Verryl

I have been using Helicon for focus stacking with my 18-55 Nikon kit lens to photograph my very long and straight model railroad benches, 50 to 60 feet long, shot from the end. The idea is to get a sharp focus in 6-8 exposures focused every 6 - 10 feet. To see the manual focus I use the back screen highly magnified on the various points, but the kit lens, and all my lenses, change focus too rapidly with just a tiny rotation amount for precise focus at a given distance. As a result the stacked shots are not evenly spaced. Are there lenses made that focus more "slowly," that is require a much longer angular twist to vary the focus point?

Attached is an example.

A related question is how do macro photographers focus at the tiny increments required for a very small subject, like an insect? Unless a macro lens, which I do not own, should have a very slow thread for focusing.

TriX Loc: Raleigh, NC

Older manual focus lenses typically have a much larger focusing ring movement than modern AF lenses when used in manual mode (which may have only a quarter turn of manual focus movement).

ecobin Loc: Paoli, PA

Try a focusing rail which will move camera and not require using the focus ring.

aphelps Loc: Central Ohio

Can you select a smaller focus increment (differential) in the camera? Many images of smaller incremant work best for small targets and focus sensitive lenses.

lamiaceae Loc: San Luis Obispo County, CA

A prime lens for sure, a Nikkor 35mm (DX) or Nikkor 50mm (FX). A vintage "film" Nikkor lens should do the job for you at a lower cost. A pricier solution and can also give multiple other uses would be a 50mm or 55mm Micro Nikkor. Best to have whatever that can be focused manually by hand and with click stops.

For any critical work I use Prime lenses and usually in some all Manual mode. But then I have 30+ Lenses to choose from, many over 40 years old!

rjaywallace Loc: Wisconsin

👍🏼👍🏼👍🏼

lamiaceae Loc: San Luis Obispo County, CA

There are basically two types of focus stacking. One is used for landscapes and is usually only three exposures, focused on Foreground, Midground (or Main Subject), and Background. From one position you change the focus from shot to shot changing nothing but focus. Pretty easy actually. Easier and more effective than the old hyperfocus trick from the film days. The other type of focus stacking is used for Close-up or Macro photography. A bit trickier and needs more precision. Again same exposures, but you may either focus through the small subject or using a focusing trail of some sort move the camera closer and further with out touching the lens' focusing ring.

What you are proposing or trying to do is a bit in between these two techniques. I think I understand what you are trying to achieve. Your basic plan seems sound to me. And I get your problem with the focusing of your lens. See my other Reply about lenses for your project. Also note, some lenses (mainly higher end ones) have IF (Internal Focus) and the front of the lenses does not move in and out. You're in luck there as many Nikon lenses have that type of focusing mechanism. It is rare for my Pentax lens collection. Also what is probably your annoyance is that the focus on many lenses does not appear to be linear but almost logarithmic. I notice this annoyance most on Wide Angle lenses and least on Normal Macro / Micro Lenses. And I believe some Micro-Nikkors have IF. How cool is that? Remember you may need a somewhat small aperture, say f/11.

Some photographers have automated systems for macro / micro focus stacking. I either suffer through turning the lens imprecisely as you say or I use a focusing rail and manually focus with that. In either case it is a lot of precise work and make take more than one attempt. Also with the way I do it to minimize diffraction and lens issues, I stop down a bit only to say f/5.6 for an f/1.4 or f/2 or f/2.8 Lens. So there is little DoF in any one shot. But I find that there is still enough overlap. I get pretty good results that I am happy with using say 10 good frames. I realize some people with automated electronic systems my take a hundred exposures. But that may be overkill unless they are using microscope objectives for super high micro shots! Most of my stacked macros are of flowers most of which are far larger than my camera sensors. I also stack images of Sea Shells. As before, you might search for a vintage film era ~ 50mm Micro-Nikkor or Normal 50mm Nikkor used. An everyday used film era 50mm f/1.8 Nikkor AI should be really cheap on eBay.

robertjerl Loc: Corona, California

A. not nearly enough shots for the size of the subject.
B. you really need a better lens
C. as stated a focus rail with register marks would help
D. or clamp the camera down on a tripod so it doesn't move, use temporary markers (or something on the layout) as a focus point for each shot and overlap the depth of field about 25-30% for each frame - some people do focus stacks of 100s of frames for certain subjects.
OR:
Invest in a Helicon FB Tube about $210 for just the tube and around $400 in a package with Helicon's stacking software and other goodies - yes you have to be serious about focus stacking to go to this. But it works great, esp for macro but also stuff like your layout and landscapes. The tube has a processor and changes the focus on the lens for you. I found a remote trigger for the camera also helps as you don't have to touch and cause movement in the camera.


