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Messages - dtaylor

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226
EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 17, 2012, 06:21:06 PM »
I find it interesting that many would like to make it sound like an "underexposure" is the end of the world, and a photographical failure.

For the record: I believe that a "correct" exposure is the exposure that maximizes the qualities you desire for the scene. If you wish to capture the maximum possible dynamic range, your exposure may be over/under to take advantage of your particular sensor/film.

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Now try to understand the implications the sentence in bold above sets. Getting an exposure "right" is NOT the same as trying to make 14-16% gray as you see the image conform to a certain photometric exposure at the film surface!

Agreed 100%.

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Film has more latitude, but much less usable DR within a fixed scene

DR and latitude are simply two ways of looking at the same thing. They are not separate characteristics.

Latitude, or room for exposure "error", is basically sensor or film DR - scene DR.

The rest of your observations are spot on.

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EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 17, 2012, 06:15:14 PM »
This is taken 15 min ago and shows the difference in shadows, low levels 5dmk2 and d800. I  have lifted the motive exactly the same.

RAW files please.

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And regarding  to ISO and   "holding iso" Canon 1dx is exposed richer in tests like  Imaging Resource, this means that 6400iso is more like if 1dx has been exposed after 4000Iso compared to Nikon D4 and therefore it is not a valid test

Stop. You have already been told this is not the test scene they use to compute DR, noise, etc. Don't make this mistake again!

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EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 17, 2012, 06:11:58 PM »
Their dynamic range is their dynamic range. Period. You can reduce it. You can shift tones around, lifting shadows and such. But you can't extend it.

Is that the assertion? Or is the assertion that a 36 MP sensor with 13.2 bits of DR at 36 MP should be described as having 36 MP of resolution and 13.2 bits of DR?

Camera 1 has 36 megapixels and 11 stops of dynamic range per pixel, camera 2 has 20megapixels and 12 stops of dynamic range per pixel.

Which camera has more dynamic range if I display or print their images at the same size ? If I downsample the 36mpx image to 20mpx, I will get more than 11 stops of dynamic range, but do i get more than 12 ?

I think this is a pretty valid question, provided you intend to view the whole image on print or screen, as opposed to just viewing 100% crops.

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EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 17, 2012, 06:09:29 PM »
Well, if I have a noisy image (ie with poor DR), it will be usable only at smaller print sizes than a less noisy one. That is a real world example of down-sampling, and if what you claim were true the small print would show exactly the same noise and DR than the larger one.

It does show exactly the same DR. You're making a subjective, aesthetic judgement as to acceptable print/view size due to noise. (And it's not down sampling unless you have a really crummy printer.)

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As to the continued assertion that downsampling can not increase bit depth,

No. That's not the argument. (This is like pulling teeth!)

Pay careful attention: down sampling cannot increase *** photographic dynamic range ***

In photography dynamic range is the range of usable detail, not the range between white and black points.

You have a RAW file. It has some noise. Black is not black, but a really dark gray because of the noise. You down sample and kill some of the noise. "Aha! My blacks are blacker! My bit depth is greater!" So what? You didn't gain one drop of detail. In fact you threw some of it away!

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BTW, downsampling a 1 bit image is not an artificial example. Early monochrome printing relies on this technique. If you stand up close you see a noisy mess of dots. If you stand further away (making the image smaller - ie downsampling), you start to perceive the image as have graduated tones rather than just patches of plain white or plain black.

Everyone knows this, but it's false analogy.

230
EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 17, 2012, 05:52:38 PM »
Where is your evidence or explanation?


For real, usable DR tests, look to IR and DPReview. (Unfortunately DPReview no longer posts RAW DR, but their tests are still valid for JPEG.)

The explanation has been posted repeatedly, and was posted again just a second ago.

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I tested the DR myself and got same results and so have others.


You're making the same mistake as the others. Noise inflates the black point. Down sampling reduces noise, lowering the black point. But the black point is not actually the floor of dynamic range. The floor is the point where usable detail ceases to exist. Down sampling actually throws away detail. It cannot extend DR.

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I've seen improvements over that time period. DPReview saw improvements.


On what? 5D3 has actually worse DR than the 1Ds3.


In JPEG the 5D3 is better, as noted by DPReview. Unfortunately they did not post RAW values for the 5D3.

Imaging Resource has Imatest RAW values for both, and the 5D3 is one stop better.

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real world, accounting for banding, I'd say D800 does more than 3 better than 5D3 and even ignoring banding it's more than 2.


"Real world"...that would be a switch. Please post real world shots that prove this. Include a transmission step wedge. Oh yes: downloadable RAW files for analysis are mandatory.

