What exactly is different inside a lens in Macro mode?

On 6/8/2018 1:22 PM, Sammy wrote:
On Fri, 8 Jun 2018 10:18:35 -0400, Ken Hart wrote:

On 06/08/2018 07:09 AM, Sammy wrote:
What exactly is different about a lens in Macro mode? Does the lens alter
its optics in some way to focus more closely?

My Galaxy S7 lens doesn't seem to have enough space inside to shift any
elements in a different way. Although my point and shoot has a lens which
comes forward and is made of 6 elements in 5 groups. How do these cameras
provide Macro mode?

If a camera can provide close up macro focusing then why isn't it provided
as part of Normal mode?


The simple answer is in order to focus more closely, the lens must be
moved farther away from the focal plane (the film or image sensor). This
is why, in the "old days", we had bellows units (or extension tubes)
that could be fitted between the lens and camera body. A common large
format view camera is designed with a bellows and focusing rail that may
allow the lens to move away from the film sufficiently to give 1:1
magnification.

That's the simple answer, and generally applies to a common single
element convex lens. Very few cameras use a single element convex lens-
the Holga is a common exception.

If you want an exact, specific answer, it will cost you: probably a PhD
in physics and light, and in mechanics. See you back here in six to
eight years!

The cheap and dirty macro method is to get a set of close-up lenses that
mount on the front of your camera lens. I get quite reasonable results
(good enough for eBay) by holding a +2 close-up lens in front of my
point & shoot camera. I get exceptional results by mounting a bellows or
extension tubes on my 35mm SLR and using a macro lens.

Thanks for the answer. My smartphone camera and my point and shoot don't
seem to have any arrangement to move lenses further out or do much anything
different.

Is Macro mode on such cameras essentially a con because their Normal mode
can focus as close as macro mode?


It depends. For example, I use a Nikon 105 f2.8 micro. It does not open
as wide as 2.8 on my cameras. Here's a link to a discussion of the issue:
https://www.dpreview.com/forums/thread/2248343



--
PeterN