Graflex.org

[bartbob]

Today's task was to check the focusing accuracy of rangefinder vs. ground glass. To begin with, both the fresnel field lens and ground glass were smudged with finger prints and some dust and/or lint was between these two parts. They're easily removed and cleaned with optic lens cleaner then dryed with lint-free lens cloth. Both pieces went back in ensuring the fresnel lens grooves mated with the ground surface of the glass then installed with the field lens's smooth side towards the lens; ground glass smooth side towards the back.

With the rangefinder zeroed at infinity, buildings a mile away were made sharper after slightly misaligning the split image. I used a 10X loupe on the ground glass to get precice focus then checked the rangefinder; 'twasn't coincident. At about 12 feet, the lens had to be moved forward about the same amount from rangefinder coincidence to focused image on the ground glass.

Does this mean the infinity stops need to be repositioned on the track? They'll have to move about .040" to make rangefinder coincidence and sharpest focus happen at the same.

Bart

[45PSS]

The Graflex Service Manual says to focus the rangefinder at infinity on a target over 5000 feet away and rack the yoke (rails) inward until they are .040 ± .010 inch from the yoke stop (fully retracted) and lock them in this position. Next loosen the actuator slide bracket and move it until the RF is in coincidence with the target then tighten the actuator slide set screw.

At this point you are ready to check the infinity stop position or install a new set of infinity stops for another lens.

Slide the front standard with lens attached to the infinity stops and lock the front standard. Operate the press to focus of the lens or open the shutter on T, O on the Graphic 1000 shutter, set the aperture to its widest opening, smallest f number, and check the focus on the ground glass. If the focus is in error, slide the front standard back, loosen the set screws on the infinity stops until they will just slide on the rails. Unlock the front standard, slide it until the lens is in sharp focus on the infinity target and lock the front standard. The focus will shift slightly on locking the front standard. Reposition as needed so that the lens is in sharp focus when the front standard is locked down and the standard is square to the rails. Use a fine graduation ruler or caliber to check each side of the front standard to the end of the rail. They should match perfectly. Once done slide the infinity stops up to the front standard and tighten the exposed set screw down. The infinity stops should just touch the front standard without putting pressure on it. Move the front standard back and tighten the remaining screws on the infinity stops. Recheck lens infinity focus as the stop(s) might shift slightly when tightened. A correct infinity stop will have a flat bottom screw on the front of the stop and a pointed bottom screw on the rear set screw. Over tightening the pointed screw will indent the rails causing adjustments of .001 to .1 inch difficult.

The manual says to install the factory cam for the lens then proceed with the infinity stop setting. You have a lens that does not have a cam. Use an existing cam and set the rails/RF to infinity and lock the rails. Attach the lens matched to the cam and verify the infinity setting. Attach the second lens and position the front standard so that the lens is sharp at infinity as before and install the infinity stops for it. Make a secondary distance scale for this lens by focusing on measured distances then transfer the RF distance reading to the scale you made for this lens.

Want to make a cam from scratch for a lens, see
http://graflex.org/helpboard/viewtopic.php?t=4653
Rangefinder needs repair, see
http://graflex.org/helpboard/viewtopic.php?t=4647
_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.

[bartbob]

[45PSS]

Yes its the yoke stop or fully retracted.

I edited the post. Sorry for the omission.

The manual says to send the rangefinder assembly to a service center for repair. Graflex repair centers are long gone. No specs are listed either. I was buying restorable Super Speeds off ebay and had a few with factory matched cams and lens on hand. Several members were asking about cams and calibration. On a warm smoggy day I sat down with a rangefinder, camera body, the lens/cams, and a digital caliper accurate to 3 decimal places with inch/mm readout.

I like to use the moon on a clear day or warm evening for an infinity target. I also have a sheet of special mylar that blocks the harmful rays for viewing the sun. The sun makes a nice dot to align on.

Looking direct at the sun without the proper filter will damage your eyes.
_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.

[bartbob]

[45PSS]

Check the lens focus on the ground glass at closer distances and compare to the RF and indicated distance on the flash calculator scale to verify the cam matches the lens.
http://www.graflex.org/speed-graphic/super-graphic-cams.html
Someone may have switched the lens/matched cam out and not reset the infinity stops.


Foggy nights are very common here on the peninsula so the moon is now always available when it is up.

I made E5 with minimum time in grade/ time in service when I was in the Air Force in the early 70's. I worked on air to ground nuclear missiles. I got out because I did not want to sit in Minute Man silos for the next 4+ years. I have worked various technical service jobs and retail since.
_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.

[bartbob]

[45PSS]

I make my replies not only for the poster but the others that may read it now and in the future. I prefer technically accurate information not colloquial jargon.

Remove the ground glass and Ektalite Field Screen, Graflexspeak for fresnel. Wash in warm, mildly soapy water. I use Dawn dish soap. Rub the glass and fresnel with your finger tips only. On the ribbed side of the fresnel rub in the direction of the ribs only, do not rub across them. Any stubborn spots allow the piece to soak until it will rub off with your finger or pop off with a finger nail without scraping. Rinse thoroughly and stand on edge to air dry or wipe dry with a lint free towel. Handle by the edges only during the rinse, drying and reassembly. A drop or two of photo flow can be used in the final rinse water to aid in drying.
_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.

[bartbob]

Thanks for the info for the ground glass and Ektalite Field Screen.

Would one of those new micro-fiber cloths work for drying? They appear to be lint-free.

Bart

[45PSS]

The heavy weight ones work great for cleaning lens and the occasional smug off the ground glass. I do not like the thin ones. They work but I find them good for light dusting, not heavy cleaning.
_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.

[bartbob]

45PSS,

I took your suggestion about using dish soap to clean the ground glass and fresnel lens. My finger tip was used with the soapy water then both were well rinsed with warm water. They stood for about 2 minutes while I got a can of air. At low pressure, the canned air blew off most of the remaining water. Then used a medium-weight microfiber rag (givaway at Shell gas stations some time ago) to dry them. I let 'em stand for half an hour before reassembly.

"Twas the difference between night and day as to how much brighter both were after they dried for half an hour. And no lint or micro anything on them. After replacing them in the back, checking with my loupe showed about 200% improvement. Clean as new except for a few micro scratches on both but not enough to effect image quality for precise focusing.

Thanks for your help.

Bart

[45PSS]

Another satisfied customer.
_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.