Why does everyone like DOF preview buttons?

Discussion in '35mm Cameras and Accessories' started by 5stringdeath, Apr 26, 2010.

  1. 5stringdeath

    5stringdeath Member

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    Even on cameras that I've owned that have them, I never use them. Personally I find them pretty useless. Yet I see lots of discussions on different bodies here where people say "only thing wrong with it is it lacks a DOF preview."

    So I'm just wondering how people put them to practical use.

    I might add that I've shot with a lot of rangefinders in my days (so no DOF buttons) and that I shoot a lot of wide angle work (often at high fstops) so I'm pretty aware of, and quite like, a lot of depth of field.

    Ergo, this post is prejudicial :D
     
  2. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    I use them all the time. Especially shots where I juxtapose background and foreground focus.
     
  3. photomem

    photomem Member

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    I use the DOF preview on my Medium Format quite a bit. However, on my AE-1, I hardly ever use it.
     
  4. Q.G.

    Q.G. Inactive

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    Balance between in and out of focus is one of the creative tools at our disposal.
    Why let it go to waste?
     
  5. 5stringdeath

    5stringdeath Member

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    I guess my main problem with them has been, in general (and maybe its just the ones I've used) they darken parts of the focusing screen .. and I can't really tell anything about the DOF beyond what I already know in my head -- or what I can tell by looking at the DOF scale on the lens (which I'll admit I rarely ever did.) I guess I already have a general idea what 5.6 or 1.8 is going to look like at a given focal point .... so I haven't ever found the DOF preview to be any more accurate than my imagination.
     
  6. 5stringdeath

    5stringdeath Member

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    So are you saying you can't possibly do this without a preview?
     
  7. photomem

    photomem Member

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    Well, it would darken the focusing screen, since it is stopping down the diaphragm. Usually, going from f1.8 to f5.6, I ignore the DOF button. I usually will only use it if it is a very bright day and I am using a higher fstop.
     
  8. 5stringdeath

    5stringdeath Member

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    So it may be true they are more useful on longer lenses? Also, I know WHY it darkens the focusing screen, I just never found that function to be particularly useful visually.
     
  9. photomem

    photomem Member

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    Yeah, I do wish there was a way to see a DOF preview without it going dim. I find them more useful at higher fstops because I am usually trying to reach out and get something distant in focus. If I use it and then squint, I can usually tell if its in focus or not.
     
  10. MattKing

    MattKing Subscriber

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    I find them most useful when I am trying to evaluate how out of focus different parts of the foreground and background are.

    A highlight in the background or foreground which is pleasingly blurred at the maximum aperture of f/2.8 may still be sufficiently blurred at f/4.0 but by f/5.6 or f/8.0 it may show sufficient contrast and detail to distract from the rest of the image. The depth of field preview helps me evaluate this.
     
  11. 5stringdeath

    5stringdeath Member

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    As an aside funny to this, while randomly googling this issue (cause I'm waiting for prints to wash) I stumbled across this response to a discussion of the DOF preview button on DSLRs:

    "“Of course in digital photography it doesn't take a lot to access DOF by actually taking the shot and assessing it in review mode on the camera's LCD. And in film it’s not needed because the aperture is changed manually"
     
  12. photomem

    photomem Member

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    Well, with my old digital camera I had plenty of lenses that I had to set the aperture manually. I would thing that a DOF preview would be pointless on a digital, since you could just shoot it and look at it. On that note, I was doing a shoot for a coffee shop the other day.. the owner kept asking me if she could see the pictures. I told her sure, give me about 3 days.
     
  13. lxdude

    lxdude Member

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    Aw, Geez. We poor pitiful film users don't even know about auto-diaphragm lenses. :rolleyes::rolleyes:
     
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  15. alanrockwood

    alanrockwood Member

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    I use it occasionally, earlier this afternoon for example.

    I actually don't think it gives a fully realistic impression of depth of field. I believe the depth of field is typically a little narrower than it appears in the darkened view finder, but the depth of field preview is at least somewhat helpful in some cases.
     
