Macro focussing rails

Started 5 months ago | Questions thread
John K Veteran Member • Posts: 8,649
Re: Macro focussing rails

mawyatt2002 wrote:

John K wrote:

mawyatt2002 wrote:

John K wrote:

mawyatt2002 wrote:

Ive used the Stackshot, WeMacro and MJKZZ older type rails & controllers. The Stackshot is the most versatile and the WeMacro best value. Never used the MJKZZ rail because at that time the controller didn't support a Mac, later a controller was offered which didn't require a computer and works well, but the rails were bypassed because better rails were available. All the rails can be operated with different controllers if you prepare a proper interface cable to the stepper motor (they all use 4 wire steppers), and setup the proper motor parameters.

Later developed custom rails based on the THK KR20, 15 and 26 surplus linear rails. These are precision devices and can be operated with various controllers, including a set of custom developed controllers based upon the Trinamic chips that offer exceptional performance.

Eventually this evolved into Stack & Stitch setups, below shows some of the THK rails and custom controllers. Much has been posted on these developments over at the mentioned Photomacrography site.


Horizontal setup on modded WeMacro Stand and THK KR20 focus rail

Vertical setup shown in back.

Excellent post, and your wife has taken some impressive photos!

If I ever get into stacking, beyond doing it hand held, I'm gonna do it right and get a microprocessor controlled rail. But I'm more interested in stacking larger subjects (like bees and beetles, for example).

Agree a computer controlled stage is the best approach IMO.

If you are interested in larger subjects like your bees, then you'll likely be around 1X. The old Nikkor PN105mm F2.8 reproduction lens on a FF camera is about as good as it gets at 1X. This lens was used to reproduce 35mm film for movie theaters, so highly optimized for 1X. This lens is shown on the horizontal setup above.


Actually I think that most of my stacking would be in the 4x and higher range. Below 4x diffraction isn't that big of a deal, and I can control where the area of acceptable focus falls so that I'm not wasting any of it.

Tech Specs: Canon 80D (F11, 1/250, ISO 200) + a Canon MP-E 65mm macro lens (set to roughly 2x) + a diffused MT-26EX RT (E-TTL metering). This is a single, uncropped, frame taken hand held.

A lot depends on what you want in the final image. Diffraction begins to eat into your IQ around 18, this is where most of the excellent Mitutoyo objective lens have a effective aperture (EA) of ~18. Remember EA is actual lens aperture times magnification + 1. Most cameras like Canon (Nikon reports EA) do not report EA, only Lens Aperture, so when you are at 4X with a lens aperture at F11, this equates to an EA of F55!!

Understood, but diffraction by itself really isn't that bad. Lens sharpness (or more importantly a lack of it) and motion are actually a bigger problem because they have a synergistic relationship with diffraction. As long as I can take as much control over the motion as possible, and freeze what's left with a short duration flash, and use a sharp lens then diffraction softness is manageable. I'm not printing 100% crops, and no one is saving them to their PC or phone as wallpaper...

Recent blind deconvolution software I pointed you too can remove some of the diffraction effects, but not all.

That's a really cool concept, and I'm waiting for the day when the camera can do that level of processing.

One of the big benefits of stacking is this removes the trade-off between diffraction and DoF. Generally you use a lens setup with the best IQ setup (usually the lowest lens aperture at lowest EA), and stack to recover the shallow DoF.


For example the superb Mitutoyo 5X NA=0.14 with EA of ~18 at 200mm tube lens, has a DoF of just 0.028mm (28um).


I know that once I really dive into it I'm gonna have a lot to learn.

-- hide signature --

Also known as Dalantech
My Book:
My Blog:
My gallery:
Macro Tutorials:
Always minimal post processing and no cropping -unless you count the viewfinder...

Post (hide subjects) Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow