Why is everyone using the 24-105 f4?

[shikaka1]

I mean there is no doubt that it's a great lens, but why don't people use a f2.8 or even lower aperture lens? Even the multiple 3.5-5.6/6.3 lenses offer a bit better work in low light at the closest focal length. And if having a fixed aperture is what makes an image sharp, then why not use a 2.8 zoom lens?

[shadowsports]

Greetings,

Generally speaking, having a constant aperture isn't what makes an image sharp.  I have the RF Trinity, f2.8.  I understand the flexibility it offers.  There is only one stop between f4 and f2.8.  Lens with faster apertures certainly offer greater flexibility, but this convenience also comes at a price.  There is a big difference between $1300 and $3000, making the f.2.8 out of reach for some.  Shooting scenarios also need to be taken into account.  Some people shoot outdoors the majority of the time, so they may use a faster aperture less frequently.  An f2.8 lens also weighs more.  There are many reasons why someone might choose a lens with a variable aperture over one with a constant one. People buy what they need based on intended use, and what they can afford.