DOF preview button- do you really use it? When?

Discussion in 'Beginner Questions' started by trisha_f, Jul 11, 2009.

  1. I am wondering how many of you actually use the DOF preview button. I have been learning photography for a while, and have never actually used it. I had a difficult time seeing what it actually does. I kind of get it, but it seems like an extra step that is not that easy to see.
    Honestly it seems that experienced photographers wouldn't really need to use it because they know from experience what the DOF will look like for the aperture they choose. Until I get to that point, it would seem much easier to "cheat" and just take a test shot and look at the LCD screen on a DSLR. I know that wouldn't have worked for film, but technology has made things easier, so why not take advantage of some it.
    I am shooting mostly portraits, if this makes a difference.
    Thanks!
     
  2. Only when an inch or two in or out of focus is really important. You learn to do without it when you have enough experience with a particular lens. A very bright light may be temporarily used for focusing when stopped down.
     
  3. I didn't have one for years; now that I do, I use it a fair amount. They are very useful with macro shots; useful to the point of really making a difference. It's basically another tool at your disposal, and how you use it is up to you.
     
  4. Thank you for your response, so I think I will probably not use it too much since I am mostly doing portraits. It would be more useful for macro work maybe? Also I'm not really sure what you meant by "A very bright light may be temporarily used for focusing when stopped down."
    Thanks again!
     
  5. When you are not using the depth of field preview, it is common for the camera to show you the brightest image, at the widest aperture. When you "stop down," closing the aperture to whatever you've chosen [using the DOF preview button or lever], there will be less light entering the viewfinder. Sometimes, there is so little light that it may be hard to see the subject or focus manually.
    There are two ways a bright light can be used in that situation. One, you could shine a bright light on the object to illuminate it temporarily. Or, you could place a bright light right next to the subject, temporarily, and focus on that point of light [this method works best for for very dark setups]; it will appear sharper and pointy when in-focus; it would be a blurry globe if it was out of focus. When your checks are completed, keep the camera set up as it is, remove the lamp, make the picture.
     
  6. I tend to use the DoF preview a fair amount, but that's because I tend to want precise control over what is and isn't in focus...and because I don't tend to shoot the same scene twice.
    Yeah, it's harder to see...but there's actually a pretty amazing solution to that.
    I just got a new toy last night: a 5D Mk II. The DoF works in live view! And, even more amazing, you can do live view on your computer, *with* DOF! I can't even begin to tell you how excited I am. Oh -- and you can adjust the focus, on the computer, in the smallest step the focus motor will drive the lens. And have a *full screen* 100% pixel preview.
    Basically, you know, with absolute certainty, exactly what you're getting before you press the spacebar, and you can control everything except camera position from in front of your widescreen computer monitor.
    And, once I save up enough for a laptop, I can do all that out in the field, too!
    Sorry to sound like a Canon shill, but I'm really, really, really thrilled about this. Canon has basically re-created the view camera experience and then some. The DoF function is a significant part of that, especially since the display automatically compensates its exposure to match the final exposure. In low-light scenes with small apertures the display can start to get noisy, but I find it's a lot easier to judge focus on an actual-brightness 3" screen with some noise than in an angle finder. Much, much, much easier. Indeed, it'd have taken several times as long to get the shot I just posted in the No Words forum, but with the 5D I got it right on the second try. Next time, it'll probably be the first....
    Cheers,
    b&
     
  7. I don't use it because it's too hard to see at smaller apertures.
     
  8. Hardly ever. After 40 years, I've rarely relied on DOF preview, even tho' most of my serious SLRs have offered it. When I have a critical application I do what I did with my medium format cameras, most of which have been TLRs - use a chart I kept in my camera bag. Otherwise, with 35mm and my dSLR, I wing it based on experience. I've rarely missed focus due to underestimating the aperture needed for a particular situation.
    With macrophotography and landscape or architectural photography, it's usually easier to consult a chart. You can print 'em out and even laminate 'em so they're handy in the field. Since I do a lot of low light shooting the DOF preview is completely useless for those scenarios. It's already hard enough to see at dusk or night without stopping down.
    If it was up to me I'd permanently re-assign the DOF preview button on my D2H to some other more useful function. The very few times I've used it was to trigger the "modeling flash" feature on my SB-800 flash, which has been helpful... hmm... maybe three times in four years. Fortunately the D2H has a second similarly designed and placed function button that can be assigned to actually useful features.
     
  9. I find it most useful in macro photography, and not for what you might think initially. I don't use it to judge what will be "sharp enough" versus "almost sharp enough". The finder is usually too dark and small to use it for that purpose. But what it DOES do is let you see what the out of focus background is going to look like. At macro distances, when viewing with the lens wide open, the background is usually completely and totally blurred. But at taking aperture, it may not be quite so blurry, and sometimes twigs and things become sharp enough to distract from the composition, even though they're still way to blurry to be considered in focus. A quick check using DOF preview lets you catch background problems and move the camera around a bit to make sure the background doesn't distract from the composition.
     
