f/3.5-5.6 limit on camera lenses?

Question

i'm looking a lenses for my canon camera, and there are lenses that list 3.5-5.6 limit. why? when i turn the f stop to 16 or above, i can easily see that it goes above 5.6. i'm confused here

Answer 1

AAARRRGGGHHHHHHH.





Those figures are the largest aperture you can use at the bottom and top end of the zoom.



SO..... if it is a 70-200mm zoom then at 70mm the largest aperture is 3.5

at 200mm the largest is 5.6.



Largest being the size of the aperture not the number.

Answer 2

You are going the correct route. A DSLR is more than a body, it is a camera and lens. All too often, neophytes buy the most expensive camera they can, then skimp on the lenses as they don't have any more money. A budget DSLR vs. high-end pro DSLR are both going to give you great photos (although the pro DSLR might have better low-light capability, etc), but a crappy lens vs. a high-quality lens is going to make a lot of difference. So there is merit into buying the best lenses you can. A great camera + crappy lens = crappy photo. In the overall scheme of things, you should have 80% of your camera dollar invested in lenses. Assuming you have a DX (cropped camera), I would go with the Nikon 10-24mm f/3.5~4.5 or Tokina 11-16mm f/2.8 for landscape rather than the 24-120mm. For the 40mm macro, it is a tough call. I own both the Nikon 40mm f/2.8 micro and Tokina 100mm f/2.8 macro, and I have occasion to use both. Even though they are both 1:1 macro lenses, the 40mm is my lens of choice if I am doing more close-up than macro, while the 100mm is used for extreme macro. The reason I like the 40mm is that the DoF is a lot wider at 40mm than it is at 100mm. At 100mm, the DoF is wafer thin, and in some situations (say the object is not perpendicular to the lens), you will have a hard time keeping the entire subject in focus. But for the best extreme close ups, I go with the 100mm. You can do wildlife on a 70-300, but if you are looking at birding, I would go with something more in the 400-500mm range. My telephoto gear consists of a Nikon 80-200mm f/2.8 for sports and action photography, and a Tokina 80mm-400mm f/4~5.6 for wildlife. I like that approach (although it is a bit more expensive to buy two lenses) as each lens is more or less tailored to it's purpose. Specifically the 70-300mm will not work very well for fast action/sports photos - at least not nearly enough as a 70-200mm f/2.8. And the 70-200mm f/2.8 is just too short for birding, etc. And since you will need a tripod for the longer lens anyway, and due to the nature of wildlife, a slower lens is not as much of an issue. But realize that you are getting into very expensive lenses when you go telephoto, and what works for me may not work for you. If you are not sure, consider renting a few lenses and see how they work out for you before you buy one.

Answer 3

The smaller the number, the bigger the aperture. All lenses have a range of apertures, as you have discovered usually down to f16 or f22 or similar. The quoted f3.5 to f5.6 relates to the maximum aperture at the different zoom settings. Max aperture is quoted because that is what 'sells' the lens, e,g an f1.8 or f1.4 is more expensive than an f3.5, and will take photos in lower light levels.



Small apertures such as f11, f16, f22 are good for large depth of field, such as a landscape where you want the nearby people and the distant mountain both to be in focus (sharp).

Answer 4

3.5-5.6 is actually the largest aperture you can use on the lens, which is typically more important to people than the smallest aperture. Most lenses can go to F22 or smaller, regardless of whether they are low quality or high quality glass. It costs more to get a faster lenses with an aperture that goes to F2.8



At the widest angle, your maximum aperture if F3.5. As you zoom in, and then are fully zoomed in, your largest aperture is F5.6. Larger apertures mean you can get by with less light.

Answer 5

Okay, when the lens is all the way zoomed OUT, you can't use an f/ stop wider than f/3.5

and when the lens is all the way zoomed IN; you can't use an f/ stop wider than f/5.6... You can try it but when it's zoomed in; you can't have an f/ stop thats lower than f/5.6. You can use a narrower f/ stop though..



This isn't the case with all lenses though, there are sharp fast zoom lenses out there that are a bit more expensive; but they can stay at a constant aperture through out the whole zoom range.

Like the 24-70mm f/2.8; it can stay f/2.8 at the 24mm end; and even when zoomed in to 70mm you can still use f/2.8.

Answer 6

Zoom lenses.



Lenses are marked/classified by the largest aperture they are capable of (i.e smallest f-number). So 3.5-5.6 means at the wide end of the lens (completely zoomed out) you can set f3.5 upwards, at the long end (completely zoomed in) you can get f5.6.



Apertures smaller than those mentioned are possible (how far depends on the lens but common is somwhere between f16 and f32 depending on the lens).

Answer 7

The aperture (aka f-stop) of a lens is the opening formed by the movable blades of the diaphragm inside the lens. It is expressed by numbers such as f1.4, f2, f2.8, f4, f5.6, f8, f11, f16, f22, f32. The smaller the number the larger the opening and the larger the number the smaller the opening. If we had a lens marked as shown then f1.4 would be the largest opening of the diaphragm and f32 would be the smallest.



If you are looking at, say, the Canon 18-135mm f3.5-5.6 zoom, at 18mm your maximum aperture is f3.5 and at 135mm your maximum aperture is f5.6. This is a variable aperture zoom and as you zoom from 18mm to 135mm you lose 1-1/3 stops. So if you are shooting "wide open" at 18mm (f3.5) and your shutter speed is 1/200 sec. and you zoom to 135mm (f5.6) your shutter speed will drop to approximately 1/67 sec.



Of course you can "stop down" from f3.5 to f8 or f11 or f16 just as you cab "stop down" from f5.6 to f8 or f11 or f16.