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Old 14-05-2005, 19:10   #1
zorro
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Help with Depth Of Field

Just got my new 350D, but struggling with using/adjusting DOF

I have set the camera to AV mode.

I then focus on an object, using the centre focus point.

I adjusted the Aperture setting to 4.5, which gave me a shutter speed of 1/30

I then adjusted the aperture to 22, but this gave me a shutter speed of 0.8sec (seems too slow to work with )

l photographed an object 3 feet away from the camera.

looking at the pictures, there is little/no difference

Any suggestions as to what I am doing wrong?

Do I need to set both the aperture and shutter speed manually?

Any help appreciated please.

Thanks
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Old 14-05-2005, 20:58   #2
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Hi Zorro,

Once you've got to grips with DOF you will undoubtedly start producing some great pictures out of seemingly boring things. Its great fun experimenting with it. There are some quite in depth explanations around and calculators but I think this quote below say's it in a nutshell

Quote:
There are 3 ways to manipulate depth of field: Iris, Focal Length and Camera-to-Object Distance.

One can achieve a great depth of field by using a great camera-to-object distance, a short focal length and/or a small iris opening (high f stop number)

One can achieve a shallow depth of field by using a short camera-to-object distance, a long focal length and/or a large iris opening (low f stop number)

The longer the focal length, the shallower the Depth of Field. The shorter the focal length, the greater the Depth of Field

The greater the distance between the camera and person/object, the greater the Depth of Field. Conversely, the shorter the distance between the camera and person/object, the shallower the Depth of Field.
Hope that helps, let us know how you get on.

Example >>

Shallow DOF

HERE

ps - You got your camera in the right mode, different shutter speeds have no affect, Doesn't mean you dont need to consider shutter speeds for other reasons though

Last edited by Goatface; 14-05-2005 at 21:09.
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Old 14-05-2005, 21:07   #3
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Zorro, I started working out DoF in a really simplistic fashion.

Here's how:

I got four batteries. And a table.

I put approx five cm between each battery (stood up) and focused one by one on the batteries, side on, close up. From the front.

Starting at F2.8 just the front one was in focus. By F11 the first three were clearly in focus. By F22 the whole lot were stark. When you get past F11 you really should start thinking about a rest for your camera, aka monopod or tripod.

I really recommend you buy a book called Understanding Exposure by Bryan Peterson. He covers this in great depth together with shutter speed and all that gubbins. Find it at amazon, here
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Old 15-05-2005, 06:12   #4
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Hi Stormy

I just did your DOF battery example, and it seems really helpful - took 6 shots below, increasing F by 3 or 4 each time, starting at starting at F4.5. Is this the sort of thing you'd expect:

http://www.odysseus-software.co.uk/D...t/_dsc0001.jpg
http://www.odysseus-software.co.uk/D...t/_dsc0002.jpg
http://www.odysseus-software.co.uk/D...t/_dsc0003.jpg
http://www.odysseus-software.co.uk/D...t/_dsc0004.jpg
http://www.odysseus-software.co.uk/D...t/_dsc0005.jpg
http://www.odysseus-software.co.uk/D...t/_dsc0006.jpg
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Old 15-05-2005, 08:49   #5
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To emphasis DOF, use the top end of your zoom range.
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Old 15-05-2005, 08:52   #6
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Here is a link to a site that has a few DOF articles and a DOF calculator.

http://www.dofmaster.com/dofjs.html


Here are some examples of a narrow DOF

Here

and

Here

Last edited by davepop; 15-05-2005 at 08:53.
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Old 15-05-2005, 11:14   #7
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Andy, that's the sort of thing you would expect, yes.

As others have said on here, you see the most acute examples of DoF using longer lenses - it's pretty hard NOT to have shallow depth of focus on a telezoom such as a 400mm prime, for example.

Likewise, wide angle lenses (short ones, aka the 18-70 Nikon kit lens, 18-55 on the Canon) will make it easier for the photographer to enjoy deeper focus - that's why they're favoured by landscape photographers (as well as being able to take in more of the panorama, of course!)
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Old 15-05-2005, 11:36   #8
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The easiest way to get quick shallow depth of field shots are long telephotos as said or focusing on something very close with a wide aperture.

