October 24, 2014, 03:56:23 AM

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Messages - Lee Jay

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1
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 23, 2014, 11:39:27 PM »
To get that crop reach advantage, you need a GREAT lens. A lens like the 100-400 or the Tamron 150-600 is not sharp enough.

Not true.

I'll challenge anyone to go out with a 1DX or 5DII or III and get a moon shot like this one with a 100-400L.

Nice image, well processed; but not sure I see the point.

It was shot with a 100-400L + 1.4x TC - so you could not even capture that image on a crop camera with the 100-400L alone.

Phil.

And what's the purpose of a TC?  Answer:  To compensate for the sensor under sampling the lens.  A 1.4x TC can be thought of as shrinking the pixels by 1.4x or as doubling the pixel count, rather than doing anything optically.  They are equivalent, and in both cases if the lens isn't resolving the detail, the extra pixels or extra magnification won't help.  But it does help as you just said yourself.  And you are right.

2
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 23, 2014, 11:35:49 PM »
To get that crop reach advantage, you need a GREAT lens. A lens like the 100-400 or the Tamron 150-600 is not sharp enough.

Not true.

I'll challenge anyone to go out with a 1DX or 5DII or III and get a moon shot like this one with a 100-400L.



Hand held.

http://www.canonrumors.com/forum/index.php?topic=435.msg120132#msg120132
And here,
http://photography-on-the.net/forum/showthread.php?p=10014826

As I said...not even close.

3
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 23, 2014, 11:11:28 PM »

SNR = sqrt(photon count)

True, but I believe that's photon count per pixel. I'm trying to understand how the the total photon count on the sensor matters.

If you only look at one pixel, the per-pixel photon count would be all that matters.  If you look at a whole image, the whole image photon count is what matters.

I don't think so. You've probably seen this before
http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/

For the shot noise, its only a function of the number of photons captured by a pixel.

The shot noise for that pixel.

Quote
Its the physics of why the crop (smaller pixels) shot noise can never be as low as the FF.

Shot noise is also called "photon counting noise".

If you have a larger sensor with the same pixel count, the shot noise per pixel is lower.

If you have a larger sensor with the same sized pixels, the shot noise for each pixel is the same, but you have many more pixels.

You can use software (noise reduction and downsampling) to trade all that extra resolution for much lower noise in the overall image with the same sharpness (resolution), and in fact that's what you end up doing when you compare the two images at the same final size.

All those photons that are collected by all those extra pixels count in the total signal (sharpness) to noise (noise) of the final overall image, and that's the reason that a larger sensor out-performs a smaller sensor in low-light despite having the same sized pixels.  It's also why cropping 1.4x (linear) is like increasing ISO by 1 stop, and cropping 2x (linear) is like increasing ISO by 2 stops (as far as noise is concerned) - the same as a teleconverter requires for the same shutter speed.

4
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 23, 2014, 10:12:03 PM »
To get that crop reach advantage, you need a GREAT lens. A lens like the 100-400 or the Tamron 150-600 is not sharp enough.

Not true.

I'll challenge anyone to go out with a 1DX or 5DII or III and get a moon shot like this one with a 100-400L.


5
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 23, 2014, 09:37:20 PM »

SNR = sqrt(photon count)

True, but I believe that's photon count per pixel. I'm trying to understand how the the total photon count on the sensor matters.

If you only look at one pixel, the per-pixel photon count would be all that matters.  If you look at a whole image, the whole image photon count is what matters.

6
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 23, 2014, 09:12:30 PM »
In the real world, with the cameras Canon makes now, FF wins the IQ contest in all but one scenario... and that scenario is when you are focal length limited, can't move any closer, have a GREAT lens, and good lighting. Under those conditions (happens a lot with small birds) the quality of your crop pixels is fairly close to your FF pixels, but you have more crop pixels on target so you end up with a better image from the crop camera.  Everywhere else, FF wins.

No, there's another one - when you're magnification (as in macro) limited.

7
EOS Bodies / Re: 4K Products Coming From Canon [CR2]
« on: October 23, 2014, 08:22:17 PM »
Who would be okay with Canon implementing 4k on the lower end products (7D2, 5D4, C100, high end compacts, etc.) through a 1:1 pixel implementation?  That would give the 7D2 an additional 1.425x crop on top of the 1.6, for example.  It would require a lot less processing power and software.

