What really makes big sensors produce more appealing images? *Serious*

Started Mar 13, 2014 | Discussions thread
bobn2 Forum Pro • Posts: 55,644
Re: What really makes big sensors produce more appealing images? *Serious*

Just another Canon shooter wrote:

bobn2 wrote:

I don't quite agree with that. I had a long argument with regular poster Anders W, who claims the exact opposite of you, that smaller lenses are intrinsically better than big ones. I think where you're wrong and he is also, is the assumption that small lenses and big ones would be built the same way. The quality of a lens is ultimately decided by how much you're willing to spend manufacturing it (and the trade off like most things goes towards getting more for less outlay as progress is made) - but manufacturing trade-offs really are size dependent - at different sizes different manufacturing techniques become feasible and relative prices for different ways of building things change. So, in th end, I don't think its a given that small lenses would be build or designed like big lenses.

One of the physical constraints is that you still use the available glass to build smaller lenses - you cannot change the index of refraction just to squeeze the lens in one direction (FL) but keep the physical aperture the same.

Sometimes you can, the point is if the lens is smaller you might choose a different optical material, because the price equations are different - one quarter the amount of an exotic glass might be feasible within the cost profile. The same is true of 'extreme optical profiles' in a smaller design they might be produced by precision moulding as opposed to grinding. Phonecam lenses have some quite ridiculously non-sherical surfaces which would be completely impractical in a larger design.

As a result, smaller lenses with the same light gathering ability have more extreme design, need more glass, and have more aberrations. The 43 system has some f/2 monster zooms, overweight and overpriced even by American standards;

Yes, they are, but I think they could have been smaller for the same spec. they are big because they are essentially the equivalent FF design with a focal reducer behind them. A designed from the start f/2 zoom might well have been smaller. One interesting case is the Sigma 50-150/2.8 zoom. The old version was a scaled 70-200/2.8 and quite compact. The new version is a 70-200/4 with an afocal converter, and thus big. Good lens though.

and they are just f/4 equivalent. The Voigtlander 25mm f/0.95 Lens for MTF is 410g, while the new Sony FE 55/1.8 is 281g, and much better, AFAIK.

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