Accurately comparing FF vs APS-C sensor performance? An open discussion.

Started Apr 8, 2013 | Discussions thread
OldClicker Senior Member • Posts: 2,322
Re: You misunderstand

One more try.

VirtualMirage wrote:

OldClicker wrote:

Those are mathematical models.

So now you are flipping your stance and admitting that DoF and its related variables are based on mathematical formulas?

No, your backwards.  Reality is NOT based on the model.

All math models make assumptions.

Welcome to the world of math and science!  It doesn't make it any less accepted or valid.

I'm a chemical engineer.  My education and career were based on mathematical modeling of real world processes.  That's all engineering is.

You want to use the models and deny the assumptions.

Examples, proofs?

Example, proofs of what?  You are saying that pixel size/density has no effect because your model, that totally ignores it, says so.

What assumptions am I denying that play an impact on the values that I have given you

The only thing I am seeing from you is based on your perception, only what you are seeing.  Your perception may vary from mine, it might not.  Your perception might work for you but not for someone else.  Other than going by your word, there is no way to prove this.

What realistic assumptions are these calculators doing wrong?

Assumptions aren't wrong - all models make assumptions.  It is only the misuse of the model that is wrong.  I believe the DoF calculators assume something like 20/20 vision at 1 meter for an 8x10" print at 300 DPI.  If these are not true, then the model is being misused and may be wrong.

Yes, many mathematical models usually assume the tests are being carried out in a vacuum, a perfect world.  We know that in real life our scenario wouldn't match this, but the results are usually very accurate for everyday use with exception to the extreme situations or when you are trying to get to a extremely accurate numbers (ie, to several decimal places) that would only need to be registered in a lab environment.  We are not working in a lab, we are not working in the extremes or on another planet, and thus this would not apply.

No, models are not based on "tests being carried out in a vacuum".  The best model for any process is the simplest model that gives the desired result.  Example:  A model of the earth orbiting the sun.  If you want to photograph my birthday party and use the calendar as your model, you will probably be there on the correct day.  If you want to photograph a sunrise on my birthday, then you are going to need a model that predicts the time and compass direction for sun rise on that day.   If you want to send a ship to Venus for to photograph the rings and have it return to earth to show those photos at my birthday party, your model is going to be much, much more complicated that a calendar.  This would not make the calendar model wrong; only misused.

Been nice.  Over and out.

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Some would have you believe that having to adapt to new technology is a workaround, but having adapted to old technology is photography.

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