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And not that I want to go here, but you've finally gotten me partially to this point, and sure even the most brilliant are wrong at times, absolutely true, and I'm not saying who here and on the other forums is who, but there are not only engineers but theoretical physics PhDs and other such, including some who are world renowned, posting in some of these threads and on some other threads and.... not on your side on this.


What is this: an appeal to imaginary authorities?  ::)

http://www.nizkor.org/features/fallacies/



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Whether or not the 5D4 has better DR has nothing to do with these stupid threads, and everything to do with their engineers. I have little doubt they are working on it.


Did you know that another division of Canon sent a patent for better DR to the DSLR division and got told to get lost, DR, what?, why? bye. Apparently they didn't even let their engineers look at it! So maybe they do need to be woken up.


Source?


A Canon employee (non-DSLR division) on another forum.


More imaginary friends = no source. Don't repeat the claim without a source.

231
EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 17, 2012, 05:37:47 PM »
Please feel free to post any unanswered "critiques"


All of them from what I can see.

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Far from rebutting, it's not clear to me that you or jrista understand the implications of normalization, or the basic math behind benchmarking,  so aren't in much of a position to criticize it.


http://www.nizkor.org/features/fallacies/

232
EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 17, 2012, 05:33:56 PM »
Downsampling doesn't "create detail", but it moves the black point.

* Photographic dynamic range is the range of useful detail.

* As you conceded above, down sampling does not create detail. In fact, it throws detail away.

* Down sampling therefore cannot increase photographic dynamic range.

* DxO's normalized results are therefore false.

Can we move on now?

233
EOS Bodies - For Stills / Re: 5D III, or 6D+7D combo - your thoughts?
« on: October 17, 2012, 04:16:53 PM »
I don't want to get flamed by 7D lovers, but I always found my 7D images to have a rough quality to them. I'm not talking about ISO noise -- that body let me make lots of great images at 3200, but a general granularity of the images even at ISO 400-800 (which should be very smooth these days).

Crop sensor shots can be a little more "rough" due to pixel size. But I never had any trouble killing this and making them FF smooth...without losing detail...with Noise Ninja. (Just not with the default settings.) At least not at low to mid ISO. High ISO is a different story, and where FF truly distinguishes itself.

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The images are beyond compare to the 7D images, though.

Comments like that are what cause flames  ;) "Beyond compare" quickly becomes "I can't tell the difference" when asked to identify unlabeled, processed crops and 24" prints. That means it was never "beyond compare" to begin with.

That said, at high ISO the 5D3 is "beyond compare" vs. any current crop camera.

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Bodywise, your hand will fall onto the 5d3 controls instantly. Not sure about the 6.

The 6D takes its design from the 60D. Another reason to be annoyed with it  >:(

234
EOS Bodies - For Stills / Re: 5D III, or 6D+7D combo - your thoughts?
« on: October 17, 2012, 04:09:16 PM »
Here is my dilemma.  I want to buy a FF camera to do more portraits, landscape, etc.  Do I sell my 7D and get a 5D III, or keep my 7D and get a 6D for a second body? (I couldn't justify the cost of the 5D III unless it could replace the 7D as well)

There's going to be very little difference between the two for landscape and portraits, contrary to the unsupported claims of people infatuated with FF. (I say unsupported because we never see photos or crops that illustrate any real difference at low ISO.) That said...

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With the 5D III, I really only give up a couple of FPS vs the 7D and some reach which I would probably only miss in football.  I gain much better ISO performance for the indoor sports like volleyball, where the 7D can struggle (even with an 85mm f/1.8 I need ISO 3200 which honestly is poor on the 7D).

You can gain the reach back for football with a 1.4x tele, assuming your telephoto lens is compatible. While I do not concur that 3200 is poor on the 7D (if it is, you're processing it wrong), I think the 5D3 will show you the greatest difference with indoor sports. 3200 is excellent on the 5D3, and it's not the limit like it is on the 7D. (I will concur that by 6400 the 7D isn't doing so well.) For indoor sports the 5D3 is the camera to grab.

I love the 7D. I think it is one of the most well rounded bodies ever released by Canon, and still the king of crop 3 years later. But now that the 5D3 has a real AF module, a 5D3 + 1.4x can do the things that used to require a 7D.


235
EOS Bodies - For Stills / Re: 5D III, or 6D+7D combo - your thoughts?
« on: October 17, 2012, 04:01:03 PM »
Not sure if anyone else has said it, but the "reach" of the 7d vs a 5d3 is BS. Crop into the 5d3 frame and it will still be sharper than the 7d.

