Mamiya Press 50mm 6.3 Lens: How to Zone Focus? Markings don't make sense.

[MattKing]

To aid in clarity:
1) "zone focus" applies in the situation where one sets a rough, approximate focus setting (close, medium, far) and relies on the inherent depth of field to achieve usable results. A 50mm lens on a Mamiya Press is probably a good candidate for this when light levels are high;
2) "scale focus" applies where one either estimates the distance to the subject, or measures that distance with a separate rangefinder, and then transfers the result of that estimate/measurement to the setting on the lens - the red triangle, in the case of the subject 50mm lens. Using "scale focus" and estimates is very practical with that lens for everything down to quite close distances, again due to depth of field;
3) hyperfocal focus involves maximizing the range of in focus items in the photo. You accomplish it by using the depth of field scale on the lens - set the infinity setting on the focusing scale on the lens opposite the far example of the aperture you are using on the depth of field scale. The near example of that aperture on that scale will show you the closest distance that will be in acceptable focus;
4) the depth of field scales on most lenses are rather optimistic. In many cases, if you are exposing with one f/stop - say f/16 - it is prudent to use the depth of field by referencing instead the f/stop that corresponds to one stop more light - in this case f/11.

 

[wiltw]

1. For focus, the ONLY place in which a Point is represented as a Point is only along the Plane of Focus exactly.
2. All deviations from Point representation, away from the Plane of Focus, a Point is represented as a CIRCLE which fools the eye and brain into thinking 'This is a Point'.
3. When a Point is represented as a Circle, when it gets large enough the eye and brain think "This is no longer a Point, it is Out of Focus! This size is commonly referred to as the Circle of Confusion size. The representation of this circle size is generally depicted by imperfect human vision...in reality, that Circle cannot be as large as most DOF tables or DOF scales show...which explains why the use of DOF Scales usually results in perceivable out of focus blur (circles), contrary to what the DOF Scale claims!
4. The CofC size varies by format size, simply because each format needs a different level of magnification to fill an 8"x10" print
   The CofC of 135 is 1/2 as large as Medium Format and 1/4 as large as Large Format, and Medium Format is about 1/2 as as Large Format (4x5) which is 1/2 as large as the visible CofC of an 8x10 print

 

[cayenne]

I should mention that when you run out of focus distance numbers on the lens, and you are using hyperfocal setting with one of the DOF points at infinity, the close end of the scale will be at 1/2 the distance the lens is focused for. In the above photos f22 and infinity are lined up. The red diamond shows an optimum focusing distance of a bit over 4 feet. The close DOF distance will then be one half of four-and-a-bit feet or roughly equal to two-and-a-smidge.

The hyperfocal method is generally not a good idea unless you want to use your camera like a box camera. The lens should always be set to the actual distance to the subject. If you want great depth of field then pick the f-stop that gives the DOF to the near or far point you desire. If you can't reach it with the lens focused at the subject distance then consider the best compromise you can reach with the subject distance as close to the focusing distance as possible.

DOF scales can be just as useful for making sure something is blurred. I use the DOF preview on a camera a lot as I find the pleasantly blurred background I see in the finder pops into distracting focus when the lens stops down. That was nice thing about Exaktas with their external stop-down/shutter release button - you always got a DOF preview of the picture.

Preseting a lens to be in focus from say 4 feet to 20 feet can be useful for street photography or other situations where you won't have time to focus. Realize, though, that only things about 8 feet away will be in really sharp focus. Henri Cartier-Bresson used preset focusing for many of his shots and it is the reason so many of his photos are slightly fuzzy; I got so used to HCB's fuzzies that I find the occasional in focus shots to be somewhat jarring and lacking in that HCB 'look.'

Actually, that's precisely the reason I was trying to learn hyperlocal/zone focusing....due to using some cameras that you do not see through the lens, or even rangefinders that are sometimes slow to focus if action is happening.
For example, with the Leica M10M or the MA....whenever I take those out, I'll generally preset them to sunny 16 or a variant....and then preset the focus based on the aperture so that I can just pull it up and fire away if something suddenly presents itself as interesting.

For this new camera, that I can't ever focus optically in any fashion...I was hoping to figure how to do the same to preset it to carry. Whenever I have time to measure and set up and shoot, of course I'll do that, but I figured that once past that shot, I'd still pre-set it for fast shooting like I do my Leica manual focus cameras to carry about.

With my manual focus cameras I try to walk with the always preset for best focus I can, in case I find quick action I wanna pull up and just snap away.

Thank you again!!

C

 

[cayenne]

No, that's not what saying "the DOF marks are off" means. Look, do you have an SLR with a manual focus lens that has a depth of field scale that you can practice with to understand? Because this scale is the same thing, and with the SLR focusing screen maybe you can focus the lens back and forth to understand depth of field.

The red mark in the center indicates the distance you are focused at. That should be correct if the camera was made properly. The aperture numbers to the sides indicate the range of distances that will be in acceptable focus. What we are saying is that Mamiya's idea of "acceptable" was too broad, so you have to use the marks for one stop closer together. You could do something like put a piece of tape over the f/11 mark that says "16" to remind yourself of this.

Yes, I have a manual lens with DOF markings...my Leica M10M was my first one....its rangefinder.
That was my first experience with DOF markings....but on all those lenses, whenever I set infinity on one side...there is ALWAYS a number marking on the other side showing the range.

This example confused me in that not every setting of infinity on one side...and any corresponding setting on the other side of the DOF scale.....and then on top of that, folks were explaining that with the Mamiya lenses, you couldn't really trust them even when the markings were all there.

I think I have it now...but those were my confusion points initially

Thanks for all the help and insight!!
C

 

[wiltw]

This example confused me in that not every setting of infinity on one side...and any corresponding setting on the other side of the DOF scale.....and then on top of that, folks were explaining that with the Mamiya lenses, you couldn't really trust them even when the markings were all there.

As I clarified in post 27, "in reality, that Circle (of Confusion) cannot be as large as most DOF tables or DOF scales show...which explains why the use of DOF Scales usually results in perceivable out of focus blur (circles), contrary to what the DOF Scale claims!" You cannot 'trust' ANY manufacturer's DOF Scale or Table, because we humans have better visual acuity that the common used CofC sizes are presumed can go undetected as 'out of focus'!