relationship: a beginners question, on lens we have a aperture, focal length and diameter. could someone explain how relationship works. thank you...

ansamstuff

a beginners question, on lens we have a aperture, focal length and diameter.
could someone explain how relationship works.

thank you

Linda From Maine Loc: Yakima, Washington

Since others are going to get really technical, I'll give the quick and basic version: the size of the aperture determines how much light hits the sensor, as well as the depth of field. The focal length is basically how much you want in the picture: 25 mm would be considered "wide angle," seeing more than your straight-ahead-vision; 200 mm would be considered "telephoto," showing you something closer, working like a telescope. Not sure what you mean by diameter. As for the relationship among them, and throwing in ISO, now you're talking about determining exposure (how light or dark you want the photo to be). Can you go into further detail with your question?

ansamstuff

thank you for your response,i have a 50mm/1.8, 52mm diam; a wide angle 10-24mm/3.5-5.6, 77mm diam and a 18-250mm/3.5-6.3, 58mm diam.
and my question is what roll the diam size plays.

again thank you.

Danilo Loc: Las Vegas

The practical application of physical lens diameter (52mm, 58mm, 77mm) is it tells you the size of "filter" you need for that lens. Back in the film days, people could have dozens of filters for various effects, but in digital there are only a few that see any regular use (circular polarizer, neutral-density, and general protection).

Linda From Maine Loc: Yakima, Washington

Danilo wrote:

The practical application of physical lens diameter (52mm, 58mm, 77mm) is it tells you the size of "filter" you need for that lens. Back in the film days, people could have dozens of filters for various effects, but in digital there are only a few that see any regular use (circular polarizer, neutral-density, and general protection).

Three different diameters - does that mean the lenses are from different manufacturers? Seems curious to me.

ansamstuff

danilo, is this dimension have something to do, regardless with lens aperture and light going throught the lens

ansamstuff

the diameter i had mentioned is not on the mounting side

selmslie Loc: Fernandina Beach, FL, USA

Linda From Maine wrote:

Danilo wrote:

The practical application of physical lens diameter (52mm, 58mm, 77mm) is it tells you the size of "filter" you need for that lens. Back in the film days, people could have dozens of filters for various effects, but in digital there are only a few that see any regular use (circular polarizer, neutral-density, and general protection).

Three different diameters - does that mean the lenses are from different manufacturers? Seems curious to me.

Same manufacturer will product different diameter filter sizes.

At one time, Nikon used 52mm as their main "standard" filter size. But they have used different sizes to allow for larger maximum apertures (smaller F/numbers) on longer focal length lenses and larger zoom lenses.

They still try to have only a few standard filter sizes so we don't have to invest in too many filter sets and have a little money left over to buy lenses.

Pepper Loc: Planet Earth Country USA

ansamstuff wrote:

the diameter i had mentioned is not on the mounting side

The diameter he's talking about is simply the diameter of the lens at the lens cap end (opposite mounting end). Yes the diameter makes a difference in how much light is available to the sensor (passing through the aperture). The primary reason you need to know the diameter is as mentioned, what size filter you need or what size lens cap you need should you loose or break one.

ansamstuff

thank you both, that is something i considered important for all beginners in photography.

SharpShooter Loc: NorCal

I would like to add that, though only indirectly related, that since some of the very large lenses may have such a large diameter objective lens(the one on the front) diameter, That it would be impractical to even use filters of that size. Since these filters could need to be as much as 150mm in diameter, the cost would become prohibitive.
Therefore many of these types of lenses use a "drop in" filter that goes near the rear of the lens. In this area, a lens with a diameter of 150mm may only need a filter of less than 50mm. Making them practical and more affordable. This may not be of interest to you, but some may wonder why there are no really big filters.

Frapha Loc: Tulsa, Oklahoma

ansamstuff wrote:

a beginners question, on lens we have a aperture, focal length and diameter.
could someone explain how relationship works.

thank you

Try using some of the live simulators at this site and you can actually see how each one and various combinations will affect a shot. http://camerasim.com/

sueyeisert Loc: New Jersey

I assume you've spent money buying a camera and lens etc, why not go to the library and take out a book on photography so that you can read about the basics.

photobuf Loc: Mississippi

Karl Taylor has a great photography video tutorial for beginners on the basics of photography for beginners---if you can get by the British accent--:-) Just kidding, he is a good teacher.

rmalarz Loc: Tempe, Arizona

ansamstuff wrote:

a beginners question, on lens we have a aperture, focal length and diameter.
could someone explain how relationship works.

thank you

An excellent tutorial on focal length, look for others by him regarding f-stop, etc.

http://www.youtube.com/watch?v=t3A3SnPFPk0