What makes a lens sharp?

Is it formula, coating, material of the glass, build of the glass? Why are 50mm f1.8, 70-200mm series sharp lens.

tripod and good light

learncanon wrote in post #11655243
Is it formula, coating, material of the glass, build of the glass? Why are 50mm f1.8, 70-200mm series sharp lens.

Actually, shutter speed, a steady hand, good light, and a whole lotta luck (J/k about the last element.....kind of....)

Hi guys,

I think my qn wasnt put clearly. I mean for example Lens A and B are different in MTF/sharpness. Why is it that the more superior lens is sharper? I wld like the ans to be like coating reduce CA.....smthing like tt.

Lenses redirect light beams, Better and longer polished lenses makes light rays focus better all the way to the sensor. There are some other things than just lens polishing.

SimonParadis wrote in post #11655644
Lenses redirect light beams, Better and longer polished lenses makes light rays focus better all the way to the sensor. There are some other things than just lens polishing.

i guess it must be very expensive to 'polish' these things. however the 50mm f1.8 is really sharp. anw, what did e engineers do to build lens sharper than e others?

Using its prime F stop. Usually 1 to 2 stops from wide open. Example - Canon 300l F4. It would be sharpest at 5.6.

That question should be asked of optical engineers and lens designers, not of online hobbyists. Even if there are engineers and designers on this forum, they probably won't answer your question unless you pay them first.

digital paradise wrote in post #11655745
Using its prime F stop. Usually 1 to 2 stops from wide open. Example - Canon 300l F4. It would be sharpest at 5.6.

My 300 f4L is quite sharp at f4. Hmm..

Why is it sharp? Because they designed it that way. Mainly, it is precision engineering, better materials and attention to detail. Also, as in the case of the 50mm f1.8 - simplicity makes the design easier. It's the same reason why certain gourmet dishes taste better or why a certain bike is faster and more smooth to ride.

http://www.opticalres.​com/gentle_introductio​n.html

Many things make lenses sharp optically..

Type of glass used.
Lens construction.
Lens coatings.
The physical design of the lens.
Lens element alignment.
Materials in the moving parts.
Quality of manufacture.