Personally, I'd be okay with that.

8
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 23, 2014, 07:48:49 PM »

True, but the 2.56x greater area of the FF sensor will gather more total light.  Comparing noise at the pixel level isn't the same as comparing noise at the image level.

There's shot noise, which is clearly related to the size of the pixel and I thought that the signal processing to convert the analog to digital was done on a pixel-by-pixel basis, which would make the read noise related to the pixel photon count, too.  Is that so? If so, what else would make the image level noise different? In other words, how does the total amount of light collected by the sensor come into the noise calculation?

SNR = sqrt(photon count)

9
EOS Bodies / Re: Canon Announces the Cinema EOS C100 Mark II
« on: October 23, 2014, 10:48:12 AM »
SHARING - WIFi, wireless iOS and Andriod inegration with cameras, file transferst etc, THEY NEED IT NOW

FASHIONABLE PRODUCTS - COLOR COLOR COLOR, they turned out a great white SLR, but ARE NOT SELLING IT RIGHT!!! You sell it as a Dolce Gabbana camera and shoot the spring campaign on it, and then make fabulous bags and sell it in fashion retail stores. It's not hard! General population doesn't care to go to B&H to see a white camera, it needs to be where the fashion is!

These are what are important to you?  That's pretty sad.

10
EOS Bodies / Re: Canon Announces the Cinema EOS C100 Mark II
« on: October 23, 2014, 10:28:51 AM »
I also see no reason to record 4K today.

So I can stabilize in post, crop, downsample, and still have 1080p left.

This is a legitimate response, but this camera is aimed at people using professional-style rigs, no? So stabilisation isn't really an issue.

For fast objects, it always is, even with a fluid head, optical IS, and electronic stabilization.

11
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 22, 2014, 05:33:05 PM »
For canon, exposure for a 400mm 5.6 on a crop (640mm 5.6) is the SAME exposure as a 400mm 5.6 on a full frame. By using a crop sensor the aperture doesn't magically shrink. Just like taking the center section of a full frame image to give the same view as a crop sensor does not shrink the aperture.

Jarrod

No, the aperture stays the same.  Aperture = 400mm/5.6 = 71.43mm.  If you're going to call that a 640mm equivalent lens because of the smaller sensor, you have to call it a 640mm/71.43mm = f/9 equivalent f-stop too.

12
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 22, 2014, 09:53:52 AM »
Have you seen the "ZUIKO DIGITAL ED 300mm F2.8"?  In FF equivalent it is a 600 f/2.8 ...

600/5.6.  You don't get something for nothing.

It's always both amusing and rather sad that people don't understand the word "equivalent".

It's very odd, especially when the same people don't make the same mistake with teleconverters, which do exactly the same thing as smaller sensors (crop and enlarge).

13
EOS Bodies / Re: Canon Announces the Cinema EOS C100 Mark II
« on: October 22, 2014, 03:34:01 AM »
Frankly, I don't care all that much, since I think the quality of the imagery in video is usually mostly irrelevant.  The only time I'll ever make an effort to get higher video quality than, say, my SDTV, is when I visit a real IMAX theater (you know - the 15 perf 70mm horizontal version) to see a documentary where the photography is just totally outrageous, the bulbs are 15 kilowatts, and the screen occupies around 90 degrees of my field of view.

Hmm I couldn't possibly disagree more.
Why do you even shoot more than a 1MP stills cam then?

For stills, IQ matters a whole lot more.  You don't get all that extra information from having lots and lots of frames stung together.

14
EOS Bodies - For Stills / Re: How to differentiate crop vs. FF
« on: October 22, 2014, 03:16:24 AM »
Have you seen the "ZUIKO DIGITAL ED 300mm F2.8"?  In FF equivalent it is a 600 f/2.8 ...

600/5.6.  You don't get something for nothing.

15
EOS Bodies / Re: Canon Announces the Cinema EOS C100 Mark II
« on: October 21, 2014, 09:13:25 PM »
I also see no reason to record 4K today.

So I can stabilize in post, crop, downsample, and still have 1080p left.

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