It's also worth picking up one of the books in this thread to learn this kind of stuff...

Recommended photography books
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Old 16-05-2005, 14:41   #9
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Thanks for the tips guys - much appreciated

Going to try the battery test and also look at some of the books recommended here.

Cheers
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Old 16-05-2005, 21:07   #10
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Talking of DOF...here's a really shallow example.....

400mm@f7.1 1/400s
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Old 23-05-2005, 13:55   #11
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is it possible to get DOF effects with a compact digital camera (Fuji A303) and if so how (and any tips for cameras with only a zoom lens and auto-focus?)

Cheers
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Old 23-05-2005, 14:38   #12
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Quote:
Originally Posted by homerjhandley
is it possible to get DOF effects with a compact digital camera (Fuji A303) and if so how (and any tips for cameras with only a zoom lens and auto-focus?)

Cheers
I remember doing it once with an old Canon Sureshot Megazoom.
It was basically wild flowers in the foreground and an old house in the background.

I got as low and as close to the flowers as I dared (because of minimum focusing) and the house - which was several hundred yards away - was thrown pleasingly out of focus.

There are some nice basic interactive examples of the principles on this page:
http://www.ted.photographer.org.uk/p...ce_control.htm

A.
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Old 23-05-2005, 20:27   #13
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With the A303 I think you can set the aperture in the options. Make it the lowest number you can in order to get the shallowest depth of field.

Fully zoomed it's f/4.8, and at the widest angle it's f/2.8. Play around, go wide (zoom right out) and get very close to your subject, as close as it'll still focus at, with your aperture set to f/2.8 and see how blurred the background is. Then move further away and zoom right in at f/4.8 and see how it looks.
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Old 23-05-2005, 20:45   #14
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no aperture in the options, only white balance and EV.
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Old 23-05-2005, 21:53   #15
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Quote:
Originally Posted by homerjhandley
is it possible to get DOF effects with a compact digital camera (Fuji A303) and if so how (and any tips for cameras with only a zoom lens and auto-focus?)
Certainly possible, but the problem with compact digitals is the focal length is much smaller due to the smaller lens & sensor sizes (we're talking figures like 6mm!). Though they have equivalent fields of view to typical "35mm film" lenses, the focal length is still very small and this makes for a deep depth of field, thus less chance of that funky shallow DOF effect.

However you can still do it with exactly the same rules as for SLRs, i.e. one or more of these get you a shallow DOF...

1. Longer focal length... i.e. use the optical zoom on the max setting
2. Wide aperture (low 'F' number). Some compacts have manual settings others have 'Aperture Priority' which lets you set values like f/2.8 (my old Fuji used to have that).
3. Short focal distance... i.e. get right up close to the subject (bonus of compact digitals is they can focus a lot closer than SLRs without the use of a special macro lens).

A combination of the 3 will yield the best results, but even 1 and 3 will do if you can't set the aperture.

You may not get as good results as you'll get with an SLR, but you can still get some reasonable results in the right conditions.

Last edited by DeadKenny; 23-05-2005 at 21:59.
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Old 31-05-2005, 11:29   #16
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Quote:
Originally Posted by DeadKenny
1. Longer focal length... i.e. use the optical zoom on the max setting
2. Wide aperture (low 'F' number). Some compacts have manual settings others have 'Aperture Priority' which lets you set values like f/2.8 (my old Fuji used to have that).
3. Short focal distance... i.e. get right up close to the subject (bonus of compact digitals is they can focus a lot closer than SLRs without the use of a special macro lens).

A combination of the 3 will yield the best results, but even 1 and 3 will do if you can't set the aperture.

You may not get as good results as you'll get with an SLR, but you can still get some reasonable results in the right conditions.
thanks for the tips guys I just tried this with my old casio Z3 tiny compact and got some great results
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