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    Focus bracketing

    Some of the new cameras out recently like the RP and the 90D come with the built in facility to do focus bracketing. However, it looks like there is a lack of detail on how it works and how to set it up judging by a query on this subject by a member recently. Those that have cameras with this facility may well welcome an article that describes how it works in the camera and how to set it up.

    Ian
    Ian

    Flickr page https://www.flickr.com/photos/154026104@N07

    #2
    Thanks for the suggestion. However, we covered focus bracketing in an 8-page article in EOS magazine October-December 2019.
    Robert
    robert@eos-magazine.com

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      #3
      Originally posted by Robert Scott View Post
      Thanks for the suggestion. However, we covered focus bracketing in an 8-page article in EOS magazine October-December 2019.
      So you did Robert - but the article does not adequately answer the specific question raised by BobSapey in the "Digital Cameras" part of the forum.
      John Liddle

      Backwell, North Somerset - "Where the cider apples grow"

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        #4
        Originally posted by Robert Scott View Post
        Thanks for the suggestion. However, we covered focus bracketing in an 8-page article in EOS magazine October-December 2019.
        It is an interesting article and I have read it, but there is nothing in it about how to decide on the focus increment which is an important part of the process. I've tried some experiments which I posted in the Digital Cameras section yesterday, but it would be easier if you were able to find out from Canon how the Focus Increment scale works. It's a pity they haven't yet published it.
        Using Tapatalk

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          #5
          As far as I know, there is nothing from Canon on this at the moment. As a general rule, small subjects will be best shot with narrow increments (settings 1 to 5) while larger subjects will require wide increments (settings 6 to 10). My guess is that there is no 'correct' setting. Since, most of the time, you will be photographing a static subject, it will be easy to shoot using different focus increments and then choose the result you prefer.
          Robert
          robert@eos-magazine.com

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            #6
            I have been using focus stacking for a few years now. I don't know how the 90D and RP implement this, but the general rule I have used is to increment in half or one third depth of field steps.
            You can see the DOF more clearly in live view, and take a series of shots focussing from the front of the scene you want sharp to the back, setting the focus of the next shot so that its front DOF overlaps with the rear DOF of the previous shot. The DOF you need to work to is dependent on the scene and magnification. For macro I often need 20 shots, but for landscapes, 2 or 3 might be sufficient with a WA lens. If you need to know DOF limits you can use a chart (I built an Excel one) to calculate front and rear limits assuming a 20 micron circle of confusion (EOS wrote about this a while back). For example a 50mm lens at f/8 gives you about .06m DOF for a 1m focal distance but extends to about 0.5m at 3m, and virtually anyting beyond 20m should be sharp. So for a landscape sharp at 1m to infinity you'd need the first increment at .05m, say, then 0.1, then 0.2 approximately (I haven't checked the details) gradually until somewhere around 20m when you'd get the "hyperfocal distance" and "infinity" should be sharp(ish).
            Whether the 90D works on a sort of expanding or logarithmic scale I don't know as I haven't looked into it.
            For macro, generally you need to keep the focal length fixed anyway and adjust the camera position to avoid "focus breathing" magnification errors.
            Maybe, if you have a 90D or RP you can check the settings against a given scene you can measure with a tape measure to find out what it is doing.
            Last edited by neonlamp; 22-06-2021, 16:04.

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