What Makes Telephoto Lenses Have a Longer Focal Length Than Convex Lenses?

Thread starter copitlory8
Start date Sep 17, 2010
Tags

Convex Difference Focal Lenses

AI Thread Summary

Telephoto lenses are designed with a longer focal length compared to single convex lenses due to their unique optical construction, which includes multiple lens elements that work together to magnify distant subjects. This design allows telephoto lenses to compress perspective and provide a narrower field of view, making them ideal for capturing distant objects. The longer focal length results in a shallower depth of field, enhancing subject isolation in photography. Additionally, telephoto lenses can achieve greater magnification without increasing the physical size of the lens. Overall, the combination of these features distinguishes telephoto lenses from standard convex lenses.

Sep 17, 2010

copitlory8

Why is a telephoto lens considered to have a longer focal length than that of single convex lens?

Physics news on Phys.org

Sep 17, 2010

DaveC426913

Gold Member

copitlory8 said:

Why is a telephoto lens considered to have a longer focal length than that of single convex lens?

The first few sentences http://en.wikipedia.org/wiki/Telephoto_lens" seem to cover that off nicely.

Last edited by a moderator: May 4, 2017

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...

View full post »

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...

View full post »

Thread 'Explain this asphalt sheen'

This problem is two parts. The first is to determine what effects are being provided by each of the elements - 1) the window panes; 2) the asphalt surface. My answer to that is The second part of the problem is exactly why you get this affect. And one more spoiler:

View full post »