If you want to jump immediately to which f-stop you should use for a given situation, here are some examples. What are common f-stop settings? The barn was far enough from the camera that I could have used f-8, or maybe even f-5.6 and still had everything in acceptable focus. Some landscape photographers adjust their shutter speed and ISO settings to keep the aperture as close to that ideal as possible.įun Fact: The term “stops” comes from the early days of photography, when metal plates with holes of different diameters, called “Waterhouse stops,” were inserted into the lens to change the aperture. You can learn more about the interplay between f-stops, shutter speed and ISO here.Įach lens will be sharpest at a specific aperture, usually somewhere between f-5.6 and f-11. It’s a pretty simple concept, but there are numbers involved, which leads to math, which make it seem more complicated than it really is.Īlong with your shutter speed and ISO setting, your aperture is part of the “exposure triangle.” Adjusting each of these settings can give you a variety of different effects. The smaller the opening of the lens, the less light hitting the sensor but the deeper the depth of field. The larger the opening of the lens, the more light hits the sensor, but the shallower the depth of field. The f-stop, or aperture, is one of the key camera settings every photographer must master because it controls two critical things: the amount of light going through the lens and how deep the field of focus (depth of field) goes in your image. The distinctions may be subtle between a couple of middle apertures, but you’ll know at least which ones are visually sharper than others.Older cameras had the f-stops marked on the lens barrel. You’re likely to see the differences in sharpness in the definition of the smallest examples of type in the frame. It’s bound to be somewhere around three stops from wide open-so on an ƒ/2 lens that would be ƒ/5.6 or even ƒ/8. (You’re also likely to see fairly pronounced vignetting when shooting wide open.) Using a program such as Lightroom, it’s easy to switch back and forth between frames, or even compare them side by side, in order to determine which aperture produces the sharpest results. You’ll notice right away that the wide open exposures and the fully stopped down shots will both be not quite as sharp as those in the middle of the aperture range. Then adjust to ƒ/16 at one-quarter of a second, and so on, proceeding all the way down to an exposure at the widest aperture-ƒ/2 at 1/250 th.Īfter shooting an exposure at every aperture on your lens, import the images into your computer and take a close look at the details. Shoot a picture, then adjust to ƒ/22 and half a second before taking another picture. Let’s say you’re starting with an exposure of 1 second at ƒ/32. Something like a page of newsprint with very small text is an ideal candidate. It’s this detail that will test the resolving power of your lens. You’ll also want a flat subject with some really fine detail. This will allow you to not only check focus precisely but also ensure you’re not causing any camera shake since you’ll be tripping the shutter remotely. But the only way to know for sure which aperture is your lens’ sharpest is to test it.Īll you need to perform this test is a light, a tripod and a cable release-or even better, a tethered connection to a computer. It’s bound to get you close to the sharpest aperture. This rule of thumb has guided photographers to shoot somewhere in the neighborhood of ƒ/8 or ƒ/11 for generations, and this technique still works well. The sharpest aperture on any lens is generally about two or three stops from wide open. One of those tips involved choosing your lens’ sharpest aperture. Last week, we talked about several tips for making sharp photos.
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