grichie5

My new Sony 7 R 111 does not offer "built in" focus stacking. I have considered acquiring a focusing rail to permit incremental movements between several images in order to achieve a stack. This would be as an alternative to manually refocusing for each of several images which might cause camera movement.

Does a noticeable change of perspective occur as a result of the small forward movements necessary to focus on various points and what effect does this have on the merging of the stacked images?

Appreciate any thoughts on this topic.

lamiaceae Loc: San Luis Obispo County, CA

Good question. I often do Focus Stacking manually and I still have some of those same questions and others. So hopefully some UHH'ers will post some good explanations of the optics of focus stacking (and no so much about the software). I have a manual rail but not a motorized incremental rig. What I really wonder about is, as the OP asked about changes in perspective occurring from focusing the lens or moving the camera to change the plane of focus thru the subject? Say using a rail vs just the lens vs a "regular" (extending helical) lens vs a lens with internal focus (IF) so the distance be tween subject and sensor does not change. Perhaps easy to do with a Micro-Nikkor Lens but not so easy with a Pentax Macro Lens.

UTMike Loc: South Jordan, UT

I would be interested in the answer.

User ID

If you can deal with the FLs required to
deploy a bellows, you can 100% avoid
changes in perspective. Most bellows
allow you to focus from either end, and
some only move one end. Either way, a
bellows allowing you to focus from the
rear without moving the front standard
will eliminate perspective changes. But
OTOH if you are working at moderately
high [or higher] magnification, you may
get too much focus breathing.

It's not possible to assign any numbers
to "high [or higher] magnification" cuz
they would vary with subject distance
and lens FL. But longer FLs which allow
longer subject distances, provoke LESS
focus breathing than shorter FLs and
subject distances.

bleirer

Info from zerene seems to say the regular lens focusing ring or the rear bellows is the way to go unless the object is very tiny. http://zerenesystems.com/cms/stacker/docs/troubleshooting/ringversusrail

SHWeiss

The newest Camranger will micro focus the lens on the newer Sony cameras. Stack shot is a great automated rail for macro stacking.

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

My opinion is that in camera stacking changes focus points, and motorized rails advance a fixed focus distance from front to back.

A change in camera position (which is exactly what happens when you use a rail) = a change in perspective.

A change in focus distance does not change perspective.

However, with many new internal focus lenses a change in focus distance at or near the minimum focus distance will likely introduce "focus breathing" which changes the focal length, and will result in images with a smaller angle of view as you focus deeper into a subject. Comparing the first and last image in this type of stack will easily confirm this.

The good news is that nearly all the focus stacking software I have used is written to address these characteristics, so either approach is fine.

If you are focus stacking a landscape, there is no way you can use a change in camera position anyway, and the software will do its job regardless.

Helicon Focus remote changes the focus, Helicon will also work with a motorized rail, which clearly indicates that either approach works just fine.

Anyone who argues that moving the camera doesn't change perspective doesn't understand the basic concepts of camera position and how it relates to perspective.

tcthome Loc: NJ

Using the Rail system is going to change the perspective. The idea is to move the camera on the rail in very small increments. Once you load the set of pics into the software your using it should be able to align the pictures.

Kaib795 Loc: Maryland, USA

I believe the Nikon D850 can refocus the stationary camera to as many increments as you desire - a built in Focus Stacking feature on that camera. I cannot see why you would ever want to use a rail to move the entire rig around but if your camera cannot perform this function, it's an alternative. It's a very simple procedure on the D850.

jerryc41 Loc: Catskill Mts of NY

If I was doing focus stacking on a regular basis, I might buy equipment, but it's just an occasional thing for me.

Focus stacking -
https://www.youtube.com/watch?v=F3Dz34MMjQ0&t=142s
https://northrup.photo/my-account/download-sdp-ebook/stunning-digital-photography-video-index/landscape-focus-stacking/
https://digital-photography-school.com/post-processing-focus-stacked-images/
https://digital-photography-school.com/photograph-images-needed-focus-stacking/
http://www.earthboundlight.com/phototips/focus-stacking-software-photoshop-helicon-combinezp-zerene.html
http://www.lightstalking.com/focus-stacking-in-photoshop/
http://zerenesystems.com/cms/stacker/docs/purchasing
http://www.heliconsoft.com/heliconsoft-products/helicon-focus/
http://www.picturecorrect.com/tips/simple-steps-for-focus-stacking-in-photoshop/
http://digital-photography-school.com/how-to-improve-your-long-exposure-with-photo-stacking/

Focusing rails -
https://lensvid.com/gear/choosing-the-best-focusing-rail-for-macro-photography/
https://www.fotozones.com/live/index.php?/forums/topic/40395-comparing-common-focusing-rails/

Kentski Loc: Michigan

Excellent link. Explains and shows pros and cons examples of each approach. Thanks for sharing!

Denny142 Loc: Kentucky, Maui

I have used a WeMacro rail in combination with Helicon Remote using its live view on a 28" 4K monitor while automatically importing into Lightroom Classic, then stacking with Helicon Focus as a plugin to return the stacked image as a dng raw image for further processing in Lightroom Classic and Photoshop as needed.

bleirer

The OP does not have a d850. Another option is to see if there is a cell phone app or wireless remote that will control the focus ring. This way you can accurately increment the focus. Canon and Nikon allow it via the cell phone app, I believe, so Sony probably should.

fetzler Loc: North West PA

I have used both focus motor adjustments and rails to make macro photographs. The choice largely depends on the magnification. If you are using a macro lens that focuses to 1:1 then focus motor adjustments can be used to 1:1. It is best to use software to do this. I use Helicon Remote to do do this with my Nikon. (Helicon works with Nikon and Cannon). If the magnification is greater than 1:1 (achieved with a special lens, extension tubes or the the addition of Raynox lenses, then a computer driven rail is necessary as the focus motor adjustments will not be fine enough. At high magnification vibration is very important. Indeed your room may vibrate. I place my subjects on a 1/4" plate of steel and another hogger uses a stone table. It is best to avoid touching the camera or set up. I use flash to minimize small movements. If you use a rail at low magnification perspective changes can cause stacking artifacts.

For further discussions can be found on this site. https://www.uglyhedgehog.com/s-102-1.html
A fairly inexpensive rail is made by Wemacro ( https://www.wemacro.com/ )

I use both Nikon (D7200) and Olympus Cameras (Pen F) for macro. I like the Pen F best for high magnification. Olympus has a focus bracketing. This takes a series of pictures with different focus points. Software is then used to produce the stacked image. The Pen F has a focus stacking function but this is very limited in its capabilities as eight ( and eight only) exposures are made. Does your Sony have focus bracketing.
Read your manual carefully.

fetzler Loc: North West PA

This app is available for SONY cameras. Check this out.

https://www.youtube.com/watch?v=XZOdZKWb1Fk