Well yes, if you add the additional factor of visually aligning the art work with the viewfinder edges, but that is the way I'm doing it now if you read my original post. I want something more precise and less subjective. The Versalab Parallel seems to be my choice at this point. Eronald, Versalab Parallel is a mirror and laser system. I'm mounting my art work to be copied on a wall vertically.
Hi,
For a one man operated alignment, the "Parallel" can be 'mounted' at the subject, but then it's harder to see (depending on distance). That seems to be a potential issue for vertical objects (
especially when they are not vertical). You probably do better with alignment by positioning the "Parallel" flush with the lens barrel (which BTW may not be equally parallel to the sensor plane). A similar issue is with mounting the reflector mirror of the Zig-align at the subject, and which also assumes that the sensor and lens filtermount are parallel.
If you can solve the issue of mounting a simple mirror parallel to the subject surface, I think that you can already get very accurate results with a well centered reflection of the image of your lens. Especially at some distance, the reflected lens image will be small enough to allow very precise centering and parallel positioning in all dimensions.
I don't know what type of laser alignment method was hinted at by Rudy Lorejo's blog post, but maybe it's a bit similar to my home made method.
As a partial solution, I occasionally use some components that I already have (see attached image), and which avoids having to touch the surface of the subject. I use a Leica Disto mounted on a parallel RRS bar. Fully shifted left I measure the distance (millimetre accuracy), and fully shifted right I measure the distance. This will provide for a measurement base of upto 80 cm (31.5 inches). That will allow in a few iterations to achieve very good (< 0.1 degree) parallelism of the left and right sides of the artwork relative to the (presumed parallel) camera bracket on tripod. If the sensor is mounted parallel to the camera base, it should be adequate for the intended purpose.
The as yet unknown amount of tilt will then be relatively easily estimated (because it is only one degree of freedom) by visual comparison of the edges (assuming a rectangular subject/frame). Otherwise one could use the same procedure with a tripod head rotated by (approx.) 90 degrees, or use an additional bar in vertical orientation. The bar(s) can be removed for the actual shooting (or the horizontal bar can be used for Stereo photos of surface structure, or of objects with depth).
While a bit slower than with an art-surface mounted mirror or "Parallel", the main benefit is a contactless measurement, which is probably accurate enough for the purpose. Another benefit is that the subject does not have to be parallel to the wall or support it is mounted on, because it is only the relative subject / sensor parallelism that counts.
Cheers,
Bart
