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Author Topic: 70D vs D7100 ISO Comparison at 100%  (Read 25709 times)

Apop

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #75 on: September 03, 2013, 04:44:11 PM »
no explain Jrista , and keep it short, i have some problem to read your posts, 5% information and the rest a lot of words
so please explain
do you mean that this forum could not be better with all people like Pi and  Hulls knowledge as two example ?
I know David from dpreview since years back
That neuro has not been understanding or misunderstood
or what?
sorry but  you two are used that people are not question you.
what good  does that lead to?
a little self-criticism would be good, especially if you're wrong


 Neuro and Jrista strike me as the people who like to share their knowledge, but also read others opinions which might influence their beliefs/point on certain topics.

I like the way they constructively explain things, in a ''slightly'' less aggressive way than yourself.
It seems like you feel the need to attack anyone that disagrees with your pov, how can that ever lead to a serious discussion?

The reason that people won't question them as much as you, Is that they actually explain things or support it with facts/research. The way they approach people (and ignorance) is also working for them ;).

I asked a rather stupid question about exposure/exposure compensation, instead of getting flamed at that I am a dumb idiot that doesn't understand how a camera works and that the one accusing me of being so has been doing it for 30 years and has great knowledge, they just fed my ignorance with information ...(actual useful information).

That you don't like a lot of words seems to support my feeling you have a rather short fuse.
And the 5% you do read is most likely what you had filtered out and interpreted as an insult.

This forum would be better if there weren't as many flaming people around like yourself,
If anyone is to get a ban ( I doubt it), it's more likely you than Neuro .
( that can be based on the fact alone that the admins eyes disagrees with dxo mark results, so i don't expect him to be in your corner ;) lol)



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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #75 on: September 03, 2013, 04:44:11 PM »

jrista

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #76 on: September 03, 2013, 05:13:04 PM »
End of discussion for me in this thread

an apology can I  probably  not expect from a man who has committed jokes at my expense, and where he has shown great ignorance.

Why would you expect an apology from someone you have been insulting for much longer than he's been making jokes at your expense? As I said...it is human nature to retaliate. Maybe if you apologized to him for all the insults and derogatory comments you've made about him, he might apologize to you for the jokes.

As for me, you regularly bring my name up in threads I have never participated in, just to include me in an insult of one kind or another. I have no interest in hiding my dislike of you, Mikael, but I'll apologize for any insults I may have levied at you in the past. That does not change the fact that I think you are continually, and pointlessly, antagonistic here on CR forums, and that we would probably be much better off without you around at all...but here is my apology nevertheless. I'm sorry if I've ever insulted you.

ME

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #77 on: September 03, 2013, 06:14:22 PM »
I have explain what is actually does several times in this thread

Yes, and every time you've explained it incorrectly.

Mikael, why do you think that typing your explanation for how HTP works in bold will make it correct?  You're still wrong.  Even if you use ALL CAPS AND A LARGER FONT, you'll still be wrong.

Ok to be fair, you're not totally wrong.  You are correct, in an analogous way to a broken/stopped analog clock that is correct twice per day.

You have (repeatedly) asserted that HTP reduces by half the number of photons reaching the sensor.  In some cases, you specifically state that shutter speed/time value is changed.  In other cases, you mention f/stop might change, too.  That is true under the following conditions:

  • Turning on HTP with the camera set to ISO 100 and Av changes the shutter speed to reduce by half the number of photons reaching the sensor
  • Turning on HTP with the camera set to ISO 100 and Tv mode changes the aperture to reduce by half the number of photons reaching the sensor
  • Turning on HTP with the camera set to ISO 100 and P mode changes the shutter speed or aperture (usually the former) to reduce by half the number of photons reaching the sensor

It does that because ISO 100 is not available as a selection when HTP is enabled, so if ISO 100 is selected when HTP is enabled, the camera changes it to ISO 200.  If you happen to be in an autoexposure mode, the camera then changes another parameter (aperture or shutter speed) to maintain the metered exposure.  Setting HTP at ISO 100 is an oxymoron - if you enable HTP, your camera isn't set to ISO 100 anymore.

