I see images posted here and elsewhere and most of the time the aperture people use are either the widest the lens has or it's f/8, f/11, f/16, f/22. I hardly see people saying their image was taken at f/7.1 or f/13 or other f-stop numbers.
Why is that? Is there something special about those four f-stop numbers apart from 8 being half of 16 and 11 half of 22? Just a beginner wondering.
It's an old habit coming from the pre-AF film era, when the aperture was set directly on the lens - with only the full stops indicated there. I also feel somehow more comfortable using full stops (although don't use them exclusively now) but maybe it's just the old habit. Don't know whether it has any sense from the point of view of optics theory. Anyone?
n0b0 wrote:
I see images posted here and elsewhere and most of the time the aperture people use are either the widest the lens has or it's f/8, f/11, f/16, f/22. I hardly see people saying their image was taken at f/7.1 or f/13 or other f-stop numbers.
Why is that? Is there something special about those four f-stop numbers apart from 8 being half of 16 and 11 half of 22? Just a beginner wondering.
people usually buy a lens to use it wide open, why get a f/1.4 lens when your going to be shooting @ f8 most of the time? Also, people shoot at smaller apertures to in reap the benefits of it, usually being a sharper image.
BenV wrote:
people usually buy a lens to use it wide open, why get a f/1.4 lens when your going to be shooting @ f8 most of the time? Also, people shoot at smaller apertures to in reap the benefits of it, usually being a sharper image.
You seem to be missing the point here mate. I understand the concept of fast lens and the sweet spot of a lens at certain aperture, f/8 being chosen the most so far. What I don't get is why do people skip certain f-stops like f/9 and f/10 straight to f/11 then again skip f/13 and f/14 straight to f/16 and so on. Does it really make that much different to shoot at f/7.1 instead of f/8 or f/10 instead of f/11?
n0b0 wrote:
You seem to be missing the point here mate. I understand the concept of fast lens and the sweet spot of a lens at certain aperture, f/8 being chosen the most so far. What I don't get is why do people skip certain f-stops like f/9 and f/10 straight to f/11 then again skip f/13 and f/14 straight to f/16 and so on. Does it really make that much different to shoot at f/7.1 instead of f/8 or f/10 instead of f/11?
No, it doesn't. But unless they're using a handheld meter (in which case they may be given a number like f/5.6+4/10), it's a whole lot easier to do the math of finding your aperture/shutter speed sweet spot when dealing in full stops. I don't think it's an epidemic, it just depends on what metering mode you're using.
no, it doesn't make any difference, but when you shoot in Av people tend to shoot at "whole stop" values, as obroni said, it's more from habit. Sport, waterfall shooters etc. will tend to have even stop shutter speeds and then their f-stops will be where they fall for exposure.
I don't agree that people "usually buy a lens to use it wide open." More like noobs who have just discoverd the concept of DOF. Most people buy a fast lens to have the aperture when they *need* it.
obroni said it already : "when the aperture was set directly on the lens - with only the full stops indicated there. " The numbers you see as commonly used are the ones in the series x, x/sqrt2, x/2 etc from the early days. The ability to set the f stop between those numbers has always been there between the clicks (e.g. between f/11 and f/16) but it's not as though f/12 and f/13 and f/14 and f/15 have been marked and "skipped" as you seem to be asking about!
also , once i find the real sweet spot with a lens i try to make that aperture "fixed" in my work. I use a Nikkor 85mm PC while shooting sculpture and table top works and i will do whatever i have to do to shoot it at f11. It is simply staggeringly sharp at that f stop. Other lenses i use may have their own unique abilities at different f stops and subject distances etc
also, for those of use used to Sunny-16 think is full stops, so when you set an aperture you guess at the shutter speed without making test readings... intuition is only good for for a full stop of resolution...
I don't agree that people "usually buy a lens to use it wide open." More like noobs who have just discoverd the concept of DOF. Most people buy a fast lens to have the aperture when they *need* it.
Crap, I must be a noob! Stupid 'monkey buys 300 f2.8's and shoots them at f2.8
Think of all the money I could have saved getting an f4...but then I'd be a noob
AGAIN for shooting that wide open. 40 yrs of doing it all wrong...is there any hope
What a lame word. Go use it on another forum. We don't do the N00b call here. We're kinda friendly people. Or trying to be.
And it depends what you shoot. If you shoot landscapes, 2.8 is not going to be what you use. I shoot Portraits, Sports, live shows etc. I need speed and a blurry background (I don't got no muslin or lights).
Let's just keep the name calling to ourselves okay?
Now where does that put the "We" as in "We don't do the noob call here" on FM?
I agree that noob isn't the most tactful word and its easy to misunderstand. On the other hand I agree with mh2000 that many people use (super)fast lenses only wide open because they seem to be stuck in that single mode.
Sure I'm in love with my 85/1.2, but I use f/1.2 with moderation after the novelty* wore off!
It all depends on the lens you are using. I think I probably take more pix at f/13 than just about any other aperture. For macro it can be great as you start to get less IQ if you go over f/13 or so. For Wild birds I often use f/13 for the increased DOF.
obroni wrote:
Don't know whether it has any sense from the point of view of optics theory. Anyone?
Closing one full "f-stop" will divide the quantity of light by 2 (aperture area 'A' will be half).
The f-stop number is actually the diameter of the aperture D and is noted f (focal length) / D.
Now the question is: by how much should you reduce D to get half of the area A when closing one stop?
From A = pi * Dē you get D = √(A/pi)
To get A/2, you need D = √(A/pi) / √2
To get A/4, you need D = √(A/pi) / √4 (or √(A/pi) / 2)
To get A/8, you need D = √(A/pi) / √8
To get A/16, you need D = √(A/pi) / √16 (or √(A/pi) / 4)
√2 being 1.4142... and √8 is 2.83... rounded to 1 decimal (to get 2 digits), you see the story...
For me it's not about old film habits. (Never seriously shot film.) I shoot at f8 when outdoors doing walkaround photography. Why? It happens to be a convenient balance between dof, shutter speed, and sharpness when snapping shots.
Shooting with strobes? Set ISO, shutter speed, then dial in aperture to whatever necessary. This is when I use the intermediate apertures most often.
Macro? I can get a feel in my mind for roughly how much dof I'll have at f8, f11, f16, f22, and f32 and adjust accordingly. I'll dial in what I want and just start shooting. Maybe it would benefit from a slight twiddle of the aperture, but no big deal. When chimping, full stops give me enough of a change in dof to be sufficient.
Landscape? f8 is a good rule of thumb. I don't regularly shoot the wide angle shots that require f22 or f32. The only time I use those apertures are if I'm shooting moving water and want the longer shutter speed, or if I'm shooting landscapes with a telephoto and need the deeper dof. f25 or f29? Sure. It may save a little sharpness due to diffraction. It's easy enough to take a shot at f32, back off a bit and shoot another. Aperture bracketing in a sense. Pick the best shot.
n0b0 wrote:
Does it really make that much different to shoot at f/7.1 instead of f/8 or f/10 instead of f/11?
No, it does not. And that's exactly the reason that people tend to choose even aperture values. When you set the aperture yourself (Av or M mode), you have an idea of the depth of field that you want. The difference in DoF between full stops is enough to warrant changing the aperture.
