ltcarizona

There's a lot more that goes into your question than what you are asking. All lenses are not equal due to the quality of the lens. Nikon, Canon, and Sigma have lenses that have some very fine lens elements/optics which contribute greatly to lens sharpness, flare, vignetting, etc. But you have to be willing to spend the money. Sometimes you can get a lens that might be a lower cost lens where the optics are outstanding but the lens materials may not be as good. Also as the aperture increases(largest) in size: F/2.8, F/1.8 and F/1.4, etc the price goes up sometimes a lot, but this depends on the type of landscape photography you are going to do. Is it going to be night landscapes? Then too as one mentioned in this forum you have to consider that the optimal aperture is for each lens. Each lens has one and it is based on what has been determined by testing or actual use to be the sharpest and distortion free aperture. And that is not always the largest aperture. You will find in many cases it may be F/2.8, F/4 or smaller. This will sacrifice in some cases your lens low light sensitivity, but this can be offset by the time you allow light to enter into the lens at the smaller aperture. But that comes with increase in noise which can ruin a photo if too high. Last, but not least each wide angle prime has it's special uses, for example astrophotography requires a 20mm or better, thought some other can work again if you want more noise or distortions, as do all wide angle lenses greater than 35mm for the most part.

One more point to consider are the usually higher priced zoom lenses that cover a wide angle range. But that depends on the type of photography you are using for landscape like depth of field and broken. Some of these lenses from the manufactures I mentioned have terrific optics and can obtain just as good photos as a fixed lens, although there is a lot of debate out there on this based on personal photographer experiences. And then too a top quality wide angle zoom like I use can cover a lot more varieties of landscape without limiting you or forcing you to move all around and also leaving one less lens to carry especially when traveling and weight can be a concern.

I may have given you a lot of advice, but it is based on the possibility that you are not beyond a amateur or beginning photographer based on the wording of your question. Otherwise all this information would have been known to you. Last, but not least do your research between lenses.

PHRubin Loc: Nashville TN USA

What no one yet has mentioned is that there is a secondary consideration hurting focus. As you stop down to smaller and smaller focal lengths (larger f/#) the effect, fringing, gets worse. Since f stop is related to focal length, the wider the focal length, the sooner you encounter this effect as you stop down.

drmike99 Loc: Fairfield Connecticut

No. There is only ONE variable: the aperture size. The others are all functions of the former. The aperture (size of the hole) determines the DOF because it is pure physics, the size of the aperture compared with the wave length of light. A shorter lens gives a smaller aperture at a given "f stop" value. F stops are written f/1.4, f/8, f/16 etc. That is a ratio of the focal length of the lens to the numerical constant we assign as an "f stop." So an 80 mm lens at f/8 has a 10mm aperture. A 16mm lens at f/8 has a 2 mm aperture. BOTH ADMIT THE EXACT SAME AMOUNT OF LIGHT AND WILL GIVE THE SAME EXPOSURE WITH A GIVEN SHUTTER SPEED AND ISO. But the 16mm lens, having an aperture of 2mm, as compared with the 10mm aperture of the longer lens, gives a greater DOF because of the physical size of the aperture. F stops are NOT the aperture, they are a convenient way to get equal exposures with different focal lengths. In short, f/8 is a different size aperture for different focal length lenses, but a CONSTANT amount of light admitted. The idea that the small sensor relates to the DOF follows from the fact that a small sensor (or film size) requires a shorter focal length to achieve the same field of view as a larger sensor. And the shorter focal length lens has a smaller physical aperture for a given "f stop" and therefore a greater DOF. It is ALL a function of the size of the aperture and nothing more.

maren

Thanks for the website and information about it CO.

rehess Loc: South Bend, Indiana, USA

Don't you focus totally open, and then stop down to take actual picture?

mcveed Loc: Kelowna, British Columbia (between trips)

Yes, but you don't have to do it - the camera does it for you. The lens is wide open until you press either the shutter button or the depth-of-field-preview button.

dsmeltz Loc: Philadelphia

Most auto focus systems work that way. But it will depend on the camera body and the effective largest aperture. I have a Canon 80D that will focus as long as the maximum largest aperture is 8.0. But is I have a a lens with a 6.3 and a 2x extender, I will not get AF. A lot of older bodies do not get AF at 8.0, so the restriction is greater.