Focusing distance by body size in finder

Somewhere I remember seeing an article about focus distance based on the size of the image in the finder. (example: you're shooting people and the person is seen from head to feet the focus will be X. If it's a head shot which fills the viewfinder then focus at Y.)

Any reference will be appreciated.

Wilhelm

You may be crossing over to target shooting, hunting, or military sniping. Had not heard of that method being used photographically. Here is a link to a pretty comprehensive article on that subject. Ryan Cleckner: How to Estimate and Adjust for Target Distance - The Truth About Guns

THanks, Sandy, but not quiet what I'm looking for.

Wilhelm

That's a technique I learned when shooting weddings with a TLR and a manual flash, long time back - before there were "auto" flashes, like the Vivitar 283. I've mentioned it a couple times on forums, but I don't think many people listen, so I don't bother repeating.

 

Basically you do your shooting in several discrete "distance zones," which you decide before the shot. With weddings I'd typically work with either full length, 3/4, or half. As a note, with a "normal" lens on a 2 1/4" square neg, these distances will each be about an f-stop apart with respect to flash exposure. So you preset both focus and lens aperture for what you're gonna shoot, then use the sportsfinder to move in/out for the appropriate framing. (I liked using a Graflex Stroboflash with the power setting switch on top - instead of changing lens aperture, I could just click to 1/4, 1/2, or full power.) It'd be a good idea to write down your basic settings, distance and lens aperture, and tape it to the side of your flash.

 

It's not precise, but within limitations it works great. If you can get down to f/8, or even 5.6, the DOF will cover up the focus errors. Of course, if you have time it's good to improve the focus, but you often cannot do this with wedding shots. For example, you could easily move around taking half-length shots on a dance floor that is so dimly lit that you could barely see through the viewfinder of an SLR. Thru the sportsfinder you can watch for a good expression, plus you can see if anyone blinked on a flash shot.

 

Regarding precision of focus, you can easily try it out. Have someone stand on a mark, away from which you have marked distances on the floor. For a full length adult, with distance of roughly 8 or 10 feet, you can probably easily get your distance within a foot. This is working just by eye, using the sportsfinder.

 

To be clear, the times when you would want to use this technique is when working with 1) a manual flash, and 2) either a dynamic situation or place where it is too dark for viwfinder focusing.

Edited January 29, 2018 by Bill C

I vaguely remember that on 35mm film or for an FX sensor and using a 35mm lens, the distance to the subject equals about the height of the subject (camera in portrait orientation). In other words, if a 6ft person fills the viewfinder of a camera held vertically, the distance is about 6ft.

I have some older, low end Polaroid pack film cameras that don't have a super-imposed type rangefinder. Rather, there are a series of lines in the viewfinder that indicate distance and an arrow that points to the lines as the focus is racked in and out. The instructions tell you specifically how to frame a persons face within those lines and then focus until the arrow points to the line at the bottom of their chin.

 

It's a clunky and limited system, and if one is going to use an old Polaroid folder something like a 250 with a real Zeiss glass coupled rangefinder is in every way better. None the less, I'd guess a lot of photos were taken with that sort of system.

The Kodak Instant film camera (the one that got sued by Polaroid) used such a technique for focusing. There are 2 lines in the viewfinder and as you focus the 2 lines come closer or further apart. You set the focus to fit a person chin to forehead.

This should be obvious, but just to state it.

This applies to FIXED focus prime lenses, NOT to zooms.

And it will vary based on what fixed focus lens you use.

It works best for a FIXED lens camera, so the lens variability is eliminated.

 

It is also dependent on the specific camera and veiwfinder, as not all are the same.

So what may work for one camera may not work for another.

 

The link that Sandy linked to answers what you asked about, but in a different situation.

You just apply same idea to camera at closer distance, as Bill said.

 

The problem with using a person's height is that people are different height; some are 6ft10in others are 5ft 1in and everything in between. The average German is much taller than the average Japanese. But even within nationalities, there is SIGNIFICANT height difference. So defining average height is a problem.

 

If you want to do it, it is pretty easy.

• Get a tape measure
   
  
• On a wall, mark what you think is an "average" person's height is.
   
  
• Then looking through your viewfinder, move till the floor to mark fills the viewfinder
  
• Then measure the distance to the wall.
  

Do the same for head to waist and head and shoulder height.

Gary, all my Minox's have 15mm lenses.

You could just put a subject at various measured distances, then look through the viewfinder and see how big they appear. This is a rainy day project and you could develop your own simple picture chart.

When I attach a 4X Tamron aux telephoto lens to my IIIs via the bino clamp I visualize the reduced area when looking through the viewfinder. It's just a mental trick a person can develop. Same thing with how big a person appears in the viewfinder.

With regard to Minox and its 15 mm lens I just guesstimate distance to subject my imagining my own height laid out on the ground and never had any diffuculty. A number of my 35mm cameras require estimating focus distance: Retina B, Rollei 35. Unless shooing at f1.5, f2 or 2.8 depth of field is sufficient for most pics. In fact, a rangefinder can sometimes be a handicap. Leica M3 has a little notch in viewfinder which showed permissible wiggle room for focus.

All this seems easier than measuring height of image in viewfinder for most general picture taking.

How to Estimate Distances

 

Your arm is about ten times longer than the distance between your eyes. That fact, together with a bit of applied trigonometry, can be used to estimate distances between you and any object of approximately known size.

Imagine, for example, that you’re standing on the side of a hill, trying to decide how far it is to the top of a low hill on the other side of the valley. Just below the hilltop is a barn, which you feel reasonably sure is about 100 feet wide on the side facing you.

Hold one arm straight out in front of you, elbow straight, thumb pointing up.

Close one eye, and align one edge of your thumb with one edge of the barn.

Without moving your head or arm, switch eyes, now sighting with the eye that was closed and closing

the other.

Your thumb will appear to jump sideways as a result of the change in perspective.

How far did it move? (Be sure to sight the same edge of your thumb when you switch eyes.)

Let’s say it jumped about five times the width of the barn, or about 500 feet.

Now multiply that figure by the handy constant 10 (the ratio of the length of your arm to the distance

between your eyes).

Now you get the distance between you and the barn—5,000 feet, or about one mile. The accompanying

diagram should make the whole process clear.

With a little practice, you’ll find that you can perform a quick thumb-jump estimate in just a few

seconds, and the result will usually be more accurate than an out-and-out guess. At a minimum, it will

provide some assurance that the figure is in the ballpark—which, in many cases, is as close as you need

to get.

from How to Easily Estimate Distances -Old Farmers Almanac

 

Also

 

PP 1941-01

Edited February 6, 2018 by JDMvW