Why do large aperture telephoto lenses cost so much more than

>>3077580
Takes more material and higher quality material to achieve that aperture. It's not as easy as just "making it larger". the glass has to also be larger, and the larger a round piece of glass is, the more it costs.

>>3077582
Ah, I see. Simple enough.

>>3077582
It's not just the extra material, it's the R&D involved in correcting the aberrations such a large piece of glass introduces while maintaining that aperture.

>>3077580
F2.8 means more light available to you. You are paying for versatility among other things.

>>3077580
Top quality optical glass is over a grand a kilo, and you get it in a solid block that you have to carve the lens out of yourself.

As aperture is a ratio, the size increase of the glass is exponential.

All in, good lens is expensive.

>>3077582
when using materials like fluorite also, it becomes costly and time consuming when making elements of that size

the fluorite elements in the canon 1200mm 5.6 (extreme, I know), took about a year to grow iirc

>>3077580
>why does bigger, more precise stuff cost more money?

>>3077640

>questions are bad and everyone should think they know as much as I think I know

>>3077643
>I blame other people for my own stupidity
And you wonder how Trump, May and Orban could get in power.

>>3077580
it's not only because the aperture is bigger, the f2.8 is constant from 70 to 200mm. Every extra stop is multiplied by root of 2, that means the aperture is twice as big.

>>3077682
Constant aperture is a specific optical design. The aperture that you calculate from the focal length and the f value is a virtual aperture, an apparent diameter opposed to a physical diameter.

>>3077689
What are you even talking about?

70/2.8 is different from 200/2.8 the diameter has to change.

>>3077775
Do you actually believe the lens diameter changes on a zoom lens?

>>3077670

lol wut

>>3077580
f/2.8 is 4 times "as much lens" as f/5.6

So you'd be at $800 already.
Then add better build quality, more complex optical formula, better coatings, faster AF motor that has to move 4 times as much glass.

>>3077777
Who said that, stupid fuck? The aperture diameter is different for different focal lenghts, that's just math.

>>3077796
That is virtual. The aperture mechanism is not the same diameter and doesn't move during zooming.

>>3077844
Of course it moves, it's a zoom lens.

>>3077850
He means the aperture blades don't open or close when you zoom in or out.

And he's correct.

>>3077796
That's not how constant aperture lenses work literally Google it and there's a diagram that shows your retardedness

>>3077580
because jewish tricks

>>3077861
>>>/pol/

>>3077796
http://www.pierretoscani.com/teleobjectifs-1.html

>>3077865
Hmm... looks like the page for the constant aperture telezoom optics was taken off...

>>3077864
can't.
whole country is b& because they can't handle the bant.