  10. I usually use it only when shooting landscapes with medium format gear, optical viewfinder the size of modern dslr lcd screen helps a lot compared to aps-c sensor vf, but even then only when I have subjects quite near me and focus and camera distance are very critical.
    Nice for macro too but I don't do that much.
     
  11. I use mine on a large portion of my shots because I often like to isolate the subject from the background (or foreground). It becomes especially important with longer lenses and especially at large apertures because these can result in a fairly narrow area in the shot which will actually be in focus. When shooting distant subjects, at small apertures, or with wide angle lenses, I rarely use the DOF button but I shoot mostly nature at what you might call portrait distances and like to focus on the subject with a complimentary but out of focus, background. I rarely use autofocus. In low light situations it can be difficult to see the subject with the stopped down aperture but if you give your eye a minute to adjust to the low light, it is usually possible. I shoot both digital and film and wouldn't own a camera without a DOF button.
     
  12. 2 thoughts-
    1.years ago the only way you set the exposure was to use the dof bar on a slr to engage the dof which made the meter active. not fun, though you got used to it. by setting the exposure you also automatically got to see the dof.
    2.i used to use the dof bar/button on my slrs but after a while i could just visualize the dof with any fstop and lens that i was going to use. over time i eventually stopped using it at all. i do not think i have ever used it either of my 2 dslrs. i simply select the fstop and know how much dof i am going to get. experience is what gives you this knowledge. if using the dof button helps you get good shots, by all means use it. after all, that is what the photog is there to do.
     
  13. William Michael

    William Michael Moderator Staff Member

    "I am wondering how many of you actually use the DOF preview button."
    Very rarely, almost never.
    "it seems that experienced photographers wouldn't really need to use it because they know from experience what the DOF will look like for the aperture they choose. Until I get to that point, it would seem much easier to "cheat""
    Get a DoF Chart, Dial or similar device.
    " just take a test shot and look at the LCD screen on a DSLR."
    Cumbersome, time consuming and not necesarliy accurate method, IMO.

    Have a read of this:
    http://www.photo.net/wedding-photography-forum/00TskV
    WW
     
  14. Mostly I just use the DOF preview to look at the background. If you want to subjects in focus, Canon has an A-DEP mode which takes care of this for you. If you are shooting landscapes, a DOF calculator is the ticked if you are using a zoom. If you are using a prime, they often have DOF indicators on the lens itself (the little lines marked with the f stop). When the lens is set at the desired focus distance the lines corresponding to your chosen f stop indicate the depth of field.
     
  15. I use the DOF preview button every time I use a graduated neutral density filter. In fact, it is virtually IMPOSSIBLE to use graduated ND filters properly without DOF preview on many cameras, because that's the only way to close the lens' aperture down to its shooting value.
    Let's say that your lens opens to a maximum aperture of f/4, but you are going to shoot at f/11.
    Problem 1: You have to line up the filter so that the transition between the light (clear) part and the darkened part lines up with the light and dark sections of your photo, e.g. the foreground and a bright sky.
    Problem 2: When you look through a modern, computer-controlled lens, it stays open at the maximum aperture (in this case f/4).
    Problem 3: When you change to your shooting aperture (if it's different than the maximum aperture), the filter transition line will be located in a different place than it was when the lens was wide open. You have to re-adjust the filter placement when the lens is stopped down to your shooting aperture.
    Problem 4: The aperture on a modern, computer-controlled lens with NO APERTURE RING must be controlled from the camera via the DOF preview button.
    The DOF preview button solves all four problems and allow you to place your graduated ND filter in exactly the right location.
     
  16. I actually used the DOF Preview button for the first time I can remember. I was shooting with a Nikon F3, and wanted to ensure both a railing and a metal sign were in focus. Since I was shooting film, I didn't have the ability to simply bump the ISO up a bit and hedge my bets with a large DOF. Without the preview button I would have guessed f/5.6 would have covered me, but after using the preview button I realized I in fact needed to bump it up to f/8. Did it help? Yes, but its hardly an earth shattering, make it or break it feature. A little experience, and a quick look at the built in DOF chart on the lens is all that's needed 99% of the time.
     
  17. William Michael

    William Michael Moderator Staff Member

    It is quite likely that the OP has lens(es) which do not have any DoF scales, on the lens.
    WW
     
  18. It is quite likely that the OP has lens(es) which do not have any DoF scales, on the lens.
    WW​
    Pardon the ignorance, but which lenses these days do not have a DoF scale on them? My oldest lens, a 50mm f/1.2 Non-AI has one, all the way up the most recent Nikon DX lenses I've handled. The only exception I've personally seen is the new Nikon 35mm f/1.8. What am I missing?
     
  19. William Michael

    William Michael Moderator Staff Member

    Chris,

    Firstly, my apologies for the brevity of my comment - I was in a rush - on reflection it could seem I was rude, it was not meant as such.

    My logic is this: the question is posted in the Beginner's Forum. It is very likely that Trisha has a DSLR and the kit lens - that will be a zoom lens with AF.

    In this case it will be likely that her kit lens will NOT have any DoF scales on it.

