When yous aim to photograph a subject up close, a macro lens is perfect. Only most lenses don’t let you focus shut enough to achieve life-size, 1:1 magnification. Merely how tin can you attain it without ownership a dedicated macro lens? Or what if you lot want your macro lens to focus fifty-fifty closer?
This is where extension tubes come up into play. They extend the close-focusing limit extensively, allowing for macro and close-up photography.
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What Are Extension Tubes?
The further away your lens is from the sensor, the closer your lens tin focus. For macro photography, you lot’ll need shut focusing.
Lens extension tubes extend the magnification of your lenses. They provide an cheap and effective starting point in building a macro photography kit.
These tubes fit between the camera body and the lens. They twist onto your photographic camera as a normal lens would, and and then the lens attaches to their front.
Technically, they increase focal length while holding the aperture bore and the minimum focus distance abiding.
They allow your lens to focus closer, as the focusing element will be further away from the sensor. Consequently, magnification increases, until information technology reaches its limit at the minimum focusing distance (MFD).
Simply what exactly is magnification?
Magnification is the ratio of the real size of an object compared to its size cast onto the sensor. The maximum magnification of a lens is reached at its closest focusing distance.
About non-macro lenses have a maximum magnification ratio between 1:eight (0.12x) and 1:iii (0.33x). That’south plenty for shut portraits or production photography, just not enough for macro shots.
Y’all tin decrease the focusing distance and thus increase the ratio by calculation extension tubes.
How to Summate Magnification
Derived from the general magnification formula, hither’s a quick way to calculate the magnification ratio when you lot add an extension tube:
extended magnification =
original magnification [in 0.10 course] + (length of extension tubes / focal length of lens).
Let’due south have a look at our favourite lens for macro photography, the Catechism 100mm f/2.eight L IS. This lens is capable of 1:1 magnification by default, but nosotros oft increase that further with tubes.
We like it, especially because calculating its magnification is very like shooting fish in a barrel, thanks to the round, 100mm focal length.
Below y’all come across a 25mm and a 12mm extension tube stacked and placed betwixt the camera and the lens. Y’all can only add them up, so it’s 37mm of extension in total.
Let’s substitute the values nosotros know into the formula:
M = 1.00 + (37mm/100mm) = 1.37
So, our new magnification, in this case, is
(or 1.37:1, if you similar that course better).
Now, if we were to add those same extension tubes onto a 180mm macro lens (one:1, too), the situation would be different.
M = 1.00 + (37mm / 180mm) = 1.21
As you tin can see, the ratio is now merely 1.21x. So, the come up-off is this: the shorter your lens, the more difference extension tubes make.
Add those tubes, for one concluding fourth dimension, onto a 50mm lens that has a magnification of 0.25x on its own. This is a blazon of lens that yous probably have in your own kit.
M = 0.25 + (37mm / 50mm) = 0.25 + 0.74 = 0.99 ≈
So, you lot’ve just created a one:ane ratio macro lens from a patently 50mm lens. Easy, right?
To exist completely fair, this maths is a bit simplified. As the formula is originally relevant for single thin lenses, some variations tin occur.
According to the real-earth testing done by Shutter Muse, these variations might reach 25-30%, especially with circuitous zoom lenses.
Then, to be entirely certain of the functioning of your macro system, you lot should do your own tests.
How to Use Extension Tubes
You can become ii types of extension tubes. There are cheaper ones without electrical contacts, and in that location are more than advanced ones which transfer electronic signals.
Extension Tubes Without Electric Contacts
These are very cheap. The depression price, of course, indicates limited possibilities, merely they are enough for sure situations.
They are lacking electric contacts to the camera. In full general, this means that:
- You lot cannot autofocus them
- Y’all can’t ready the aperture
- Lens metadata is not transferred
- The camera volition not recognise the lens
With focus-by-wire lenses (similar Canon STM lenses), yous can’t even manually focus. If y’all take such lenses, you’ll need to get different extension tubes.
In that location are modern lenses that allow you to set the aperture manually with a band. These include the brand-new Sigma 35mm f/ane.2 Fine art, for example. For such lenses, non-electrical extension tubes pose no problem.
Not-electrical extension tubes are best used with lenses that are fully manual by default. Vintage lenses (a Helios 44-2, for example) combined with extension tubes provide a distinctive look to your images. They are very cost-efficient, as well.
For extension tubes without electrical contacts, nosotros recommend the Fotodiox Canon EOS Macro Extension Tube Set (for Catechism EF-mount systems).
With Electrical Contacts
These tubes transfer electronic signals between the lens and the photographic camera body. Yous can choose between OEM (Original Equipment Manufacturer) and tertiary-political party offerings.
They are basically the same thing, except the price of the OEM extension tubes could exist more than than twice the price of the third-political party versions.
There is nothing very special about these extenders. In that location are no moving parts or glass. Tertiary-party manufacturers tin brand products that are but as adept every bit the OEM versions.
For OEM extension tubes, we recommend theEF 25 Ii and
EF 12 Twofor Canon and thePK-thirteen Ai and
PK 11Afor Nikon. For third party products, you can’t go wrong withKenko extension tubesfor Canon and Nikon.
Advantages of Extension Tubes
Extension tubes are much cheaper than macro lenses. The whole point of them is to empower lenses you already own to produce life-size macro images.
They are also smaller in size than a macro lens. Yous won’t have to carry around a hefty actress lens simply to have a few macro shots.
You tin utilize them with lenses that you love (for their special await or treatment), but can’t focus close enough with them. Combining a tilt-shift lens with extension tubes can produce extremely unique images, for example.
You can also utilize them with vintage drinking glass.
Disadvantages of Extension Tubes
Extension tubes are less effective with telephoto lenses than with shorter lenses. We’ve seen this in our calculations previously.
Just in that location’s a bigger problem. By using lens extension tubes, yous trade magnification for calorie-free. When you lot add them, less light will reach the sensor. This is due to increased focal length, and the thus decreased relative aperture.
Yous might be able to account for this by using a wider aperture or a ring flash. It is also possible to heighten your shutter speed or ISO, but it may affect your subject if they are moving.
How and When to Use Lens Extension Tubes
The best fashion to use these lens extension tubes is with manual focus. Do this past using the manual focusing on the bailiwick. Turn on Live View and enable 10x digital magnification for most authentic focusing.
The depth of field volition exist very shallow at this close focusing range. Plough up your ISO, and cull a narrow aperture. This fashion, you can achieve a deeper depth of field, although at the toll of more than racket.
If you are able to ready a tripod, you can photograph static objects improve. Yous can continue your ISO low, and your shutter speed longer.
You can also fix your discontinuity to where your lens is sharpest and shoot multiple photos while changing focus. Afterwards, you tin can combine those shots into a single, precipitous composite image. This technique is chosen focus stacking.
Using a tripod for moving subjects, such as flowers in the air current or beetles, is not possible.
For handheld macro photography, yous volition need a fast shutter speed to counteract camera milkshake. You’ll notice that motion blur is much more prevalent when shooting shut-up.
And so, with a 50mm equivalent macro lens, employ at least a 1/250sec shutter speed. With a 100mm equivalent lens, i/500sec should be good.
And that’s information technology. Extension tubes are a elementary and cheap way to improve your macro and close-up photography.
Now, head out in that location and take some photos!
For more macro photography tips, check out our posts on taking macro photos of eyes, cool macro ideas or art macro!
Posted by: Fusiontr.com