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Messages - dtaylor

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EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 05:44:40 PM »
In JPG Canon claims a lot

Yes. My assertion is not based on Canon's claims, but on comparing literally hundreds of frames chosen for use out of thousands of frames fired. I see the same thing comparing single frame landscapes.

RAW saw a good 2 stop improvement. HTP brought a similar improvement to JPEG.

It has been claimed in this thread that Canon users are ignoring/denying that Exmor sensors have wider DR. Here you are denying that Canon has made any improvements in 8 years when they most certainly have.

EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 05:39:16 PM »
Honestley the pictures you have seen do not need a lot of DR when the purpose is press but Dynamic range may be needed for annual reports, glossy magazines, etc and you have  not a clue what the benfits of large DR and exposure latitude are -do you and I have now been showing that  a number of times

You haven't shown anything. Please post an example of a photograph that can be taken with an Exmor sensor but not a Canon sensor.

Better yet, check out the Galen Rowell archives (http://www.mountainlight.com/). He produced that body of work with films that had 3-5 stops lower DR then a modern Canon DSLR.

Looks like he got his exposure right  ;D

EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 05:34:52 PM »
And yes Im intresting to discuss why Canon are sleeping regarding DR , they have not improved that much since 2004

I've shot surfing...where you cannot blend multiple frames...on Canon DSLRs since 2004. Canon DR has improved by at least 2 stops over that time period.

EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 03:55:25 PM »
read earlier answer, you must get your exposure" more right because of inferior DR and exposure latitude in Canon"
try to understand the difference
and if you expose them "right" (same parameters) you have 14 stops DR in Nikon d800 and about 11,5 stops in Canon , not including pattern noise/banding

Yep. Nikon has perfect ADCs with perfect performance and efficiency that yield data right up to their rated bit depth, something not seen any where else in the industry, not even in components for NASA and the Defense Department  ::)

Mikael - go to Nikon. Please.

EOS Bodies / Re: DxOMark Sensor Performance: Nikon vs. Canon
« on: October 16, 2012, 03:30:23 PM »
What is the freaking big deal with just admitting Exmor sensors have more DR and that it can be useful both save one of messed up shots and, much more often, to allow you to expand your photographic possibilities, or even to simply save time in post processing at times and drop it all?

Without sorting through this entire mess of a thread...

* Exmor sensors do have more DR, and it can be useful.

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

* Canon sensors are not as limited as they are claimed to be by Exmor fans.

* The impact on one's photography is simply not as great as claimed by Exmor fans.

* The number of posts on this topic have far exceeded reason.

Canon users underexpose and then lift shadows all the time. I've done this with countless Canon RAW files. In ACR (Photoshop CS4) I am not limited by noise until about 60-70 on the Fill Light slider. With an Exmor sensor I could take that slider to 100. It would be nice. But it's not worth 20 page threads.

In terms of DR and impact on my photography, getting an 8 fps camera (my first 7D) had a greater impact on my shooting than an Exmor sensor would. Before that I could not easily hand hold 3 AEB frames for exposure blending / HDR. Now I regularly do this and AEB is on my user menu. When I do this I obtain greater DR then you could hope to achieve with a single Exmor frame. Which is good, because the scenes I use it with have a greater DR then an Exmor sensor could achieve in one frame. I don't know where the exact cut off is in terms of shooting speed and ability to hand hold for 3 identical frames, but I could never do it consistently before the 7D.

Do you see any 20 page threads from me about this technique? Do you see me constantly telling people with slower cameras that their cameras are trash? Do you see me berating Nikon because they can't achieve 8 fps, outside of their super expensive pro sports body, without battery grips and compromised bit depth? Do I flood the forum with comments about how Nikon users should not tolerate their crummy drive motors, crummy 12-bit limitations in high speed shooting, or Nikon's laziness in allowing Canon to out fps them?

No. And do you know why you don't see page after page of this from me?

Because it would be ridiculous.

So is this Exmor nonsense. Right now Sony sensors have lower read noise and Sony has a patent on the technique. It results in a little bit more DR. The advantage will be there until Canon works around the patent or licenses it. Or possibly until other advances in sensor fabrication render the point moot. How much more needs to be said about it?

Why do so many have to make up lies about DxO?

Nobody is "making up lies" about DxO. DxO's methodology is flawed. So is their presentation. They publish IQ scores all over the place, but tuck away the note that says you can't compare scores between sensors of different resolutions. Then they produced normalized scores with obviously flawed normalization (i.e. >14 stops DR from a 14-bit pipeline).