In M mode, enabling HTP changes neither aperture nor shutter speed, and the number of photons reaching the sensor is unchanged.  So, in M mode, your explanation of what HTP does is wrong.  At ISO 200 or higher, enabling HTP changes neither aperture nor shutter speed and the number of photons reaching the sensor is unchanged, and again your explanation of how HTP works is wrong.

Therefore, as a general explanation of how HTP works, your statement that it works by halving the number of photons reaching the sensor is WRONG. 

I know you understand the goal of HTP.  Guess what?  So do I (despite your repetitive and annoying suggestions to the contrary). I also fully grasp how HTP works.  Maybe you partially (or even fully) grasp how it works, but no one would know that, because you can't explain it properly. 

Maybe you should try reading Emil Martinec's explanation of HTP, he does a much better job:

Quote from: Emil Martinec
Instead of using the ISO gain set by the user, the camera uses a lower ISO (but exposes with the indicated aperture and shutter speed), effectively underexposing the image; this provides more highlight headroom. In post-processing, the image data can be brought back up while preserving the highlights with a modified tone curve in higher exposure zones. The place where image quality suffers is in shadows at lower ISO, precisely as the above quantitative model predicts.
Does he mention a reduction in the number of photons? No. He states that the exposure is "with the indicated aperture and shutter speed," and if that's the case, how exactly is the number of photons being reduced, as you have repeatedly stated is occurring?

Maybe you think that an analog clock with the hands stopped gives the right time, because it just happens to do so twice per day.  But the reality is that such an analog clock is broken, just like your explanation of HTP.   
                                                                                                                                                                 
Thanks for your explanation of HTP Neuro. Another poster gave what seems to be much confusing garbage as an explanation.
« Last Edit: September 03, 2013, 06:19:12 PM by ME »
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Factor7

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #78 on: September 03, 2013, 06:18:34 PM »
Hope you're happy, MichaelTheMaven..!
 ;D

Pi

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #79 on: September 03, 2013, 06:27:40 PM »
Light also behaves as a wave, so when it passes through a lens and encounters the diaphragm, it must spread out. For a given light illumination in the scene, you have a fixed incoming "light pressure". Reducing aperture therefor must increase the diffraction of light.

OMG!

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #80 on: September 03, 2013, 06:47:28 PM »
DO YOU HAVE FACTS TO SUPPORT YOUR HYPOTHESIS ANKORWATT SUCH AS EXIF INFO AND HOW YOU SET YOUR CAMERA (ISO,SHUTTER SPEED & APERTURE) BEFORE ENGAGING HTP & AFTER SNAPPING THE SHUTTER? BEFORE & AFTER INFORMATION, THAT IS. EVIDENCE. FACTS.
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Jim O

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #81 on: September 03, 2013, 07:16:22 PM »
End of discussion for me in this thread

an apology can I  probably  not expect from a man who has committed jokes at my expense, and where he has shown great ignorance.


facts about what?

I guess you were wrong...
When people see you arguing with an idiot on the internet, all they see is two idiots arguing.

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #81 on: September 03, 2013, 07:16:22 PM »

jrista

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #82 on: September 03, 2013, 07:21:24 PM »
End of discussion for me in this thread

an apology can I  probably  not expect from a man who has committed jokes at my expense, and where he has shown great ignorance.

Why would you expect an apology from someone you have been insulting for much longer than he's been making jokes at your expense? As I said...it is human nature to retaliate. Maybe if you apologized to him for all the insults and derogatory comments you've made about him, he might apologize to you for the jokes.

