 Justin G. |
Digital, limited DOF? I've read through a few threads on here about how digital cameras have limited/less DOF than a film camera. I'm kinda confused by this and wonder how in the world this is possible. It was my understanding that the focal length and the lens opening diameter were the factors for DOF, not whether film or digital. Would it have to do with different sensor sizes? I understand that different film formats have different DOF's (ie. f/8.0 on a 6x7cm camera is MUCH more shallow than on 35mm). So if this is true then this limited/less DOF is only a factor on P&S digital and DSLR where the sensor is smaller than 24x36, correct? There shouldn't be any difference between a full frame and a standard 35mm film, right? Just trying to learn more about the "other" medium (lol).
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Dan C. |
Yes, as I understand it the depth of field is influenced by the sensor size as dof is influenced by large format vs. small format film cameras. I personally find the increased dof of digital cameras a big pain in the booty. I am constantly being frustrated in situation where I want to selectively highlight a subject in a shot with dof, but find that even when the camera is wide open I can't even begin to achieve the shallow dof I desire. Here is a good article about dof and digital cameras: http://www.wrotniak.net/photo/dof/ Regards,
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John P. Sandstedt |
Justin - Take a look at almost any picture in a newspaper from Iraq, Afganistan, etc. These photos are amazing in that there is almost limitless DOF. It's my understanding that, with digitals, minimizing DOF - and, therfore achieving, for example, selective focus - is the problem. But, remember, DOF is optical property, that is, it relates to the lens you use. So, there is the inconsistency of the two opinions expressed so far.
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David Earls |
Two points: The depth of field for dSLR is exactly the same as DOF for any interchangeable lens 35mm camera. The "limitless" DOF judgment applies only to fixed lens digitals. Second, there's an easy way to deal with limitless DOF in fixed lens digitals. Just switch to manual focus, and you'll get a DOF that's about what you'd expect. In fact, you'll find yourself limited by too shallow a DOF, because most fixed lens digitals will only stop down to about f8. That, at least, was my experience with Nikon 5700 and Nikon 8700 - probably the same lens.
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Dan C. |
Second, there's an easy way to deal with limitless DOF in fixed lens digitals. Just switch to manual focus, and you'll get a DOF that's about what you'd expect. David, Appreciate the info. I am striving to learn more about the nuances of digital photography. I have searched extensively and cannot find any articles mentioning this. Would you be kind enough to forward a (web) link or refer me to a book or magazine that discusses what you mentioned about decreasing DOF by switching to manual focus. Thanks, and regards-
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David Earls |
Dan, I have never found anything published in print or on the web about this. I simply observed with my Nikon 5700 and Nikon 8700 that this occurred. Both of these cameras share a common lens, so it may just be a function of this particular camera. There are some easy ways to determine if this will occur with your camera. You can lay a ruler down on a table in front of the camera and take a series of shots with different f-stop settings. Obviously, if they're all equally and crystally clear, your have the "infinite depth of field" thing going on.
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Dan C. |
Second, there's an easy way to deal with limitless DOF in fixed lens digitals. Just switch to manual focus, and you'll get a DOF that's about what you'd expect David, I appreciate you taking the time to reply. In fact, I did not know you replied. I was about to make a follow-up post in this forum when I read it. I am not here to start an argument, but when the item above was first posted I questioned it. Before replying, tho, I wanted to research it. Since then I have received a reply from an engineer at Canon and from Michael Reichmann, a well-respected professional in the field who also functions as a consultant to numerous companies for product design. Both stated this is not true. Whether you focus the lens (manual) or the camera focuses it or you, the relationship between the aperature and the smaller capture area in a digital camera is not changed. The DOF will be the same. On the other hand, by switching to manual focus you can enhance the DOF effect by how you focus. You can move your focal point in front of, or behind your "object of focus." By placing your object of focus on the front side or back side of your field of focus, you can increase the dof effect. Perhaps this is what you are seeing, David. Unfortunately, depth of field in digital cameras is what it is. Considering your average digital camera with an average sensor, the DOF between a digital and a 35mm camera are about 5 stops apart. Setting a digital camera at f2.0 will achieve the same DOF as a 35mm camera would at about f11. It sucks, but hey - there's always the blur tool in photoshop. Regards,
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Kitty Cross |
Dan Just reading your response--particularily the last one. I'm on the brink of purchasing a d70s. Is it your understanding that your statement: Setting a digital camera at f2.0 will achieve the same DOF as a 35mm camera would at about f11 is true for dslr as well? As you say, that WOULD suck. I expect to be shooting manual most of the time and am used to choosing the dof myself. thanks and regards
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Dan C. |
dSLR cameras can be different because of factors such as the larger size of sensors and speed of lenses. I would recommend reading and researching before making a purchase. Don't only read about bodies. Fast lenses are also a factor. If you google keywords such as "depth of field dslr" or "depth of field digital slr" you will find tons of articles and tutorials on the subject. Regards,
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Christopher A. Vedros |
Kitty, Dan's description of the DOF problem with digitals is correct, but it applies mostly to compact point & shoot digitals. As the physical size of the sensor increases, and the resulting lens factor decreases, so does the DOF problem. So the DOF problem is worst with a P&S, not quite as bad with the larger "SLR-like" digitals, and hardly a problem at all with a digital SLR. I can get very shallow DOF with my digital SLR and any of my lenses set at a wide aperture. I haven't done any tests to see how the DOF I get with a lens on my dSLR compares to the DOF with the same lens on a 35mm film SLR, but I would suspect that it doesn't change much. Please keep in mind, also, that when I talk about the physical size of the sensor, this is not the same as MegaPixels. An 8 MegaPixel compact P&S still has a much smaller sensor than a 6 MegaPixel digital SLR. Chris
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Kay Beausoleil |
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Kay Beausoleil |
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Kerry L. Walker |
Kay, it is not so much a matter of film vs digital, it is a matter of the size of the sensor. It is the very small sensor of a digital P&S that gives the greater DOF at a given focal length and aperature. The difference between the D100 and an F4 would be minimal. In fact, at the same aperature and the same EFFECTIVE focal length, there should be no difference at all.
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Kay Beausoleil |
Thanks, Kerry -- your first sentence cleared up my puzzlement beautifully!
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