Focus Stacking with the Canon EOS R5 - Settings

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In my pre­vi­ous report, I intro­duced the Focus Stack­ing of the Canon EOS R5. Since there were ques­tions about the opti­mal set­tings in the menu “Focus Back­et­ing”, I took up the top­ic again. Unfor­tu­nate­ly, Canon does not give any fur­ther assis­tance. There are three options in the menu “Focus Bracketing!

  • Num­ber of shots
  • Focus incre­ment
  • Expo­sure smoothing

With the EOS R5, there is unfor­tu­nate­ly no way around sim­ply try­ing out the “num­ber of shots” option. At the begin­ning of the series you should first focus on the clos­est point of the object that you want to get in focus, using the focus mag­ni­fi­er if nec­es­sary. Then, I do a test run with a rather gen­er­ous esti­mate of the num­ber of images need­ed. Super­flu­ous images can eas­i­ly be delet­ed after­wards. If the focus of the last image of the series is not already behind the desired focus range, you just have to repeat the series and increase the num­ber of images.

Expo­sure smooth­ing should always be activated.

Expo­sure smooth­ing should always be acti­vat­ed. This , accord­ing to the man­u­al of the Canon EOS R5, does not apply to the fol­low­ing lenses:

  • EF100mm f/2.8L Macro IS USM
  • EF180mm f/3.5L Macro USM
  • EF-S60mm f/2.8 Macro USM

With these three, acti­vat­ed expo­sure smooth­ing might cause changes in the image brightness.

Final­ly, there remains the “focus incre­ment”. Here, Canon pro­vid­ed a sim­ple gra­da­tion from 1-10, with a gray mark­er above lev­el 4, which prob­a­bly marks the default position.

Which focus increment to choose?

To exam­ine the whole thing a bit clos­er, I shot a series of pic­tures with the “Focus brack­et­ing” option of a cen­time­ter scale at an oblique angle with the EF 100mm f/2.8 Macro USM* with 20 steps each (once with open aper­ture f/2.8 and anoth­er time with aper­ture f/8).

With the step size “4” and sub­se­quent stack­ing in Heli­con Focus, the result is as follows:

As is clear­ly vis­i­ble, the EOS R5 selects the step size depend­ing on the aper­ture. At aper­ture 2.8 (left), approx. 2mm are sharply dis­played, so the step size is obvi­ous­ly approx. 0.1mm in this case. At aper­ture 8 (right), the steps are larg­er, they are prob­a­bly about 0.3mm, so that a larg­er area of about 7mm (right image) is dis­played sharp.

I then tried this again by set­ting the “Focus incre­ment” to the max­i­mum step size of 10:

With the select­ed step size of 10, the steps of the focus planes are already much wider. At f-stop 2.8 in this exam­ple, approx. 8mm (step size approx. 0.4mm), at f-stop 8 even approx. 38mm (step size approx. 1.9mm) of the cen­time­ter scale are in focus. Sur­pris­ing­ly in this case, even with step size 10, the tran­si­tions between the planes are obvi­ous­ly suf­fi­cient­ly sharp.

Is the step size of 10 now sufficient?

To answer this ques­tion, I pho­tographed a some­what more com­plex object, again a pock­et watch. First I took the pic­tures with step size “4”. I select­ed 40 as the num­ber of shots and then stacked the sin­gle images in Heli­con Focus:

Pocket watch
Focus stack of 40 images with step size 4

And then, for com­par­i­son, the same clock, but this time with a step size of 10. Here I only need­ed 12 sin­gle images:

Pocket watch
Focus stack of 20 images with step size 10

At first glance, both images look very good. And if you take a clos­er look at the result­ing pic­ture with step size 4, every­thing is fine, too. The clock is sharp from front to back, there are no vis­i­ble blur­ry tran­si­tions between the indi­vid­ual images.

How­ev­er, the step size of 10 is no longer suf­fi­cient in this case on clos­er exam­i­na­tion. Par­tic­u­lar­ly at the linked band shown in the fig­ure, there are clear­ly vis­i­ble blurred areas on pix­el level:

Left step size 4, right step size 10

Thus, the focus incre­ment of 4, which is marked in grey by Canon, seems to be the opti­mal set­ting. I will con­tin­ue to use it by default for now.

*= Affil­i­ate Link

This Post Has One Comment

  1. Andreas Friedl

    Thank you for this nice dis­cus­sion. I haven’t used this fea­ture much in the field because I was intim­i­dat­ed by all the pos­si­ble vari­ables (focal length of lens, clos­est focal dis­tance etc). In addi­tion to the ones you men­tion. I sup­pose it’s a mat­ter of tri­al and error and expe­ri­ence. I will prac­tice in the backyard.

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