Stiletto Assembly Adjustments
| The Series IV 'Stiletto' assembly is composed of a ronchi 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 and is protected on each side by clear optical glass. A calibration mark is placed at the factory setting for your particular camera to indicate the proper position as it left our factory. Little or no adjustment should normally be necessary. The following instructions are provided as guidelines should you prefer to optimize your Stiletto assembly for a particular non-standard camera setup or when using an unusual combination of mounting adapters. |
Recalibrating the Assembly
| The 'Stiletto' assembly may be easily recalibrated. Before making any adjustments, take note of the existing calibration mark so that you can easily return to the initial factory position if necessary. First, break the seal which keeps the focusing tube in place. A small amount of medium-strength Loctite holds it in place. You should be able to free the tube by gently turning it with your fingers. If leverage is necessary, carefully use a pliers to grip the outer threads of the focusing tube to turn it to break the seal. Take care to avoid touching the surface of the delicate ronchi screen at all times. 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 modular mount may be returned to us for recalibration free of charge (other than shipping). Please refer to the Series IV Instruction Manual for complete details on the recalibration procedure. |
Changing or Replacing Ronchi Screens
| To remove the ronchi screen, grip the color-coded aluminum ring which encases the snap bushing. Gently life the ring up evenly on all sides a little at a time so that no undue pressure is placed on the screen through flexing. Undue and uneven pressure may crack the delicate optical glass which protects the screen from moisture and inadvertent contact. The optical glass is only .2 mm thick so utmost care must be taken to avoid damage. Always secure the screen assembly by the aluminum ring taking care not to touch the optical glass |
| To place a new ronchi screen in the Stiletto focusing tube, secure the outside of the aluminum ring with two fingers and push it gently into place. The assembly should be slowly pushed all the way into the tube using even pressure around the circumference. Make sure that the surface of the aluminum ring is perpendicular and lies flat on the focusing tube. |
| 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 Modular Mount
| Over time,
the modular 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 for it to function properly.
A stray fingerprint or minor dust will have no affect on its usage at
all. The ronchi screen is sandwiched between two layers of optical
glass which protect it from inadvertent damage. A standard air
duster spray is recommended to eliminate the accumulation from the glass
surfaces . 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. Do not use too much acetone since it can dissolve the ronchi screen if it penetrates around the protective glass. The snap bushing housing the screen and optical glasses should never be disassembled for cleaning. When the modular 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. |
