Author Topic: NEW DATA Is the D750 still the low ISO champion???  (Read 23830 times)

David H. Hartman

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Re: The D750 is still the low ISO champion
« Reply #75 on: October 15, 2017, 23:42:44 »
New D750 Photographic Dynamic Range (PDR) data has been collected and published which I discuss at length elsewhere.
As it turns out the D750 comes up 0.14 stops short of retaining the crown of "low ISO champion".
I'm attaching a new PDR comparison.
Although no longer the "champ" the D750 still acquits itself quite well; particularly below ISO 400 before dual conversion gain kicks in for the D850.

Didn't Wheeler Dealer, "The Man With A Tattoo" predict some of this regarding the D850?

Dave

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According to Photons to Photos my D800 has better DR at 100 to 320 ISO...

Photons to Photos: D800 v. D810 v. D850

Who wants to *trade? I'll pay the postage both ways!

Dave Hartman

*A New in the box D850 for my D800 with 30,000 clicks.  :D
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Frank Fremerey

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #77 on: October 17, 2017, 10:54:18 »
Now that gets more interesting the longer the thread lasts.

I appreciate Bill's effort very much. Real science means not to stop until you have got the answer or know why the question cannot be answered
You are out there. You and your camera. You can shoot or not shoot as you please. Discover the world, Your world. Show it to us. Or we might never see it.

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JKoerner007

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Re: The D750 is still the low ISO champion
« Reply #78 on: October 17, 2017, 19:12:07 »
I don't accept your "chain of evidence" in assuming that Nikon marketing correctly conveys information from Nikon engineering.
FWIW, I used to write published articles and I can't tell you how many times editors tried to improve my wording but changed the meaning so I would have to explain to them why they needed to retain the original wording.

That's fine; we disagree.

My position was Nikon does not produce their sensors 'by accident.' My scrutiny was based on common sense: the fact Nikon knows exactly what they're trying to produce ... and price/position them accordingly.

What I didn't accept was the idea that Nikon 'accidentally' made the D750 sensor superior to the D850. I knew there had to be a mistake in your graph.

Regarding wording, it is easy to digress to a further tangled mess by arguing points (through word manipulation) that were never actually said (or implied) to begin with.



With marketing material there are multiple points at which things can get lost in the translation. I never claim to be a sensor developer; but I have been analyzing sensors for over 10 years (longer than DxOMark has existed).I take this to be "only" one of two since I don't accept your Nikon marketing "evidence" but only actual measurements as evidence.The issue is becoming clearer and the underlying data issue is not trivial.
Regarding the D750 I am collecting additional data.

Again, it's not a matter of 'marketing language,' but of the entire intent of Nikon corporation to develop, position, and price certain cameras based on certain capabilities. It was not 'reasonable' to believe a massive corporate oversight on the part of Nikon 'not knowing' which sensor was their finest; it was more reasonable to believe there was merely a graph anomaly on your website.



Initial indications are that the D750 PDR (as currently published) is in fact too high (!)
I see an anomaly in the initial data collection that went undetected.
I'm surprised because normally bad input data produces obviously wrong (usually quite low) results.
If the new results hold up then it will be the first time ever that bad input data produced unnaturally high PDR values.

As was suspected all along ... the initial result just didn't make sense.



So, with respect to the initial topic of the thread, your observation may be born out.
However, I stand by my assertion that PDR is a better measure than DxOMark Landscape score.
And I stand by my methodology regardless of any human error that might affect a specific result.


Well, I appreciate the integrity to re-evaluate. I had no doubt this would be the outcome.

Again, there was never a slam on you, or your site, or your methods. Just scrutiny over a graph result which was in conflict with everything tested/known by others of merit. Anytime there is a discrepancy like that, scrutiny is called for.

At the end of the day, any- and everyone is subject to human error, regardless of education/position, etc.
If that were not the case, I couldn't be a casualty investigator ... looking into (often catastrophic) losses to determine liability ... if no one made mistakes.
And, yes, to me it is ultimately trivial ... "which sensor has the highest base ISO scores."
Compared to cases where structural engineers miscalculate, which result in fatalities, or massive property loss, I think this issue here can be put into perspective.
If highly-educated, cum laude persons didn't make mistakes, there wouldn't be such things as legal and medical malpractice, ENO (Errors and Omissions) coverage, where high-profile folks get put under the microscope, and found guilty of being in err.

