[wim]

interesting that the different wavelengths of light effectively cause different resolution limits. Going back to the 100-400, from the tables Klaus linked to at luminous landscapes (https://luminous-landscape.com/wp-conten...TABLA3.jpg) we can see that at blue wavelengths at 400mm then lens should be able to resolve enough detail for a 16MPix sensor, however at red wavelengths it will not.

 

Sounds like Panasonic have designed a surf lens (not to be used at sunset!)

 



 

All kidding aside, I wonder if this is noticeable in use? 

 

In film photography, we never did worry about this, we just used the Rayleigh criterion, which essentially uses green light with a wavelength of 5120 Angstrom or 512 nm. Green light was chosen because that is what the human eye is very sensitive to.

 

It does indeed make a difference when pixelpeeping, as visible light ranges roughly from 390 to 700 nm, although you could argue it goes from 380 to 750 nm. That is approximately a doubling of wavelength, and halving of resolution, roughly speaking.

 

It will still resolve enough at 400 mm, I can assure you, because the resolution of teh sensor does not actually change, it is the total system resolution that changes because the diffraction limits changes. However, the better a lens is, the closer it gets to the diffraction limit, and certainly at the smaller apertures almost all lenses will be diffraction limited.

 

Do also note that MP limits as discussed are really system MP limits, based on resolution at specific apertures for a lens and sensor system.

 

I'll see if I can work out a few examples to show you what I mean. However, that has to wait till the weekend - away from home for work currently, and limited in what I can do as a result.

 

Kind regards, Wim