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MissJezabelle
05-20-2005, 09:36 PM
OK so when it says

Lens Constructions: Groups 7 / Elements 7

Lens Constructions: 8 groups / 11 elements

I assume as logic would have it the 2nd is better. Is this true?

What is the actual reason?

TheObiJuan
05-20-2005, 09:49 PM
Usually, since the added elements are apochromatic, to reduce chromatic abboration; aspherical, to control distortion; ED, for sharp pics, and etc.
These added elements add lots of weight though.
There are different types of lens elements that are utilized for different purposes. The most common are molded, grounded, and hybrid. Depending on what is in the element also determines its characteristics. Some older ones had non-environmentaly friendly chemicals that are no longer used.

MissJezabelle
05-20-2005, 09:57 PM
Usually, since the added elements are apochromatic, to reduce chromatic abboration; aspherical, to control distortion; ED, for sharp pics, and etc.
These added elements add lots of weight though.
There are different types of lens elements that are utilized for different purposes. The most common are molded, grounded, and hybrid. Depending on what is in the element also determines its characteristics. Some older ones had non-environmentaly friendly chemicals that are no longer used.

Cool I Have seen lenses that say ecological friendly. So which of the two is a better lense?

TheObiJuan
05-20-2005, 11:00 PM
The older stuff, that is has aresenic in it apparently was pretty good stuff.
Canon made a 200mm f/1.8 lens with some non-environmentally friendly glass and it was a superb lens, if not canon's best lens ever.
They stopped producing it since they no longer wanted to use the unfriendly glass. I hear that they can't reproduce the optics and lens characteristics that the 200mm f/1.8 is loved for, with the new elements, and for this it is not being produced anymore.

I dunno, I just want some great glass for cheap. ;)
I can't wait to see what the future brings.
Canon has been utilizing Diffractive Optics in their newer telephoto lenses to cut down weight. The lenses are not spectacular and produce some odd background blur. I will give this technology a few years to be ironed out.
I wouldn't mind a 400 f/2.8 IS DO that weighs as much as the Canon 200mm f/2.8 and is as sharp as the 300 f/2.8L IS. :eek:

Norm in Fujino
05-21-2005, 03:48 AM
Cool I Have seen lenses that say ecological friendly. So which of the two is a better lense?

Don't worry, the better lens is the one that takes the better pics :D The number of elements and groups is not itself what makes a good lens. Big zooms, mostly, have lots of elements since they have to shift their arrangement in order to cover long ranges of focal lengths, but it's not quite so simple as "more is better." If you're considering a lens--or lenses, it is probably a good idea to do a google search using the lens' name and "review" as keywords. To see what the idea of elements/groups is, click on any of the lenses on Sigma's home page:

http://www.sigmaphoto.com/lenses/lenses_all.asp

TheObiJuan
05-21-2005, 12:38 PM
Also internal focusing lenses have additional elements to focus without extending the barrel. Even nicer is when the front element doesn't spin. ;)

The higher quality primes, that dont zoom, like the tack sharp 300 f/2.8 has something like 23 elements. :eek:

MissJezabelle
05-21-2005, 05:23 PM
and all approve. My Camera was delivered yesterday (I got a canon D-rebel) I bought a sigma Sigma 70-300mm 4-5.6 APO Super II Macro Lens. I obviously am not buying canon lenses I cannot spend $500 and up per lens. I think I did fairly well. I still need a small range lense and am looking at a tameron for that. Thanks for all the help and guidance y'all have been giving me, and I hope to share some pics soon. I still need to get a CF card as my old camera was SD.

TheObiJuan
05-21-2005, 05:38 PM
Lexar 80X or Sandisk Ultra II are great cards.

I have the sigma 70-300 apo super macro II too.
It is a good consumer lens. I only use it at f/8 though, so it has limited use.
The macro feature is nice, as I do little macro shooting so it holds me over.

the tamron 28-75 f/2.8 xr di is a stout lens, the wider tamron 17-35 f/2.8-4 is a nice supplement to it.

MissJezabelle
05-21-2005, 08:06 PM
I almost bought a scandisk ultra II tonight, but it was only a 60x speed. So I went to another shop and they were out of Lexars, but I did get Pretec brand 1 Gig 80X for $94 tonight, so I think thats pretty good, It also came with a great warrenty.

TheObiJuan
05-21-2005, 08:30 PM
I don't know about that pretec brand.
Never heard of it. The Ultra II is fast, really fast. It is faster than the Lexar 80X apparently. I, however, don't notice a difference in my 20D.