  16. photomem

    photomem Member

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    I wonder what the AF on my 645AF stands for then? Oh... it must have been designed for the Air Force..
     
  17. MFstooges

    MFstooges Member

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    I always use DOF when I need critical assesment. I love DOF button in fact there were times when I tried to find the button on my motorcycle :tongue:
     
  18. Soeren

    Soeren Member

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    Offcource it is. You are watching a 24X36mm area at best, which is to be enlarged up to .......
    Doing close ups and macro shots I used the DOF button a lot both for evaluating DOF, for accessing OOF areas and to look if I get hexagonal highlights anywhere in the image.
    Best regards
     
  19. Poisson Du Jour

    Poisson Du Jour Member

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    Depth of field can be more accurately ascertained with a magnifier attached to the eyepiece: it's pretty darned hard otherwise. Note that with ultra-wide angle lenses of 17mm+ you won't gain much from using the DOF preview button because the depth is so great in UWA optics. As noted in other posts, the viewfinder darkens and this is not a welcome development in low light, which is when most of my photography takes place; for such times I use the DOF markings on my 24mm lens to set hyperfocal.
     
  20. Worker 11811

    Worker 11811 Member

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    One of the reasons I didn't buy a new digital camera and went back to using good, old film was because of focus and depth of field control. I could not find those controls on any digital camera that I liked which was in my budget.

    I use a Canon Digital Rebel at work. It is a nice camera. I like the auto focus features but there are plenty of times when it screws me up.
    There are some subjects such as open sky or close-focus situations where the camera can't "lock" focus. You are forced to turn off the auto focus feature and focus manually. There are also a lot of times when I want to control depth of field and/or exposure. I don't want to have to go through 9,000 fiddly little menu screens to get to something I could just use my finger to flip a button for.

    I would rather just press a lever for DOF preview.
    I would rather simply twist the focus ring.
    I would rather press a button or twist a knob to change shutter speed on the fly.

    I want to feel as though the camera is transparent to getting the shot. I have yet to find a good, affordable digital camera where I can get that "becoming one with the camera" feeling.

    I have two Pentax 35mm cameras. The one that I find myself wanting to use the most is the one with the fewest automatic features. I prefer the ME-Super over in Aperture priority mode to the Super Program in full-auto mode. If I could get my K-100 to work right I'd probably use it even more. If the ME-Super had a DOF preview like the Super Program does I'd probably only use the ME-Super unless I want to shoot two kinds of film.

    When I see a shot, I can focus, twist-click the f-stop, check the meter, recheck the focus and have the shot in about 2 seconds. If and when I want DOF preview, I know just where to reach with my finger to press the lever. I bet I have missed more shots with the automatic Digital Rebel than I have with my Pentaxes.

    Regardless of whether you use a digicam or a real camera, you often only have one chance to get the shot. I hate having to press buttons or take 3 shots and delete two of them, only to miss getting the shot you really wanted in the first place.
     
  21. Steve Smith

    Steve Smith Subscriber

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    I think the only time I use the depth of field control on a camera is to test if it works!


    Steve.
     
  22. lxdude

    lxdude Member

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    In your case, you clearly don't have much need to preview depth of field, for the exact reasons you stated.



    Depth of field preview is useful because it allows seeing what the final image will look like, instead of just visualizing it. This is especially useful when DoF is very limited. I do use it with wide angle lenses too, when I stretching the limits of the lens' DoF. For me, what's out of focus, and how much, is as important as what's in focus. While not a perfect representation of how the final image will look, DoF preview gets darn close. Being able to see size and shape of out of focus highlights affected by a closed aperture is also very useful.


    DoF preview allows one to take greater advantage of the SLR's strongest point: the ability to see and focus through the lens that makes the image.


    At close focusing distances, like say a couple of feet, and in low light, I can determine the aperture needed to give me the DoF I need, and then I can tell if I have enough light to hand hold.

