Kenko Extension Tubes for Dummies

There isn't really a quick source of information for extension tubes so i decided to make a crash-course on them instead of having people search and browse through all the threads related to them to understand what they do. This is mainly a for-reference-use-only type of deal and i am by no means an expert or professional on anything photography related. This is just my take on what extension tubes do after my little experimentation.

First off the test bed:
Canon 50D with 50mm 1.8 mk 1 (Most shots were at ISO 400 f/8 except for 2)
Kenko Extension Tubes 12mm, 20mm, 36mm
No flashes were fired
Distance shots (the one with the ruler) were taken by a Canon IXY point and shoot mounted on Manfrotto 190XPROB + 322RC2 ballhead
Cactus Wireless Shutter Release to eliminate shakey hands

The standard distance and how far away the subject has to be to focus properly

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Now the tubes are stackable so thats what i did. a 20mm and 36mm stacked together for a total of 56mm extension. Now i had to shoot this f/8 ISO 1000 to avoid exceeding 30sec exposure time.

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For those that have better insight on extension tubes, please feel free to chime in and correct any of my errors so i do not mislead the community. Thanks in advance!

It would appear from your very nice test here that the 12 and 20 seem to give you the best results. Looking at the distance that the camera moves in towards the subject from the 12 position to the 20 position is rather negligible for the magnification gained although I prefer the IQ of the 12 image.

Thanks very much.

I have some cheap extension tubes (US$10), does that mean I have no need to buy expensive macro lenses.

Yes extension tubes are fun. I bought this a week ago. I found that extension tubes are not suitable for shooting living subjects (like insects) as the MFD (minimum focus distance) has been shortened and we need to get closer to take the shot which might scare off the subject.

If want to take burning matches I think have to get very close also which might heat up the lens. (Have not tried this yet).

I have not used a macro lens before, but I guess that's the difference and advantage macro lens have over extension tubes, i.e macro lens still can take macro shot without going too near to the subject.

DigitalTechLife wrote in post #12226439
I have some cheap extension tubes (US$10), does that mean I have no need to buy expensive macro lenses.

That depends.....

You will need to stop down the aperture to shoot macro due to the very narrow depth of field at high magnification. Which lenses do you plan to use? How will you stop down the aperture?

DigitalTechLife wrote in post #12226439
I have some cheap extension tubes (US$10), does that mean I have no need to buy expensive macro lenses.

i own the 100L also macro lens. having extension tubes only allow u to what i call "step into" the world of macro photography. it by no means replaces macro lenses. Remember, this test was done with a 50mm lens. If i was to use the 70-200. it means i am that much more closer to the subject i want to capture. Extension tubes are a cheap way to get into macro-photography but it works for still subjects majority of the time... If you wanted to capture ants or something that moves, it is very hard due to the DOF u traded in for putting on the tubes.

Personally i think you did a wonderful job, and Thanks for your time & efforts to share the tube explanations for folks that may not be owners just yet.

As most folks know you can also buy a reverse adapter and turn a nice little CY 50/f1.7 MF lens into a fairly nice macro lens. Saw some examples in the past with folks reversing some different lenses and they posted some fine outstanding macro captures.

Regards,

msowsun wrote in post #12226537
That depends.....

You will need to stop down the aperture to shoot macro due to the very narrow depth of field at high magnification. Which lenses do you plan to use? How will you stop down the aperture?

I aim to use my 50mm and the 55/250mm and I set the aperture prior to putting on the tubes. As my tubes do not enable aperture control.

@YouTellMe
I have never used a macro lens before, and wasn't aware that extension tubes decreased DOF although I should have considering how tricky manual focusing is using tubes. So a 50mm macro lens has the same DOF as a 50mm non macro lens?

DigitalTechLife wrote in post #12226721
I aim to use my 50mm and the 55/250mm and I set the aperture prior to putting on the tubes. As my tubes do not enable aperture control.

That's a good answer, but have you tried it yet? It is a lot harder than it sounds.

At the same magnification, and the same aperture, and the same focal length, the DOF will be the same. This is always true and it doesn't matter if this is achieved with tubes or a macro lens.

Extension tubes don't cause the decrease in DOF. It is the high magnification resulting from the close focus ability of extension tubes that cause the reduction in DOF.

Not to change the subject matter of the OP`s thread but below is an example of using a reverse adapter to achieve some pretty remarkable macro captures with a cheap MF lens as an alternative or addition to ext. tubes:

https://photography-on-the.net …p=11901646&post​count=1796

Regards,

YouTellMe wrote in post #12225810
2)As you add on more tubes, your depth of field shortens (because you lose infinity)

I think this needs to be claified a bit.

Your DOF does become smaller, but not because you lose infinity focus. The DOF (area in focus) becomes smaller due to the shorter working distances allowed with extension tubes.

Your working range becomes shorter as you add tubes. Your working range with just the 50mm may be 1m (meter) to infinity. When you add a tube the working range may become 1/2m to 1m for example. Adding another tube may change it to 1/8m to 1/4m. This is the biggest downside to tubes IMO. They are great for still subjects but offer a very small working range sometimes which can be limiting when working with moving/live subjects.

silvrr wrote in post #12226890
I think this needs to be claified a bit.

Your DOF does become smaller, but not because you lose infinity focus. The DOF (area in focus) becomes smaller due to the shorter working distances allowed with extension tubes.

Your working range becomes shorter as you add tubes. Your working range with just the 50mm may be 1m (meter) to infinity. When you add a tube the working range may become 1/2m to 1m for example. Adding another tube may change it to 1/8m to 1/4m. This is the biggest downside to tubes IMO. They are great for still subjects but offer a very small working range sometimes which can be limiting when working with moving/live subjects.

I agree, but they do serve a nice additional purpose like adding them to a tele prime to decrease the MFD so you can sit in your backyard and shoot birdys within 25 ft. !

Regards,

Silverfox1 wrote in post #12226951
I agree, but they do serve a nice additional purpose like adding them to a tele prime to decrease the MFD so you can sit in your backyard and shoot birdys within 25 ft. !

Regards,

I 100% agree, however, I was trying to explain that when that when that birdy flys beyond 25 ft. or whatever you new maximum focusing distance is that you will not be able to get a shot. I think a lot of people know that the tubes will get you closer but a lot do not know that they also limit the far end.

That being said I love mine and once you learn to work with them it really doesn't become that big of an issue.