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Messages - Lee Jay

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196
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 02:50:54 PM »
Dare I wade into the pizza war?  :P

Perhaps I can translate it into a wooden pizza to fit one of my other hobbies: If I have a 15" maple disc, cutting it into 6 pieces WOULD give me more maple surface area than cutting it into 8 pieces. Why? because there is waste from blade kerf. If I have a 1/8" kerf, I lose an approximately 1/8" slice of material with each cut. Let's say now that we fill in each cut with a 1/8" slice of ebony so we don't lose overall surface area when we glue it all up. The disc maintains its original surface area, but there is still less maple surface area with 8 slices than with 6. Using a 1/16" kerf blade will increase the ratio of maple surface area to ebony, but there will still be less maple surface area with 8 slices than with 6.

Now imagine the disc is actually a rectangle, and the pieces are squares instead of pizza slices. The maple is the photo-sensitive portion of the sensor, and the ebony is the border around each pixel. If sensor size and transistor size are constant, doesn't increasing the number of pixels increase the number of borders and transistors, and doesn't that reduce the portion of the overall sensor that receives light? Is moving from a 500nm process to a 180nm process like going from a 1/8" kerf to 9/200" kerf?

I'm obviously not a sensor geek, so I might be completely misunderstanding pixels, borders, et cetera. What am I missing in this analogy?  :P

What you're missing is gapless microlenses, which essentially render the "blade kerf" largely moot by concentrating the light into the light-sensitive area between the "kerf lines".

197
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 02:48:42 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

198
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 11:40:14 AM »
A 12mp sensor would have better high ISO performance,

No, it wouldn't.  This myth just won't go away.

Quote
utilize the center of lens elements,

Which is wrong on two levels - every pixel uses all of the lens elements.  You may have meant "image circle" instead of lens elements.  Secondly, using the "sweet spot" is nearly always detrimental compared to using the entire image circle because of increased enlargement.

Quote
And also, a 12 mp crop sensor is 150% of the "reach" and 16mp is 200% of the "reach"... As you put it.

"Reach" means "resolving power" and it goes with the square of pixel count.  You want to double resolving power?  You need four times as many pixels.

Whatever... my opinions are derived from "field" observation... and interestingly I have found that most things being equal, larger pixels translate to higher ISO noise usability.... and that the center of images are always sharper and have less distortion than the edges.  But who needs field observations when we have all of these "theoretical" photographers here on the forum to prove us all wrong??

I've got a quarter million shots under management in LR.  I wouldn't call that theoretical.

You're noise observation is wrong because you are comparing at different enlargement ratios (1:1 with all pixel counts).

Your center image circle is wrong because you aren't comparing crops and full image circle images at constant final size.

And what I said about "reach" (resolving power) is correct.

199
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 10:40:29 AM »
I'm not sure either, unless they sell this for $300-400 or something.  Perhaps they see it as a 28-135 IS replacement more than a 24-105 replacement.

Bingo.

200
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 10:30:09 AM »
Who the heck would want a FF lens that only goes to f/5.6 at 105mm? 
Not me, but people that want a light, cheap lens for landscape, travel, & studio use where shallow DOF is never used.  6D shooters would likely be the target for this lens.

Your logic makes about as much sense as saying who would want a crop sensor, or would want a camera any less tough than the 1D X.

There's this little thing called market segmentation.  It's how big companies make money.  Reference Canon's profits on the Rebel line vs. the 1D line.

I think the logic is ok.  You are talking about what people will accept, not what they want.

I'm thinking about how dSLR's continue losing ground, and that putting out mediocre lenses which will produce disappointing results for new buyers accelerates that.

I'm committed to Canon.  I'm satisfied with my gear, in some cases extremely pleased.  I'd recommend Canon.  Their CPS is fantastic.

But I do think it is ok to point out blunders and express disappointment.

Just because a lens is slow does NOT mean that's it's optically lousy.

201
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 29, 2014, 10:03:53 AM »
A 12mp sensor would have better high ISO performance,

No, it wouldn't.  This myth just won't go away.

Quote
utilize the center of lens elements,

Which is wrong on two levels - every pixel uses all of the lens elements.  You may have meant "image circle" instead of lens elements.  Secondly, using the "sweet spot" is nearly always detrimental compared to using the entire image circle because of increased enlargement.

Quote
And also, a 12 mp crop sensor is 150% of the "reach" and 16mp is 200% of the "reach"... As you put it.

"Reach" means "resolving power" and it goes with the square of pixel count.  You want to double resolving power?  You need four times as many pixels.

202
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 09:24:28 AM »
Great!  Three lenses in which I have absolutely no interest.  Canon is saving me money all over the place!

There are three lenses that interest me right now and, would you believe it, they're all Tamrons!
If Canon were to introduce any three lenses, you can guarantee that a fair share of photographers out there will have zero interest in the products.

Each one of these rumoured lenses, if well executed, could have a great reputation and sales for their segment - regardless of whether they suit my needs or yours.

The 100-400L replacement is already 10 years overdue.  A 24-70/2.8 IS is also way overdue.  Yet, they're looking at a 400/4DO II that maybe a few thousand people will buy, ever while these mainstream lenses are missing?

203
Lenses / Re: New Lens Information for Photokina
« on: August 29, 2014, 08:31:21 AM »
Great!  Three lenses in which I have absolutely no interest.  Canon is saving me money all over the place!

There are three lenses that interest me right now and, would you believe it, they're all Tamrons!

