jerryc41 Loc: Catskill Mts of NY

I like extension tubes. I have the cheap ($20) manual ones, and they work fine. The alternative is an expensive macro lens. If I were doing mostly macro work, I'd get one or more lenses, but the tubes are fine for me.

StanMac Loc: Tennessee

Narrow depth of field is the nature of the beast when focusing closely.

Stan

RWR Loc: La Mesa, CA

Extension tubes are better - they will increase the magnification. At the cost of reduced depth of field, though.

Canisdirus

A macro lens isn't a new way of doing it...though the optical elements are designed for close up in mind.
They are basically set up with the extension tubes...built into the cake already.
You just don't see it.

Thomas902 Loc: Washington DC

use a shorter focal length...
On an FX Nikon Mount the popular 105mm micro at a distance of one foot @ f/16 has a DOF of 0.02 feet
At the same distance & F-Stop the epic 60mm f/2.8D micro has DOF of 0.07 feet

Yes you'll have to crop the 60mm image a tad but with a D810 or D850 not a problem...

Too funny, Maslow's hammer once again... please choose the right tool for the job Ron :)

gvarner Loc: Central Oregon Coast

IMO, the Narrow DoF is a function of how close you are to the subject and your aperture, not how you got there. Macro is like using a microscope.

Nalu Loc: Southern Arizona

Understand the issue, however if looking for greater DOF; how about less magnification, further away using a high MP sensor and crop?

User ID

A shorter FL will gain you nothing, except possibly an inconvenient lack of gear-to-subject clearance/distance. And cropping is useless.

No solution in that “advice”. You seem to believe DoF is determined by the actual magnification of the image, on sensor or film. That is not the reality. Only the FINAL magnification governs apparent DoF. “Apparent” is not a special case. ALL DoF is apparent, there’s no other version of it. Thus backing away and/or a shorter FL accompanied by cropping is a zero sum move. The cropping undoes the backing away/shorter FL.

The ONLY determinant of of DoF is final/ultimate magnification, mean the image as viewed, on paper, on screen, in VR head gear, etc, etc. Any image AS CAPTURED actually has no fixed DoF, despite GUIDANCE tools such as formulas, lens scales, apps, dials, etc. The guidance offered by such tools aids in “baking in” the user’s desired DoF into the recorded image relative to the final/ultimate magnification/use/viewing of the image.

amfoto1 Loc: San Jose, Calif. USA

DoF is determined by three things:

1. Lens focal length... the longer the focal length, the less DoF
2. Lens aperture... the larger the aperture, the less DoF
3. Distance.... the closer you are, the less DoF

It's always a balancing act... getting the DoF you need, as well as correct exposure, having sufficient working distance, etc.

But if you were to compare a 100mm macro lens at 1:1 magnification to a non-macro 100mm lens with enough extension tubes added to give the same 1:1 magnification, you will see EXACTLY the same DoF.

Stop down. That will get you more DoF. But you might need more light to do that, so may need to use flash.

And don't stop down too far... very small lens apertures cause "diffraction", an effect that reduces fine detail in images. See the two pages of info about diffraction here: https://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

Learn and do focus stacking. This is a process where a series of images are taken at slightly different focus points, then the sharp portions are combined in post-processing. Doing this is particularly popular for macro work and allows more flexibility about the aperture, ISO and shutter speed you can use. There are ways to make the multiple exposures manually and fairly simple software that can be used to later combine the images.... as well as advanced, specialized software, motorized and computer controlled gear to make the series of images.

See this website for more info and lots of focus stacking examples: https://www.heliconsoft.com/



The problem is that "at the same distance" doesn't accomplish the same thing.

The Micro-Nikkor 105mm closest focus is about 12". That's where it gives full 1:1 magnification and at f/16 a DoF of only 0.24 inches (6.09mm).

The Micro-Nikkor 60mm lens closest focusing distance is about 7.25". That's where it gives full 1:1 magnification and at f/16 a DoF of only 0.28 inches (7.11mm).

For all practical purposes, by the time you set up both lenses to achieve full 1:1, because of the change in distance there is virtually no difference in DoF. If you can visibly see a difference of 4 hundredths of an inch (1mm) change in DoF, well more power to you!

Plus, f/16 is pretty small aperture, with real potential for diffraction issues. In addition, there's the concern about working distance between the front of the 60mm lens and the subject, which will probably be less than 3". (Min Focus Distance for 1:1 is measured from the film/sensor plane of the camera.... a significant part of that space is occupied by camera body and the lens itself.... the what remains is "working distance".)

Yes, backing off a little and shooting with the 60mm at slightly lower magnification, then cropping the image in post would work. But you can accomplish exactly the same thing backing off with the 105mm, using it at the same slightly lower mag, and then cropping the image. There's no significant advantage to using the shorter focal length, because the gain in DoF it offers is being offset changes in distance.

User ID

Thaz the three things eternally parroted as DoF Gospel. But it’s actually only two things. Magnification and aperture. The 1st and 3rd things cancel out each other. If you increase FL, you then get to also increase distance while still maintaining same magnification ... and vice versa.

Not saying gospel ain’t gospel. Just saying that the old “three things” chapter and verse fails to emphasize the real simplicity of the dance and thus leads some users into confusion. Gospel should “lead us not into confusion, but deliver us” ... from unnecessary complexity :-)

You mentioned how it’s a balancing act. With two things you have a balancing act. With three things you have a juggling act. Which act is less complex, balancing or juggling ?

As you point out, only stacking can break us free of the limits of the “2 or 3 things” law ... and even then, a live subject rules out stacking :-(

petrochemist Loc: UK

And as always the 'circle of confusion' which quantify how blurred the image can be while looking acceptably sharp on the desired output.

For Macro Distance & focal length can be combined as magnification. If the final output magnification is employed that incorporates changes in the CoC term too (but some constant is still needed for how sharp will do).

sippyjug104 Loc: Missouri

I use extension tubes when I take the Nikon Z6 in the field. I put them on the 28-70 zoom lens and they are autofocus extension tubes. The images it captures are as good as any macro lens that I have....HOWEVER...the focus distance between the end of the lens and the subject is ever so close. I mean really close.

Great for capturing little wildflowers and textures of rocks and bark however quite spooky for live critters that shy away. Also, illumination becomes much different as well than when using one of my macro lenses so getting light between the lens and the subject also takes different techniques that often get in the way when standing in the field with thick vegetation all around.

ecurb Loc: Metro Chicago Area

Laws of physics. The closer you get, the less your DOF.
Use small stops, more light and/or focus stacking.

RWR Loc: La Mesa, CA

1. Nonsense.
2. True.
3. Nonsense.

User ID

All of that is true, and is the reason that the final magnification, NOT the on-sensor in-camera magnification, governs DoF. Coc does exist in-camera but the tolerable size of the on-sensor coc is dependent on the printed or the on-screen magnification of those coc (and the real world viewing situation). As you summarized it “how sharp will do”.

While I do agree with you, coc discussion is just “inside baseball” chatter.

Practitioners’ need-to-know never covers coc. Coc is the underlying principle, but it’s useless to the actual activity of making photographs. Inside info is important for developers, but useless to users.

Drivers think the steering wheel actually makes the car go left or right. They know nothing of coefficient of friction, etc etc. And if they encounter black ice, knowing about all that won’t help them anyway.