DOF and Cropping take 2

Started 10 months ago | Discussions thread
awaldram
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Re: DOF and Cropping take 2
In reply to Ian Stuart Forsyth, 10 months ago

I don;t get it

Just as was stated the first time.

Your 'proofs' only show what I've been sayin, You alter the magnification factor to alter DoF.

The fact you then go one to match that DoF to various focal lengths seem pointless.

I've stated (repeatedly)

1 a lens does not alter its characteristic it aperture is fixed by it focal length and entry pupil these do not alter dependant on format

2 DoF does not alter what alters is the 'standard' viewing distance so perceived DoF changes.

3 Altering magnification will alter perceived DoF

4 Cropping alters magnification so alters perceived DoF

Everyone of your examples prove what I'm saying so just as last time I'm lost for words.!

Your only slight chink of righteous is perspective which does alter but its effect is variable depending on focal length, Short lengths more noticeable than long.

But this is a feature of the focal length and not related to and FF vs APS-c

On another subject you keep saying iso100 on aps-c = iso 225 on FF

Again your doing some kind of weird 'equivalence' to push some FF agenda

Hence why I pointed out you do not expand the APS-c image into some kind of stretchy FF version.

the light hitting the focal plane is identical irrelevant of format for the same lens it doesn't alter.

If you had and 18% grey test scene using the same lens exposure woudl be correct for any format lens and woudl be the same across formats.

Think logically for a second if this was not true then not only Sunny 16 would be broken but it woudl be impossible to use a light meter on any format besides that which it was specified for.

You find me 1 light meter that states FF use only and maybe you have some point .!

But you may have noticed besides you and MC everyone appears to understand and agree (at least in principle) with my point , so maybe it's not me that can't bare to be wrong ?

Maybe it because without a FF agenda I look objectively at the data and don;t get hung up.

Manufacturers most be laughing their socks off, they take 2 16Mp aps-c sensors bond them together and suddenly they have the emperors new clothes.

The sensor now has less noise , more DNR and takes better pictures than the two separate sensors !!

wow Pixie dust gone mad.!

You may point me to DXO now to show the improved SNR etc and I'll just retort it shows the fallacy of equivalence, that DXO dumb down everything to 8Mp camera equivalence so the higher the resolution the higher the measurements.

Logic and common sense dictates if you take two identical pixels with the same well depth etc then they must behave the same irrelevant if there fitted to a MF,FF , or aps-c sensor.

There are a lot of reasons why FF can be a better tool for some but you have presented none of them.

And on the subject of people giving to hoots, this subject has now run two threads yet how many active participants.?

Sort of vindicates my nobody cares , it's  a FF forever thread and only die hard FF enthusiasts have any real interest.?

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