Newbie question on lens

[ryt321]

Hi,

I just started on photography and was comparing lens available to go with the DSLR. From what I have been reading, the two key characteristics of a lens are its (a) range of aperture size (denoted by f, the smaller the number, the bigger the aperture); and (b) the focal length (which controls the zooming ability of the lens). Other characteristics include image stabilisation and auto focus capability.

Other than the above characteristics, what else differentiates one lens from another (other than the obvious different brands - presumably some manufacturers are better than others)? Say if you bought a lens whose focal lenght is 18mm - 200mm, would you still need any other lens which have focal lengths between 18mm - 200mm?

Thanks in advance for any help!

 

[Rashkae]

Quality, sharpness and other lens characteristics. It's up to you, really... Many will have an 18-250 for general travel, but still have the "less zoom" lenses since they have less compromises and use those for when "keeper" shots are needed.

 

[madmartian]

Say if you bought a lens whose focal lenght is 18mm - 200mm, would you still need any other lens which have focal lengths between 18mm - 200mm?
Thanks in advance for any help!

18-200mm is a versatile 'kit lens'. It does not give you a constant aperture throughout the whole focal length. @18mm it's usually f3.5 & when you zoom it out, the aperture is f5.6. In other words, you can't shoot @f3.5 in the 200mm range which let in less light & you shoot @ a slower shutter speed.
Yes, there are many photographers who own prime lenses in between the zoom range you mentioned. As this prime lenses have a fix aperture, example f1.4.
The whole thing boils down to what are your needs & whether you have a deep pocket or not

 

[markyen]

like what Rashkae mentioned, also u may have to decide if you like the pic taken from one lens to another. Put it simply Zooms gives you the freedom and flexibility to change focal length easily but the pic taken at times are less magnificent than primes. So you may have a 18-200 for walkabout and when you have the opportunity or occassion to take a potrait shot you may use 85mm f1.4 prime etc.

That said I like zoom cuz I prefer the flexibility. Well one more thing is the quality of the glass used that will definately make a big diff between any lenses.

 

[horizon_grazer]

Welcome to CS !