Would you rather we all deny it and praise Canon and tell Canon we don't care since it doesn't matter and then have Canon be like hey why bother? Or would you rather the 5D4 maybe has the better low ISO DR???

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.

But it still isn't hard for me to hit situations where I am like man if it only it had exmor low ISO performance, man, man, man.

Your imagination is always greater than the real difference. I see this all the time in photography. People are always saying "man if I only had X or Y", not realizing they can do whatever they want with what they already have.

I just hope I don't and you are not helping us any (or helping to educate anyone when you constantly give out mixed-up misleading information on normalization).

What makes you think it's other people giving out "misleading information"?

EOS Bodies - For Stills / Re: Canon EOS-1D X DXOMark Sensor Scores
« on: October 16, 2012, 10:02:01 AM »
Maybe you should learn to be more of a geek before you start calling names while at the same time getting everything you are talking about wrong....

Well...I see from the down sampled 4x5 Velvia scan you attached that I was wrong.

OH WAIT. You didn't attach one  ;D

EOS Bodies - For Stills / Re: Canon EOS-1D X DXOMark Sensor Scores
« on: October 16, 2012, 09:57:50 AM »
Aye. I have the exact same problem with the 7D. Granted, the 7D is a hell of a lot better and more capable than any other AF system I've ever used, but when it misses, it really misses. That tends to be really bad for BIF, as that can mean a lot of misses in sequence.

You've probably played with this, but...for BiF have you set AI Servo Tracking Sensitivity to the fastest setting? I don't achieve or expect 100% for BiF with the 7D. But I don't seem to have sequences of dramatic misses either. It's usually one or two more subtle misses out of a sequence.

EOS Bodies - For Stills / Re: Canon EOS-1D X DXOMark Sensor Scores
« on: October 16, 2012, 09:48:26 AM »
Try this: shoot 4x5 Velvia. Drum scan it. Down sample to 10 MP. Did you all of a sudden gain 3-4 stops of shadow detail? No? Hmmm...

Here's a different test for you -- sample it at 10MP, create another image at 40MP. Then compute the "blackpoint" (SNR = 0db) of the two images.

Now I take it that we agree that the images both have the same "true"  dynamic range, but I put it to you that the measured blackpoint on the 40MP will be at a higher luminance level, and therefore the measured per-pixel dynamic range will be lower on the 40MP image.

The second test is irrelevant because measuring the black point is not the same as measuring the floor of useful photographic detail. Assuming that it is leads to flawed extrapolations, such as DxO's 'normalized' DR graphs, or 9-stop scanned LF Velvia.

EOS Bodies - For Stills / Re: Canon EOS-1D X DXOMark Sensor Scores
« on: October 16, 2012, 09:27:10 AM »
You must have never used the sheer awesomeness of the canon 61-Point AF system And yes, I've used nikons excellent 51-point system as well. So yes, I can say the Canon AF system is better than nikons right now. Plus, I never said that point count makes a better AF system, because then S0&y would be the best then.  ::)

My apologies for assuming that your judgement was based merely on AF point count. I read that into your statement and it was not warranted.

EOS Bodies - For Stills / Re: Canon EOS-1D X DXOMark Sensor Scores
« on: October 15, 2012, 06:22:31 PM »
What should be remembered is that doubling the resolution adds:

    3dB to the normalized SNR
    0.5 bit to the normalized DR

So according to DxO if we drum scan 4x5 Velvia, a 6 stop film, and down sample to 8 MP, we will end up with 9 stops of usable photographic detail?  ::)

Go ahead and try it  ;D

EOS Bodies - For Stills / Re: Canon EOS-1D X DXOMark Sensor Scores
« on: October 15, 2012, 06:15:53 PM »
Canon 61 pt AF > Nikon 51 pt AF. done.

Nonsense. Point count != superior AF. In my experience the 7D's AF is superior to the D7000's, practically on par with the earlier 45 point 1D bodies and several Nikon 51 point bodies, and it only has 19 points.

I don't honestly know who has the best AF right now because I don't spend sufficient time with the top tier bodies. But AF is an extremely complicated thing to objectively test, and subjective opinions are open to bias and error. AF performance can also be better on body A for situation 1, but better on body B for situation 2, etc, etc. Not to mention that lenses are at least as important as anything in the body, and it's a mistake to assume similar lenses from two manufacturers have similar AF.

Even with a case as one sided on paper as the 6D and D600 you can't conclusively say one body is always better than another. There's little point in discussing the top tier bodies unless you happen to own and shoot both regularly under a range of challenging conditions.