And good lighting so you can use f/8-f/16 for better DOF on each frame.

martinfisherphoto Loc: Lake Placid Florida

If your focusing manually try using a sharp piece of chalk to place a hash mark on the lens barrel and then on the focusing ring. As you advance forward your focusing ring you can see how far you've advanced. This way you don't adjust forward or backward too far as you focus. Now make a hash mark with the chalk on the lens barrel again. This will show you the distance your focusing ring traveled when you turned it. Now you should be able to eyeball the same distance as you focus forward again. Now keep repeating the hash marks. This should make it easier and to keep the focusing distance the same. It may be only an 1/8th of an inch, but you can at least keep track of it.......

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Macro lenses have long slow threads, even the current ones. Keep in mind that the key is to overlap depth of field. If you had even increments by ring rotation, the near shots would have considerably less depth of field than the farther ones.

Your lens is fine - and quite crisp at F8.

Focus rail only works when you have a very short distance to stack - 4 - 9 inches. it won't work at all for longer distances. In your case, you'd need a 50 foot long focusing rail.

I would suggest a focus target that you can move in precise increments based on a narrow interpretation of the data that are in DoF charts and let the camera do the focus. What I mean is if you are using your lens at 35mm and F8, and your near focus point is 6 ft, the DoF charts and calculators will show a DoF of 4.86 ft to 7.84 ft. I would suggest using approx 5.5 ft and 7 ft as a more critically focused DoF.

The next shot might be at 8 ft - chart shows 6.09 and 11.7 - I'd use 7 ft and 10 ft.
The next would be 10 ft - chart shows 7.18 and 16.5 - I'd use 8.5 ft and 14 ft

And so on until you have covered the linear distance you are aiming for.

However with practice, the manual focus thing should work if you use live view.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Over a 60 ft distance?

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A 50 ft long focusing rail could be rather pricey.
They do exist ... at Hollywood rental houses :-(

Simpler to just use an old MF lens. I'd avoid the
Micro Nikkors, cuz they focus rather fast in the
10 to 60 ft range, due to having to focus down
to a few inches in 3/4 turn of the ring ... so the
focusing helix is pitched much too fast.

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That is simply not true.

Just compared MF Nikkors, both same era,
a 50/2.0 and a 55/3.5 Micro. To focus from
infinity to 5 ft, the f/2.0 turns a full 45 deg.
The Micro turns only 15 deg. IOW, it takes
a much faster pitch to accomplish the long
focusing throw of a macro lens, unless you
build one that uses multiple [2 or 3] turns
to get to its near limit.

========================

I have an old Schacht Travenar macro that
uses multiple turns and a fine, slooow pitch.
But multiple turn designs cannot have auto
stop-down iris mechanisms, so the very few
fine pitch macros ever built are all ancient
preset lenses.

.

JimH123 Loc: Morgan Hill, CA

This answer doesn't help you with your problem, but Olympus cameras can be set up to provide focus stacking or bracketing which take multiple images in which the lens is focused under control of the camera. Focus stacking takes 9 images and combines in camera. Focus bracketing can take up to 999 images and only saves the images, meaning that the stacking can be done in post processing. It matters not whether you are doing macro or not macro.

The models that can do this are the EM1, EM1ii and EM5ii. And only with certain lenses.

Provides for a very convenient and easy way to accomplish the task.

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I don't see why you need "evenly spaced" focus point over
a depth such as 10 to 50 feet. It makes sense to tighten up
the spacing more and more as you focus closer, due to the
decreasing DoF. Your use of the live view magnifier should
be showing you that while you're working.

I've never used your kit lens, but however quick is its focus
mechanism, the magnified live view will show you a rather
exaggerated impression of that issue. Acoarst you're doing
all this on a tripod, so you should or could be working with
more than enuf DoF such that whatever focus accuracy you
manage with the kit lens's mechanism should be more than
good enuf as you refocus for each distance. Nevertheless, a
legacy MF Nikkor would certainly be more ergonomic.

(As to your related question, for small subjects the usual
method is a focusing rail.)