NVFCASTEL-M

Novoflex CASTEL-M focusing rail for magnification ratios up to 5:1

Depth of field is one of the most challenging aspects of macro photography.
As magnification increases, depth of field decreases, especially above 1:1. Shrinking depth of field at reproduction ratios greater than 1:1 requires highly accurate and precise camera advance to create identical distances between different shooting positions in a typical stacking sequence.
Precise overlaying of each individual image is necessary for the stacking software to create a successful composite image.

CASTEL-M can be combined with a wide range of specialized lenses, such as the Canon MP-E 65mm f/2.8,-5x Macro Photo and the LAOWA 25mm f/2.8 2.5-5x Ultra Macro, frequently used by macro photographers who use focus stacking in their workflow.
It has been specifically designed to help macro photographers achieve consistent and predictable results when engaged in this repetitive task and allows for the optimization of several different magnification factors.

The heart of the CASTEL-M is a spindle that advances the sliding camera support with extreme precision for each shot.
The spindle also features handy indexing steps for zoom factors of 2:1, 3:1, 4:1 and 4:2, 3:1, 4:1 and 5:1, which are selected by a lever located inside the barrel of the focus wheel.

Releasing the locking lever on the slide block disengages it from the chuck and allows the base to slide freely to be positioned freehand at the initial point of focus.
Once the base has been positioned, the base can again be anchored firmly to the spindle using the same lever.
Advancement through the sequence of shooting positions is accomplished with a single clockwise click of the focus wheel, which advances the camera in precise incremental stops to the focus point of the next image.

No need to worry about calculating step size and precise overlay of individual images, the guide does it automatically. The shots of the individual stop points of the advance have been calculated in order to optimize the work by predicting the behavior of the most difficult lenses: they have been calibrated for Full-Frame cameras with 35mm lenses at an aperture of f/4. Cameras with smaller sensors can be used reliably up to a magnification of 4:1 in the case of APS-C sensors and up to 3:1 in the case of M43 sensors.

Alternatively, the photographer who wishes to manually control the camera's progress can set repeatable measurements with the help of the laser-etched scale on the focus wheel.
If necessary, it will be possible to avoid using the mechanically assisted feeds and act on the manual feed knob, full rotation of the focus wheel equals moving the camera slide block by 0.8mm, and the engraved scale allows incremental advances as low as 0.01mm.

For use in product photography, the CASTEL-M can be combined with the CASTBAL-PRO bellows, transforming it into a full-fledged optical bench.
In this configuration, the stacking phases are performed by moving the rear standard of the bellows, while the standard of the lens remains fixed.
Using this approach, the position of the lens does not change relative to the subject, which can be important for controlling unwanted reflections, especially when photographing jewelery or the like.
Thanks to the use of the bellows, objects with a depth of more than 100 mm can be photographed with the stacking technique without problems, as only the focus is adjusted, without having to move the entire camera the full distance.
The advantage of stacking compared to the Scheimpflug rocking technique is understandable. With focus stacking, maximum sharpness can be achieved uniformly across the entire subject area (front to back and top to bottom simultaneously), in contrast to the Scheimpflug method. where maximum sharpness can be achieved in a single plane, regardless of adjustment.