Hey guys, so I've really been experimenting with my camera the last few weeks, and Im trying to get to know my camera and the more i do it the more motivated I am getting. However, I would like a few things explained to me, in a way that won't just make my head hurt in confusion.
DOF.
So I've been trying to learn the concept of a long depth of field, and by that I know that I need to have:
-A higher aperture, and a slow shutterspeed??
-adjustment to the ISO depending on lighting....
and for a low dof,
- small aperture, errrmm... fast shutterspeed.
Im working with a 18-55mm at the moment, and maybe it's me, but I can't seem to get a really long dof when focusing on landscapes. I always have to subtly edit the contrast on photoshop as well. would a higher aperture sort that problem?
Im sorry if I sound stupid and I am slightly embarassed because everybody here are experts :/
Im thinking of investing in a better lense, with a better focus and focal length, ideas? Everybody has recommended the 50mm prime.. will that do the job? Thanks
Board index ‹ Photography ‹ Technical Questions ‹ Understanding Dof long post.. please read
Technical Questions
Understanding Dof long post.. please read
8 posts • Page 1 of 1
- Posts: 540
Wed Mar 14, 2007 2:16 am
What settings are you using? f/11 focused on infinity or a little bit closer should do the trick.
Nikon D300, D200
Nikkor 50mm f/1.8D, 55mm f/1.4 micro, 18-70mm f/3.5-4.5G DX, 80-200 f/2.8D
Apple PowerBook G4, MacBook Pro
Adobe Lightroom, Photoshop CS3
Nikkor 50mm f/1.8D, 55mm f/1.4 micro, 18-70mm f/3.5-4.5G DX, 80-200 f/2.8D
Apple PowerBook G4, MacBook Pro
Adobe Lightroom, Photoshop CS3
- Posts: 224
Wed Mar 14, 2007 10:06 am
Firstly, there are no stupid questions here, we all had to ask too along the way. 
Your understanding of DoF is correct so far. Some other points to consider:
I presume you are using a sturdy tripod and either a cable release or self-timer if your shutter speeds are below (e.g., we are all different in our abilities to hand hold steadily) 1/60th? Don’t confuse poor DoF with camera shake.
Digital bodies suffer from diffraction badly, so that sharpness suddenly drops off at a set aperture (defined by sensor size and type). You might like to experiment here at see at what aperture this happens on your body, possible f/16 or f/22 might be as small as you’d ever want to go.
To get maximum DoF for landscapes, you ideally should be using the hyperfocal distance method. Unfortunately Nikon make some lenses without the distance scale ideally needed to do this (I’ve never understood how they think it’s acceptable to sell a lens with no distance scale). Regardless, it’s worth knowing the technique anyway. Using an online DoF calculator (such as: http://www.dofmaster.com/dofjs.html), and imagining that we are shooting a landscape with the lens at 18mm focal length, with an aperture of f/16, we can see that focussing at 3.38ft (1.03 metres) will give us everything from 1.69ft (0.51 metre) to Infinity in focus.
Finally, if you are still having DoF field issues, note what renowned Nikon expert Dr. Bjørn Rørslett has to say on lens design:
‘The internal focusing (IF) principle may unfortunately also introduce some colour fringing outside the plane of sharp detail. This can give rise to disturbing red, green, or purplish fringing of unsharp highlights. Lack of concurrent focus for the primary colours also leads to a certain fuzziness in the depth-of-field (DOF) zone. In the focused plane, colours may coincide more or less perfectly to diverge in front or back of that plane of maximum sharpness. Thus, many wide-angles will never attain anything like the theoretical DOF due to their residual colour aberration. Even very expensive lenses clearly exhibit such problems. I often find older lenses to behave much better in this respect - although their peak sharpness may be lower than the modern designs, they more than make up for this with improved rendition of the out-of-focus areas.’
From http://www.naturfotograf.com/lens_surv.html in accordance with Dr. Rørslett’s terms.
Perhaps if you posted a picture showing the lack of contrast other might be able to help.
The Nikon 50mm f/1.8 is great value for money, but’s that’s only true if you actually desire this focal length.
Hope that all helps.
Your understanding of DoF is correct so far. Some other points to consider:
I presume you are using a sturdy tripod and either a cable release or self-timer if your shutter speeds are below (e.g., we are all different in our abilities to hand hold steadily) 1/60th? Don’t confuse poor DoF with camera shake.
Digital bodies suffer from diffraction badly, so that sharpness suddenly drops off at a set aperture (defined by sensor size and type). You might like to experiment here at see at what aperture this happens on your body, possible f/16 or f/22 might be as small as you’d ever want to go.
