### Rule of thumbs of Hyperfocusing with Minox 35mm camera

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## Focusing a field of flowers Rule of thumb of hyperfocusing with Minox 35mm camera.

-- martin tai (martin.tai@capcanada.com), December 21, 1998

### Focusing a Field of Tulips

At summer you see a field of tulips, you take out your Minox GTE or 35ML, compose a vertical shot. Looking through your viewfinder,you see there are so many flowers, from near to far, the nearest flowers are at the bottom end of of viewfinder, the furthest ones are at top of your viewfinder. Now you have two distances, a near distance X and a far distance Y; you also know that you should focus at Z = 2*X*Y*(X+Y).

But do you know where the point Z is in your viewfinder ?

It can be mathematically proven, that the center of the viewfinder points exactly to point Z.

A few years ago I posted an article in rec.photo news group:" Hyperfocusing the Tulips" about this interesting relationship in the viewfiner. The next question is how to choose the aperture ? Of course, you can do it the hard way, that is estimate the near distance and far distance, then use the depth of field scale on your camera to find the proper aperture.

But there is a simpler "rule of thumb", which I shall write about next

Back to field of tulips. The right focal point Z is pointed to by the center of viewfinder, what is the aperture to use such that the near points (at bottom of viewfiner ) and far points (at top of viewfinder ) is adequately covered by depth of field ? Answer, if you standup, and hold camera at eye level, and if your eye level is 1.5 meters or more from ground, then 1/3 of focal length is sufficient. With Minox GTE, 35mm lens, then 1/3 of 35 is about 11; set F11 and shoot the field of flowers too !

### One Third Focal Length Rule of Thumb

When I travel with my Minox GTE, I usually use it for landscape shots. I usually take these picture hand held, with camera at my eye level; most tourist-photographers do the same.

When holding the camera horizontally, the closest point cut off by the viewfinder is a few meters away from my feet, let us say it is point N, and the furthest point seen from the viewfinder is infinity. What is the proper aperture to choose on Minox GTE (or other Minox 35 camera ) such that the hyperfocal point is N, the nearest point seen through the viewfinder, and the furthest point is infinity ?

A few years ago I went to Ottawa in May, for its Tulip Festival. When photographing the field of colorful tulips, the question of where to focus, what aperture to use came to me. After returning home, I worked out the rules of thumb. I discoverd that for horizontal shots, set aperture to one third of focal length, for upright shots, set aperture to one quarter of focal length. In our case of Minox GTE with 35mm lens, if you take scenics standing up as I do, set aperture at 1/3 of 35 or F11 for horizontal shots, set aperture to 1/4 of 35 = F9 for vertical shots.

To even simplify matter, as long as you standup and set aperture at 1/3 of focal length, you should be able to get the whole depth of field within your viewfinder, horizontal or vertical.

With Minox GTE, set aperture at f11 and set focal point at infinity and shoot.

-- mt (cg081@torfree.net), December 27, 1998.