Academic expertise does not preclude oversight/error/bad sampling, etc.

In fact, one of my favorite wry quotes is, "I am never wrong; once I thought I was wrong ... but I was mistaken."


__________________________________________



Very interesting unexpected turn of events.

Actually, it was not 'unexpected' at all ... in point of fact the anomaly was debated 5 pages worth ... until a re-exam bore out the the original call into question.

Chip Chipowski

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #79 on: October 17, 2017, 19:34:56 »
 "I am never wrong; once I thought I was wrong ... but I was mistaken." Thank you for posting this quote JKoerner007 ;)

simsurace

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #80 on: October 17, 2017, 20:21:13 »
John, I wonder how you explain the fact that the D750 is slightly above the D810 in terms of PDR for most ISO values, despite the latter camera being marketed as the more advanced tool? Why was it an issue only in the case of the D850?
Simone Carlo Surace
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JKoerner007

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Re: The D750 is still the low ISO champion
« Reply #81 on: October 18, 2017, 04:44:53 »
Didn't Wheeler Dealer, "The Man With A Tattoo" predict some of this regarding the D850?

Dave

---

According to Photons to Photos my D800 has better DR at 100 to 320 ISO...

Photons to Photos: D800 v. D810 v. D850

Who wants to *trade? I'll pay the postage both ways!

Dave Hartman

*A New in the box D850 for my D800 with 30,000 clicks.  :D


There are likely many uncontrolled figures that could bear some closer scrutiny ...

JKoerner007

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #82 on: October 18, 2017, 04:46:08 »
"I am never wrong; once I thought I was wrong ... but I was mistaken." Thank you for posting this quote JKoerner007 ;)

 :D

JKoerner007

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #83 on: October 18, 2017, 05:03:51 »
John, I wonder how you explain the fact that the D750 is slightly above the D810 in terms of PDR for most ISO values, despite the latter camera being marketed as the more advanced tool?

A rhetorical question. Why do you expect 'me' to explain something that has nothing to do with me?

Just to play along, my best answer is the D810 was designed for absolute excellence at base ISO ... while the D4/5 were designed for excellence at high ISO.

The D750 was designed not to occupy neither extreme ... but to be a very solid, economical middle ground. I have no problem accepting the D750 is a better value than either.
For this reason, the D750 is very solid across the board ... but not quite 'there' at either extreme. Again, this was not 'by accident,' but by design.

For this reason, if any lone graph showed the D750 DR as ranking higher than the D5 at extreme ISOs ... in defiance of all other reviewers/testers ... as well as Nikon's own price point, literature, and product placement ... I would similarly call that graph result into question. In exactly the same fashion as before, it just wouldn't make sense.

Remember, just because someone 'runs a test' and 'posts a graph' doesn't make the presentation correct.



Why was it an issue only in the case of the D850?

Because I never saw someone claim the D750 was "the low ISO champ" before ... until this thread.

Hope this clarifies.

simsurace

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #84 on: October 18, 2017, 10:26:54 »
A rhetorical question. Why do you expect 'me' to explain something that has nothing to do with me?
I ask you because you proposed the idea that PDR measurements should be correlated with pricing.
Whom should I ask instead?

Personally I don't believe that the pricing is a good guideline to predict how a given camera should perform in a PDR measurement (when it is correct).
Pricing is likely a function of many things, none of which may be directly related to PDR.
Even if Nikon did measure some metric which is strongly related to PDR and used it to price their cameras, they also likely would have a dozen other variables, like resolution, frame rate, build, number of buttons, viewfinder, etc. to determine pricing.
Since we do not know how they do it, it is impossible to predict how pricing correlates with PDR.

As for other reviewers/testers: you have to closely examine how and what they measure in order to come up with a prediction of whether it ought to correlate with PDR or not. They might measure something irrelevant or they might want to measure something relevant but with a flawed methodology. Many reviewers don't do any precise measurements at all, but only look at images by eye. As such, they are very prone to confirmation bias ('that camera has such a high price point, it has to test superior, so I'm not paying so much attention when it does').

