it doesn't mean they're not breaking the law.
That's why I love my SX-50.... it really does have a 1200mm F6.5lens :)

64
Photography Technique / Re: Shooting in a Dark Skating Arena Advice
« on: October 16, 2014, 05:41:29 AM »
I am probably going to get shot for saying this on a Canon forum, but if you are thinking of renting...... Why not a Sony A7S?

It is the low light king.... And apparently the right tool for the job.....

65
EOS Bodies - For Stills / Re: So what makes a camera a "pro" camera?
« on: October 16, 2014, 05:38:33 AM »
In general, doctors use very low end microscopes... if at all.  Now lab technicians.... they have decent gear... but if you really want to see the good stuff go to a physics lab for a scanning tunneling electron microscope so you can see those individual atoms...

A real "pro" goes for the gear that get's the job done, not the very best. A doctor in a fertility clinic is not going to get the very best.... they want to watch how the sperm moves, not kill it and check to see if all the atoms are in the right place :)

So are you saying that there is no such thing as "pro grade gear"?

My point is that there is, and it is up to the manufacturer to label it as such.

The 1D X is obviously a pro camera, especially for sports shooters. The 400 f/2.8 ii is also a pro lens. Is it only bought by individual pros? No, agencies, publishing houses, enthusiasts and those that want the best purchase it too.

Does it fit every pros needs? No, but that does not make it any less pro-grade.

If a pro sport shooter sits on the sidelines and shoots pictures with his Samsung Galaxy Note 3 are you seriously suggesting that that phone is a pro piece of photographic kit?

You may say that is a bad example, but would you say that if the guy was using a 5D Mark III because he could not afford the 1D X? But if so, what if you can't afford the 5D Mark III or even II, but you can afford the Samsung Galaxy Note III which double up as a phone when you are not shooting.........

To say that it is the operator which makes his or her tool a pro grade piece of kit is ludicrous in my mind. But it is not a big deal, it is just my humble opinion.
What I was trying to say is that a pro will use the appropriate level of gear for the job at hand. I don't think that anyone would dispute that as you move towards higher end gear that image quality improves or that cameras like a 1DX increase the odds of capturing that shot under difficult conditions.....and in general captureing the shot is the highest priority for a pro, but it is the task that determines gear and priorities, not some "pro" designation on the gear.

A good example of this is inspection photography. The goal is to determine if there is visible wear and to determine if there is adequate grease on the gears, look for signs of rust, etc.. The access port is 1.5 inches by 6 inches, so the camera must fit through the slot. The camera used takes crappy pictures, but it fits into the gear and the pictures are good enough for the task at hand. I have a so called "pro" camera and L glass in a pelican case on a shelf behind me, but it is the wrong tool for the job, despite being a vastly superior camera. On the other hand, when things are spread out on the bench I love that 100L macro lens.....

66
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 11:31:27 PM »
Yes, the bulk of the market is now tablets and laptops,  but there is a very vibrant market for "power systems". If you want something with decent power, that's the way you go.

Adobe likely doesn't want to exclude 90% of their market by making products that only work properly on very high-performance machines.

By the way, my current laptop is about 100 times faster than my previous desktop - a desktop on which I ran the first versions of Lightroom.
It doesn't exclude anyone. You write the software to take advantage of a GPU. If you don't have one, the software works perfectly. If you have one, it is faster. The user can run it on their tablet, thier laptop, or their desktop ( rack mount for me :) ). If you want more performance, buy better hardware. It is better to have that option than no option at all.

67
Landscape / Re: Fall colours
« on: October 15, 2014, 10:56:29 PM »
Don't have vast expanses of fiery red maples here, or any expanses really. So...
Nice!, love the first one!

68
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 10:52:46 PM »
It's possible to rewrite Lightroom to operate primarily off the GPU. You could solve all the performance problems.

Keep in mind that something like 90% of all new machines use the on-CPU (embedded) GPU.  You have to be able to support those who use those as well.  The machine I use at work for running LR has no separate GPU, and buying a machine with a separate GPU isn't really allowed where I work.
But when we buy a computer, we buy it for the task at hand...

