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Depth of Field - Do we really need it?

Discussion in 'General Equipment Chat & Advice' started by BigWill, Jan 13, 2001.

  1. BigWill

    BigWill Gorgeous oversensitive Nikon-loving cream puff

    From reading some of the other postings in the Camera Chat and Pentax sections,I see that there is a fairly diverse view on the need for a depth of field preview function on cameras. I would be interested to hear other contributors views on this subject. Is it an essential tool for any serious photographer or just an obsolete and outdated relic of the past when we all used manual focus SLR,s? Let me hear your views.

  2. Benchista

    Benchista Which Tyler

    OK BigWill, I guess as I'm king of the pro DOF preview brigade, I should go first.
    I believe that depth of field control is of critical importance to every type of photography, and the use of AF, MF or digital doesn't change that.
    Depth of field can be controlled by information on the lens barrel, a depth of field preview function (or just looking at the screen on an LF camera), or by a mode similar to Canon's DEP or (inferior) A-DEP modes. Failing that, it's going to be hit and miss - unless you're VERY knowledgable. So I say it's absolutely vital, and I wouldn't buy a camera without at least one of these fuctions. ANd for beginners, it's the quickest way of learning what DOF is and how to control it. So to my mind, it's no contest.
  3. heath

    heath Member

    I've used various 35mm cameras and a very old bronica s2a, with DOF previews, and the bronicas waist level finder helps me to use the DOF more often, with the 35mm cameras and small apertures, everything goes too dark for me to see anything at all. I've tried letting my eyes get used the light, (or the lack of it), coming through, but my problem with small viewfinders is always the same, my glasses, maybe I should try contact(not contax!) lenses. I'm just too lazy to use a DOF all the time, I just guesstimate by reading the barrel markings on the lens, it works for me, and lets be honest that is all that matters. so a DOF preview isn't my main priority when using a camera.


    DoF Preview is one of those functions that you don't miss until you really need it. It must be remembered that the image in the view finder is only a guide to the sharpness of the image from foreground to infinity, the image that is recorded on the film could be significantly different. I bemoan the loss of X sync, cable release, self-timer, double exposure - a very rare camera that has all of these functions nowadays. Overall DoF preview is a valuable tool, once the rules are learned it becomes second nature to use it. Admittedly some cameras leave a lot to be desired in the viewfinder brightness, so the lens markings are perhaps more reliable to determine focus. My old Hassleblad 50mm and 80mm lenses use Dof indicators on the focus ring that are very easy to understand, if you have seen them you will understand, they also have a preview switch.
  5. BigWill

    BigWill Gorgeous oversensitive Nikon-loving cream puff

    Nick Roberts has very eloquently argued a strong case for having D.O.P. preview fitted to all cameras. I find it difficult to argue with his reasoning but if I may open up the argument a little more, perhaps we should examine the reasons "WHY" we tend not to use depth of field preview these days. I would like to suggest that it is in no small part due to the modern tendancy of camera manufacturers fitting their products with a "slow" zoom lens. I am of course referring to the maximum aperture here and not the speed of focus. A typical 28/80 zoom as fitted to most modern AF SLR's will typically have a maximum aperture of f4.5 at the tele end. The situation with 80/200 zooms is even worse with the maximum aperture usually being around f5.6 at the tele end. Because of this it has become very difficult to achieve a differential focusing effect with a blurred background. Perhaps people have come to accept this as the norm and only those who are prepared to spend large amounts of money on fast aperture zooms will be able to create this effect. It was for this very reason that I purchased a 50mm f1.8 lens for my Canon AF outfit this year. Achieveing an out of focus background with this lens is no problem. But wait a minute, didn't all cameras used to be fitted with a 50mm lens as standard! Have we sacrificed quality at the expense of convenience by fitting zoom lenses as standard? I think I may well have opened up another topic for debate here? Any further thoughts on this guys (and girls of course).

  6. Benchista

    Benchista Which Tyler

    You're absolutely right - up to a point, as you still get a pretty good out of focus effect with a 200mm lens at f5.6. But I've still got an old Praktica MTL5 with 80mm f1.8 and 135mm f3.5 lenses, which can do a better job at this than my all-singing, all-dancing Canon zooms - and they have decent depth of field markings, which allow easy use of hyperfocal focusing. Sure, I'd love to buy some other Canon prime lenses (I have the 50mmm f1.8 - it's great optically), but I can't afford them, and in truth the zooms I have are pretty good quality, even using slide film.
    I also think that some of the other reasons why we don't use DOF preview so much are that we trust the technology to produce a satisfactory result, and film is so (relatively) cheap now that we (well, often me, anyway) don't worry about wasting a few frames, and put less thought and care into many shots....
    Another topic for discussion?
  7. woody

    woody Active Member


    I bought my Eos 300 6 months ago with no experience in photography. The DOF Preview has been a god send to me, as I am trying to learn how the different apertures and shutter speeds affect the final image. (The 28-80 lense that came with my camera has no markings for focusing or DOF.)

    The other point you raised is that camera's now come with a zoom as standard, rather than a quality fixed lense of good speed. As a begginer, the zoom has also been great, allowing me to experiment with different effects.

    Camera Kits, like mine, are mainly aimed at new photographers, and the zoom is right for them. More experienced photographers usually have a system they have built up, and this will often include fast fixed lenses. (This appears to be why more advanced camera's are sold body only).

  8. Joachim

    Joachim Member

    Hi BigWill, I find the preview most useful to gauge the out of focus picture. The range of focus is in my view best estimated from a DOF scale. How ever there is more to out of focus than just out of focus. Things could be out of focus but still very recognisable and sometimes distracting, or they may be completely blurred and have vanished. The only way to tell how out of focus something is, is the DOF preview unless you have experience in the shooting situation you are in.

    I hold DOF preview as very important and use it a lot. I would not buy a SLR which doesn't provide this feature. For several mounts (e.g: Minolta MD, Nikon AI, Pentax K) you can preview by partly unscrewing the lens, if your camera doesn't provide this feature. Be careful you don't drop the lens. Hope this helps Joachim

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