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07/09/2004 09:44:43 PM · #1 |
Bear with me while I try to ask this question carefully.
I know what Depth of Field is, I know it is a product of aperture size, focal length, and distance to the object focused upon. I know there are several web sites that have interactive web pages to calculate DoF.
Given focal lengths of 18 - 400, aperatures of 2.5 to 36 ( likely even wider), and an infinate amount of distances to a subject; how do most people learn how much DoF a particular setting will yield?
If by memorizing charts, that seems to be a lot to digest. If by trial and error that seems to be a huge number of photographs. Is there any other method for learning? |
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07/09/2004 09:52:13 PM · #2 |
A first step might be to print out and laminate charts for common focal lengths, apertures and distances. Refer to these while you're in the field. After a while, you wil start to get a good feel for what your DoF will be. You can also bracket youaperture setting +/- one stop and look at the effects. You have another distinct advantage in shooting digital; you cna review results immediately, and that does shorten the learning curve.
As long as it seems, there si no substitute for learning by doing, for really developing a feel for what a particular combination will produce.
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07/09/2004 10:01:31 PM · #3 |
I tend to just press the DoF preview and change the aperture to see the effect. Not sure if the D rebel has that though.
The other way to get a feel is to put the camera on a tripod, set it up and shoot it at various apertures to get an idea how it changes. |
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07/09/2004 10:11:04 PM · #4 |
Originally posted by kirbic:
A first step might be to print out and laminate charts for common focal lengths, apertures and distances. |
got a link for such a chart? |
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07/09/2004 10:32:32 PM · #5 |
Originally posted by longlivenyhc:
got a link for such a chart? |
//www.johnhendry.com/gadget/dof.php |
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07/09/2004 10:32:50 PM · #6 |
//dfleming.ameranet.com/ On occasion I also carry a palm pilot with this and planetarium software for sunrise/set info and DoF calculations.
Message edited by author 2004-07-09 22:33:28.
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07/09/2004 10:34:29 PM · #7 |
Hi.
After reading about DOF a little bit, I have a question:
DOF is better when aperture is smallest, right ?
Is there a reason than, to set the aperture to a higher value (say f/2.8) except for decreasing the shutter speed ?
Thanks.
garrywhite2, sorry if I interrupted your question, but the two seemed related to me. |
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07/09/2004 10:45:19 PM · #8 |
Originally posted by guy17il:
Hi.
After reading about DOF a little bit, I have a question:
DOF is better when aperture is smallest, right ?
Is there a reason than, to set the aperture to a higher value (say f/2.8) except for decreasing the shutter speed ? |
I guess it depends on what you mean by "better". A larger aperture (lower F/value) will cause the background to blur, most useful in portraits. With a larger F/value, your shutter speed can be faster with the same results (hence the term, fast lens). A smaller aperture (higher F/value) will cause the background to be in focus.
Hope this helps...I'm still learning myself :) |
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07/09/2004 10:46:15 PM · #9 |
Originally posted by guy17il:
Is there a reason than, to set the aperture to a higher value (say f/2.8) except for decreasing the shutter speed ? |
Sure, if you goal is to intentionally have a Shallow DOF this is practically essential.
Small aperture/deep DOF is not better, just different, and one of the factors to consider in composing your image. Not all images benefit from a deep DOF ... |
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07/09/2004 10:59:29 PM · #10 |
I've been having some problems with macro focus lately, and found out that it's because I leave the camera on auto-mode too much (auto loves low aperture values).
That's why I defined a deep DOF as 'better'.
Thank you both for answering :P
( this my only second message in the forums, are there no smiley-icons here ? ) |
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07/09/2004 11:21:03 PM · #11 |
Originally posted by guy17il:
( this my only second message in the forums, are there no smiley-icons here ? ) |
No, you have to use the ugly keystroke method or link to them somewhere's else :( |
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07/10/2004 02:22:28 AM · #12 |
Thanks Fritz, Gordon, Jeff
I had forgotten about DoF Master and the wheel. I really like the link Jeff gave, had not saw that one before.
Gordon I gave some thought into the palm pilot awhile back, just sounded a little expensive since I wouldn't use it for much else. I get the sunrise/sunset from my gps.
I'll take the advice, it's the best I've heard; print out the charts for the standard lenses/apertures/distance and refer to them when I need/can.
I think I tend to be on the conservative side, having too small an aperture when really not necessary but I also screw up photos like this one  where I wish the DoF was just a bit more.
The Rebel does have DoF preview, but I must not be very good at using it. For me it's too dark most of the time to see anything clearly.
Thanks again everyone! |
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07/10/2004 04:58:21 AM · #13 |
For me, I just follow my gut, and adjust from their. Of course as my gut becomes more experienced the better I am, but it does well for itself. Can't say I've ever glanced at such a chart, seems boring to me when you could instead learn it by feel.
Lee
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07/10/2004 06:12:28 AM · #14 |
I carry a laminated chart which shows the hyperfocal distance of different focal lengths at different apertures. I usually only refer to it if I want to maximise DOF (like the Deep DOF challenge). I downloaded the DOFMaster Hyperfocal Chart and used it to create two charts and pasted them together before laminating. It's a pretty crappy app but it does the job.
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07/10/2004 07:01:20 AM · #15 |
Another question if I may:
On the lens of my canon A70 camera, it is written "5.4-16.2mm 1:2.8-4.8".
I am guessing that 5.4-16.2mm are the focal lengths, what does the second part mean ?
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07/10/2004 07:06:09 AM · #16 |
The second part identifies the largest aperture at wideangle and zoom ends of the lens. So the largest aperture at 5.4 would be 2.8 and at 16.2 would be 4.8.
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07/10/2004 07:21:43 AM · #17 |
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