Shutter speeds are even easier to remember as they are also reciprocals and are exactly half the speed before them and allow twice as much light: 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15. 1/8 (close enough to 1/7.5), 1/4, 1/2, and 1/1 which equals a shutter speed of 1 second.

Just learning these numbers and the relationships is not enough. One should test each lens to find the sharpest f-stop. Tests are not that important for wide-angle lenses but become more important as the size of the lens increases. For instance a 600mm lens is probably sharpest at around 5.6, while a 50mm lens is probably sharpest around f11. I have never hand-held many lenses as I always use a tripod, but the old rule of thumb says don’t try to hand-hold unless the shutter speed is about the same as the lens. For example, for a 200mm lens, the minimum shutter speed for hand-holding is 1/250. There are other little “gotcha’s” like 1/15 of a second is the absolute worst shutter speed to use when using a big telephoto. You could talk to 10 pro nature photographers and half would probably say not to use f22 as diffraction effects will soften the image while the others would say f22 is fine as the diffraction effect is so minor. Again, there is a reason to test each lens to find the sharpest f-stop.

One doesn’t have to go on a $5000 photo trip to perform the tests. Tape a piece of newspaper to a wall and shoot it with the camera on a tripod at every f-stop for the test. Before you go on the $5000 trip, you should know what f-stop to use for maximum sharpness, and you should practice practice practice adjusting the f-stops and shutter speeds until you don’t really have to think about it. All you need is the camera and one lens to practice, and you can do it watching TV, having a quick lunch, etc. The $5000 trip is not the place to finally take your camera manual out to read either.

Good shooting. Charlie

I still believe I can do all that using aperture and shutter priorities. They don’t prevent me from changing the ISO, and if one uses aperture priority and uses exposure compensation, that only changes the shutter speed, and vice versa.

I certainly couldn’t get the results I get without understanding the exposure triangle and how the f/stops work, how my camera’s meter works, and even a general knowledge about the sunny 16 rule, but I’m still not convinced actually memorizing the f-number series is that important for me or for most people using digital cameras these days.

Being able to pick up older cameras with ease is the most compelling reason for memorizing the f/stops I’ve read here. If I were using an older camera, I expect I would carry my digital camera too and use it basically as a light meter. I don’t own a macro lens and have tried some macros reversing my 50mm lens, and I need to manually meter for these, so it is similar to using an older camera. I usually just take a few photos with the lens on the right way to get an idea of the settings I want, keep the sunny 16 rule in mind, and go from there, checking my histogram until I get it right. Other times I’ve found I need to use manual exposure are for panoramas and situations where I want a series of photos with the same exposure, for long-exposure night shots, and for the rare occasions when I’m using my speedlight (and there is where I get confused, and knowing the f-number series by heart here might be very helpful).

I am a relative novice at photography and self-taught (I read a lot), and I admit it’s very possible I’m missing something. I like to bake bread, and to me baking with a bread machine is just not getting the full effect,even though I have more control over the bread than if I bought it in the store and even if in the end it tastes pretty much the same as what I would make fully from scratch. Perhaps using my camera in full manual mode will become like that to me, but for now aperture and priority modes are working fine.

Add to this understanding the metering mode (spot, center-weighted, matrix) and focus and that is pretty much it for shooting without flash–except for large format type camera movements. All the other menus, buttons, wheels etc. become redundant. My DSLR has over a hundred settings menus — that menus, each with multiple options. Very few of them add any value over the five basic settings (f/stop, shutter speed, iso, metering mode, focus.)

@Deirdre – I think Tim answered your question pretty well, so I’ll just add one little thing: knowing this f-number series can help you think quickly about the different options you have when making a photograph. For example, let’s say you’re photographing hummingbirds and shooting handheld: you try shooting at f/5.6 and 1/1000 sec but then realize that f/5.6 isn’t getting you enough depth of field, so you want to shoot at f/8 but then you know that this will change your exposure to 1/500 sec (which is a little too slow for handheld shots and a long lens), so to keep that 1/1000 sec shutter you know you have to make up for that stop somewhere else now (like ISO).

@Tim – thanks so much for that great response!

I find aperture or shutter priority to be beneficial when there is simply no time to make fiddly adjustments — the shots are coming too quickly and I have to respond instantly. Without that time pressure however, I am much more likely to get the shot I have in mind (out of focus background or background included, motion blur or stopping fast motion) if I shoot in full manual. Motion blur, camera shake, depth of field, ISO noise can all make for very different results.

When shooting in one of the priority modes exposure is semi-automated, but this doesn’t mean that these automated changes can’t profoundly affect the nature of the image. With aperture priority you can easily find yourself shooting at shutter speeds that are too slow for hand-held, and in shutter priority you might not want full depth of field, or extremely shallow depth of field depending on the image you have in mind. You determine the setting of your priority manually, but you may not want all possible adjustments to the automated setting.

Exposure compensation can be great, but it might be important, depending on the situation, to know what is happening to the image when you dial in that compensation. Are you changing the depth of field? How much? Have you just lost the ability to prevent a blurring of the leaves in the breeze? Knowing the major f/stops allows you to make appropriate adjustment to aperture, shutter speed, or iso to compensate for automated adjustments that take the image out of the realm you have in mind.

When it somes to setting f/stops I tend to think in terms of three regions. Shallow depth of field being the open stops, maximum depth of field be the smallest stops (highest numbers), and greatest sharpness being the middle region (f/8 or f/11, generally). I know this is a very broad brush, but I find it useful for just that reason. In the open and middle f/stops focus can be critical, but in the smaller stops it is much more forgiving due to the greater depth of field. If I am working in shutter priority and move into the shade I can suddenly find myself with minimal depth of field — if that happens I will probably want to know it.

On the other hand, it can be very liberating to shoot on P, or with a Holga and enjoy the surprises! Being comfortable with full manual stops just gives me greater ease with precise control when I need it.

I usually shoot on aperture priority, sometimes on shutter priority, and I make liberal use of exposure compensation. If, for some reason, I need to shoot on manual, I first put my camera in aperture or shutter priority, get the exposure right there, and then I move to manual and put in those same settings. Or I just fiddle to get the exposure right in the in-camera light meter.

I did memorize this stuff at one point, but because I so rarely have any need for it, I no longer have it memorized. I’m stsill not sure why I should.

santosh gaikwad