As for me, you regularly bring my name up in threads I have never participated in, just to include me in an insult of one kind or another. I have no interest in hiding my dislike of you, Mikael, but I'll apologize for any insults I may have levied at you in the past. That does not change the fact that I think you are continually, and pointlessly, antagonistic here on CR forums, and that we would probably be much better off without you around at all...but here is my apology nevertheless. I'm sorry if I've ever insulted you.
if we shall throw pies at each maybe we should do it by mail

So, it's clear apologies don't actually matter to you. Figures.


and go back and look how this started, neuro accuse me to be wrong
later on he now confirm everything and have also learn what a head is and why it  must be  created  so HTP works at base iso

 and to you other, if you do not understand how HTP works, read again my earlier posts, it is nothing hard to understand

I've read your explanations. They are wrong. You claim the camera changes the shutter speed, in manual mode, at ISO 100. That is incorrect.

First, you cannot use ISO 100 in manual mode when HTP is active. Your lowest selectable ISO setting is 200. The camera does not change either aperture or shutter speed when HTP is active. It uses whatever aperture and shutter speed you select. The camera reduces ISO by one stop from what you have selected (or, from what the camera originally metered was necessary.) This is a fact. It is not an assumption. Therefor, your explanation that the use of HTP (or ADL, for that matter) requires the camera to "halve" the amount of light reaching the sensor either by increasing shutter speed or reducing aperture is wrong. The camera does nothing to change the exposure (total amount of light over time reaching the sensor)...all HTP or ADL does is force the USER to change exposure.

I am sorry, Mikael, but I do not accept your explanation of how HTP works. I do not need your assistance in learning how it works. I agree it is not hard to understand, but it is clear you do not understand it. Hence the debate.

jrista

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #83 on: September 03, 2013, 08:32:21 PM »
ask me strait question then
short and concise

ds/ps  , you have been writing the same as I have from the beginning
 HTP at 100iso  = exposure after 200iso = create a head room  compared to a 100iso exposure due a shorter time= halving the in falling light compared to a 100iso exposure. AND to that a 100iso gain + another s-curve/contrast curve

SO what shall  you and I discuss now?

my old head room figure and iso
100is near clipping
200iso ? 1 stop of head room
etc
etc

Well, it seems you've changed your explanation now. Originally, you were saying the camera changed the shutter speed with HTP enabled in order to halve the actual amount of light. That is the point at issue. If you are using manual mode, with HTP on, and select a shutter speed and aperture that over-exposes enough to clip highlights, then you've over-exposed. HTP can't fix that. Nothing can fix that. The user is still in control of the exposure. As I said before, it is a user-conditioning setting...HTP has the tendency to force users to select a faster shutter or slower aperture...but that does not guarantee the user will comply.

As for your headroom figure, I think that is inaccurate...at least, as far as how Canon sensors work (and Nikon uses sensors from so many sources, I couldn't say if that diagram conforms to any of the sensors they use.) Highlight headroom is, in my opinion, a misnomer. You don't really have any highlight headroom (rather, you have shadow footroom)...highlights cut off where they cut off, regardless of ISO setting. If you expose past that point, any "headroom" values are simply clamped to the white point. I believe Canon sensors work more like this diagram demonstrates:



When it comes to HTP, highlight headroom, or shadow footroom for that matter, doesn't come into play. HTP forces the user to assume a higher minimum ISO setting that does not actually get applied when the exposure is made. The user assumes they must compensate for a higher ISO, therefor reduces exposure by selecting a lower one with their chosen shutter and aperture. The camera then exposes, according to their selection, at a one-stop lower ISO setting. That's all. There isn't any electronic trickery, or headroom, or anything special about the hardware here. It is all virtual...actual trickery, and the user is the gullible culprit.  :P

ME

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #84 on: September 03, 2013, 08:34:04 PM »
Thanks AlanF for the link to Galileo Solutions. One line from this article "It is clearly evident from my findings that the effects of HTP are quite different to what is achieved by underexposing by 1EV, which simply gives an underexposed image". I suggest that angkor what? could benefit from reading this article. http://www.galileosolutions.co.uk/blog/highlight-tone-priority-with-canon-cameras-review/  .                       ankorwatt, how did you come up with the idea for your avatar? That's not a copyright infringement is it?  3 shots from you would help clarify what you are trying get across:  1)Use another camera to take a picture of the settings you are using on your HTP camera. 2)Activate HTP, and take another picture of iso,shutter speed, and aperture used.3)Snap your picture. Get the exif info. Post all 3 on cr. Very simple to prove your point, or not. ::)
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Pi

