difference in camera lens


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lufu

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#1
hi,

what is meant by Fast (f/1.8-f/2.6) ,aspheric lens design, with 10 elements in seven groups as compared to

f/ 3.0 - f/ 3.6, 11 elements in 9 groups

should higher f be better or lower? what is elements and groups?
 

Kevin

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#2
Hi Lufu, Welcome to the Oly C2040 Family. I just came back yesterday.

Regarding the Fast lens, F1.8 has the biggest lens hole to allow more light to enter at the same time. F2.8 would be smaller compare to F1.8. This is also called the Aperture. It is a calculated ratio so the higher the number the smaller the hole (kind of weird isn't it?). When you use F1.8 to capture a scene, for example night shots, it need 1s to capture the same amount of light that is equal to a F2.8 using 2s in order to capture the same amount of light.

As in higher F is better or not depand on what you are trying to capture. I will let the rest of Gurus to explain to you as I am only a newbie.;)
 

lufu

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#3
thanks,

so a large aperture, smaller f value.
what is the purpose of such large aperture and small aperture, what kind of effect would be achieve

Thanks
 

Jayan

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#4
Originally posted by lufu
thanks,

so a large aperture, smaller f value.
what is the purpose of such large aperture and small aperture, what kind of effect would be achieve

Thanks
Large aperture lets in more light....meaning all being equal...can use a much faster shutter speed (to 'freeze' fast action or to minimize blurriness due to shaky hands) to get the correct amount of exposure.

At small sperture, the shutter gotta open up longer to get the correct exposure.

Also, a larger aperture gives a shallower depth of field effect.....like those portraint shots whereby the subject is in focus but the background is slightly out of focus to create a blurry, soft effect.

Ur F1.8 lens is one of the fastest on a DC...the C-3040Z and C-4040Z also has such fast lens......on comparison the Canon G2 is F2.0, the Oly C-2100Uz is F2.8 and the Casio QV2900UX is F3.2.
 

YSLee

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#5
Elements refer to the number of pieces of glass; groups, well, refer to how they're grouped together. Aspherical element means that the particular element is not of a spherical shape, usually it has some plastic added to it to give it the shape needed. Sometimes it is a ground glass element, but that's usually for the very expensive lenses. Bokeh with aspherics can be a bit odd, if you're the type that notices that.
 

Jayan

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#10
Originally posted by Flare
Issit? Hee Hee... Sorry Sorry.... but if got 1.8 then I smile till my head disappear...
I think it's difficult to design a long-zoom lens (like urs, 7x) that's very fast.....so gotta have some compromise.

:D
 

lufu

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#11
thanks for the lessons.

thinking, of how do you determine what aperture or shutter speed to set for a particular scene, after knowing what these are.

most website I saw only teach on on what is aperture and shutter, but not in helping you to explore those settings.
 

rochkoh

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#12
Originally posted by lufu
hi,

what is meant by Fast (f/1.8-f/2.6) ,aspheric lens design, with 10 elements in seven groups as compared to

f/ 3.0 - f/ 3.6, 11 elements in 9 groups

should higher f be better or lower? what is elements and groups?
lufu,

this might give you some idea of what constitutes a fast lens.

http://www.jafaphotography.com/frstfast.htm

enjoy!
rOCh
 

Klause

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#13
Larger F value(smaller aperature) = more dept of field
Smaller F value(larger aperature) = lesser dept of field
 

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