For example, when I built my computer for home, I wanted something for image processing and my software supported GPUs with CUDA cores.... So I got a solid state "scratch" drive (on a card, NOT one of the slow SATA drives) and a video card with 1024 CUDA cores....

If they re-write Lightroom, they are going to look to the future, not the past. This is why software packages have "recommended hardware"

In the past, all GPUs were off-CPU.  Now they are 90% on-CPU.  In the past, 100% of computers were desktops.  Now, they are more than 70% laptops.

The last time I bought a desktop was 2004.  If they are looking to the future, they are looking to smaller devices that are not going to include board-based SSDs and huge off-CPU GPU cards, since both are going away as fast as CRT televisions.
I guess we had better tell the gamers about that...

Yes, the bulk of the market is now tablets and laptops,  but there is a very vibrant market for "power systems". If you want something with decent power, that's the way you go.

69
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 10:37:32 PM »
It's possible to rewrite Lightroom to operate primarily off the GPU. You could solve all the performance problems.

Keep in mind that something like 90% of all new machines use the on-CPU (embedded) GPU.  You have to be able to support those who use those as well.  The machine I use at work for running LR has no separate GPU, and buying a machine with a separate GPU isn't really allowed where I work.
But when we buy a computer, we buy it for the task at hand...

For example, when I built my computer for home, I wanted something for image processing and my software supported GPUs with CUDA cores.... So I got a solid state "scratch" drive (on a card, NOT one of the slow SATA drives) and a video card with 1024 CUDA cores....

If they re-write Lightroom, they are going to look to the future, not the past. This is why software packages have "recommended hardware". This is why my panorama software lists a decent Nvidia card as "recommended hardware", yet still runs without.... just a LOT more slowly.

70
EOS Bodies - For Stills / Re: So what makes a camera a "pro" camera?
« on: October 15, 2014, 10:26:24 PM »
Generally speaking, a manufacturers top of the range product is aimed at pros. Take knives, pans, laptops (the business lines), and I presume microscopes etc.

My Calphalon Commercial cookware was bought at Macy's, and my Wusthof pro knives came from Williams-Sonoma...not a restaurant supplier. 

The top end is aimed at people who are willing and able to pay the higher price.  "Pro" is purely a marketing distinction.
I worked my way through school cutting meat in a butcher shop. Knives were a disposable item. You sharpened them several times a day and they did not last. No butcher would consider getting "pro" knives... and those silly handles are not meant for someone who uses them 8 hours a day.

71
EOS Bodies - For Stills / Re: So what makes a camera a "pro" camera?
« on: October 15, 2014, 10:16:00 PM »
Generally speaking, a manufacturers top of the range product is aimed at pros. Take knives, pans, laptops (the business lines), and I presume microscopes etc.

My Calphalon Commercial cookware was bought at Macy's, and my Wusthof pro knives came from Williams-Sonoma...not a restaurant supplier.  I've never seen a 'pro' microscope.  General Motors ran a marketing campaign for their Professional Grade trucks...I know a few people who use them to commute to their professional office jobs.

The top end is aimed at people who are willing and able to pay the higher price.  "Pro" is purely a marketing distinction.

I do not see why you think where you bought something has to do whether it is pro-grade or not.

You are right to say "The top end is aimed at people who are willing and able to pay the higher price".

But is also true to say those products tend to be of a better build, quality and lifetime expectation which are things that pros look for!

I know nothing about microscopes, but I would doubt that a consumer grade microscope is the same as those used at multi-million dollar R&D departments or in hospitals that demand the best.

Are you saying that if a trained doctor is using a consumer-grade microscope then it automatically becomes a pro-grade microscope?!

No of course it does not.

Same as if a pro photographer uses a 10D or a point and shoot or a phone to capture his shots. It does not make those cameras pro grade, and as such they are not pro cameras.

