# Using Macro Extension Rings for People Portraits

Started 2 months ago | Questions thread
Re: Using Macro Extension Rings for People Portraits

BBbuilder467 wrote:

Dem Bell wrote:

BBbuilder467 wrote:

charley5 wrote:

Dem Bell wrote:

Holger Bargen wrote:

Don't know if it helps - but if you look at this calculator you can see whatt happens if you add extension tubes:

https://www.photopills.com/calculators/dof-macro

Just go up with the extensiontubes and see what happens with magnification and DOF.

Be careful interpreting the results from this calculator. "Focusing distance" is the distance at which the lens is in focus without the extension tube attached. For example, if you set infinity focus by using the distance marks on the lens barrel while it is attached to an extension tube, the "focusing distance" required by this calculator is infinity while things that are actually in focus will be much closer to the camera (because of the use of the extension tube). Confusing, right?

Ouch. I can't deal with this. For me, photography is a pleasure, not a math problem. Although I understand that other people have a different view on what is pleasurable or not.

It's all about the math. You said that you are adding extension tubes to an 80mm lens and doing portraits from 7 feet away.

20mm tubes with an 80mm lens at infinity should be 1:4. A postcard would barely fit in the frame.

I don't know how you can be using 2 of 3 extension tubes and still do portraits.

Well spotted! I guess it is possble that the helicoid is attached in such a way that the lens can focus from about 3 meters to well pass infinity. Then adding a 7mm or a 10mm extension tube will make the lens more usable for portaiture.

This is what I was referring to earlier. Somehow, he managed to adapt the combination to a mm or two beyond the register distance. It would work at short distances, but it's not actually adding extension tubes.

So BB, are you saying the extension tubes don't matter in the final analysis?

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Sony a7 II Sony a7R III Zeiss Otus 55mm F1.4 +2 more
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