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #85 on: September 03, 2013, 08:47:54 PM »
A much less artistic but more telling picture of how Canon sensors work is at sensorgen.info. You can see there the clip point in photons per pixel, and the read noise. How the converter and the user processes this, is another conversation.

Roughly speaking, for low ISO, each stop of increase of the ISO halves the saturation capacity (even if more photons are actually registered by the sensor, the AD circuit clips them). The read noise halves as well, approximately. This keeps the DR more or less flat up to ISO 800. Sony/Nikon sensors have more consistent read noise, less dependent on the ISO.

jrista

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #86 on: September 03, 2013, 09:07:14 PM »
ask me strait question then
short and concise

ds/ps  , you have been writing the same as I have from the beginning
 HTP at 100iso  = exposure after 200iso = create a head room  compared to a 100iso exposure due a shorter time= halving the in falling light compared to a 100iso exposure. AND to that a 100iso gain + another s-curve/contrast curve

SO what shall  you and I discuss now?

my old head room figure and iso
100is near clipping
200iso ? 1 stop of head room
etc
etc

Well, it seems you've changed your explanation now. Originally, you were saying the camera changed the shutter speed with HTP enabled in order to halve the actual amount of light. That is the point at issue. If you are using manual mode, with HTP on, and select a shutter speed and aperture that over-exposes enough to clip highlights, then you've over-exposed. HTP can't fix that. Nothing can fix that. The user is still in control of the exposure. As I said before, it is a user-conditioning setting...HTP has the tendency to force users to select a faster shutter or slower aperture...but that does not guarantee the user will comply.

As for your headroom figure, I think that is inaccurate...at least, as far as how Canon sensors work (and Nikon uses sensors from so many sources, I couldn't say if that diagram conforms to any of the sensors they use.) Highlight headroom is, in my opinion, a misnomer. You don't really have any highlight headroom (rather, you have shadow footroom)...highlights cut off where they cut off, regardless of ISO setting. If you expose past that point, any "headroom" values are simply clamped to the white point. I believe Canon sensors work more like this diagram demonstrates:



When it comes to HTP, highlight headroom, or shadow footroom for that matter, doesn't come into play. HTP forces the user to assume a higher minimum ISO setting that does not actually get applied when the exposure is made. The user assumes they must compensate for a higher ISO, therefor reduces exposure by selecting a lower one with their chosen shutter and aperture. The camera then exposes, according to their selection, at a one-stop lower ISO setting. That's all. There isn't any electronic trickery, or headroom, or anything special about the hardware here. It is all virtual...actual trickery, and the user is the gullible culprit.  :P

read what I have write, I have said nothing about M
and look again on my sketch
it illustrate also foot room and DR

You repeatedly mentioned manual mode and ISO 100 in your earlier posts about HTP.

Your diagram does not illustrate dynamic range, though. Your diagram, as currently drawn, indicates that each ISO setting has the same dynamic range, which isn't the case. The sensor itself has a constant dynamic range (the ratio between read noise and FWC at ISO 100). As ISO is increased, the white and black points change within that dynamic range (in the case of Nikon, the black point is fixed without a bias offset, so only the white point changes), but from a hardware standpoint, it is a fixed attribute. Your diagram doesn't really portray that.

