focusing rails. I have four or five of them but seldom use them. If
you are into photomicroscopy (microscopic focus stacking) you may
need a focus rail. Period. If you are a close-up or a macro
photographer you probably don’t really need one.
Here is what I know about these rails: If you are a nature
photographer in the field then they are one more thing (and weight)
to lug around. I will skip over here there endless on-line debate
about the difference in stacked layers obtained by moving the lens
barrel while the camera stays fixed (standard photography) and
moving both the camera and lens as one piece (focus rails). Moving
the lens changes your magnification while using the focus rail
changes your perspective. For stacked photos, which method you
use can affect how easy it is for your focus-stacking software to
process your stack of images. In order of quality (the best), here
are the three main methods.
(1) Mount the lens on the front standard of a bellows and lock it.
Mount the camera on the back standard of the bellows and move it.
This produces the best stacked images, but will not work for many
lenses.
(2) Use the focus ring on the lens. This is a good way to go IF the
focus throw of the lens is long enough.
(3) Last choice is mount the camera/lens on a focus rail and move
the whole thing.
And most of the focus rails on the market, pardon my French, really
suck. I hope you speak French. There are gobs of them on Ebay
and elsewhere on sale for next to nothing (or for a lot) and most of
them, even brand names, are terrible. Focusing rails are one of the
few pieces of equipment that paying more money for will not
necessarily get you a better product. I am not going to get into
trashing them brand by brand too much but if you read the web
carefully, user reviews will tell you all you need to know. Both the
RSS and Kirk rails are routinely trashed by critics. Many focus rails
are cheaply made, move in a jerk-like manner (which is just not
tolerable even if it works), are two lightweight, and on and on.
I own a bunch of them, three of which are pictured here, including
the much applauded Novoflex Mini Castel focusing rail (newer
model) and the Velbon Super Slider macro rail. The Velbon is not a
quality piece of work and the Novoflex is too lightweight IMO to