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Messages - Lee Jay

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1
Lenses / Re: New Lens Information for Photokina
« on: Today at 05:59:42 PM »
I am not asking anybody to do a hand hold test for me, I am suggesting they do it for themselves and put the "reach advantage" myth to death once and for all.

Maybe you don't see a difference, but I do.

Three cameras (5D, 20D [same pixel size as 5DII]), T2i [same pixel size as 60D/7D]), two different lenses (100-400L, 70-200/2.8L IS II), two different targets, all handheld, all with AF, all the same result - smaller pixels win easily.

Neither lens was shot at optimal aperture or focal length (70-200 at 200mm and f/4, 100-400L at 300mm and f/5.6).


2
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: Today at 12:00:42 PM »
A full-frame sensor at point nine microns would be a GIGAPIXEL sensor. Assuming were at least at 16-bit ADC by the time such a sensor arrives, we would need in-camera data throughput of over 2.3GB/s just to process one frame per second, and data throughput of approximately 13GB/s to process six frames per second.

That kind of technology is beyond extreme. Relatively few things process data at such incredible speeds...high end, high power GPUs are one of the few that come to mind, along with the level three and lower data caches on a CPU. Those devices require considerable amounts of power to operate.
I'm smiling right now because I am waiting for a test to finish.....
I have a 60Ghz spectrum analyzer in front of me that takes 64 bit readings.... 480GB/s... but no way is it portable or affordable :)

Like I said...relatively FEW things process data at such high speeds. CPUs and GPUs were only a couple examples, there are a few other things that can process immense amounts of data per second...but...not many. And, as you stated, your spectrum analyzer is not portable. :P

RED has designed an ASIC (like DIGIC for Canon) that processes almost 2 gigapixels per second, including wavelet compression of the raw data.

3
EOS Bodies / Re: Are you planning to purchase a 7D2
« on: August 31, 2014, 10:38:03 PM »
I'm kinda in the "once you go full frame you don't go back" camp. The main reason would be the extra reach, which I'm reading here is over-rated. More like 1.2 not 1.6. So, that makes it a very expensive teleconvertor. I've already got the ff lenses. So, not sure what the advantage would be over a 6D. If I wanted a second (great) body (have 6D and T5i and 2 EOS M) would be more tempted to buy another 6D, one for longer zoom, the other for wide zoom at athletic events.

I agree with the conventional wisdom offered here that has been born of the crop vs FF debates.  (In essence, what you have stated above about real world 1.2 reach, etc.)  However, there is more to it than that.  In real world use, a new technology sensor in a new crop sensor camera gives me...

-  Faster fps (10 for the 7D2, 8 for the 7D and 7 for the 70D.)
-  1.6 (1.2?) crop factor reach advantage without a TC in the way
-  2nd body & lens (not a TC on a single FF)

A TC still costs you a stop of light and a loss of IQ compared to a crop sensor with no TC in the light path.  Having both a FF and a crop camera hanging by your side with two different lenses at a sporting event has its merits.  And if you are shooting sports, you are shooting a lot of frames of fast moving action.  You need fps.  And you need reach.  Trying to crop FF images later in post is a LOT of work when you are looking at several thousand images over a day or two of action.

That's why I bought a 70D a week ago for $836 from Canon Refurb.  It's likely going to give me at least 2/3 of (what I need) the 7D2 will give for possibly 1/3 the cost.  It's likely got a similar (if not the same) sensor and 7 fps is fast enough for my needs.  I'll know for sure after swim season starts.   :)

Not if you take equivalence into account, if you do, and you should, the ff has an iso advantage greater than the stop of aperture loss.

If the sensors perform the same per unit of area, there will be no difference.  Cropping does the same thing as a teleconverter from a total light captured point of view.  Equivalence says you multiply the f-stop by the crop factor, same as a teleconverter.

4
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 30, 2014, 11:32:24 AM »
Interpolate the small one up, not the big one down.  Reducing the big one costs you the resolution advantage it has.

As I said I don't really see this as an accurate comparison unless you are going to enlarge beyond 100%,

You aren't.  You're keeping all the smaller pixels instead of removing them.  The larger pixels have to be enlarged because they don't have all the smaller pixels.

Quote
but anyway I up sampled the lower px file in photoshop, and here is the result, shown at a 50% crop.
Where you have now eliminated half the resolution, so there should be essentially no difference.

5
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 30, 2014, 09:51:53 AM »
Interpolate the small one up, not the big one down.  Reducing the big one costs you the resolution advantage it has.