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #87 on: September 03, 2013, 09:24:16 PM »
So please explain what happens if you set your cameras at M and base iso 100 HTP  and if the exposure time or f-stop is not changed? (have I understand you correctly) And why there are a choice of HTP in other modes as AV etc

from now and in the future, meet me with facts
When I have my camera in M mode at ISO 100 and I enable HTP, the ISO is changed to 200 and the exposure meter reading is increased by 1 stop.  The meter reading only, not the exposure.  The aperture is not changed.  The shutter speed is not changed.  That is not theory, that is a fact.  If the aperture and shutter are not changed by enabling, the number of photons reaching the sensor is also not changed by enabling HTP, and that is also a fact.

Say, for example, that with my M mode settings of 1/100 s, f/8, and ISO 100 resulted in a 1-stop underexposure based on the camera's meter.  If I then enable HTP, the ISO is set to 200, and the exposure reading is centered.  But the exposure is unchanged, the same number of photons would hit the sensor whether I captured the image at 1/100 s, f/8, ISO 100 without HTP or 1/100 s, f/8, ISO 200 with HTP.  The same number of photons, not half the photons.  So, your explanation that HTP means Half The Photons is wrong.  I don't know how I can make it any clearer.

I cannot set my "cameras at M and base iso 100 HTP."  Can you?  I challenge you to do so - enable HTP and set ISO to 100.  Show me a picture of your camera's rear LCD, like this one below, where the display in the upper right shows ISO 100 and the D+ symbol which indicates that HTP is enabled.  Meet me with facts, Mikael.




I'm going to strip you naked
I'm not sure what you mean by that, but it sounds immoral and possibly illegal.  I assume you're not threatening me with a physical assault of some sort, are you, Mikael?  That would be a mistake.  Regardless, it's a threat of some sort, and totally inappropriate.


I have reported you to the moderator- lies and falsification of my posts and data
In what way have I falsified your posts and data?  Refuting your bogus claims and misunderstandings is quite different than faslifying your posts.  Trying to correct your factual errors so that others who don't have your 30 years of experience aren't confused by your incorreect statements is quite different than falsifying your posts and data. 


End of discussion for me in this thread
Well, we can add that to the list of things you were wrong about.  I count 6 posts by you in this thread after that statement.  Maybe 'end of discussion' means something different to you. 


an apology can I  probably  not expect from a man who has committed jokes at my expense, and where he has shown great ignorance.
Yes, call me ignroant then by all means expect an apology. You've called me worse in the past. That's about as logical as your reasoning on other subjects, so no surprise there.

Please recall that this whole discussion started when you questioned a statement I made in jest.  I assumed it would be obvious that if I initially stated that the 'test' conducted in the original post was, "Uninterpretable and no conclusions can be drawn," subsequently concluding that, "The D7100 has problems with color fidelity and exposure metering that occur specifically at ISO 800," was a joke.  I already apologized for confusing you with that joke.  You subsequently offered the following: 

I admit if Im wrong show me please what you are talking about
and if not fu... of
and

if you  still going on- i tell you to f... of
Is that how you conduct yourself in everyday life, telling people you disagree with to fuck off, and then threatening them?

Regardless, I proceeded to tell you exactly where you were wrong (one example of many, I've provided two more in this post already)...and you proceeded to not admit it.


read what I have write, I have said nothing about M
Really? You, who tells everyone else to read, don't even read your own posts, do you?  You mentioned M mode in the first post that I quoted above.  So, wrong one more time.  I'm losing count of your factual errors and conceptual misunderstandings, Mikael.
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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #87 on: September 03, 2013, 09:24:16 PM »

bvukich

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #88 on: September 03, 2013, 10:23:31 PM »
Mikael, you are hereby banned for life.  Don't make a new account, don't come back.  You will be noticed, and we're not going to give you another chance.

You are knowledgeable and and can bring a much needed voice of dissent at times, and because of that we regret doing this, but you bring out the worst in everyone here, and your behavior can no longer be tolerated.

EVERYONE ELSE....

Your behavior in this thread has been no better.  You should be ashamed of yourselves.  Act like adults, and have civil discussions.

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Re: 70D vs D7100 ISO Comparison at 100%
« Reply #88 on: September 03, 2013, 10:23:31 PM »