Lens Diameter

[idpsys]

Hi,

I tried to search but so far cannot find this thread.

What's the difference between smaller abd bigger lens diameter given the same focal length ? For example, is there any difference (better quality, wider coverage, or whatever) between 58 mm diameter lens and 67 mm diameter lens ?

Thanks in advance.
Steven

 

[Scaglietti]

Usually larger lens = faster lens. i.e. larger max aperture. E.g. 85mm f/1.4 is larger than say 85mm f/1.8.

 

[idpsys]

Usually larger lens = faster lens. i.e. larger min aperture. E.g. 85mm f/1.4 is larger than say 85mm f/1.8.

Hi Scaglietti,

Pardon me for not understanding.

Are you talking about lens diameter that usually determine the size of filter (e.g. UV filter), 58 mm, 67, 72, etc. ?
This was actually my question.

 

[frenchbean]

Yeah, I think he is referring to the filter thread size. Well, better quality lens tends to be bigger in size due to the use of better and more optics in the lens. That's why a lot of f2.8 zoom lenses uses 77mm filters while those variable zooms are 72mm or 67mm. Compare the 70-300 f4-5.6 and the 70-200 f2.8 and you can see the difference in size and also the difference in the quality of the pics.

That said, there is actually no direct relationship between the filter size and the quality of the lens. Take some mirror lens for example, huge filter and focal length, but quality wise cannot be compared with a well built "non-mirror" lens.

 

[idpsys]

Scaglietti and frenchbean,

Thank you very much for the explanation.