Dave_G wrote:
ok -
better build - I am careful with my lenses and don't thow them around so "build" doesn't really come into it.
metal mount - Is this really deterimental to the way a lens performs? Ok, if the lens is on and off on and off on and off of the body 2000 times a week it might make some difference?! if once a day then probably not...
distance scale - Do you use the distance scale on any kind of lens?! Totally superfluous to requirement if you ask me!
all the rest like larger aperture and faster focusing make sense, but the above points don't.
Is f1.8 really that much slower than f1.4? I see in your sig you have a 50 1.4, have you used a 50 1.8?
can/worms blah
Don't get defensive. It's just a lens. The build, the mount- those things are factors that will determine how long it will last. How durable it is. Think about if you, for example, have to get that lens on your body quick, because a shot depends on it. You whip out your 50 1.8, put it up to the camera mount, aww MAN! a piece of the plastic BREAKS OFF! Sheesh..there goes your lens. Fat chance on breaking the steel mount on the 1.4 off. Build is another that means the better built lens will last longer. I know it's not even $100, but does that mean you don't care if it lasts or not? I'd sure like mine to last, if you ask me. The metal will just simply hold up better.
Now...as for that distance scale. Some people prefer manual focusing. In some situations, it can be quite helpful in more than one way to know the distance of your subject. It can mean a difference in your lighting, too, by the way. Kinda handy to know just by focusing the camera how far away your subject is. For manual folks, that's useful information.
Also, some people shoot infrared. That infrared index is absolutely a good idea.
Now, before a mod has to clean this up, play nice. Don't attack me because of my VERY brief opinions on a lens.
Oh, and I've never owned one, but yes, I used a 50 1.8 before. It felt cheap, light, and "plasticky". The 1.4 simply feels good in your hands. You know you're holding one hell of a lens for the price.