Remember, just because someone 'runs a test' and 'posts a graph' doesn't make the presentation correct.
Correct, the presented data may be erroneous.
It was pure coincidence that the error in data analysis coincided with your pointing out a mismatch between PDR and pricing.
In fact, in any number of other camera comparisons (like the D810 and D750) you may also see a mismatch between PDR and pricing (hence my question above).
Are you suggesting that these measurements all suffer from the same error in data analysis?
Simone Carlo Surace
suracephoto.com

Frank Fremerey

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #85 on: October 18, 2017, 11:12:11 »
Coincidence and causality are very hard to distinguish in real life phenomena over time. Not only in this case.
You are out there. You and your camera. You can shoot or not shoot as you please. Discover the world, Your world. Show it to us. Or we might never see it.

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JKoerner007

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #86 on: October 20, 2017, 01:45:37 »
Personally I don't believe that the pricing is a good guideline to predict how a given camera should perform in a PDR measurement (when it is correct).
Pricing is likely a function of many things, none of which may be directly related to PDR.
Even if Nikon did measure some metric which is strongly related to PDR and used it to price their cameras, they also likely would have a dozen other variables, like resolution, frame rate, build, number of buttons, viewfinder, etc. to determine pricing.
Since we do not know how they do it, it is impossible to predict how pricing correlates with PDR.

It's not just pricing: it's pricing and intended placement.

When certain cameras which are priced and deliberately positioned and placed by a multi-billion-dollar corporation (at the top of its game/innovation) ... to perform certain functions (one a high-res, extreme base ISO, extreme quality single-image entry ... another an extremely fast-action, very high-ISO, extremely adept/functional entry ... and then a mid-level camera, somewhere inbetween, good, but not as good--and not as expensive--as either one) ... it's only reasonable to expect the performance values to follow.

When you see a company like Nikon price, position, and place a mid-level camera accordingly ... and when every other measurbator rates this mid-level camera where it belongs ... but one rates it as 'numero uno' ... it demands a second look.

Which is what happened here ... and common sense prevailed.

simsurace

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #87 on: October 20, 2017, 13:06:28 »
It's not just pricing: it's pricing and intended placement.

When certain cameras which are priced and deliberately positioned and placed by a multi-billion-dollar corporation (at the top of its game/innovation) ... to perform certain functions (one a high-res, extreme base ISO, extreme quality single-image entry ... another an extremely fast-action, very high-ISO, extremely adept/functional entry ... and then a mid-level camera, somewhere inbetween, good, but not as good--and not as expensive--as either one) ... it's only reasonable to expect the performance values to follow.

Yes, it might be reasonable to expect it, but as I said there are plenty of cases where the pattern does not hold.
This leads me to believe that it is less reasonable to expect this pattern to reoccur than to think there are many additional factors determining pricing.
You are of course free to think otherwise.
Simone Carlo Surace
suracephoto.com

JKoerner007

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #88 on: October 20, 2017, 13:40:33 »
Yes, it might be reasonable to expect it, but as I said there are plenty of cases where the pattern does not hold.

Name one single case were a mid-range pro-sumer camera (from the same manufacturer) out-performs a contemporarily-released topnotch action camera at high ISO ... or a contemporary topnotch landscape camera at base ISO.



This leads me to believe that it is less reasonable to expect this pattern to reoccur than to think there are many additional factors determining pricing.

Your denial of reality leads me to believe that you are less than realistic.



You are of course free to think otherwise.

And I surely do.

David H. Hartman

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Re: NEW DATA Is the D750 still the low ISO champion???
« Reply #89 on: October 20, 2017, 14:19:10 »
Can it be demonstrated that Nikon or any camera maker purposely makes inferior sensors for a lower model?

I would think as a general rule the better performing sensor cost more to make and that is part of what makes a higher model cost more. Also the newest sensor has a good chance of better performance regardless of which camera it goes in. That is a sensor launched today has a good chance of outperforming one released four years ago.

It seems to me there are a lot of variables here to consider not just retail price. 

Just thinking out loud...

Dave Hartman
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