In general, doctors use very low end microscopes... if at all.  Now lab technicians.... they have decent gear... but if you really want to see the good stuff go to a physics lab for a scanning tunneling electron microscope so you can see those individual atoms...

A real "pro" goes for the gear that get's the job done, not the very best. A doctor in a fertility clinic is not going to get the very best.... they want to watch how the sperm moves, not kill it and check to see if all the atoms are in the right place :)

72
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 09:50:59 PM »

Creating a Jpg out of the RAW file is a completely different story... Processing that RAW file is a massively parallel operation... the image is typically broken up into 8x8 blocks and run through the jpg compression engine... then groups of blocks are run through the compression engine... and so on until the whole image is done. The 18Mpixel sensor makes an 5184x3456 image... and that makes 279,936 blocks to compress on the first pass, 4374 blocks on the second pass, and 68 blocks to finish off on the third pass..... Since it is essentially the same sequence of operations on each block, parallel cores on a GPU can speed things up by well over a magnitude....


Same thing holds true for rendering images in software to display on the screen or to create print files...


Aye. It wouldn't matter if you were rendering to JPEG or simply rendering to some kind of viewport buffer. Each pixel can be independently processed. Since you have millions of pixels, and each one is processed the same, you can write very little code, and run it on a GPU which is explicitly designed to hyperparallelize pixel processing. You would simply be executing pixel shaders instead of standard CPU code. With the modern architectures of GPUs, you can make highly efficient use of the resources available.

YES!
The GPU's are far more efficient than general purpose CPUs for running shaders and the like.... as mentioned above, That's what the chip was designed for!

73
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 09:47:00 PM »
I've been curious for some time why Lightroom doesn't make extensive use of the capabilities of my video cards...if games can render vastly more complex scenes 60 to 120 times per second using a GPU, Lightroom should be able to do what it does on a 5-layer RAW quicker than it renders a bayer RAW now.

Agreed.  DxO Optics Pro used to be rather slow at displaying images at 100% on my Mac, and even filmstrip thumbnails weren't very fast.  A version back (IIRC), they added GPU acceleration and it sped the rendering up significantly.

The guy that writes the Camera Raw code says GPU acceleration would help very little with the Camera Raw pipeline.


I honestly have a very hard time believing that. There is no way the current code is as parallel as it could be when run on a GPU. CPU's simply cannot achieve that kind of parallelism. I wouldn't be surprised if they had to completely rewrite the ACR pipeline to properly take advantage of GPU power, but I think they should do that anyway, and build in support for pipeline-level plugins so third parties could add things people have been asking for since v2 was released...like debanding support, or AF point overlays, etc.

For creating a RAW file in the camera, it is doubtful that GPUs would accelerate the process. Creating the RAW file is a read/dump process with very little (if any) processing being done. It is basicly read from the sensor as fast as you can and dump to the buffer....

Creating a Jpg out of the RAW file is a completely different story... Processing that RAW file is a massively parallel operation... the image is typically broken up into 8x8 blocks and run through the jpg compression engine... then groups of blocks are run through the compression engine... and so on until the whole image is done. The 18Mpixel sensor makes an 5184x3456 image... and that makes 279,936 blocks to compress on the first pass, 4374 blocks on the second pass, and 68 blocks to finish off on the third pass..... Since it is essentially the same sequence of operations on each block, parallel cores on a GPU can speed things up by well over a magnitude....

Same thing holds true for rendering images in software to display on the screen or to create print files...

The CR Pipeline doesn't create 8x8 blocks of compressed data.  It creates uncompressed raster data that's highly interdependent (think about applying gradient filters, healing spot corrections, brushed adjustments, etc.).
Different words, but close to what I was saying.... (RAW data is NOT highly interdependent)
Sensor to RAW - serial process.... all you need is a single core to read the sensor quickly and dump to memory. There is no way to "parallelize" the process unless you redesign the sensor and A/D to dump out enough bits at a time to make it worthwhile... in other words, instead of reading one pixel at a time, read multiple pixels at a time.... perhaps it will be done that way in the future, but as things stand now with Canon sensors and A/D you get a byte at a time and any attempts to throw multiple cores at that process would probably slow it down.

