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Thread: Idea: autofocus bracketing for Helicon Focus

  1. #1
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    Idea: autofocus bracketing for Helicon Focus

    Given the availability of MF cameras like the PhaseOne DF and AFD, and the Hasselblad H series, and software such as Helicon Focus, it should be possible to add the functionality to automatically create a focus bracket.

    It would be nice to do the following:

    • Set the camera to "focus bracket" mode.
    • Adjust the focus to the nearest point that should be in focus (manually, or possibly using autofocus).
    • Push a button to inform the camera to record the near focus point.
    • Adjust the focus to the distant point of focus.
    • Inform the camera to record the distant point.
    • Set an aperture (if not already done).
    • Push the shutter release.
    • The camera computes how many exposures to make, and what focus points to use, so that each exposure contains one "slice" in which a range of distance is in focus. It can use the focal length and aperture to compute the depth of field for each slice, and make some overlap between each slice.
    • The exposures are later loaded into Helicon Focus, and the focus blending is performed. Each file contains information about the focus distance, focal length, and aperture, if this information is of use for focus blending.


    The cameras already have all of the mechanics and information they need to perform this task. It seems like firmware changes are all that is needed to implement it.

    Helicon Remote has the ability to perform focus bracketing with some Nikon and Canon cameras when they are tethered to a computer, but it would be more practical for field use if the cameras could shoot the focus bracket without tethering.

    Any comments?

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    Re: Idea: autofocus bracketing for Helicon Focus

    The Hy6 already does this.

    Best,

    Mitchell

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    Re: Idea: autofocus bracketing for Helicon Focus

    Quote Originally Posted by Mitchell View Post
    The Hy6 already does this.

    Best,

    Mitchell
    I don't recall that it was ever implemented in the Hy6. Was it?
    It seems like such a useful idea. You have to wonder why Phase and Hasselblad(and Canon and Nikon for that matter) have not implemented it if it really is so easy to do in the firmware.

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    Re: Idea: autofocus bracketing for Helicon Focus

    The Hy6 does do focus bracketing. You can choose 3-9 frames.

    It also does Focus Trap. You set the focus and when something moves into focus the camera shoots. I don't think the focus trap is implemented as well as the Focus Bracketing.

    The Hy6 has a lot of useful features, well implemented.

    Best,

    Mitchell

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    Re: Idea: autofocus bracketing for Helicon Focus

    Quote Originally Posted by Mitchell View Post
    The Hy6 does do focus bracketing. You can choose 3-9 frames.

    It also does Focus Trap. You set the focus and when something moves into focus the camera shoots. I don't think the focus trap is implemented as well as the Focus Bracketing.

    The Hy6 has a lot of useful features, well implemented.

    Best,

    Mitchell
    Can you elaborate on just how the Hy6 implements Focus Bracketing? Is it doen just the way the OP described it, using information as to the near and far focus points entered by the user, the focal length of the lens, and the aperture selected?

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    Re: Idea: autofocus bracketing for Helicon Focus

    Focus Bracketing is one of the shooting modes. It of course only works with autofocus lenses. 3,5,or 9 shots are specified. Once the shooting mode and number of shots is selected, the shutter button is pushed. The mirror goes up for the duration of the series.
    The camera shoots the series changing focus from far to near. As the manual states, "The steps sizes of the deviations of the focal plane depend on the selected aperture, and are set automatically by the system. The step size can also depend on on the lens type used."

    Best,

    MItchell

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    Re: Idea: autofocus bracketing for Helicon Focus

    Mitchell -

    Interesting about the focus bracketing. Have you used it? How big are the step sizes - for example, are they in inches, or in feet of variation? Anything in the manual, or in use?

    Interesting concept. By the way, I have been delving into the user manual for the 6008AF, and have found a lot of customizable settings in the electronics I never knew about. You can set up a quiet shutter (more lag, but less miror slap), change the intensity of the LED displays, sleep time, how many points for autofocus, etc. Rather remarkable, and unheralded. A tinkerers delight - how to program with camera buttons!

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    Re: Idea: autofocus bracketing for Helicon Focus

    Hi Geoff,

    I've tested the focus bracketing and the focus trap. They work on the camera, but I haven't used them yet at all to construct an image so I can't tell you much. I can only refer you back to the quote from the manual above. I think it's clear that the purpose is to give a large DOF, and the camera takes into consideration aperture, lens, and how many frames you specify to give the largest DOF possible. This also of course varies according to distance as well.

    Like the 6008 AF, the Hy6 has a lot of possible settings. I find it quite simple and intuitive to use, but I haven't begun to explore all the possibilities.

    Best,

    Mitchell

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    Re: Idea: autofocus bracketing for Helicon Focus

    Of course the big thing about the camera doing auto focus bracketing, aside from the convenience, is that you don't touch and hence move the camera between shots.

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    Re: Idea: autofocus bracketing for Helicon Focus

    It is very interesting to learn that the Hy6 implements this feature, which shows that it can be done. It seems that the Hy6 is a thoughtfully-designed system! It is too bad that it is in a limbo state, at this time, as it has some nice features to recommend it (rotating back, focus bracket, etc.).

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