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Thread: Hyperfocal with tilt, on Tech cam

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    Hyperfocal with tilt, on Tech cam

    Hi,
    I would like to use more the movements on my tech cam, for the "typical" landscape shot, where you want sharpness from near to far, without closing too much the aperture to avoid diffraction.
    I have a few DOF calculators in my iphone, which also include tilt, so I'll experiment with that. But as starting point and sanity check, I was wondering what you guys use, for a given lens for:
    - Focusing distance
    - Tilt angle
    I would say for a "typical" tripod height. What kind of value for CoC do you use ?

    I'd be most interested in values for 32mm, 50mm and 90mm lenses. I use an IQ160.

    Thanks !
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    Workshop Member Wayne Fox's Avatar
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    Re: Hyperfocal with tilt, on Tech cam

    Personally I use LiveView and focus foreground and background when tilt can be used for depth of field. I suppose some specific settings would be repeatable but never really bother writing them down.
    wayne
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    Re: Hyperfocal with tilt, on Tech cam

    I do have the variable ND filter for the patented Wayne Fox LV focusing method, so I will try that too.
    I just thought having a starting point not too far from the final value may speed things up.

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    Re: Hyperfocal with tilt, on Tech cam

    For the typical landscape picture, where you want the ground to be sharp from front to end, the tilt angle is defined by atan(f/h), where
    -f is the focal length and
    -h is the height of your tripod.
    It is a simple geometrical construction, where the plane of the ground, plane of the sensor (which is supposed to be vertical) and plane of the lens should meet right below the tripod. For typical values of f and h, you will find a bit less of 2.

    If you are doing that, you don't need any depth of field for the ground. You will need depth of field for objects not in the plane of the ground (like the top of nearby trees, etc...), but this depends on each particular picture.

    In practice, 1.5 and f/11 works in most of the cases.
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    Re: Hyperfocal with tilt, on Tech cam

    Thanks Jerome. Do you keep the focus at infinity ?

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    Re: Hyperfocal with tilt, on Tech cam

    Quote Originally Posted by miska View Post
    Do you keep the focus at infinity ?
    The focus will be close to infinity on most tech cams if we suppose that we keep everything square and only photography a flat ground. In practice, we don't take landscape photographs by having everything square and orthogonal as in a geometrical construction, so a bit less than infinity is probably better. Since I don't use a tech cam, but the Hasselblad HTS system, I can focus on the ground glass. I usually tilt down about 1.5 and focus on a far object. 1000x focal length is probably a good value (so 35 m for a 35 mm lens).
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    Re: Hyperfocal with tilt, on Tech cam

    @Jerome :
    Focus a 35mm with 1.5tilt at 35m at f11...well, You should be able improve a lot your tilt technique

    @Miska:
    You first have to really undertsand what tilt actually do (it modified your plan of focus and also your depth of field in a cone way)
    Take a look at This page(from a member): http://www.ludd.luth.se/~torger/phot...landscape.html

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    Re: Hyperfocal with tilt, on Tech cam

    using the arctan (f/h), and a 5' (1500mm height), i get:
    32mm lens: tilt of 1.2,
    60mm lens: tilt of 2.3
    90mm lens: tilt of 3.4

    pretty consistent with my findings

    nice article by the way
    Last edited by jlm; 12th June 2015 at 06:09.
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    Re: Hyperfocal with tilt, on Tech cam

    There is a slight focus change required to keep the center focus when tilting. After some trig, I get f/(1-Cos(tilt)), or approximately 2 f/(tilt^2) as the new "infinity". In the case of the 90mm lens with 3 degrees of tilt, that yields about 65 meters. Similarly, I get 100 meters for 60mm at 2 degrees tilt, and 200 meters for 30mm at 1 degree.

    That's infinity focus. For (fairly distant) hyperfocal, you'd turn the helicoid by the same amount as for infinity focus. For Arca users, that means adding the same offset to the focus.

    --Matt
    Last edited by MGrayson; 12th June 2015 at 08:06.

