High Precision Mount Calibration
All 'Stiletto' camera mounts are calibrated to within .001mm of the backfocus specification provided by the camera manufacturer. This is accomplished using Mitutoyo digital depth gages, SPC statistical software analysis, and a special calibration technique. This involves setting the focusing tube assembly with ronchi screen in place accurately.
Mounts are positioned directly on the surface of the depth gage platform, medium-strength LocTite applied to the focusing tube threads, and the tube assembly adjusted until the tip of the depth gage contacts the inner surface of the ronchi screen at the specified backfocus distance.
To avoid calibraton errors due to differing touch in feeling the position of the depth gage, the focusing tube is adjusted visually until the ronchi screen glass surface is barely deflected. The deflection is noted visually using a USAF test chart which reflects this pattern on the surface of the ronchi screen. The assembly is then left in place to allow the threadlocker to cure.
This exclusive technique enables positioning of the screen extremely precisely to guarantee superb compatibility with your camera.
Stiletto Assembly Adjustments
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The Series IV 'Stiletto' assembly is composed of a r |
onchi screen which is mounted in a helical focusing tube. The focusing tube rotates within the modular mount and adjusts the distance from the ronchi screen to the front of the mount. This distance should correspond precisely to the film-plane distance of your 35mm camera, or to the backfocus distance of your CCD camera. The ronchi screen itself is mounted within a removable snap bushing . No adjustment is necessary. The following instructions are provided only as guidelines should you prefer to optimize your Stiletto assembly for a particular camera setup which is out of specification.Recalibrating the Assembly
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The 'Stiletto' assembly may be easily recalibrated. Before m Normally, only very small adjustments of the tube assembly are necessary. A half-turn of the focusing tube in either direction will make significant changes in the focus. The threads on the focusing tube are 32 tpi. Normally, focusing tubes may be adjusted a minimum of 2mm in or out. Making small changes in the position of the tube will allow you to do A-B comparisons with either developed film or the CCD images on your screen. Once you optimize the tube position, be sure to mark the tube and the calibration circle for future reference. Should you have any problems, the Stiletto camera mount may be returned to us for recalibration free of charge . Please refer to the Series IV Instruction Manual for complete details on the recalibration procedure. |
aking any adjustments, first remove the ronchi screen assembly from the focusing tube. Then, break the seal which keeps the focusing tube in place. A small amount of medium-strength Loctite holds it. You should be able to free the tube by gently turning it with your fingers. If more leverage is necessary, carefully wedge a long-nose pliers on the inner surface of the focusing tube. Turn it to break the seal. If necessary, low heat may be applied to the focusing tube to break the LocTite seal.Changing or Replacing Ronchi Screens
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To remove the ronchi screen, grip the aluminum ring which encases the snap bushing. Gently lift the ring up evenly on all sides a little at a time so that no undue pressure is placed on the This procedure is shown in our video tutorial 'Changing Screens'. |
screen through flexing. Undue and uneven pressure may crack the delicate optical glass. |
To place a new ronchi screen in the Stiletto focusing tube, secure the ou |
tside of the
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Finally, check to make sure that the snap bushing has been completely pushed in and that the aluminum flange is lying evenly around the |
circumference of the focusing tube. This step is essential to maintain the proper film-plane distance or backfocus distance between changes to different resolution ronchi screens or if installing the True Knife-edge Option.Maintenance of the Stiletto Camera Mount
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Over time, the camera mount and Stiletto assembly may become dirty from everyday use. In reality, quite a bit of debris can accumulate before focusing becomes impaired. Do not conclude that the surface of the ronchi screen needs to be impeccably clean f To remove a fingerprint or similar smudge, however, a cotton tip lightly soaked with industrial grade acetone may be used. Take care to use a minimal amount of acetone and avoid touching the plastic bushing. The snap bushing housing the screen and optical glasses should never be disassembled for cleaning. When the Stiletto camera mount is detached from the Series IV body, take care to protect it with the body and focusing tube caps supplied with the unit. Always store your Series IV and mount in a cool, dry place. Please refer to our video tutorial on 'Maintenance' for more details.
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or it to function properly. A stray fingerprint or minor dust will have no affect on its usage at all. A standard air duster spray is recommended to eliminate the accumulation from the glass surfaces. 
