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Does laser based focusing work in the field when the sun is shining bright?

Paul Spinnler

Active member
I have a question for those who may have dabbled with technical cameras and rollfilm adapters; can one in the field use a Leica Disto or a similar laser pointing device to successfully double-check whether the focusing distance remains the same while one does some adjustments to a composition after having previously focused something with a ground glass?

Let's say I have an Alpa and just use it in an analogue form. Let's also say I want to do a portrait with a Rodenstock 70, for example. I focus the subject either via ground glass and then swap it for a film back or I work with HPF rings.

Is is practical to use a laser distance measuring device to make sure the subject hasn't moved more or less? Can one use a Leica Disto outside in bright sunlight and get an accurate reading of how far a person's head is from the point of measurement?

Best
Paul
 

stngoldberg

Well-known member
I have a leica disto and find it ok for some applications but my Bushnell range finder is a much more user friendly instrument for sighting distance as I can look through the lens to site the object that is my target.
the Bushnell is equally accurate
The leica is problematic is many instances in my experience
stanley
 

Paul Spinnler

Active member
Thanks Stanley. This is why I love this forum. I didn't know this brand!

What about a portrait of someone standing 10-20 feet away from you outside. Can you measure precisely whether this person's head has moved in between you setting up focus on shooting the film?

Is the Bushnell only good for long distance?
 
I also have the same needs as yours, Paul, especially for the short distance portrait shooting.
I hope the App of "Viewfinder" would have the distance measurement function in the live mode.
 

Paul Spinnler

Active member
Hi Sun

Yes, I see, we had this discussion in the other thread. The problem arose because I got hold of a Zeiss Planar 3.5 135mm and I want to use it on a 4x5 field camera to make portraits. Now if I want to use the shallow DoF effect I need the subject to stay put perfectly at clost distance ... which I think will be tricky if it is strangers.

So in my view there are following options:

1) Use a thread or a physical market to make sure person stays in place
2) Be fast and keep an eye on the subject and re-do if confidence is lost
3) Stop down to f8, use zone focusing
4) Use a distance measuring device like a laser or similar to double check

3) I want to avoid, 1) is what I would tend to do or 2) and 4) is what I am exploring, but not sure works outside in all conditions.

Best
Paul
 

stngoldberg

Well-known member
The Bushnell allows you to sight the object (in your case a person’s head) and the press the button at that moment for a very accurate measurement
stanley
 

da_eltsch

Well-known member
Hey Paul,

I understand your point and approach. What just came to my mind: I would hesitate to use a Laserpointer for the measurement on persons (eye) as though I have no idea what kind of laser the mentioned system uses. For everything else these devices work fine.

OT: do you use those clamps where - some decades ago - people would rest their necks against to hold the distance stable :) ...

Best,
Helge
 
Last edited:

docholliday

Well-known member
You could always do it the way we did when I shot 8x10 or 11x14 LF portraits... string. Get some simple string (kite string works well). Put a paper clip on one end and use that to hook onto the tripod or camera base. Have the subject pull the other end taught and hold it against their chin or nose tip. You could alternatively have an assistant hold it taught for them, but against the same point. I've even had the subject hold the string in their teeth (use cheap string so each person gets a new piece).

Focus the camera, close the shutter, load the film/back. Step around camera with release in hand.

Have the subject drop the string and set their arm down (or close their mouth and smile/smirk).

Fire.

It doesn't matter what the distance is with string...it's not measuring anything. It's just there to keep the subject from swaying away from the focused point.

Lasers (even the "weak" class in pointers or measuring devices) are harmful to the eye, especially if the subject has glasses. They should never be pointed at a person's eye. The ultrasonic distance measurement devices aren't accurate enough anyways. On some, the laser is just a visual tool to aim - they still measure using ultrasonics.
 
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