6
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 05:24:03 PM »
No you didn't, the request was for comparisons between a 7D/70D and a 5D MkII/5D MkIII/1Ds MkIII/6D/1DX handheld with AF.

I don't care about your request (which changes every time), I care about a controlled test demonstrating the point.  And I provided that.

Well you did care enough to argue the point, and you failed.

My request hasn't changed, I just broadened it to include more cameras to make it easier. Here is the original request:

Quote
Show me one test done with the same lenses from the same place shooting the same subject handheld whilst using AF that demonstrates the 7D's resolution advantage.

If by showing tripod mounted shots from a 20D and a 5D you think you have demonstrated the 7D's resolution advantage when hand held you have a different understanding of Engish than I do, or, to quote you, "Idiot".

I demonstrated it with a controlled test, not an uncontrolled one.  It's not my fault you don't have the skills to extract full resolution from your systems in real-world shooting.

7
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 05:19:55 PM »
If you just check how 300 2.8 mk2 IS perform on 1ds iii in DXO showing 21mp of 21mp resolving power.
Witch means almost perfect lens for this size/mp sensor.
Same lens on Canon 70d produce 17mp from 20mp. This means 3mp is throw away due to smaller sensor. And this is in perfect test conditions. On the field you will throw out  even more 10mp for sure.

And, at the same range, the 21MP will be reduced by a factor of 1.6^2 (2.56), leaving 8.2MP.

In other words, the larger sensor only has an advantage if you can use a larger lens or wait until the subject is closer.  At the same range, it has a disadvantage because of its large pixels.

8
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 04:46:13 PM »
No you didn't, the request was for comparisons between a 7D/70D and a 5D MkII/5D MkIII/1Ds MkIII/6D/1DX handheld with AF.

I don't care about your request (which changes every time), I care about a controlled test demonstrating the point.  And I provided that.

9
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 04:43:04 PM »
So moving to a smaller process to shrink the borders does not affect the amount of light captured for each pixel because of the gapless microlenses?

Pretty much, yes.

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If microlens size = photo site + border, then it would seem that a larger pixel-with-microlens would gather more light than a smaller pixel-with-microlens. Are you saying that the resolution (given the same sensor dimensions) is higher for the smaller pixels so when you compress the image to the same resolution as the sensor with the larger (fewer) pixels, the overall light/data collected for the multiple smaller pixels, now sized-down to the lower resolution end up producing essentially the same image quality?

Yes, though if you do the down-sizing properly, the smaller pixels will generally win, and quite easily.

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Am I understanding this right? Does this mean that if I want to enjoy the same image quality as the sensor with fewer pixels I have to compress the resolution of my images to match?

That depends on what you mean by image quality.  Resolution?  Noise?  With the smaller pixels, you have the option to reduce noise at the expense of resolution.  On the larger pixels, that part has been done for you and you have no choice.

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One other thought: microlenses perfectly focusing the light on the photo site sounds great on paper. How precisely do the lenses do this in the real world? If they're nearly perfect, how in the world do they accomplish such precision on such a small scale? Simply amazing to me...

The efficiency varies with the design, but it's quite close to all of the light.  They do this using the techniques of photolithography, which is quite a precise thing, especially in the more modern versions.

Quote
If the microlenses do their job, then I guess it's not light/surface-area that makes the difference between crop and full frame. Could it be that for the smaller pixels, there's more opportunity for noise to be introduced by the supporting circuitry? Something must be happening, because it seems that sensors with larger pixels seem to do better for noise at high ISO.

They do this because they use more sensor area, not because they use larger pixels.  When you have the same f-stop, the light intensity (called "illuminance" - light per unit of area) is the same (for a given scene), and that means a sensor with more area captures more light.  Since signal-to-noise ratio goes with sqrt(total light captured), more area (bigger sensor) means better signal to noise ratio for the same f-stop.  That's why larger sensor perform better in low light.

Another way to look at the same thing is to express f-stop as its definition - focal length / aperture.  So, a lens with a 100mm focal length and a 25mm aperture has an f-stop of 4 (it's often written as its reciprocal - 1/4 or 1:4).

Well, let's say you want to use your 100/4 on your full-frame camera.  To what do you compare?  Well, on a 1.6-crop camera, you might use the same lens zoomed out to 62.5mm so that you have the same angle of view.  62.5mm / 4 = 15.625mm compared with 25mm on the full-frame camera.  That's a lot smaller hole for the light to squeeze through, and so you get a lot less.

The two explanations are equivalent.

