The characteristics of lenses

[zenpmd]

As I get more into photography, I realise there are other things, like colour and contrast, that give each lens its characteristics.

I can get my head around what happens inside a lens for it to be more or less sharp than another lens - I can conceptualise, for example, imperfections creeping in and causing the loss of detail.

But I do not understand either how some glass, or some arrangement of glass, changes things like colour and contrast and also why there is not some objectively good colour and contrast that all lenses try and get close to.

Can anyone help? Or suggest I read anything?

[andy lee]

good glass costs money to make $$$

so some lens manufacturers use cheaper glass to keep costs down plus the lens internal element design makes a huge diffenace

Tessar , Planar , Sonnar etc etc

 

you get what you pay for with lenses

[zenpmd]

Yeah but whats actually happening and whats the difference, in scientific terms?

[userage]

In scientific terms? I think you better enroll to uni to fully understand that..

 

But essentially the different type of glass you use will obviously have an affect because of the way light acts as it passes through. As you can imagine, the structure of thorium is different to calcium fluoride so they light will refract differently as if goes through these materials which all adds to their different characteristics. The lens element design too, they handle the light as it passes through so they are shaping it which can also affect its sharpness. Manufacturing processes will also have an impact, not making the glass smooth enough will definitely show up. Lens coatings play a role as well. All of these things affect the light which causes the colours and contrast to be different..