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Thread: Manual focus technique

  1. #1

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    Manual focus technique

    Good afternoon,

    It might sound silly, but anyway... Is there any guide on how to focus manually? I guess manual focus skill comes with experience but I wonder if there are any special tricks. I am always trying focusing manually while shooting portraits, I find it more convenient. Focus and recompose is hardly possible due to narrow DoF. But even if a picture seems absolutely sharp to me, very frequently it appears slightly(?) blurred on a computer.

    Regards,
    Pavel

  2. #2
    Stagecoach's Avatar
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    Re: Manual focus technique

    Pavel,

    I do not normally take portraits but I read somewhere that a portrait photographer used the practice of manually focusing on the bridge of the nose which he believed gave him a better chance of getting the eye/s sharp. I can only assume that this was based on the theory that there's going to be a greater depth in focus to the rear of the focus point than in front.

    Grahame

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    Administrator Manfred M's Avatar
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    Re: Manual focus technique

    Coming from a SLR that was 100% manual focus I do miss the features that were built into the focus screens of that era to assist in manual focusing. With the reliance on autofocus, other considerations drive the focusing screen design. Gone are the agressively etched glass, split focus ring and other focus assist mechanisms.

    The technique I use is still the one that I used on a manual focus SLR, focus until the part of the image I am focusing on has come into focus and then keep turning the focus ring in that direction. When the subject (or target area of the subject) starts to soften, I back off a bit. I won't necessarily fix my focus in a single try. I will also shoot a stop or two slower than I do on autofocus to let DoF help with minor focusing errors.

    Generally, I find autofocus works quite well. I use a single central focus point on my camera, and will focus on the nearest eye for portraits. When I get focus, I will press half-way down on my shutter release to lock focus / exposure and will recompose the image and then press the shutter all the way to take the picture.

  4. #4

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    Re: Manual focus technique

    DSLRs are not friendly to manual focusing. The lenses are optimized for autofocus, and so do not have the nice wide focus rings and gentle throw of the old manual lenses -- they are intended to allow a focusing motor to get them in focus without having to turn too much. But that is exactly the opposite of what you want for manual focusing. And the camera itself no longer has a focusing split viewfinder unless you have retrofitted it with a third-party unit like Katzeye. It is much harder to manually focus than it was in the old days where that was what you had to do.

    If you're going to manually focus and not get your camera modified, I find that using the LCD zoomed to near-max is by far the best way to see whether you are actually in-focus. It doesn't help the touchy and awkward focusing rings problem, and you don't have a view of anything except the focusing area. Nonetheless, this kludge is about the best you can do when manually focusing modern cameras IME.

  5. #5
    RustBeltRaw's Avatar
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    Re: Manual focus technique

    Magic Lantern has a Focus Assist that can help with finding your focus on the LCD. It highlights the sharpest 1% of the display's pixels. Beyond that, try to find lenses with focus range scales (for Canon-made glass, the Ultrasonic and L series). The scale will do to start, but to really nail the focus, you either need to use magnification in the LCD, or, since many DSLRs don't set the aperture you'll be shooting at until the shutter's pressed, your camera's depth-of-field preview button (if available). The DoF preview button will set the lens the aperture the camera's programmed for so you can see the real DoF.

  6. #6
    Administrator Manfred M's Avatar
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    Re: Manual focus technique

    Quote Originally Posted by tclune View Post
    If you're going to manually focus and not get your camera modified, I find that using the LCD zoomed to near-max is by far the best way to see whether you are actually in-focus. It doesn't help the touchy and awkward focusing rings problem, and you don't have a view of anything except the focusing area. Nonetheless, this kludge is about the best you can do when manually focusing modern cameras IME.
    Tom - have you found that this works for you?

    DSLR lenses tend to be varifocal designs, which means that they do not stay in focus when you zoom in, focus and then zoom back out and compose. Video zoom lenses, on the other hand, are parfocal designs (and the focus does not change as you zoom in and zoom out) and this technique does work and is used to focus all the time.

