28-80mm f/3.5-5.6????

[edwing206]

I don't get all this mumbo jumbo. what does it mean. not just about those numbers but the diff camera numbers as well. thanks

 

[BlueCorn]

That lens is a zoom lens, meaning that it's adjustable. It zooms from 28mm to 80mm

The f/* refers to the aperture (how much light gets through). The smaller the number the more light that it lets in, and the shallower your depth of field. That lens is an f/3.5 at 28mm and a f/5.6 at 80mm and some combination of the two in between.

 

[edwing206]

so it lets in less light when you are zoomed in?

 

[edwing206]

and i still don't get tht 28-80mm part.

 

[edwing206]

so this one is a macro lense? http://www.shopping.com/xPO-Sigma-Z...-Zoom-Macro-Autofocus-Lens-for-Sigma-SA-Black
\\
and this one is for regular pics?
http://www.shopping.com/xPO-Sigma-Z...Zoom-Macro-Autofocus-Lens-for-Pentax-AF-Black
or are they the same? thanks

 

[RevHtree]

28-80mm is distance

28 being closer and 80 being farther away.

MM stands for Millimeter.

Millimeter = one thousandth of a metre

 

[BlueCorn]

<a href=showthread.php?s=&postid=8992046#post8992046 target=_blank>Originally posted</a> by edwing206
so it lets in less light when you are zoomed in?

Yes. You can get lenses that remain constant throughout their zoom range but you'll pay for that privilege in most cases.

 

[Blazer88]

<a href=showthread.php?s=&postid=8994604#post8994604 target=_blank>Originally posted</a> by beerguy
Yes. You can get lenses that remain constant throughout their zoom range but you'll pay for that privilege in most cases.

But that difference is very significant. I got very few decent shots with my kit lens because it was F/5.6 when zoomed it, there wasn't enough light to get a decent shutter speed and I didn't want to bump the ISO to 1600. I think a constant F/2.8 throughout the zoom range, or prime, makes all the difference.

 

[BlueCorn]

It may or may not be worth the money. It all depends on how and what you shoot. All of my lenses are constant aperture with the exception of my 200-500. In the real world it's of little value to me. I do primarily landscapes. As such I'm almost always above f/8

 

[Blazer88]

I agree, it completly depends on what you are shooting and how you want to do it. For corals, I use a tripod and open the aperture up to around F/16'ish depending on how the want the DOF, so having a smaller f-stop doesn't matter. But when shooting fish, it helps to have a quick lens that will still allow sufficient light at 1/200 of a second. And I found that at F/5.6 just didn't cut it for me to shoot fish. But speed has it's price, that's for sure.

 

[edwing206]

ok thanks