Very basic question-im new-f/?

Hi, I am new here and I have 1 question which I can't find the answer too.


If a camera is listed as 18-125mm f/3.5-5.6 for example.... what does the f/3.5-5.6 mean? I think it has something to do with the aperture/f-stop but I am not sure and would like the correct answer.


So for example what would the different be between
18-125mmf/3.5-5.6
AND
17-85mm f/4-5.6

It means that the max aperature is different at different focal lengths. For example, the max aperature at 18mm is f/3.5 and at 125mm it is f/5.6.

*Note: you will see some zoom lenses listed with only one aperature. For example, 70-200 f/2.8. These lenses maintain the same max aperature throughout the zoom range.

At 18 mm the largest f/stop is f/3.5; at 125 mm, it's f/5.6.

The f/3.5-5.6 refers to the widest aperture that a lens has. In the case of the 18-125mm f/3.5-5.6 lens that you mentioned the widest aperture changes from 3.5 to 5.6 depending on the focal length that you are using on that zoom lens.

oh! thanks very much for the quick response. that makes perfect sense. thank you!

And welcome to the forum.

i had no clue what that meant eiter when i first entered photography...funny because it's one of the most important factors when considering a lens...

as everybody said its the max aperture....

the difference between the 2 lenses you stated is that the 18-125 is slightly faster at the wide end (able to take pictures in less light at 18mm at the same shutter speed as the 17-85 at 17mm)
both are the same speed at the zoom end...