Go Back   Steve's Digicams Forums > Digicam Help > Newbie Help

Thread Tools Search this Thread
Old Feb 18, 2005, 7:06 PM   #1
Senior Member
Join Date: Jun 2002
Posts: 274

For someone who is not a professional nor advanced user (more of a novice photographer) who wants to get into a dSLR, what's the difference between the following two Sigma lenses (besides the focal length)?

Sigma 70-200mm F2.8 EX HSM

Sigma 100-300mm F4.0 EX HSM

This is for use on the Nikon D70. Which would be the better lens (image quality)? Also, what do people mean when they talk about a "fast lens"?

agiaccio is offline   Reply With Quote
Sponsored Links
Old Feb 18, 2005, 8:12 PM   #2
Senior Member
Trout Guy's Avatar
Join Date: Jan 2005
Posts: 132

The lower the f number the wider the lens opens (faster) thus allowing more light to enter given the shutter speed. Faster lenses (lower f number and wider opening) cost more due to the optics etc.

Normally, the longer focal length ie: 200mm vs 300mm, the "slower" (larger f number) the lens will be and thus, not perform as well in low light situations. Zoom lenses normally have a variable f number ie: 4.5-5.6 meaning at the nearest focal length the lens opens wider while at the longer focal length it does not. To get a zoom with a fixed opening, costs lots of $$$$.

Trout Guy is offline   Reply With Quote
Old Feb 19, 2005, 11:12 AM   #3
Senior Member
Join Date: Oct 2002
Posts: 544

Another issue is physical size... faster lenses are usually larger than ones with smaller maximum apatures. Take a look at the Canon 70-200 series. The f-4 ($550) is very manageable and relatively compact. The f-2.8 costs several hundred more and is twice the size of the f-4 and the 2.8 stabilized version is in the $1200 range and a load to carry around.

Both the Sigma lenses mentioned above have been favorably reviewed, but aren't compact by any standard.
Wildman is offline   Reply With Quote
Old Feb 19, 2005, 1:57 PM   #4
Senior Member
Join Date: Dec 2002
Posts: 5,803

Since you didn't tell us what type of photography you do, its hard to recommend a lens. Of course, you didn't ask "which would be the best lens for me" you asked which will lead to better image quality.

The 70-200 is a very good len. I've heard good things about the 100-300, but not as many as with the 70-200.

The description of a "Fast lens" is is correct. Cameras with smaller f-stops or larger apertures allow more light than other lenses and therefor allow for the use of faster shutter speeds. So they are refered to as "Fast."

eric s is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 3:10 AM.