#extension tubes

[sirfrogsworth]

Let's talk about macro extension tubes.

I just saw this video recommended to me.

This has so many views and it is so bad.

This is not how macro extension tubes work.

At all.

You can't just keep adding more of them to get more macro. All you are doing is reducing the amount of light reaching the sensor and making it harder to take your photo.

All lenses have a minimum focusing distance (A) and a minimum working distance (B).

The minimum focus distance is measured from the sensor. This is the absolute closest distance where you can attain sharp focus on a subject. This is usually the spec the camera manufacturer gives you, but it isn't very useful because it doesn't take the length of the lens into consideration.

Minimum working distance is how close the end of your lens is to your subject. You figure this out by adding the flange distance (google it for your camera), and then add the length of your lens, and then subtract that from the minimum focus distance.

Whatever is leftover is how close you can get to stuff.

In this example, this is as close as the lens can get to the flower before it can no longer achieve sharp focus. If you get any closer, it will be blurry.

If you have a short working distance, this can be problematic for macro work. Your lens could create a shadow on your subject. You might be so close that you disturb the insects you are trying to shoot. You risk scratching your lens if you are shooting near rocks or other scratchy objects. So finding a macro lens with a decent working distance is always optimal. You can back off from your subject and get a lot of light in there and not have to worry so much about disturbing critters.

But if you don't have a macro lens, you can increase the magnification of any lens by adding extension tubes. It is a low cost way to get into macro photography, but it isn't a perfect solution.

Before I can tell you what macro extension tubes do, let's quickly talk about what macro actually is.

Macro magnification is usually measured starting at 1:1 reproduction or 1x. (Some manufacturers start at 0.5x or 1:2 reproduction, but most photographers don't actually consider that macro. So watch out for that in lens specs.) 1x magnification means the thing you are shooting will appear on the sensor the same size as in real life.

So if a lens has a 0.25x magnification, an object will only take up 25% of the image sensor. (The rectangle on the right side.)

But at 1x magnification, it will be reproduced exactly as it is in real life on the sensor.

If you have a 2x lens or 2:1, it would appear twice as big as the image sensor.

So what does an extension tube do?

Extension tubes are just spacers that shorten your minimum focus distance. They take the red arrows and change them to the yellow.

They push your lens farther from the sensor and allow you to get closer to your subject.

This causes an increase in magnification.

Think about how a magnifying glass works. You pull it closer to you so that everything gets bigger in the lens. That's essentially all the tubes are doing.

The first downside to extension tubes is they reduce the amount of light by quite a bit. The inverse square law says the farther light travels, the lower the intensity. So the more tubes you add, the more light you have to add to the scene. Or you have to do a really long exposure on a tripod.

But the decrease in working distance is a problem as well. You may find you have to put the front of the lens a few millimeters away from your subject to get a meaningful increase in magnification. And because you can't phase into objects, there is a limit to how many extension tubes you can use to affect magnification.

At some point, you are actually placing the working distance *behind* the front of the lens. After this point you can no longer increase the magnification. You're just making your lens focus farther away.

You could keep adding more and more extension tubes, but it would not allow you to get any closer to your subject.

If you put 20 of them on, you are just doing this...

At some point, you'll have to violate the laws of physics.

The lens used in the video is already a macro lens capable of 1:1 reproduction.

This lens has a minimum focus distance of 160mm. But it has a minimum working distance of only 43mm (1.7").

Extension tubes are measured in millimeters. The ones in the video come in 16mm and 10mm sizes. He alternated them.

So in order to reduce the working distance to the point a subject would nearly be touching the front of the lens, he could put on a maximum of 3 tubes.

The red lines below show how much each tube would reduce the working distance.

A 10mm, a 16mm, and a 10mm would reduce the working distance by 36mm—leaving him about 7mm of space in front of his lens to achieve focus.

He could add another 10mm tube if he didn't mind his subject basically touching the lens, but it is very difficult to get that close in a real world scenario and achieve a decent result.

If he put on 20 tubes, that would reduce the working distance by 260mm. And since there is only 43mm in front of the lens to work with, he is overshooting the minimum possible working distance by 217mm or about 8.5 inches.

He's basically doing this...

He overshot by about 17 tubes—worth about $400. Though he probably made that money back in views. So I guess it was worth it.