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    Re: Hyperfocal with tilt, on Tech cam

    If forced to, I can do the math; but while trying to create "Art'" I don't want to get involved with algebra.
    Here is what I do to employ tilt:
    1. Focus approximately 2/3 into the scene.
    2. use 1 degree of tilt for each 30mm of focal length

    For example when using a 90mm lens, use 3 degrees tilt
    Usually provides a wide DOF
    Stanley
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    Re: Hyperfocal with tilt, on Tech cam

    Quote Originally Posted by MGrayson View Post
    If I had my tech camera, I'd test it. Sadly, it's been in the shop for four months. Cambo is working hard at losing a customer.

    --Matt
    Sounds weird, I had some trouble with my 40HR T/S mount and Cambo was very swift in trying to fix the issue and even sent me a loaner camera when they needed my camera as well.

    Have you tried giving them a call or sent them an email?

    Peter
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    Re: Hyperfocal with tilt, on Tech cam

    10 minutes ago I got the email saying it was back, and I can pick it up so I'm less annoyed. The problem was a SK 35XL that was soft on the right side.

    Off it went to the Netherlands. It came back 3 weeks later with a new mounting plate, and it was worse than before! Back it went to the Netherlands - this time, it was declared to be a problem with the shutter, so off it went to Germany. I'm shocked that Cambo didn't test the lens after repairing it the first time. The problem wasn't subtle!

    --Matt

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    Re: Hyperfocal with tilt, on Tech cam

    This is all very helpful ! :-)

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    Re: Hyperfocal with tilt, on Tech cam

    Quote Originally Posted by daf View Post
    @Jerome :
    Focus a 35mm with 1.5tilt at 35m at f11...well, You should be able improve a lot your tilt technique
    It seems that jlm and stngoldberg use similar values as I do.

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    Re: Hyperfocal with tilt, on Tech cam

    This all matches the other rule of thumb which is pretty much focal length/30 gives you a reference starting point when shot from a typical 5ft or so high tripod position.

    The fun starts when you get close to the ground or the plane of focus isn't flat along the ground.

    In general though the combination of height above the plane of focus you're after (tripod height unless the landscape is lower), the focal length will get you the starting tilt. If you think of the focal plane turning into a wedge from the base of your tripod, then the aperture will affect the height or span of that wedge. The focus on the lens has the effect of changing the tilt of the plane of focus. As you focus towards or beyond infinity, you're going to lay the plane of focus down and in fact if you're using the hinge line approach the actually at infinity you'd have half of the area in focus below the horizon. That's why there's the suggestion in the general case of say trees or mountains in the distance that you focus ahead of infinity and why often the hyperfocal distance is not an unreasonable starting point.
    Last edited by GrahamWelland; 12th June 2015 at 16:40.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"
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    Re: Hyperfocal with tilt, on Tech cam

    you mean divided by 30 :}

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    Re: Hyperfocal with tilt, on Tech cam

    Quote Originally Posted by jlm View Post
    you mean divided by 30 :}
    Damn, I wondered why I was finding it so hard to do tilts!!

    Somehow missed a zero, yes indeed 30.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"

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    Re: Hyperfocal with tilt, on Tech cam

    With view cameras, I just eyeballed the lens plane to intersect the ground under the back. I always focus on some point of the main subject. BTW, you can always check how the focal plane intersects your scene with an image. If you have instant playback, no harm in using it. I don't see the point of focusing at infinity as it does not optimize DoF through the scene. I guess I could do the math, but I have not found photography that unforgiving.

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    Re: Hyperfocal with tilt, on Tech cam

    Interesting topic. I am new to this.
    Can someone please recommend a book or online article on the mathematics of tilting the focal plane? TIA.
    With best regards, K-H.

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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Last edited by GrahamWelland; 12th June 2015 at 19:21.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"
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    Re: Hyperfocal with tilt, on Tech cam

    This iPhone app is great and has some dynamic graphical tools to help visualize on the fly.

    http://www.snapi.org/snapi/Tilt_Calculator.html
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    Subscriber & Workshop Member GrahamWelland's Avatar
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    Re: Hyperfocal with tilt, on Tech cam

    I use the Snapi Tilt Calculator on the iPhone myself. Highly recommended plus it caters for camera body tilts in addition to the lens which is really useful at times.
    Remember: adventure before dementia!

    As Oscar Wilde said, "my tastes are simple, I only like the best"
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