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Shooting Handheld Wide Open Using Rangefinder

 
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wiux



Joined: 04 Jun 2019
Posts: 40

PostPosted: Mon Oct 18, 2021 6:27 am    Post subject: Shooting Handheld Wide Open Using Rangefinder Reply with quote

Hello, just a quick question: is it an unreasonable expectation to be able to shoot wide open & hand held using a Crown (or any) Graphic?

I did a brief shoot today, but, upon inspecting the negatives, the focus is just a hair off (maybe ~ft at f/5.6 on a 135mm Wollensak Optar--I was hesitant to shoot fully open in case the rangefinder wasn't precise enough, but still wanted a bokeh).

I've been trying to calibrate the infinity stops to match the rangefinder myself & it seems I haven't quite gotten it exact, but then I started wondering whether I'm putting the ox before the cart. Can the depth of focus on large format cameras actually allow for what I'm trying to do or must I stop down for handheld & use the ground glass & loupe if I want wide open?

My calibration is admittedly rough/coarse. I've no caliper nor square & my method is simply:
1. Match infinity to the rangefinder
2. Adjust stops by examining the ground glass under a loupe,
3. Adjust distance scale for infinity
4. Test the closest distance on the scale (6 ft) using a tape measure--I use something flat, like text, measuring to where the film plane is more or less (I try to be exact, but I'm aware the tape measure isn't perfectly precise)
5. Check ground glass & scale for accuracy
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45PSS



Joined: 28 Sep 2001
Posts: 4079
Location: Mid Peninsula, Ca.

PostPosted: Mon Oct 18, 2021 6:45 pm    Post subject: Reply with quote

What are you using for an infinity target?
Which rangefinder, Kalart, Hugo Meyer, Graphic (top)?
Choose a infinity target at least 5000 feet away. If I use the east bay hills 3 to 5 miles away as my target then celestial targets are slightly off. If I use a celestial object to set infinity then everything else falls in place.
1. set yoke to desired starting position, fully retracted or .040 forward from fully retracted or similar.
2. set lens infinity on the ground glass with a loupe. Use a fine graduation ruler to check that each side of the front standard is the same distance from the front edge of the yoke at infinity. Adjust until they are.
3. check rangefinder infinity, adjust as necessary. Kalart and Hugo Meyer side rangefinder calibration procedures are on this site, the graphic top rangefinder at http://www.southbristolviews.com/pics/Graphic/manual-pdf/servicemanual.pdf . Verify the cam matches the lens, focus errors will start by 15 feet and be off at closer distances.
4. Camera shake kills many photos!!!
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wiux



Joined: 04 Jun 2019
Posts: 40

PostPosted: Mon Oct 18, 2021 9:28 pm    Post subject: Reply with quote

So you think it is possible to shoot handheld & wide open then? I don't think it was camera shake as I was using 1/100 to 1/400s & they're all a bit off in focus. I'm uncertain if the extremely shallow depth of field works well with the rangefinder (matching the yellow patch seems a bit imprecise for what it needs to be--but I don't really have a lot of experience shooting rangefinders without stopping down).

It's a top mounted rangefinder, currently calibrated for fully retracted yoke. I'm confused by your instructions: you said choose a target at least 5000 ft. away but that's only about a mile & you also say to choose something greater than 3 to 5 miles so celestial objects fall into place. Which is it? Do you mean choosing a celestial object will (conversely) reduce sharpness for objects that are closer?
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45PSS



Joined: 28 Sep 2001
Posts: 4079
Location: Mid Peninsula, Ca.

PostPosted: Mon Oct 18, 2021 10:24 pm    Post subject: Reply with quote

A 135mm lens on 4x5 focused at 145 feet has a depth of field from 71.6 feet to infinity. Lens are rarely their marked focal length, they can be 3 or 4 millimeters either side of the marked focal length. The Nominal DOf may not be accurate for your lens.

1. On PDF page 7 of the linked Top RF Service Manual paragraph C 1a states the calibration cam is to be .437 inch wide. This is how high the cam must be when installed in the rangefinder and is the point where the movable mirror is turned so that a target 500 feet or further away is in coincidence. The further away the infinity target the more accurate at infinity the rangefinder is. If you adjust the movable mirror so that a target 500 feet away is in coincidence then look at the moon through the rangefinder without moving the yoke the moon will not be in perfect coincidence.
2. With the rangefinder calibrated the yoke can be set as desired for infinity then the bed actuator moved to make the rangefinder show infinity at the infinity target.
3. With the yoke at the desired infinity position set the lens to infinity and secure the infinity stops.
DOF of a 135mm lens at f4.5 focused at 500 feet is 110 feet to infinity; 138mm at f4.5 DOF is 114 feet to infinity; 132mm at f4.5 is 106 feet to infinity. I prefer to use as far a target as I can get for infinity set up/calibration.

Whether you can shoot hand held wide open and get a tack sharp subject on film depends on how stable you are and how accurately the rangefinder and lens are calibrated.
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wiux



Joined: 04 Jun 2019
Posts: 40

PostPosted: Wed Nov 10, 2021 2:31 pm    Post subject: Reply with quote

After a couple of recalibrations, the rangefinder & ground glass seem to coincide more or less (it turned out to be wildly off after calibrating infinity to the moon & not bothering to check closer distances before calling it a night, thinking the rest of the distances would fall into place after getting infinity): it's still a hair off, but for anything other than wide open, it should be in focus. Haven't tried shooting a test shot yet, but that's next.

Tangentially related, I also read about using a piece of string with a known distance, calibrated to the ground glass, as a sort of primitive rangefinder for closer distances. Thought that was a crude but clever solution when trying to focus for distances closer than the scale shows (aligning the front standard using the bolts on the side of the rails for reference).
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45PSS



Joined: 28 Sep 2001
Posts: 4079
Location: Mid Peninsula, Ca.

PostPosted: Wed Nov 10, 2021 8:42 pm    Post subject: Reply with quote

Scales are an approximation device, a calibrated rangefinder is more accurate but loupe focusing the ground glass is the best.
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alt.kafka



Joined: 16 Nov 2019
Posts: 9

PostPosted: Tue Dec 21, 2021 2:30 pm    Post subject: Reply with quote

I love shooting handheld with the rangefinder. It depends on how well you've calibrated your rangefinder, but it's not rocket science.

Rather than use a distant target for setting infinity, I made a close target similar to this one. https://learncamerarepair.com/product.php?product=637. The advantage is that you can do all of your adjustments with the camera mounted on a tripod, so you can do them more carefully. This one is for the super graphic and won't work for a CG, but you can see how it works. The center point of the stars/crosses just have to be the same distance as the center points of the rangefinder mirrors.

You do need a calibration cam to do it well, but it's also not hard to make. You will need a calipers to get it right. I just took a piece of steel and ground it on a sharpening stone until it measured right.
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