To get maximum DoF for landscapes, you ideally should be using the hyperfocal distance method. Unfortunately Nikon make some lenses without the distance scale ideally needed to do this (I’ve never understood how they think it’s acceptable to sell a lens with no distance scale). Regardless, it’s worth knowing the technique anyway. Using an online DoF calculator (such as: http://www.dofmaster.com/dofjs.html), and imagining that we are shooting a landscape with the lens at 18mm focal length, with an aperture of f/16, we can see that focussing at 3.38ft (1.03 metres) will give us everything from 1.69ft (0.51 metre) to Infinity in focus.
Finally, if you are still having DoF field issues, note what renowned Nikon expert Dr. Bjørn Rørslett has to say on lens design:
‘The internal focusing (IF) principle may unfortunately also introduce some colour fringing outside the plane of sharp detail. This can give rise to disturbing red, green, or purplish fringing of unsharp highlights. Lack of concurrent focus for the primary colours also leads to a certain fuzziness in the depth-of-field (DOF) zone. In the focused plane, colours may coincide more or less perfectly to diverge in front or back of that plane of maximum sharpness. Thus, many wide-angles will never attain anything like the theoretical DOF due to their residual colour aberration. Even very expensive lenses clearly exhibit such problems. I often find older lenses to behave much better in this respect - although their peak sharpness may be lower than the modern designs, they more than make up for this with improved rendition of the out-of-focus areas.’
From http://www.naturfotograf.com/lens_surv.html in accordance with Dr. Rørslett’s terms.
Perhaps if you posted a picture showing the lack of contrast other might be able to help.
The Nikon 50mm f/1.8 is great value for money, but’s that’s only true if you actually desire this focal length.
Hope that all helps.
- Posts: 3780
Wed Mar 14, 2007 12:42 pm
Star wrote:
Just a quick note about this.. shutter speed does not affect dof, but it can add to the problems that tuckeruk so eloquently points out. If you're trying to get the smallest f/stop, plus even slower shutter speeds, you're actually causing extra diffraction you could easily avoid.
A simple rule, is to use a shutter speed two times as fast as the millimeter of the lens. So if you're shooting with a 50mm, keeping the shutter at a minimum of 1/100 should easily rule out movement. There's no sense in trying to lower your speeds in any situation, other than when you need to for motion effects. So try shooting at f/11, 1/100th or higher, and a tripod isn't needed on a sunny day.. and as mentioned by jdepould, focus in about 1/4 from infinity to take extra advantage of the dof you've achieved (as a simple example).
Good thread everyone.
-A higher aperture, and a slow shutterspeed??
-adjustment to the ISO depending on lighting....
and for a low dof,
- small aperture, errrmm... fast shutterspeed.
Just a quick note about this.. shutter speed does not affect dof, but it can add to the problems that tuckeruk so eloquently points out. If you're trying to get the smallest f/stop, plus even slower shutter speeds, you're actually causing extra diffraction you could easily avoid.
A simple rule, is to use a shutter speed two times as fast as the millimeter of the lens. So if you're shooting with a 50mm, keeping the shutter at a minimum of 1/100 should easily rule out movement. There's no sense in trying to lower your speeds in any situation, other than when you need to for motion effects. So try shooting at f/11, 1/100th or higher, and a tripod isn't needed on a sunny day.. and as mentioned by jdepould, focus in about 1/4 from infinity to take extra advantage of the dof you've achieved (as a simple example).
Good thread everyone.
- Posts: 258
Wed Mar 14, 2007 11:29 pm
A trick I used to use in difficult situations when I needed a full DOF was to shoot into a mirror. I had a mirror with a tripod mount. You have to watch your position and for distortion if you get too much of an angle, and of course reverse the print later.
- Posts: 2276
Fri Mar 16, 2007 8:19 pm
Vanwalree has a good article on DOF:
http://www.vanwalree.com/optics/dof.html#calc
Doug Kerr is another good source:
http://doug.kerr.home.att.net/pumpkin/index.htm
http://www.vanwalree.com/optics/dof.html#calc
Doug Kerr is another good source:
http://doug.kerr.home.att.net/pumpkin/index.htm
- Posts: 3
Tue Mar 20, 2007 11:15 am
The heart of all DOF tables is based on the hyperfocal distance. This is a formula for giving you a few extra feet/meters in your DOF. If anyone requires a Spread Sheet or a stand alone DOF calculator drop me an email.
- Posts: 537
- Location: Maastricht, Netherlands
Tue Mar 20, 2007 11:58 am
Here you can download a standalone DOF calculator: http://www.stegmann.dk/mikkel/barnack/ (Windows only...)
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