Minimum Focusing Distance…

I’ve been doing quite a bit of macro work the past two weeks, and during that time I thought it would be a fun experiment to figure out the minimum focusing distance of my Macro lenses.

I was pretty sure I was getting in-focus images closer than the specs I was finding on my lenses (I used B&H for my research).  I decided that the best way to figure it all out was to make it as scientific as possible, so I used a ruler.  Here are my findings…

Meet the Subjects…

150616_NAT_007-meeplesI used meeples from the game Stuff and Nonsense, they are about the size of a quarter.

The Equipment…

I have three lenses that are considered Macro:

  • Canon EF 180mm f/3.5L Macro USM Lens
  • Canon EF 50mm f/2.5 Compact Macro Lens
  • Canon EF 40mm f/2.8 STM Lens

150614_lensesThe Stats…

These are the stats from B&H Photo for each of my lenses…



40mmAs it turns out, my 40mm is probably not really considered a Macro, but I had included it because I can get pretty close to my subject.  Since I did do some experimental photos I thought I’d add it to this post anyway.

The setup…

My goal was to find the exact point of focus at the closest distance to my subject.

I set my aperture at the lens’s maximum f-stop (or very nearly).

  • 180mm set at f/4.0
  • 50mm set at f/2.5
  • 40mm set at f/2.5

I used reflectors, natural light, and a ring flash (on the 180mm).

My subjects were all the same size, each meeple was designated to a specific lens so that I could compare photos and know which lens was used.  The Professor (light tan) was used with the 180mm, Geoffrey the Orangutan (green) was used with the 50mm, and The Blue Explorer (blue) was used with the 40mm.

The end of the ruler was set at the edge of the lens…

150614_NAT_030-red_LR1000The 40mm was short enough that I had to pull the ruler off the table…

150614_NAT_046_LR1000The results…







I learned quite a bit about my lenses with this little exercise.

  1. First and foremost I found out that I’ve been confused when it comes to my 50mm…
    150614_NAT_013-red_LR1000The ratio in the window does not equal the ratio on the part of the lens that slides out.  When I took these photos I thought I was comparing 1:1 on two lenses… it turns out that the 50mm is actually a 0.5x lens not a 1x lens (I had to relabel all of my images).
  2. Secondly, I am very confused as to why the stated stats on each of the lenses has a minimum focusing distance longer than what I was able to achieve in the test.  I have not found an answer online… does anyone know?
  3. Thirdly, I realized that my 180mm is more bad ass than I originally thought.  Not only can I get my subjects at 1:1, but I can be 10 inches away… which means I won’t get stung or bitten (hopefully).
  4. Fourthly, I’ve always known that my 180mm is rather heavy, it is nice to know that the 50mm does pretty good at 0.5x and is much lighter.
  5. Fifthly, it turns out that my 40mm isn’t really much of a macro lens after all.  I carry this lens around in my purse for any impromptu photo shoots, but I didn’t realize I was only getting 0.18x (1:5.5) even though I can get about 8 inches from my subject.
  6. And Sixthly, I learned a lot about my lenses’ abilities and limitations, as well as my own.  I encourage you to do some kind of test on your own lenses.





Until next time…

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