    This is mentioned in the link I added to my original post and it is because of many modern lenses not having a DoF scale on them I suggested getting (or downloading) a DoF card, dial or other device. (These things are also mentioned in that thread I included)

    As specific examples: My daughter has a 400D and the 18 to 55 and 50 to 250 - neither has a DoF scale. My 70 to 200F2.8L does not, either.

    The majority of (new) photographers (especially beginning on a DSLR) never see a DoF scale on a lens, because they will only ever use a zoom lens, or two.

    I trust that makes more sense to you and also clarifies to Trisha, lest she be looking for something on her lens that she might never find.

    WW
     
  20. Chris, It's a sad truth that most zooms lack depth-of-field scales. Even worse, some entry level zooms these days lack distance markings on the focusing ring ! What could be less friendly for hyperfocal shooting?
    As for DoF preview, I don't need it all the time but wouldn't want to be without it and hope that cameramakers continue to include the feature. The ability to preview/review on the LCD has made optical DoF preview somewhat less important but it can still be useful to quickly see in the viewfinder. Like some others, I find it particularly useful to see what's going to happen to the background--like when stopping down, will it pick up more detail than I want? Perhaps digital preview/review is more authoritative in this regard, but the DoF preview is generally quicker. Live view can give quick feedback too but at present for D-SLRs its use seems to make more sense on a tripod.
     
  21. William, Andrew, thank you both for clarifying. I've proven myself to be quite the rube!
    Recently I've been spending a lot of time shooting film again. Be it with a Leica, Hasselblad or Nikon, I frequently reference the DoF lines on the lenses to confirm my focus (particularly when I'm trying to prefocus for street shooting). Since it's been a while away from my newer zooms (I prefer primes with film), I was imagining in my mind DoF lines below the distance markings. Sure enough when I look at them now, all I see are the distance markings. Quite a saddening revelation!
     
  22. William Michael

    William Michael Moderator Staff Member

    "particularly when I'm trying to prefocus for street shooting"

    This is a particularly interesting point. I note a few occasions when "what is the best lens for street?" type of questions has been asked . . . a great loss having the APS-C format very common is the lack of use a snub 35mm prime or similar now has . . .

    An old newspaper hack took me aside when I was an apprentice: "Son” he said to me, “the answer is 20ft, F/8 at 100" . . .

    He used Pan X, a Nikon and a 35mm lens: shooting outside in daylight EVERYTHING was F/8. His lens was virtually glued to 20ft and he shot at 1/125s (I think the "100" was a very old shutter speed which had been handed down to him, by his teacher).

    He would simply push or pull the development to suit the EV and crop the frame when printing, to suit the headline - a very smart operator- I never saw him ever look through the viewfinder of that Nikon when his 35mm lens was attached – he would shoot overhead or shoot from the hip, all the time - they never saw him coming.

    WW
     
  23. Wasn't it Henri Cartier-Bresson who coined the phrase "f/8 and be there"?
     
  24. I rarely use DOF-preview. I see no need for a dedicated button, and IMO it could be put in a menu. Maybe one of these days I'll pick up my manual to try to figure out how to assign something useful to that DOF-preview button. Maybe MLU or something like that.
    As for DOF markings on the lens. I don't find them very useful. DOF cutoffs depend on how large the circle-of-confusion you're willing to accept, which in turn depends on how big you intend to print and the crop factor of your camera. Furthermore, the concept of a cutoff is misleading; rather, it's a transition.
     
  25. I rarely use DOF-preview. I see no need for a dedicated button, and IMO it could be put in a menu​
    Can't see that being handy as you need to activate it while you're looking through the viewfinder for it to do any good! It seems OK to make the button configurable for those who don't use it--for example, on Pentax DSLRs that switch can be configured for 'digital preview', basically take a picture that won't be saved to the card for review on the LCD (you can then optionally save it). On the K20D this is also how live view is activated.
    It seems that electronic depth-of-field indicators, automatic hyperfocal mode might be useful. I suppose the circle-of-confusion could be adjustable?
     
  26. Richard Cochran , Jul 11, 2009; 11:57 p.m.
    I find it most useful in macro photography, and not for what you might think initially. I don't use it to judge what will be "sharp enough" versus "almost sharp enough"....
    Ie. check the background and surrounding objects.
    That's a good idea. Thanks.
     
  27. In theory, the DOF button is very handy. In practice, like others, I can't see a thing because it darkens the viewfinder so much. For macro it would seem to be useful IF there's enough light. For portraits you're probably wide open or close to wide open anyway so no need for it. Like your instincts told you, after you've used the lens a while you will know how the shot will look at which aperture. There's no substitute to knowing your equipment.
     
  28. I use it on every shot. When im using an SLR, i like to see how everything will look at a certain aperture, often after checking i akeadjustments to f stop and/or focus to get the look I want.
    With LF, i simply stop the lens down before closing the shutter, I take another peek in between to make sure im getting he shot I want.
    Of course, being 19 my eyes are still very good and I can see fine stopped down through f/22 on a normal day. I imagine as my eyes get worse and worse I will just have to guess from experiance.
     

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