    The only lens that I have that this technique seems to work for is the Tokina f/2.8 11-16mm, but I'm not sure it the design is parfocal or that because it is so wide angle that DoF takes care of my focus accuracy.

  7. #7
    DanK's Avatar
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    Re: Manual focus technique

    I don't do posed portraits, but, for what it is worth:

    If the camera has live view, you can zoom the live view without altering the zooming the lens. I use this technique for macro, and I find that 5x optical zoom on the lcd of my camera (50D) is ample, although occasionally I use the full 10x.

    If the camera is on a tripod, it seems to me that it should not be to hard to use the center point on the eyes and then recompose, since the tripod will avoid your accidentally changing the distance to the subject.

  8. #8

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    Re: Manual focus technique

    You misunderstood what I was saying -- don't zoom the lens, zoom the LCD magnification. [reply to Manfred]

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    Administrator Manfred M's Avatar
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    Re: Manual focus technique

    Quote Originally Posted by tclune View Post
    You misunderstood what I was saying -- don't zoom the lens, zoom the LCD magnification. [reply to Manfred]
    Okay - understood now. Yes that technique works (if it isn't too sunny out).

  10. #10
    dubaiphil's Avatar
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    Re: Manual focus technique

    "DSLRs are not friendly to manual focusing"

    DSLR's are fine for manual focusing - it's the autofocus lenses which aren't optimised, with their focus rings with a little play in them, no hard stop at infinity, and more often than not no distance scales. There's no black art or black magic involved! If you want then you can swap out the focus screen (not as scary an operation as you may think). Positives - you'll have a SLR style split prism to help manual focus. Negatives - you'll have a darker viewfinder when using any slower lenses that you may have (f4 or slower)

    It all depends on what aperture and focal length you'll be shooting at really - shooting at f8 for a headshot with a manual focus lens and as long as your focus point is around the eyes/face you're good to go just by using the focus confirmation light in the viewfinder. Recomposing won't affect you much. Opening up the aperture to f4 or faster would mean you'd have to be a little more careful when recomposing - it may be better to use an off centre cross point focus point and use the focus confirmation light from there. If you're shooting portraits in a controlled environment with a longer lens (85-105-135) then the focus point will pop out a lot more through the viewfinder - for critical focusing in this instance with a shallower DoF you'd be better off going with a tripod and LCD magnified to confirm your focus. However, if your focusing is that critical then small subject movement would also have to be taken into account and you may be better off shooting a few frames while focusing through the focal plane that you want to ensure a keeper or two.

  11. #11
    William W's Avatar
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    Re: Manual focus technique

    Quote Originally Posted by Destructor View Post
    ... Is there any guide on how to focus manually? I guess manual focus skill comes with experience but I wonder if there are any special tricks. I am always trying focusing manually while shooting portraits . . .
    What camera?
    With most Canon DSLR, there is focus confirmation via the Red AF Squares.
    On cameras with Live View: that is very accurate.

    Quote Originally Posted by Destructor View Post
    Focus and recompose is hardly possible due to narrow DoF.
    That’s oft discussed.
    But the maths of it often reveals that not very many situations are such that F&R stuffs up the Focus all that much. However, in very critical situations good technique is important – but there are not very many critical situations, really.

    These are all candids, with very shallow DoF (view them big).
    Managing F&R in Studio or a controlled setting is really quite simple.


    Manual focus technique
    Portrait 504468v06
    EOS 5D; EF85
    F1.8 @ 1/80s @ ISO400
    Hand Held; Available Light; Manual; Focus and Recompose, Centre AF

    So is this:
    Manual focus technique
    Portrait 504470v04
    EOS 5D EF85 F/1.8
    F/1.8 @ 1/125s @ ISO400 H.H. Manual Focus and Recompose.

    And this:
    Manual focus technique
    Portrait 8271
    "The Lamp Post will not divide Us"
    EOS 5D EF135F/2
    F/2 @ 1/100s @ ISO3200, HH, Av Priority, +1 Ex Comp; Focus and Recompose.