RAW to JPG - parallel process. The more cores the better.

Since Neuro's and Jrista's comments were about rendering RAW (or other formats) files on a computer, the comment/argument of creating RAW files in-camera is a tangent that sidetracks from the discussion at hand, which is rendering images on a computer.

In theory, using a GPU with multiple cores (There are NVidia chips with 512 CUDA cores) will speed up rendering of images. THAT IS THE REASON THE CHIPS WERE CREATED!!!!! You can plop 3 cards with dual chips into a computer for 3072 cores.... if you so choose. BTW, Cray made a supercomputer out of Nvidia craphic chips....

In practice, on my home system, rendering a panorama from 324 images took 2 1/2 hours with the GPU disabled and 11 minutes with it enabled.... about a 14 times increase in speed.

EDIT:
I was wrong about the GPU specs.... the Nvidia 980 cards have 2048 cores running at 1.2Ghz and render 144 BILLION points per second. I could fit 3 into my chassis at home for 6144 cores... that's 7.3 TERRA flops! over 12 times the GPU power I have now......

74
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 09:17:39 PM »
I've been curious for some time why Lightroom doesn't make extensive use of the capabilities of my video cards...if games can render vastly more complex scenes 60 to 120 times per second using a GPU, Lightroom should be able to do what it does on a 5-layer RAW quicker than it renders a bayer RAW now.

Agreed.  DxO Optics Pro used to be rather slow at displaying images at 100% on my Mac, and even filmstrip thumbnails weren't very fast.  A version back (IIRC), they added GPU acceleration and it sped the rendering up significantly.

The guy that writes the Camera Raw code says GPU acceleration would help very little with the Camera Raw pipeline.


I honestly have a very hard time believing that. There is no way the current code is as parallel as it could be when run on a GPU. CPU's simply cannot achieve that kind of parallelism. I wouldn't be surprised if they had to completely rewrite the ACR pipeline to properly take advantage of GPU power, but I think they should do that anyway, and build in support for pipeline-level plugins so third parties could add things people have been asking for since v2 was released...like debanding support, or AF point overlays, etc.

For creating a RAW file in the camera, it is doubtful that GPUs would accelerate the process. Creating the RAW file is a read/dump process with very little (if any) processing being done. It is basicly read from the sensor as fast as you can and dump to the buffer....

Creating a Jpg out of the RAW file is a completely different story... Processing that RAW file is a massively parallel operation... the image is typically broken up into 8x8 blocks and run through the jpg compression engine... then groups of blocks are run through the compression engine... and so on until the whole image is done. The 18Mpixel sensor makes an 5184x3456 image... and that makes 279,936 blocks to compress on the first pass, 4374 blocks on the second pass, and 68 blocks to finish off on the third pass..... Since it is essentially the same sequence of operations on each block, parallel cores on a GPU can speed things up by well over a magnitude....

Same thing holds true for rendering images in software to display on the screen or to create print files...

75
EOS Bodies / Re: Multilayer Sensors are Coming From Canon [CR2]
« on: October 15, 2014, 07:23:42 PM »
I've been curious for some time why Lightroom doesn't make extensive use of the capabilities of my video cards...if games can render vastly more complex scenes 60 to 120 times per second using a GPU, Lightroom should be able to do what it does on a 5-layer RAW quicker than it renders a bayer RAW now.

Agreed.  DxO Optics Pro used to be rather slow at displaying images at 100% on my Mac, and even filmstrip thumbnails weren't very fast.  A version back (IIRC), they added GPU acceleration and it sped the rendering up significantly.
Agreed!
When AutoPano (panorama rendering) added GPU rendering the time to render large panoramas dropped from hours to minutes. My video card has 512 CUDA cores running at a gigahertz.... WAY!!!! more computing power than a quad core Pentium....

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