On 2019-11-23 22:33, Neil wrote:
> On 11/23/2019 4:59 PM, Alan Browne wrote:
>> On 2019-11-23 14:25, Neil wrote:
> [...]
>>> If one blows up a film image, the larger the film frame, the more
>>> detail will be in the enlargement.
>>
>> Yes, but if the line frequency of the lens is less than another lens,
>> then that will affect the detail. With that in mind re-read AAA and
>> BBB above.
>>
>>
> Line frequency has nothing to do with film (or digital), is is an
> optical factor of a lens. However, the difficult and controversial line
> frequency of "the best" lenses is ambiguous. What lenses?
"controversial"? What controversy? You measure. It is.
Lf most certainly is the factor at hand where sharpness and contrast are
concerned. A lens passes a maximum linear frequency (which typically
drops off centre to edge) and film records a maximum linear frequency.
ie: some films record higher LF than others. Take the film out of the
equation (for comparison) and record the same scene with a 35mm lens and
MF lens. Returm to AAA/BBB in the preceding.
Since the MF film is larger it has a larger number of line pairs it can
record (not f) overall across the scene.
Why blowing up an image of a scene to some arbitrary large size will
look better from a MF image than 35mm, but blowing up X times from a
35mm image will look sharper than X times from MF. (For better quality
lenses of course).
I've avoided mentioning aperture in all this, and it too has a role to
play. Thus when you get into enlargement factors, depth of field of
different lenses, and so on, the whole thing gets beyond compare.
> Forget about Nikon and Canon, they are not MF lenses, nor are they "the
> best" 35mm lenses. What's more, many recognize that those two companies
> (among others) use completely different methods to arrive at line
> frequency values.
I didn't bring brand into this.
3rd party measurement use the same method regardless of lens.
And that said, I don't see how an objective (pun intended) measurement
at one company would differ from another - though they can muddy the
waters in their favour by choosing different lp f than a competitor in
order to show "better" or obfuscate "lesser" behaviors.