How to chose Aperture
I usualy stay in aperture priority mode with my D40 but I'm having and hard time choosing what aperture to use when it's not so obvious, for example if I'm shooting a portrait I'll stop the lens to it's higher setting if I want to control the DOF, or at f/10 f/11 if everything is at the same distance ex, person against a wall since it seems to be the "sweet spot" for my lens. I use f22 if I'm shooting landscape to get a much as possible in focus. My question is what about all these extra aperture setting? do you have a general rules you guys uses?.

Thank you..

Comments (11)

I think living above f/11 is eliminating many of the benefits of the DSLR..

I'd say go down to f/4 at LEAST if everything is coplanar and work up from there. F/8 should be fine for sharpness on portraits..

I suspect your shots look like P&S shots a bit too much. .

But hey, it's digital. Shoot all-around and see what you like. Put it in P mode...let the camera tell you what IT thinks is best. See if you agree or not..


Comment #1

Each lens behaves differently, however a few general statements are possible :.

(1) Diffraction limits the resolving power of all lenses. As you go above f8 ( say from f11 on ) all lenses will start to loose sharpness because of diffraction effects ( which cannot be undone or counteracted ). Going above f11 is generally not a good idea..

(2) Most lenses ( but not all ) are not very good wide open ( at max aperture ). You usually have use an aperture a couple of stops off maximum to get good sharpness..

Apart from that I suggest you consider looking at this lens review site and reading reviews. Note especially how there are compromises in making lens design, particularly in balancing cost, CA, aperture, vignetting, weight and performance..


If you look at your own lens ( if it's there ) you can compare it to other lenses..


Pentax K100DFuji S5200Fuji E900PCLinuxOS..

Comment #2

Let's say I'm on top of mt-fuji (will be in 2 month) and I want to take a nice landscape shot and have eveything from 6 feet to infinity in focus isn't stopping the lens at f/22 my only option?..

Comment #3


Short answer is "No" as you can use the hyperfocal distance as well. But you'll have to sort it out for your camera and focal length being used and aperture. There's a guide and calculator somewhere but I can't get out of this, look it up and come back....

Anyway, once you know the hyperfocal distance, all is simple. An example, on one of my cameras when at the zoom's widest all I need to do is focus manually on 4 metres and set f/4 and every thing from "near enough" to infinity will be in focus..

As I said it varies. So you either carry around a chart of else memorise (as I have) the settings for a popular mode/aperture or whatever..

For years I've said the cameras should include an "H" button to do it for you... But do they listen?.

Do a search in these forums and you'll find it quickly. There was a similar thread a while ago..

Regards, David..

Comment #4

The d-o-f calculator is here:.


With your D40 kit lens set to it's widest angle (18mm) and f/8 the hyperfocal distance is 6.7 feet; if you focus at this distance everything from 3.35 feet to infinity will be in focus. So you don't need to use f/22!.

Best wishesMike..

Comment #5

Great information, but may I add, if one were to focus at less than the hyperfocal distance, say 6 feet vice 6.7 feet, the far focus point would be about 56.72 feet rather than infinity. So, it is critical that one not focus at less than the hyperfocal distance...

Comment #6

So if the subject is at 3ft but the hyperfocal distance is 7ft I shouldnt focus on the subject?..

Comment #7

Sjgcit wrote:.

(1) Diffraction limits the resolving power of all lenses. As you goabove f8 ( say from f11 on ) all lenses will start to loose sharpnessbecause of diffraction effects ( which cannot be undone orcounteracted ). Going above f11 is generally not a good idea..

By way of a more specific example Thom Hogan says diffraction begins to affect the image on a Nikon D80 at f/13. I see no reason to disagree with him from my personal observations..

Chris Elliott.

*Nikon* D Eighty + Fifty - Other equipment in Profile.


Comment #8

If the hyperfocal dist. is 7' and you focus at 7' then everything from 3.5' to inf. is in focus. 'In focus' means within the limits of acceptable sharpness. There is still only one distance truly in focus. If your subject is at 3' and you want everything behind the subject in focus then pick an aperture with a hyperfocal dist.

Hyperfocal dist get closer as aper. gets smaller...

Comment #9

I would like to suggest something different; there is a book call Understanding Exposure by Bryan Peterson, it has a lot of great information on the use of exposure and a lot of examples of pictures he took. The thing I like about this book he explains the reasoning for the settings he used on each picture. It can be found at almost any good book store or on Amazon, I bought the book and I felt it was money well spent.David Trinkle

Comment #10


Lets try it:.

Pictures can be too dark or too light. Getting it right for the subject is what we do when we decide what exposure to give it. Or the camera or meter decides or suggests..

We get the right exposure by juggling with the aperture (which controls the amount of light coming through the lens) and the shutter speed (which decides how long it com for)..

Do I have to explain that in more detail? I doubt it: we should all know that second at f11 is the same as second at f/8 simply because we are doubling one and halving the other. So the result - how much light gets through - is the same..

But - here we go - changing aperture affects DoF and so we have to make a deliberate choice. But it's easy: large aperture (small number) is small DoF and small aperture is great DoF..

And changing the shutter speed also changes the picture by allowing blur or stopping it. So we look at the subject and decide for ourselves. Here's a clue, the cat asleep isn't in great need of 1/2000th of a second but a biker flashing past is....

Trouble is, digital does it all for us. With an old fashioned meter we get a choice..

Image control:Zoom outZoom 100%Zoom inExpand AllOpen in new window.

As you might see above the black & silver dials are showing 1/30th @ f/16 (almost dead centre of the frame), or 1/60th @ f/11, or 1/125th @ f/8 and so on to 1/4,000th @ f14 which makes life easy. And the DoF was marked on the lens when it was a prime being used (sigh)....

Hope this helps, David..

Comment #11

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