204
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 28, 2014, 07:39:18 PM »
Quantum efficiency isn't the only driver.  Read noise can be a major factor as well.  In some cases (some sensors, some ISO settings) driving read noise to zero could provide better than a 1-stop improvement.  While QE at 100% is not possible, read noise at essentially zero is possible.

Yes, I hadn't considered lowering the read noise.  Anyone know how many stops of noise improvement is practically and theoretically possible there?  I don't know enough to make sense of the info at http://www.sensorgen.info .  I want to get a number so I can spout off and say "noise performance cannot ever improve more than X stops from what we have today" every time someone expects a 2x improvement in the next model.

Unlike shot noise, read noise's impact can't be quantified this way.  At some ISOs and portions of the tone curve, it's negligible, at others, it's crucial.

205
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 28, 2014, 05:20:41 PM »

Yes, I did.  You just didn't like it because it was shot on a tripod.

I don't understand what you think you are demonstrating here. Neither is with a FF camera, neither is handheld, and neither is with AF.

The 20D pixels are the same size as those in the 5DII.  Both were handheld, both were with AF.

Lee Jay,

This is my last comment to you unless you can actually supply the images you said you could.


You have now said the same images were shot both on a tripod, and handheld, you have no credibility.

Idiot.

The moon shots were handheld, the letters were on a tripod.  Both were focused with regular AF.

206
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 28, 2014, 04:32:45 PM »
There are many 300mm lenses that are more than capable of out resolving many 500mm lenses, the reverse is true too. That is where specifics of a question become important, and my question was very specific, that you either misread it or intentionally ignored it is irrelevant, despite your assertions that "every test ever" illustrates my lack of a point, you can't actually point to one that does, including your own.

Your test isn't a test, it's a random number generator.  I provided controlled tests that demonstrated the point.

Let's say the two lenses are identical in optical performance (perfect).  Will a 500/6.3 out-resolve a 300/4 under your conditions?

If they are both "perfect" they will both resolve infinitely.

Oh, so diffraction doesn't exist where you live?

And you know darned well that I meant on the same camera.

Quote

Stop trying to break down a simple system test to a series of theoretical concepts you think you can prove, system tests don't work like that and you can't supply "evidence" to support your position.

Yes, I did.  You just didn't like it because it was shot on a tripod.

207
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 28, 2014, 04:23:12 PM »
There are many 300mm lenses that are more than capable of out resolving many 500mm lenses, the reverse is true too. That is where specifics of a question become important, and my question was very specific, that you either misread it or intentionally ignored it is irrelevant, despite your assertions that "every test ever" illustrates my lack of a point, you can't actually point to one that does, including your own.

Your test isn't a test, it's a random number generator.  I provided controlled tests that demonstrated the point.

Let's say the two lenses are identical in optical performance (perfect).  Will a 500/6.3 out-resolve a 300/4 under your conditions?

208
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 28, 2014, 03:44:13 PM »

You are asking for a highly subjective comparison.......

The hand-holdability requirement is a purposeful handicap here...

We've debated this topic over and over. You have shared your comparison of the 1Ds III and 7D a few times, and every time you do, I see a sharpness and resolution edge to the 7D that you insist doesn't exist at all......

No, I am just asking for results from real world actual shooting, because we cannot ever achieve the results we see from test bench samples.

Again, no, the handholding is important as most people do handhold most of the time. It might be difficult, but it is very relevant.

I have never, ever said it doesn't exist, in my samples I have said it does exist in artificial test type scenarios, however in real worlkd shooting other factors like AF, handholding, non optimal iso, aperture, shutterspeed, contrast levels etc etc make a bigger difference than the small differences between test bench results.

That is considerably more nuanced than your "you insist doesn't exist at all".

Let me ask you a question.

Do you think a 500mm lens will out-resolve a 300mm lens, at the same aperture?

209
EOS Bodies / Re: EOS 7D Mark II & Photokina
« on: August 28, 2014, 03:42:58 PM »
I'm sure this is posted every so often, but it bears repeating.  For everyone hoping for a full stop improvement in noise performance in the next model of a camera, it is NEVER going to happen.  Today's sensors capture very roughly 50% of the incoming photons.  So if a sensor was theoretically perfect, sensors could be one stop better.  That's the best they will EVER be, without switching from a bayer color pattern to a foveon-like sensor.  ( In that case you could theoretically get over another stop of improvement IF you were still able to maintain the same efficiency. )  So even in another 2000 years with insane technological advances there is no way that cameras could ever be 3 stops better in raw noise performance.

So even if a sensor manufacturer could get close to 100% efficiency now, they would be insane to sell it from a business standpoint.  They could release a sensor with 60% efficiency and still be the best, and give customers small improvements for years to come.
 
Quantum effeciencies:
http://www.dpreview.com/forums/post/53054826

We have been spoiled over the past decade - there was a full stop of improvement between the 5D to the 5Diii, but it just can't continue on that pace without breaking the laws of physics.

Quantum efficiency isn't the only driver.  Read noise can be a major factor as well.  In some cases (some sensors, some ISO settings) driving read noise to zero could provide better than a 1-stop improvement.  While QE at 100% is not possible, read noise at essentially zero is possible.

210
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 28, 2014, 03:40:49 PM »
The 20D pixels are the same size as those in the 5DII.  Both were handheld, both were with AF.

So, it is your contention that the 20D sensor will give the same IQ (sharpness, noise, etc.) as an APS-C sized patch of the 5DII sensor?  Things like the AA filter, CFA and microlens design, amplifier circuitry, etc., have no impact on image quality?

I didn't say they have no impact, I said they are almost the same between the two cameras and that the pixel size is the primary driver (not the only factor).

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