But it is really bad information and may cause people to buy a ton of tubes expecting to get super macro results.

The only real way to significantly increase magnification is to buy a lens specifically designed for it. They make macro lenses up to 5x and after that you are looking at microscope objectives.

With extension tubes you might be able to get a non-macro lens to achieve close to 1x or better, but there is no low cost way to get much beyond that.

To review...

Figure out your minimum working distance. If google fails to give you the answer, you can just get a tape measure and figure it out on your own.

Let's say that the working distance is 50mm.

That means you can add up to 50mm of extension tubes to get a bump in magnification. (Though that would be touching the lens, so I'd probably do 30 or 40mm of tubes maximum.)

Adding more tubes beyond 50mm will not increase your magnification.

It will just make your camera look like it is compensating for something.

[rosanacafe]

Water, lights and flower por Rosana Por Flickr: Helios + Extension tubes

[skydarcyedwards]

Nostalgia: 12 years of macro photography.

Probably my first good macro photo. I had recently bought my 60D, original nifty fifty 50mm f/1.8, extension tubes, and snoot for the built in flash. For the price it's an excellent way to get into macro photography.

An unidentified tiny hopper on a blade of grass.

Sky Edwards

2012

Canon 60D

Canon EF 50mm f/1.8

Extension tubes

[kenkotokina]

Get Closer to Your Subject with Kenko Tokina Extension Tubes

Kenko Tokina Extension Tubes help you take amazing close-up photos. These simple, easy-to-use tubes let you get closer to your subjects, giving you sharp and clear shots without needing a special macro lens. They work with many different cameras and help you capture beautiful details in your photos. Enhance your photography with Kenko Tokina Extension Tubes today!

[kenkotokinaa]

Take amazing close-up photos of tiny bugs, flowers, and more! Kenko-Tokina makes special rings called extension tubes that fit between your camera and lens. These rings are like spacers that let your camera focus much closer than normal, so you can see all the tiny details. They're a great way to get started with macro photography at a good price!

[nattikay]

actually, do ya know what common Avatar misconception is even more annoying than "they have sex with their hair"?

"they have sex with their tails"

because not only were you not paying attention when they explain what the "hair thing" is (basically a biological USB that lets them neurologically connect to the world around them), you weren't even paying enough attention to realize that the tail and the kuru are two separate body parts

[spicerackspiders]

Debbie Hairy is cooler than I will ever be.

[unproduciblesmackdown]

just in time to spin the prompt / inspiration wheel via @lotrmusical for the 1 year anniversary of watermill theater lotr musical today:

the way louis maskell says "mr gandalf—please" with a laugh in his voice as he kneels next to sam to "protect" him from being turned into anything unnatural

[autisticlenaluthor]

giggling and kicking my feet bc tonight, i get to push meds through a freshly changed j tube that isn't growing mold or hanging on by a thread, about to fall out of my body, and definitely not in my jejunum

[scribeartistjo-tan]

WARNING: A shit ton of tiny baby spiders, including some close-ups!

I mean, I'll tag it, but just in case anyone happens to not have those tags filtered, I'm using a cut as well. ^^

Doing a bit of gardening earlier today, and saw a cluster of tiny little baby garden spiders on my fence. They're soooo cute! <3

I took quite a few macro photos, although even the ones that didn't come out completely blurry still had some blurred areas. I just wanted some pictures of these little guys!

These are the best four:

And a few cropped and slightly sharpened isolated babies from other shots:

Thanks for looking if you did. I know they're not the best you'll ever see, but I'm still so pleased with them considering I'm new to macro photography, plus I couldn't use my tripod because it's too short and they were too high up on the fence! ^^

[sxlphie]

New silly headcanon hot off the press is that Sarah's weird short underlayer beneath her ponytail is actually a grown-out undercut

[rosanacafe]

Daisies por Rosana Por Flickr: For Macro Mondays: "Fill the frame" Helios 58mm f2

[individuating]

my #truth:

ep 1 = ep 7 (beatriceless)

ep 2 = ep 6 (furniture)

ep 3 = ep 5 (tools)

ep 4 = ep 8 (ange focus)

[neocogent]

Pouting Angel

(macro using extension tube, focus stack of around 10-11 images using linux script)

(Heliios 44M-4 58mm lens, on focus rail)

[odeada]

thanks scott