What is MACRO

[Zyclone]

Hi all,

Can someone explain to me in laymens terms what is the advantage of having a higher or lower macro as shown below.

Thanks!

[RobertTheFat]

---

@Zyclone wrote:

Hi all,

Can someone explain to me in laymens terms what is the advantage of having a higher or lower macro as shown below.

Thanks!

---

The lens on the left allows you to get 250 mm closer to the subject and still achieve focus. "Macro" implies magnification; and for a given focal length, the closer you can get to the subject, the greater magnification you'll get.

[ebiggs1]

True macro lenses offer a magnification factor of 1.0x or 1:1 at its closest focus setting. A true macro lens is a ‘flat field’ lens. General-purpose lenses (shown) typically suffer from field curvature, so the point of focus will be at a slightly different distance towards the corners of the frame as compared to the centre.

Neither of the lenses you show are true macro lenses. Those simply focus close. One closer than the other!

[TCampbell]

BTW, just a word about what it means to have, say "1x" or "1:1" scale magnification.  

"1:1" scale (what most of uswould call "true" macro) means you get "life size" image magnification... on the SENSOR.  

To put that in real-world terms... a US penny has a diameter of about 19mm.  The sensor dimensions on an APS-C camera body which has dimensions of roughly 22mm x 15mm (I'm rounding).  That would include every EOS Rebel model as well as every mid-level model (70D, 60D, 50D, etc.) as well as the 7D models; all of which have "APS-C" size sensors.   The name refers to the size of a single frame of film negative from the "Advanced Photo System - Classic" type film (that nobody uses anymore.)

Anyway... if you were to focus on that 19mm diameter penny at 1:1 scale then then the hieght of the sensor (about 15mm) would not be tall enough and you'd end up missing about 2mm worth of the top and bottom of the coin.  But the 22mm width would be just barely wide enough (with 1mm to spare on the left & right) to capture the 19mm width of the coin.

So that's the size of the image of the coin you'd capture on that sensor... and of course when you go to enlarge and display that on your computer screen or on a print, you'd have a rather massive image of a penny.

While a macro lens can allow you to get very close, they can also be used like "normal" lenses in that you could also focus all the way out to "infinity".  But non-zoom (aka "prime" lenses) that are macro typically have higher detail-resolving optics than a typical lens (sometimes considered "too good" for portraiture because they reveal too many skin flaws.)

Many "zoom" lenses have a "macro" range, but I am not aware of any zoom that can offer "true" 1:1 scale macro.  Zooms might offer 1:4 scale... even 1:3 scale is not very common (I've never seen 1:2 scale on a zoom).

Canon does have one specialty lens for macro that they call the MP-E 65mm f/2.8 1-5x Macro.  This lens is special in that it can ONLY do macro work.  It allows you to get close enough to capture a 5:1 scale image... but the 1:1 scale is the farthest and lowest scale image it can capture.  5:1 scale is *barely* wide enough to compose JUST the 'year' on the penny.  Grab a penny... look at the date... now imagine that occupies the entire frame of view!  The lens does not focus all the way out to "infinity" like most any other lens.  Some photographers who are specifically interested in macro photography and research will buy Canon gear specifically because of this lens (none of the other big camera brands have anything like it.)

[Zyclone]

Thanks for the tips everyone. I was not necessaraly focused of getting a "macro lens", just a larger one to allow me to zoom in further (or closer now that I think about it) when taking scenic nature pictures or family/friends.

I received both of these lenses as gifts. Obviously the newer model has some improvements. But are they drastic enough that a novice like me would even notice? I am trying to decide which one to keep and which one to get a refund for. The 2011 model is worth about 170 brand new on eBay. The 2013 model is 299 on Amazon.

http://www.dpreview.com/products/compare/side-by-side?products=canon_55-250_4-5p6_is_stm&products=ca...

[TCampbell]

You would notice the difference.  The newer lens (the "STM" model) is the better of the two.  

It's advantages are

- Improved overall optics - the newer lens is noticeably improved.

- STM focusing motors (which are NOTICEABLY faster and quieter than the original focusing motor).  Being quiet is also a big deal if you record video (the internal microphone will be able to pick up the sound of the focus motor with the older lens.)

- Inner Focusing -- which means the front of the lens will not "rotate" as you focus.  You might wonder why that would matter but some day you may opt to buy a circular polarizing filter (this cut down reflections and improve the color saturation of an image).  That filter is "rotated" to tune the angle of polarization against the light.  With the original lens, which rotates as you focus, every time you tweak focus you have to reach forward and re-tune the polarizer... which gets old.  With internal focusing you can tune the polarizer and as you touch up focus you don't have rotate the polarizer again because the lens doesn't rotate as you focus.

[RobertTheFat]

---

@TCampbell wrote:

You would notice the difference.  The newer lens (the "STM" model) is the better of the two.  

It's advantages are

- Improved overall optics - the newer lens is noticeably improved.

- STM focusing motors (which are NOTICEABLY faster and quieter than the original focusing motor).  Being quiet is also a big deal if you record video (the internal microphone will be able to pick up the sound of the focus motor with the older lens.)

- Inner Focusing -- which means the front of the lens will not "rotate" as you focus.  You might wonder why that would matter but some day you may opt to buy a circular polarizing filter (this cut down reflections and improve the color saturation of an image).  That filter is "rotated" to tune the angle of polarization against the light.  With the original lens, which rotates as you focus, every time you tweak focus you have to reach forward and re-tune the polarizer... which gets old.  With internal focusing you can tune the polarizer and as you touch up focus you don't have rotate the polarizer again because the lens doesn't rotate as you focus.

---

Inner focusing usually means that the front element doesn't move in and out as you focus. (The same for inner zoom.) And there are plenty of lenses of which the front element does move in and out but doesn't rotate. There is, incidentally, another advantage of a front element that doesn't rotate: the lens hood can be more effective, because it doesn't have to be round. And the advantage usually cited of a lens with true inner focusing is that because all exposed parts are always outside of the lens housing, the lens is less likely to ingest dust.

[TCampbell]

You're right... I shouldn't have used the term "inner focusing" and agree that it really only applies to lenses that that extend/retract by those few millimeters as you change focus.

I meant to refer to the non-rotating nature of the lens.  

I never gave too much thought about whether a lens rotates as I focus... until I started uses filters.  But the hood shape would be another good advantage.

[ebiggs1]

Canon EF-S 55-250mm f/4-5.6 IS STM  all the way!  Sell, return the other.