10
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 04:16:37 PM »
Well do you have proof of that or is it just another guess like your ff comparison without actually using a ff?

You say a lot of dumb things.  I have over 50,000 shots on my 5D, which I purchased at release.

I have talked with owners that love their 400/4DO.  Not so much the 70-300.

And you are my equal.

For all your 10,000's of shots you still couldn't post two images to illustrate your belief and assertions.

Yes, I did.  Since you're memory seems to be failing you, here it is:



And, if you prefer to see them at native (but different) sizes, here's that one too:

11
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 04:14:20 PM »
So the 6 MP p&s S3IS has better IQ of the 13 MP full frame 5D?

No, the 2.04 micron pixels of the S3IS provide better IQ behind the same lens as the 8.2 micron pixels of the 5D.  In other words, small pixels win.

Quote
Could you provide a link please so that I can see all by myself without asking you more detail? Thanks.

I don't know what link you want.  They're my pictures.

The reason this works is pretty simple - the same amount of light falls on the same area of the sensor regardless of how you divide that sensor up into pixels.  Lots of small ones or one large one, it's all the same light.  The difference is, with the small ones, you can choose to reduced your resolution down to the same as you get from the large one (and reduce noise along with it), or not.  You can't make that choice with the larger pixels.  Further, when you reduce your resolution, you can choose to use far more effective techniques than the simple block-averaging approach that is effectively what the larger pixels are doing - averaging over the large block size of the large pixels.

12
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 03:43:01 PM »
Well do you have proof of that or is it just another guess like your ff comparison without actually using a ff?

You say a lot of dumb things.  I have over 50,000 shots on my 5D, which I purchased at release.

I have talked with owners that love their 400/4DO.  Not so much the 70-300.

13
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 03:39:23 PM »
Too many of you claim that a higher MP sensor does not have more noise than a lower MP one, all conditions being equal, and support this claim with mathematics, but that's not true in the real world. Some even claim that smaller photosites have less noise than bigger ones: now, that's the kind of claim that should make all of us invoke Santa, bigfoot and rainbow-pooping unicorns going on vacation together with a flying saucer. The real world behaves differently.

Oh, really.  Same ISO, same f-stop, same shutter speed, same focal length, same subject, same lighting, shot in raw, same raw processing tool.  The pixels on the left are 1/16th as big (in area) as the pixels on the right.



Which ISO? Which f-stop? Which sensors? Could you provide a link, please? I've found this

ISO 800 (the highest setting available at the time on the small pixels.  The cameras as the Canon S3IS and the Canon 5D.

14
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 03:23:28 PM »
I don't, but I have put up with Canon's loss leading tech pet projects for a long long time, and DO is one.

It is a fair assumption that it isn't ready for prime time because of what it is and why it does wrong what it does wrong. With current tech the only way to negate the impact of putting steps into a perfectly smooth surface is to counteract it in software.

Now if Canon have invented a different way to bend light at the very least I would expect them to call it a new technology, for goodness sake they can paint a Rebel red and call it new, something like Diffractive And Micro Nano Glass Observational Optical Detail. We live in hope.

Diffractive optical elements do bend light, and they do it using a different approach than refraction.  This comes with a couple of major advantages compared with conventional refractive elements.  For one, the refractive index of the glass isn't the limitation on how much the light can be bent.  Secondly, the DO elements produce CA in the opposite direction as conventional elements thus making it greatly easier to correct CA with down-stream elements.  Both of these lead to smaller lenses that do the same job as conventional refractive lenses.

Here, read up:

http://www.usa.canon.com/cusa/consumer/standard_display/Lens_Advantage_Perf#f

I know and understand exactly how DO works, my point was they need to have come up with yet another way of bending light (hence the use of those words) to get over the intrinsic issues the DO introduces, despite the advantages, the disadvantages have proven to make the idea incompatible with consistent high quality photographic output.

I used two DO lenses for a day and instantly realised they were not good.

And yet, many owners just love them.

15
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 03:15:48 PM »
Too many of you claim that a higher MP sensor does not have more noise than a lower MP one, all conditions being equal, and support this claim with mathematics, but that's not true in the real world. Some even claim that smaller photosites have less noise than bigger ones: now, that's the kind of claim that should make all of us invoke Santa, bigfoot and rainbow-pooping unicorns going on vacation together with a flying saucer. The real world behaves differently.

Oh, really.  Same ISO, same f-stop, same shutter speed, same focal length, same subject, same lighting, shot in raw, same raw processing tool.  The pixels on the left are 1/16th as big (in area) as the pixels on the right.


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