    I shoot a lot of macro. The DoF preview gives me the chance to see what aperture I'm going to need to get what I want. For example, if f/16 gives me enough depth of field, then I don't have to lose definition due to diffraction by using a smaller stop. Scales are of limited use in a situation like that, and if my judgment says DoF is marginal for what I want, I would have to go to a smaller stop to be sure.

    By seeing what the film is going to record, I can use out of focus areas to my advantage. A lot of my macro work is done with larger apertures for the selective focus and blurring I can get. Selective focus and selective blurring are powerful compositional tools. Both can strengthen a composition and can complement each other. Without DoF preview, I would not know what the finished image would look like with as much certainty, and that would affect composition.

    At regular distances too, it helps in visualizing. I can see directly and therefore fine tune the effects of different apertures on the zone of apparent sharpness, and on the foreground or background: not just in terms of sharp or unsharp, but how unsharp. For example a person might be standing to the side and somewhat behind the subject, and I want to get them out of focus, but not too much.

    Maybe I want to frame a scene with tree branches and might either want the branches sharp or want them just unsharp enough to de-emphasize them, while still having them clearly recognizable. DoF preview is a big help at seeing what the final shot will look like.


    It's also good for evaluating the quality of the blur in the image. Say a lens tends to double lines if far enough out of focus. By using DoF preview I can see at what point the background looks best, where not enough out of focus and too far out of focus will make it more distracting.

    It's a tool. I use it frequently. I think it can help a beginner avoid surprises, though without it they'll just have learn the hard way. IMO, the Pentax K1000 would have been a better learning tool if it had allowed beginners to see and understand the effects of aperture on depth of field, either by a DoF button or by stop-down metering.
     
  23. lxdude

    lxdude Member

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    I would say that depends on the quality of the LCD image. Magnifying it helps, if available, but either way it takes longer than pushing a DoF button, if one is available, and requires taking your eye away from the viewfinder. It also doesn't allow seeing the effect of changes as the aperture is being changed.
     
  24. perkeleellinen

    perkeleellinen Member

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    I like them a lot and I sort of miss them on rangefinders, but not that much - a different type of shooting, I think. Nice to check for near focus in landscapes when you're using hyperfocal focusing. But I also find them useful when using dark filters such as an R25, then if the aperture is smallish, I can get a good sense of contrast, especially in cloudscapes.
     
  25. Steve Roberts

    Steve Roberts Member

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    To me DoF preview is like filters, a cable release, delayed action shutter release, tripod, lens hood, extension tubes and all the rest. It's one of many tools at our disposal, and though we may not use any of them all of the time, it's useful to be able to call on them when we need them in particular circumstances. Personally, I find it one of the more useful tools and indeed it was the main reason why some 24 years ago (doesn't time fly!) I traded in my old Pentax K1000 in exchange for a KX. I don't usually look at DoF preview from the point of view of "how much is sharp" but rather from the angle of "how much out of focus do I want to throw the unwanted elements of the shot.

    Steve
     
  26. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    If you use selective focus, DOF preview is useful. If most of the things you photograph with a wide to normal lens are about 15 feet away or farther, then DOF preview isn't going to tell you much.

    Of course the screen gets darker when you stop down, so it's a good idea to make some tests so that you know what you're looking at on the dark screen. Set the lens at or close to its near focus point with the camera on a tripod and set up a few focus targets on a table--they can be anything you have handy--then try different f:stops, opening and closing the lens and seeing how the DOF changes. If the screen is very dark, you need to let your eyes adjust, and you may need to shield the space between your eye and the finder with your hand and wait a moment for your pupil to open to get a clear view. It's a matter of practice.

    Rangefinder shooters just develop a different feedback loop to predict the DOF based on the subject distance, focal length and aperture, and often tend to shoot at about the same distance, with one or two lenses most of the time, preferring a certain aperture range that produces the look they're after. To develop this ability, it is necessary to be conscious of these variables and to process film and print relatively soon after the shoot. You can work this way with an SLR as well, but DOF preview lets you check on the spot before you take the photograph.