Sure it will. If you compare out of camera images with no sharpening or the same sharpening. The problem is crop sensors utilize lenses at a different point on their MTF curves and therefore require different sharpening amounts. It amazes me how many reviewers and testers fail on this single point. Failure to understand this also leads to much of the "huge, just huge difference" claims by FF fans.

Crop cameras put more pixels on target, period.

Having established that...the resolution differences are only apparent at large print sizes or with extreme cropping. Really it's only when doing both that the 7D pixel density advantage becomes clear, but you don't often have to do both. I have 20", 8-10 MP cropped 7D surfing prints that I could not have made with a 5D3 and the same lens, but that's the rare print. The subject matter you're typically trying to reach just doesn't stress MP like a wide angle landscape, and you typically don't have to crop that much for additional magnification.

I love the 7D for telephoto action (sports; wildlife). But...I could probably do >95% of what I do in those areas with a 5D3.

6 of one, half dozen of the other.

236
EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 08:28:55 PM »
You're wrong in that thread too. Typically of the DxO bashers, your MO seems to be repeating the same falsehoods and hoping noone calls you on it.

Typical of the DxO defenders, your MO is name calling and begging the question and hoping no one calls you on it.

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If you think the images truly do have the same dynamic range before and after you downsample, you need to normalize.

No, you need to perform the test and show us the results. That will put an end to this bickering.

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The downsampled image will have less noise, therefore a lower blackpoint, and therefore more dynamic range on a per pixel basis even though it doesn't have more of what you'd intuitively think of as dynamic range.

I don't give a pile of used dog food about your white point - black point definition of DR. I'm not trying to make my blacks blacker. I can do that with NR and levels adjustments. I care about real, usable photographic detail. Down sampling and 'normalization' does not magically create new detail.

237
EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 08:25:02 PM »
Not to mention, there is body-to-body variability.  Some 7Ds have very little banding, some, like mine, can show it in situations without even much of a nudge in post, let alone a 3 EV push.  I've had shots where just using "Landscape" as the raw preset in DPP is enough to bring out low ISO shadow banding.

Product variability is a real issue in any production run. If you saw this within your year warranty, the camera should have been shipped to Canon along with documentation of the problem (i.e. sample shots).

238
EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 08:22:53 PM »
https://picasaweb.google.com/106266083120070292876/DR5dmk2VsD7000

3 summers ago 5dm2 and d7000  , 7d , s-95 and Fuji  , signal / noise in lower levels and banding

RAW files for analysis please.

239
EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 08:22:13 PM »
* Exmor sensors do have more DR, and it can be useful.

finally

Nobody ever claimed otherwise.

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* Exmor sensors do not have the amount of excess DR being claimed by fans or DxO.

false

Oh, well, you used the word false, I guess the debate is over  ::)

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It hardly means you toss your Canon body into the swamp and then bash it with a sledgehammer but it sure would be nice if Canon paid attention to DR having not improved it for more than half a decade now.

I've seen improvements over that time period. DPReview saw improvements.

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Do note that most of the recent posts have been started by the DxO are liars, exmor is whatever crowd though.
Some of the same crowd goes on raves about how far behind Nikon was when Canon beats them by like just 1/2 stop SNR is a huge win that trashes Nikon and then says more than 3 stops difference at low ISO is very minor, too minor to even bother about at all.

DxO are not liars, just confused.

I don't recall people raving to this level when Canon had the lower noise/wider DR sensors. I suppose some did. There are Canon fanboys just like Nikon fanboys.

There is 1-2 stops difference at low ISO, not "more than 3."

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2. There you go again, along with Jrista, and not having a clue about how normalization works and spreading misinformation.

Your side has offered its argument for the accuracy of normalization. Our side has shown the argument to be false. Your side's only response has been "uh...you don't know what you're talking about!"

When you repeat that without answering our critiques, you effectively tap out of the debate and concede the point.

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Whether or not the 5D4 has better DR has nothing to do with these stupid threads, and everything to do with their engineers. I have little doubt they are working on it.

Did you know that another division of Canon sent a patent for better DR to the DSLR division and got told to get lost, DR, what?, why? bye. Apparently they didn't even let their engineers look at it! So maybe they do need to be woken up.

Source?

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Because some of you are totally wrong about some of the stuff you have been saying, especially when it gets to normalization and some other related topics.

Oh yeah? Well...you're totally wrong to infinity plus one, no changiees! So there!  ::)

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EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 08:09:33 PM »
Yes do that, especially when they (IR) use different parameters as shutter time in theirs test and use longer exposure together with Canon, go and take a look .

Too bad that's not the scene they use for the DR test  ::)

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