    Quote Originally Posted by Destructor View Post
    But even if a picture seems absolutely sharp to me, very frequently it appears slightly(?) blurred on a computer.
    Well, rugged interrogation might be required.
    There could be other factors.
    Please post some samples with Full EXIF and camera and lens details.

    WW

  12. #12
    GrahamS's Avatar
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    Re: Manual focus technique

    Use back button focus, single point, and focus on the eye. The tools are there - use them. Simple.

  13. #13

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    Re: Manual focus technique

    BTW I recently read that "back button focus" got the name because focus is achieved by using a button on the back of the camera. Before reading that I thought it must refer to some background object or some other technique. Just another example of keeping it simple!

  14. #14
    William W's Avatar
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    Re: Manual focus technique

    The functionality of “Back Button Focus”, is usually achieved by the User purposefully setting a Custom Function or other Camera Menu option: that’s one of the many reasons why I asked the OP to provide more information.

    WW

  15. #15
    inkista's Avatar
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    Re: Manual focus technique

    Pavel, check your shutter speed. That slight blur could be from camera shake from handholding, rather than from misfocus. Rule of thumb is 1/focal_length is the minimum you want (i.e., with a 50mm lens, 1/50s is "the limit")--this is, however, not a hard-and-fast number that applies to everyone in all cases. Some folks throw in the crop factor or double. Personal handholding capabilities do play a large role.

    For me, I'm mostly manually focusing if my lens can't focus any other way, or I'm shooting through glass or a fence. I find that AF works well for me in most cases and is often more accurate and certainly faster than I can be.

    That said. With my manual focus glass, the nice thing is that the focus throws are long and damped, and I have far more precision than with an autofocus lens, and I may even have a distance and DoF scale that are useful. Zone/scale focusing with an AF lens is (for me, at least) an exercise in frustration.

    I also have a 50D and a 5DmkII--both of which are Canon bodies that have interchangeable focus screens. I have a Katzeye split-circle and prism collar focus screen in one, the Canon "super-precision matte" focus screen in the other. Both are more useful for manually focusing with fast lenses (wider than f/2.8) than the default matte focus screen the cameras came with. The Canon super-precision is a little darker and more accurately renders DoF for the wider apertures.

    In addition, I use liveview. On my Canons, the Magic Lantern firmware add-on has given me two tools to work with: Magic Zoom--where I can trigger a portion of the scene to be magnified (w/simulated split screen option) for critical focus, but I can still frame the image accurately (unlike the Canon 10x magnificiation), and Focus Peaking, where the highest-contrast portion of the scene is colored. On my Panasonic G3, the focus assist is like the Magic Zoom feature (I have a Rokinon 7.5mm manual fisheye, and the EVF of my mirrorless G3 means I'm always using liveview).

  16. #16

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    Re: Manual focus technique

    Quote Originally Posted by tclune View Post
    And the camera itself no longer has a focusing split viewfinder unless you have retrofitted it with a third-party unit like Katzeye.
    Have you tried using Katz Eye? I am seriously thinking over upgrading my Canon 550D with that option since it does help. I have heard that Katz Eye is Сarl Zeiss recommended and must be good therefore. Your input would be much appreciated.

    Regards,
    Pavel

  17. #17
    dubaiphil's Avatar
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    Re: Manual focus technique

    Katz Eye and other 3rd party split prism focus screens are useful. The con, however, is that if you use a slower lens (f4.5 +) your viewfinder will become darker. Not significantly so, but it is noticable.

    So If you shoot with primes and f2.8 pro zooms you won't be affected, but with slower lenses you will.

    I had it on my D90, but did not bother with the Catz Eye on my D700. Why - the viewfinder is much bigger and brighter, 35mm on Full Frame is not generally as critical for manual focus for me as a longer focal length, and the focus confirmation light is spot on anyway.

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