amfoto1 Loc: San Jose, Calif. USA

Canon makes a number of different macro lenses for their DSLRs.

Just for fun, I used the online DoF calculator (DOFMaster) to see what depth of field four of them render at their minimum focus distance (MFD) and maximum, 1:1 magnification. Two of the lenses are EF-S lenses only usable on APS-C cameras, so I assumed all four lenses were used on that sensor format (not that it matters in this case). I also used f/11 as the selected aperture in all four cases.

EF-S 35mm f/2.8 IS STM lens... MFD at full 1:1 magnification: 4.88"....... DoF: 0.15"
EF-S 60mm f/2.8 USM lens....... MFD at full 1:1 magnification: 8.11"....... DoF: 0.14"
EF 100mm f/2.8L IS USM lens... MFD at full 1:1 magnification: 11.81"..... DoF: 0.10"
EF 180mm f/3.5L USM lens....... MFD at full 1:1 magnification: 18.66"..... DoF: 0.07"

Ysarex Loc: St. Louis

Just for fun, I used DOFMaster and repeated your calculation for the 180mm at f/11 and 18.66 inches along with an adjusted calculation using the 35mm at f/11 and 3.62 inches which is the distance required to maintain equivalent magnification between those two focal lengths and the results -- same DOF -- are below. In the close-up/macro focusing range at the same magnification and f/stop DOF will be the same regardless of focal length or subject distance.

(Download)

Soul Dr. Loc: Beautiful Shenandoah Valley

Like everyone else is trying to tell you. Diameter of lens has NOTHING to do with depth of field!
Can you not understand this???? One can find a lot of disinformation on the web, and the video you are championing is one such example!

will

will

imagemeister Loc: mid east Florida

LOTS of misinformation here now ......8-( I would not pay too much attention to ANY of these comments being made .....

Soul Dr. Loc: Beautiful Shenandoah Valley

The four primary factors that determine DOF are: lens aperture size, lens focal length, the subject-to-lens distance, and a concept known as circle of confusion (COC).
This is from article from B&H Photography about DOF in macro photography.
Notice, there is NO mention of lens diameter!

will

User ID

BIFS of a feather ....

User ID

Dirus and Undone ... BIFS of a feather.

robertjerl Loc: Corona, California

great image

robertjerl Loc: Corona, California

Those tiny DOF figures are why when doing macro focus stacking I use the Helicon FB tube which does the focusing with a micro-processor. However it only works with certain lens and body combos. Check their site for current compatibility charts. They only make the FB Tube for Canon and Nikon as far as I know. But they also make Helicon Remote - software for doing stacking with a camera tethered to a computer and their new Beta version adds Nikon Z bodies, Canon R bodies and some Sony bodies.

Canisdirus

Yes, that was my error... I meant to say two lenses of same focal length.

Canisdirus

I think that's why Gerald named his topic as he did.
It's not talked about.

Ysarex Loc: St. Louis

It (lens diameter) is not talked about because it's not a DOF variable. Depth of Field is and has been well understood for a very long time. In fact for many many decades before Gerald was born. I first started to learn about it from an old 1930s Leica manual when I first started working through some of the math that was published in that manual. This is not a secretive or difficult to understand subject. It's easy to get good info and reference material as long as you stay away from Youtube. The Wiki article is good and the info there is correct: https://en.wikipedia.org/wiki/Depth_of_field Anyone can read it for free. From the article:

Factors affecting depth of field

For cameras that can only focus on one object distance at a time, depth of field is the distance between the nearest and the farthest objects that are in acceptably sharp focus.[1] "Acceptably sharp focus" is defined using a property called the circle of confusion.

The depth of field can be determined by focal length, distance to subject, the acceptable circle of confusion size, and aperture.

You can go to the internet and get a good DOF calculator. DOFMaster is good: https://www.dofmaster.com/dofjs.html
The DOF calculator at Cambridge in color is good: https://www.cambridgeincolour.com/tutorials/dof-calculator.htm
The DOF simulator that Gerald referenced and that can be used to prove him wrong is good: https://dofsimulator.net/en/

Here's a splendid idea. Why don't you use one of those DOF calculators to run a couple comparisons calculations that prove you're right and bring back the results?

Ysarex Loc: St. Louis

Who are you responding to here? Looking back over the thread I find this comment of yours: https://www.uglyhedgehog.com/t-696088-2.html#12225626 where you say: "So if you have two 100mm macro lenses, and one has a smaller diameter than the other...then it will have greater DOF."

and then this comment: https://www.uglyhedgehog.com/t-696088-3.html#12226448 where you say: "If two lenses have the same magnification...the lens that is further away...will have the advantage in DOF.
So... if a 100mm macro achieves 1:1 at 18 inches from subject... and a 50mm achieves 1:1 at 9 inches ... the 100mm will yield greater DOF."

I can't see anything else that would possibly apply for the remark in this post that you meant to say two lenses of same focal length. In the first comment of yours that I note above you do mention two 100mm lenses and say the one with the smaller diameter will have greater DOF. Regardless of the diameter of the lenses when they're both set to the same f/stop and they're the same focal length then they'll both have the same size apertures.

I have a 100mm f/2 macro lens and I have a 90mm f/4 macro lens. The 90mm is so much smaller (diameter) that you could take the glass out of the 100mm and the entire 90mm would fit inside with room to bang around. Now let's just pretend for a moment that my 90mm is really 100mm. If I set both lenses to f/11 then both lenses will have the same physical size apertures. That's what will determine DOF and if you focus both lenses on the same subject and the same distance then magnification will be the same and DOF will be the same.

If you're referring to you second comment quoted above, then if the two lenses you mention 100mm and 50mm you instead intended to be the same focal length then at different subject distances the magnifications must be different and that will produce different DOF between the two.

TriX Loc: Raleigh, NC

You know, I never understand these types of “discussions”. A member comes up with a patently wrong idea from someone on UTube making a click bait assertion, and they defend it to the death no matter how much proof is provided. Just had one the other day that went on for 5+ pages about the idea that the max aperture of a lens changed (by the “crop factor”) when mounted on a crop camera. I don’t think he ever gave up despite all the proof to the contrary. Is it really that hard to read the opposing evidence and just say: “you know what, I was mistaken - thanks for the correct information”?

Leitz Loc: Solms

It would help the OP if Amfoto, Canisdirus and Sippyjug would man up and acknowledge their misinformation.