Landscape aperture?

[jamesdavidboro]

Is it important to set a small aperture on landscape shots and what Aperture is best to use? I've been useing around f/9 - f/12 but i took some shots today with the Aperture wide open right down to f/3.5 and i can barely tell the difference compared to ones taken with f/9. Surely once the cameras focused to infinity the Aperture will make littel difference to dof?

 

[Boomn4x4]

Is it important to set a small aperture on landscape shots and what Aperture is best to use? I've been useing around f/9 - f/12 but i took some shots today with the Aperture wide open right down to f/3.5 and i can barely tell the difference compared to ones taken with f/9. Surely once the cameras focused to infinity the Aperture will make littel difference to dof?

What kind of range are we talking about?

Just to make some numbers up, if at f/3.5 the dof is 10' and you are shooting at something 50' away, then everything 10' in front of and 10' behind will be in focus, the other 40' in front and infinity behind will be out of focus. You'll notice a differene. however if you are shooting mountains that are 10 miles away, the DOF at 3.5 would be 200' the DOF at f12 would be 1000', but since you are so far away, you aren't going to be able to tell much of a differnece between 800' from 10 miles away.

 

[pgriz]

To add to what Boom said above,

According to the information here: http://www.dofmaster.com/doftable.html, at f/4 and 18mm, your hyperfocal distance is 13’4”, which means that if you place your focus at 13 feet, 4 inches, everything from about 6 ft. 10 inches to infinity is in focus. At f/22, the hyperfocal distance is 2 ft. 5 inches, so that everything from about 1 foot to infinity is in focus. So you have tremendous depth-of-field at 18mm. If you change your focal length to (say) 50mm, the depth of field changes dramatically. At 50mm and f/4, your hyperfocal distance is at about 103 ft., and at f/22, it is at about 18 ft.

So to answer your question, the reason you are not seeing much difference between the shots at various apertures, is that you are shooting at the low end of you focal length (18mm probably), and at that focal length you get tremendous depth of field. If you increase the focal length to something closer to 50mm, you will see the depth of field shrink dramatically, and then the combination of f/stop and focus placement will play an important role in determining what part of your scene is in focus.

Try this experiment – it will help you determine what you can/should expect of your equipment.

Go to a landscape location you want to immortalize. Choose a time when the landscape has good side lighting (so that the shadows allow you to see detail at all distances). Choose a vantage which has foreground (say 5-15 ft. away), middle ground (50-100 ft. away) and background (essentially at infinity). Set your camera on a tripod. This is important, as you will be comparing photos shot at different focusing points and f/stops, and you want to eliminate camera motion as a contributor to lack of sharpness.

Decide on your “typical” focal lengths you will use for landscapes. Say they are 18mm, 28mm and 50 mm.
You will shoot a total of nine photos at each focal length: three focused on the foreground, three focused on the middle ground, and three focused on the background. The first set of each three will be wide open (f/3.5 in the case of your equipment), the second will be at f/11, and the last will be at f/22.

Upload your shots to your computer and examine the shots. What you will find, is that at 18mm, due to the depth-of-field, pretty much everything will be in focus regardless of the f/stop and focus placement. At 28mm, your depth-of-field starts shrinking, and focus placement, especially at the open aperture, becomes important. At 50mm, your foreground shots may show the background in focus only at the high f/stop of 22.

If you have a prime lens (and according to your equipment list you don’t), you will find the depth-of-field markers inscribed on the lens barrel, and you can use this tool to set the focus point so that your chosen scene is within the necessary range of the depth-of-field. With zooms, one has to use either a calculator or tables, as the depth of field markers on the barrel don’t work (they vary according to focal length). So I have a set of tables printed out for my camera and lenses, and when knowing the precise depth of field is important for the composition, I will look up the combination I’m using to verify that I have adequate depth-of-field.

Now did I make this as clear as mud???

 

[KmH]

pgriz hits on a focus parameter near and dear to landscape photographers: the hyperfocal distance.
http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm
http://www.cambridgeincolour.com/tutorials/depth-of-field.htm

Also Boom 4x4 almost got it right. If the total DOF is 10' about half that will be in front of the focal point and the reminder will be in back, or roughly 5 feet in front and 5 feet behind.

The short focal length lenses used for landscape photography distribute the DOF closer to 1/3 in front and 2/3 behind.

The total DOF doen't mean that everything in that range will be sharply focused. Sharpest focus will only be at the focus point. From the focal point, the sharpness of focus begins diminishing gradually. How gradual the decline in sharpness is relative to distance from the focal point is what the total DOF range is defining.

With small apertures landscape photographers also need to be familiar with diffraction and it's negative effects of the sharpness of focus.
http://en.wikipedia.org/wiki/Diffraction

 

[clanthar]

The short focal length lenses used for landscape photography distribute the DOF closer to 1/3 in front and 2/3 behind.

Diffraction - Wikipedia, the free encyclopedia

It's a little more complicated than that. The 1/3 -- 2/3 rule of thumb has been around a long time and is commonly repeated. It has no substance in reality. Take for example a 35mm lens (wide) on a 35mm camera. Focused at 12 feet in front of the camera and set to f/8 the DOF distribution would be 12% front and 88% back. Stop the lens down further or focus farther into the scene and that distribution becomes more uneven. One more stop to f/11 and the DOF in back reaches infinity with 6 feet of DOF up front. The ratio of 6 feet to infinity sure isn't 33/66.

The DOF ratio will range seamlessly from basically 50/50 (focus close and large f/stop) to 1/99 back until back reaches infinity (focus far and small f/stop). 33/66 will occur along that seamless line. If there's a common type of photograph where 33/66 is more likely it's going to be a portrait with a portrait length lens.

Take Care,
Joe

 

[KmH]

The short focal length lenses used for landscape photography distribute the DOF closer to 1/3 in front and 2/3 behind.

Diffraction - Wikipedia, the free encyclopedia

It's a little more complicated than that. The 1/3 -- 2/3 rule of thumb has been around a long time and is commonly repeated. It has no substance in reality. Take for example a 35mm lens (wide) on a 35mm camera. Focused at 12 feet in front of the camera and set to f/8 the DOF distribution would be 12% front and 88% back. Stop the lens down further or focus farther into the scene and that distribution becomes more uneven. One more stop to f/11 and the DOF in back reaches infinity with 6 feet of DOF up front. The ratio of 6 feet to infinity sure isn't 33/66.

The DOF ratio will range seamlessly from basically 50/50 (focus close and large f/stop) to 1/99 back until back reaches infinity (focus far and small f/stop). 33/66 will occur along that seamless line. If there's a common type of photograph where 33/66 is more likely it's going to be a portrait with a portrait length lens.

Take Care,
Joe

Yep. I didn't want to go overload on the info.

 

[jamesdavidboro]

Thanks guys, brilliant response! Its a lot to take in but i think i'm getting there. Some really useful links aswell. As luck would have my new Helios 44-2 lens arrived today and its got a distance scale and depth of field scale on it which along with the advice given on here has really helped me start to figures things out. Once again thanks very much:thumbup: