>>If this is true, then pixel density on the chip is a non >>factor. Correct? > >Yes, that is exactly what I am saying there. Pixel density >has no bearing on noise when noise is measured as a function >of unit sensor area.
>If you understood that then you should well understand that in >a too low light situation DX is no help at all- in terms of >noise. Y0u went to f/2.8 on the front end, gaining a stop, >and then lose that stop on the back end when you magnify the >sensor sized image to the final output.
Beyond all else, I don't understand this.
>You misunderstood me because I could have said it better. >What I meant to say just above is that the same lens, same >focal length (either both with or both without the TC) will be >the same size on the DX and FX sensor. When you drop the TC >on the DX sensor, now you have a smaller image that needs to >be magnified 1 stop more, nullifying the one stop pickup in >aperture and exposure.
If this statement is true, then I do not understand image circles and how they relate to the sensor. I guess I need to go review that.
>One post you are, and the next post you are not, and then you >are back again. This thread, like all the others, is >primarily about the D400, and you have added the general lack >of a fully Pro DX camera with integrated grip, WIFI, hard >wired internet ports, etc. - cameras that do not exist. >Since they do not exist, we can only assume all else is equal >until tests and user experience prove otherwise.
Understood, and understand your frustration here.
>The primary point I am trying to make here is that, >conceptually, if all else is equal, meaning the DX and FX >sensor is "cut from the same wafer with different size >dies", then your plan to go to DX and drop the TC won't >work.
Understand and agree.
>Once we agree on that, then if you want to talk about specific >bodies you own, you have to convince me that the DX body is >inherently less noisy than the D3, meaning it will outperform >the D3 in DX crop mode. And I think you will have a tough >time finding that DX camera in your bag now. So I'm not sure >where you are going with this.
I think I am beginning to understand where our failure of communication is happening now.
>>The only way I cam get the real world equivalent of this >is if >>I consider a D3 and a D300. The D7000 is a generation >newer, >>and the D400 may be another generation beyond that. > >Bill Claff's tests suggest the D3s in DX crop mode still beats >the D7000 by 1/3 stop. The D3s is inherently 1/3 stop lower >in noise. If you agree with my "all else equal" >concept that going to DX and dropping the TC is a push in >terms of noise, then the D3 still beats the D7000 by 1/3 >stop.
Wait, are we talking D3 or D3s? Or are you saying that the D3 and D3s have equivalent ISO performance?
>>>there is >>>one and only one way to reduce noise in the case >where >>you >>>have a fixed size subject and a fixed working >distance: >>make >>>the front element of the lens bigger. >> >>Disagree here as well. The performance of the lens could >also >>be increased. That would not show as large a gain as >making >>the front element larger. > > >What do you mean by "performance of the lens", if >not the light gathering power? The only thing that effects >noise is the amount of light and in a long tele that is simply >the light gathering power (diameter) of the lens.
I mean the lens can transmit light closer to it's theoretical idesl. All lenses lose light throgh the glass and the air spaces. No lens operates at it's theoretical F ratio. My assertion is that the this can be improved, though the gains might be slight as modern lenses do a very good job in most cases.
>Don't tend to produce sensors in the same format with varying >densities with the same technology? How about the D4 and >D800? Isn't a two month spread in announcement dates close >enough?
I do agree, and this is an excellent example which I clearly overlooked. However, I could look at the D3/D3s and D3x as a counter example. Or are you of the opinion that the D3x and the D3s have equivalent ISO performance? They should by your assertion that pixel density does not matter for chips of the same generation.
>The D4 and D800 are as identical in development era as we >could ever see.
>>My D3s has the best ISO performance of any camera I own. >The >>D800 has the same sized sensor, and uses exactly the same >>glass. It has a sensor that is at least 1, if not two >>generations further along. Yet it's ISO performance is >not as >>good. I am left to conclude that the pixel density plays >a >>significant role. > >You say the D800's performance is "not as good". >Bill Claff says it is within 0.2 stops - slightly more than >1/6 stop and probably nothing any of us would ever notice. >Only a computer would notice. DXO says the same, per my >comment just above.
Looking at the DXO numbers it rates the cameras ISO performance like this:
There are some very interesting correlations here. If we believe these numbers to be accurate and representative (and I believe they are) then Nikon has taken a step backwards from the D3s to the D4. How would you account for the difference? Clearly the technology is newer by at least 3 years.
The D3s and the D3x seem worlds apart, yet the cameras appeared less than a year apart. What do you think accounts for the difference?
And then there are the DX cameras. The D7000 is a full generation newer than the D300s, but only manages half a stop better performance. And if rumors are to be believed that the D400 will have the same 24MP sensor that is in the D3200, then the ISO performance of that chip is really just on par with the D7000. Even though it should be a generation newer.
>If you are right, then those two major independent testers are >flat out wrong. I have to go with the testers short of >substantial evidence from you.
I don't think they are wrong. I think there is something wrong with how I am thinking about this issue. And now I need to figure out a new approach.
>Yes, they "took a hit in aperture" by adding a TC >and gained that stop back in the FX advantage in noise >performance that allows them to shoot one stop higher ISO, all >else equal, but all else was not equal because the D3s totally >blows away anything in a DX format. > >Nikon actually did them a favor, forcing them to a bigger >sensor with more light gathering power, and bigger glass, with >more light gathering power, and gave them a system unequaled >in image quality.
I don't think Nikon did them as much a favor as Nikon did a favor for itself. Updating a fleet of glass at a newspaper or magazine, could be on the scale of 25-200 new lenses per publication. At $6-$10k per unit.
>But no one is ever happy, not even the pros. Not even when >they have the best technology man can produce, and at the high >end Pro level, the money to fund it.
Assuming the money to fund it is there is a pretty big leap. Newspapers are going out of business at a record pace. People, especially photographers are losing jobs at an alarming pace. And at least one large publication I am aware of recently made the decision that it would no longer fund it's photographers with more than 1 camera. Sports shooters or otherwise. Imagine trying to cover a football or basketball game adequately with a single camera. Times are tight.
>Above you argued repeatedly that you believe denser sensors >are noisier. I have argued repeatedly that that is not case, >not on a theoretical basis nor based on Bill's empirical tests >and DXO's empirical tests of the D4/D800.
Based on what I see, I am still ambivalent about it. Clearly the D4/D800 example is compelling. But then so is the D3s/D3x. So I don't know. Maybe you are right. You probably are, and I just don't understand why.
>However, just for a moment and for arguments sake, let's >assume you are right and every authority on the subject is >flat out wrong. > >Where does that leave you when you take your future brand new >24mpx DX sensor and 300/2.8 onto that dimly lit soccer field? >Isn't that new 24 mpx DX sensor going to perform far worse >than even I suggest???
Quite possibly. Particularly if we take into account the DXO numbers of the D3200 as the possible sensor twin to the D400. And if that comes to be, then it will certainly save me a several thousand dollars in not having to upgrade cameras.
>Your logic escapes me
I think the logic is ok. But the underlying understanding and data may be faulty.