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n0b0
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p.1 #1 · Why use only certain f-stops?

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.

Edited on Oct 11, 2008 at 04:48 PM · View previous versions

Oct 11, 2008 at 04:35 PM

EB-1
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p.1 #2 · Why use only certain f-stops?

I often use intermediate f-stops, but do not post images at FM. Use whatever you want.

EBH

Oct 11, 2008 at 04:38 PM

obroni
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p.1 #3 · Why use only certain f-stops?

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?

Oct 11, 2008 at 04:45 PM

n0b0
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p.1 #4 · Why use only certain f-stops?

EB-1 wrote:
I often use intermediate f-stops, but do not post images at FM. Use whatever you want.

EBH

Oh I do, sometimes at f/13 or some other numbers. I'm just wondering why those f-stop numbers are so popular.

Oct 11, 2008 at 04:46 PM

BenV
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p.1 #5 · Why use only certain f-stops?

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.

Oct 11, 2008 at 04:50 PM

n0b0
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p.1 #6 · Why use only certain f-stops?

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?

Oct 11, 2008 at 05:02 PM

bacilonur
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p.1 #7 · Why use only certain f-stops?

n0b0 wrote:
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?

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.

Oct 11, 2008 at 05:09 PM

mh2000
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p.1 #8 · Why use only certain f-stops?

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.

Oct 11, 2008 at 05:13 PM

AJSJones
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p.1 #9 · Why use only certain f-stops?

n0b0

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!

Oct 11, 2008 at 05:13 PM

n0b0
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p.1 #10 · Why use only certain f-stops?

Thanks for the explanation guys!! though I was kinda hoping for some outrageously complicated answer.

Oct 11, 2008 at 05:21 PM

jmcfadden
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p.1 #11 · Why use only certain f-stops?

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

J

Oct 11, 2008 at 05:34 PM

mh2000
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p.1 #12 · Why use only certain f-stops?

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...

Oct 11, 2008 at 06:01 PM

trenchmonkey
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p.1 #13 · Why use only certain f-stops?

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

Oct 11, 2008 at 06:05 PM

genoph
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p.1 #14 · Why use only certain f-stops?

N00B

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?

Oct 11, 2008 at 06:15 PM

rhorta
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p.1 #15 · Why use only certain f-stops?

mh2000
member since oct. 2005, +4000 posts

genoph
member since may 2008, +100 posts

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!

*read mh2000's noob factor

Ruy

Oct 12, 2008 at 06:05 AM

sirimiri
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p.1 #16 · Why use only certain f-stops?

I remember the lecture from my professor:

1/ASA = f/16 on a key day

C'est vrai?

Oct 12, 2008 at 06:13 AM

gasrocks
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p.1 #17 · Why use only certain f-stops?

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.

Oct 12, 2008 at 07:22 AM

Etadam
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p.1 #18 · Why use only certain f-stops?

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 * D² 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...

Oct 12, 2008 at 07:55 AM

Ariel Bravy
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p.1 #19 · Why use only certain f-stops?

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.

Edited on Oct 12, 2008 at 08:43 AM · View previous versions

Oct 12, 2008 at 07:58 AM

astrolucida
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p.1 #20 · Why use only certain f-stops?

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.

Oct 12, 2008 at 08:40 AM

ShutterLover
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p.1 #21 · Why use only certain f-stops?

As I learned on a full manual camera I feel comfortable with the easy maths of full stops, how they correspond to shutter speed stops, and how much brighter or darker my exposure will be a stop over or under.

With digital I'm chimping far more. If my histogram has room for a fraction more brightness, i'll nudge the aperture wider ending up on a intermediate stop.

Oct 12, 2008 at 09:13 AM

Ian.Dobinson
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p.1 #22 · Why use only certain f-stops?

looks like the monkey will have to change his name..'trenchnoob or noobmonkey'

some lenses work well wide open 300 2.8 is a case in point and I think if could afford to buy one I would want to use it wide as often as possible

as for the op's question I think its just a habbit we get into as its far easier to think in full stops when thinking about F's & shutter speeds & iso's

Oct 12, 2008 at 09:16 AM

simon_says
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p.1 #23 · Why use only certain f-stops?

It's easier to envision the relationship between shutter speed, aperture, ISO, etc. with full stops and convey it to exposure. For example, if you jump from one f-stop to the next full f-stop, you've halved the light coming in. Dealing with the f-stops in between requires a bit more mental juggling, unless you want to rely on the camera for automatic metering. Same with ISO settings - I prefer the full ISO increments (i.e. 200, 400, 800, 1600, etc.) rather than the in-between steps.

Oct 12, 2008 at 12:05 PM

ICQ

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p.1 #24 · Why use only certain f-stops?

For me, it's an old habit carried over from film days.

Now, I see that you're looking for a complicated answer. In the era of digital, the aperture settings allow more precision so sometimes I will dial in a bit more or less depending on:

a. direction I'm facing (I'll add .5 for North, .3 for South, .8 for East and .9 for West)
b. if the groom is ugly...I'll go down 3 stops
c. if the bride is beautiful, I'll go up 4 stops
d. if it's high tide, I'll increase the shutter speed by 2 stops and keep aperture constant
e. if the day of the week ends in "y", I'll dial up the aperture by 1/3
f. if the day of the week does not end in "y", I'll dial down the aperture by 1/3

Complicated enough? I try to follow those rules, but if I'm taking pictures of my significant other....I'll just move it to Program mode...I can blame the camera when she tries to point out an unflattering picture I took of her. (That is the most important rule in photography)

Dave

Oct 12, 2008 at 12:55 PM

n0b0
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p.1 #25 · Why use only certain f-stops?

HAHAHAHAHA!!

That's the best answer so far in this thread mate!! Not the most useful... but the best one nonetheless.

Oct 12, 2008 at 01:02 PM


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