EOS Bodies - For Stills / Re: Canon EOS-1D X DXOMark Sensor Scores
« on: October 15, 2012, 05:56:58 PM »
You keep repeating it, but it's still wrong. It's wrong because the low end of the dynamic range is determined by SNR, and SNR changes when you downsample.

This is the belief of a math geek who spends too much time with graphs and not enough time with real photographs. Down sampling throws away noise and detail. Dynamic range is the range of useful photographic detail. It is not the simple difference between two numbers on a graph.

Try this: shoot 4x5 Velvia. Drum scan it. Down sample to 10 MP. Did you all of a sudden gain 3-4 stops of shadow detail? No? Hmmm...

Side note: arguments like this are why I hate DR by software analysis. It has zero bearing on the real world. It just leads to paragraphs and paragraphs of irrelevant and pointless theorizing. Shoot a Stouffer transmission step wedge and look at it with your own two eyes. That tells you what you can expect in the real world.

Canon General / Re: DxOMark vs. Reality
« on: October 11, 2012, 03:49:55 AM »
If you still do not accept that it is possible to increase DR by down-sampling, I would take a look at the many applications in which oversampling is used to improve performance.

Over sampling and down sampling are two different things.

Canon General / Re: DxOMark vs. Reality
« on: October 11, 2012, 03:39:27 AM »
Ok, I take this as asking:

Nonlinearity has not yet been incorporated into sensors. You can compress more than 8 stops into an 8-bit JPEG this way (i.e. Canon HTP), but RAWs are simply not non-linear at this time.

Get a clue man, you have no idea what you are talking about. Sensors and amplifiers are nonlinear, whatever you do.

I love how the excuse for DxO's results keeps changing. It's due to down scaling. No, it's due to non-linear sensors / amps. No, it's due to... You guys need to get together and compare your notes   ::)

The sensors are not designed to expand DR through non-linear behavior. They are, for the purposes of this discussion, linear. Further more, they have noise. And like all analog to digital systems their range is actually less than on paper because of things like noise.

If they were absolutely perfect in every way you could expect a maximum of 14 stops. They're not.

Face it: DxO botched another test.

Now if you'll excuse me, I have to order my Nikon D3200 through Amazon since it's better than a Hasselblad. Talk about a steal  ;D

Canon General / Re: DxOMark vs. Reality
« on: October 11, 2012, 03:30:21 AM »
Here we go again with the same discredited arguments ...

I, for one, can't take DxOMark seriously or trust any of their numbers when they...

* Rank $40,000 medium format digital backs lower than consumer APS-C DSLRs.

There's nothing necessarily "wrong" with this per se. A medium format back is not necessarily better as a general purpose camera than an APS-C camera.

You know darn well their scores do not reflect how good the camera is as a "general purpose camera."
I doubt that anyone is seriously using the website to decide whether to choose an APS-C or a MF back, so this argument is a silly red herring (usually trotted out by camera "fans" of low scoring cameras)

It's not relevant whether or not people are looking to them, and this is not a red herring. Their scores are consistently presented by them and others as IQ scores, yet their methodology is obviously flawed if they can give a consumer APS-C sensor a higher IQ score than a MFDB. This obvious error is usually ignored by "fans" of high scoring cameras. When a "fan" wishes to compare, say, Canon and Nikon, then all of a sudden the score is a score of overall IQ that we all must concede. When the same "fan" is confronted with the fact that the score for a consumer DSLR is higher than a 40 MP MF back, all of a sudden the score isn't a score of overall IQ, and nobody is using those scores to begin with, and stop tossing out red herrings.

Which is it?

This horse has been beaten to dust. They report 13.2 bits for each pixel. You can gain dynamic range by downsampling. 14.4 stops is based on downsampling to 8mpx.

You cannot gain dynamic range by down sampling because you throw away detail with noise. If you think you can, your definition of DR is flawed.

* Report values for dynamic range that I know to be false from both personal experience and testing. (They rank the 10D, 20D, and 7D about the same. The 7D is a good 2 stops better.)

You keep saying that these are "about the same", and I keep calling you on it. They are not "about the same".

They show a 0.7 stop difference when it's roughly 2 stops.

For all the critics of DxOMark critics, I would like to point out that no less a professional and respected figure than Michael Reichmann stopped using DxOMark because of the obvious errors he observed in their results.

What precisely are his criticisms ? What exactly are his credentials as far as engineering and benchmarking are concerned ?

Visit his website.

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