Extension tubes on Macro lens?

[ClaudioG]

I have a Tamron 90mm Macro lens..i was wondering if its was possible to add extension tubes to a Macro lens and if so, what would it do for me (how does the ratio work) ? I'm looking at buying the Kenko extension tubes set.

[Shadowman]

See link.

http://www.youtube.com/watch?v=kbcrrd9eLgY

[ClaudioG]

Hmmmm..thanks John...seems like not really toooooo worth it..rather spend that cash on a 50mm 1.8 lens for portraits and stay with my macro lens...Thanks again John

[Rita]

Just to expand on Claudio's question. If that is the scope on extension tubes, what about the close up filters that screw onto the front of a lens?
Are they beneficial?

[ajohnw]

I bought 2 plastic extensions tube for m 4/3 with AF connections to try. The 1st shot was taken with both tubes on using the 75-300mm.

The 2nd with the 40-150mm on at 150mm but I suspect 100mm would be better. I also missed the focus on this one.

Basically they allow the lens to focus more closely than it usually would and will probably give better results than close up lenses. With either the camera has problems finding focus.





I've had my best results with a Pentax 100mm manual macro lens and an adapter but the target has to be framed - 7x mag selected and focus achieved by moving the camera - which is fairly normal for macro work. Keeping the target where it's wanted with 7x mag isn't exactly fun though. This is one of the better ones.

http://www.flickr.com/photos/4899461...57631535313006

It's a bit difficult to see if all is in focus.

John
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[Geoff F]

Claudio, this subject comes up occasionally and before being able to give much of a reply the question which needs to be answered is 'What will you be photographing?'

Extension tubes allow you to get closer to your subject, hence a larger image. But that is only useful if you can physically get closer.

For live subjects, like insects, I usually reckon that if I can approach to 12 ins I am lucky. And for static subjects, getting closer can sometimes cause problems with light blockage etc.

Tubes can be useful when shooting with 'standard zooms' which have a relatively close focusing distance but not as close as a proper macro lens. You do lose the ability to focus at infinity but that usually isn't a problem.

The advantage with tubes is that they don't add extra glass so there is no quality loss.

As an alternative, I frequently shoot with a 1.4x lens converter which actually increases magnification so this can be useful when moving closer isn't possible.

On the down side, there may be some quality loss but used with good quality lenses the loss isn't excessive when using a 1.4x magnification. A x2 can produce more loss and, depending on your lens, possibly a loss of auto focus.

I have also used a 12 mm tube coupled with a converter to work as a spacer which allowed a Canon converter to be attached to a Sigma macro lens.

For macro work on live insects, I use a Sigma 180 macro lens. I wouldn't work with anything less than 150 mm. In fact, my 1.4x converter plus 180 mm macro lens is my standard macro kit.

When it comes to larger flowers, I prefer a fairly close focusing standard lens. For me, that that means a Canon 24-105 or Tamron 24-70.

[Stagecoach]

Hi Claudio,

I use the Kenko set of three giving a max of 68mm extension if required on my 105mm. Results are that on my 26mm sensor width I can fill this across with a 12mm wide subject which is almost equivalent to 2:1 magnification. On your 90mm this would be slightly more.

My own view is that they certainly are worth having.

Grahame

[ajohnw]

In case any one needs to know the extension I used is 10 + 16mm on the 40-150mm and that achieves a reproduction ratio of about 2 1/4 to 1. As the shot with the Olympus 40-150mm was so bad I quickly set it up again. That can achieve 2:1 at 100mm. This is a crop reduced in size by 50%. Just sharpened in and out. The out was just to make up for the reduction. Taken at F8 - note that the rule is only marginally in focus. I would say working distance was well over 150mm from the front of the lens.



As far as detail goes there is plenty of scope for cropping.

This was using the original 40-150mm version which focuses down to 0.9m. Very plasticy but a very decent lens in practice. Mine is silver so I feel I should have a paper bag over my head when I use it in public.

John
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[DanK]

Claudio and Rita,

It depends on the magnification at which you want to shoot. Any true macro lens will get you 1:1 magnification. Depending on the focal length of the lens and the length of extension, tubes can get to to roughly 2:1. Unlike close-up adapters, you can put tubes on any lens, and you can stack them to get different amounts of magnification. The drawbacks include a dark viewfinder and the loss of infinity focus. Also, you get the higher magnification by bringing the camera closer, so you lose working distance.

Personally, I find them invaluable. I have the Kenko set and use them in all combinations, giving me 12 to 68mm of extension. My standard bug-hunting rig on a crop-sensor camera is a 100mm macro with a 36 mm Kenko tube. The formula for figuring out magnification does not precisely work with macro lenses at minimum working distance, but that gives me something like 1.5:1. This means getting very close. The MWD for that lens is 6 inches (15cm) without the tubes, and it is closer yet with the 26mm tube. Unlike Geoff, I find I can do this (in fact, I have done it with a 60mm macro lens too), but it takes a high tolerance for frustration, a lot of practice, and a willingness to have a low keeper ratio. With flowers, it all depends on the level of detail you want. Tubes are not necessary for shots of whole flowers unless they are very small, but shots of parts of flowers are often very interesting. I'll post a few examples of shots taken with tubes. The first two bugs are a 100mm lens + 36mm extension.

BTW, as one person mentioned, depth of field gets even narrower with tubes. This requires a lot of care in getting the position and angle of the bug right, and for flowers, I usually use focus stacking.

Dan





This one was a 60mm lens with 68mm of extension:



This was a 60mm lens, I think with 12mm extension

[Stagecoach]

Claudio,

For further info I found the test results I undertook with the Kenko set on my 105mm macro with 23.6mm width sensor on DX body.

Sensor width = 23.6mm

At closest focusing distance with each tube fitted the following measurements filled the frame across;

36mm tube - 16mm
20mm tube - 17mm
12mm tube - 18mm

36 + 20 + 12mm tubes - 12mm

With 2 x Converter fitted to 105mm macro lens - 11mm

With the tubes you will of course be closer to the subject blocking some light but this can be overcome with flash correctly positioned.

Grahame

[William W]

As a general comment I too find a set of three extension tubes an invaluable, light weight and inexpensive addition to my camera bag. I mainly photograph people and am not a 'dedicated' macro photographer, but I do have two macro lenses but often neither of those lenses are in my bag, but I usually carry my set of tubes all the time and that allows me a great deal of flexibility, quickly, to grab a "close up" of something that I find interesting, when I see it.

I have stacked the tubes on a macro lens, but that was to get very close for details on inanimate objects such as stamps coins or circuit boards or for certain forensic work.

I also use the 12mm tube to allow the use of a tele-extender behind a lens to which it not compatible.

*

Regarding (Rita's) the question about Close Up Filters: I have a set of Hoya CU Filters. I use them rarely but I bought them for specific uses. There are some considerations before using these Filters.

Firstly because they attach to the front of the lens, they need to be a filter size of the lens(es) that one intends to use (as opposed to a set of tubes which will attach to all the lenses in the camera bag).

A second main consideration is the optical quality (or lack thereof) and the resultant impact on the final image. The Hoya set that I have are quite reasonable quality there are many which are of a much lesser quality, though and that is quite noticeable in the final image.

A third main consideration is stacking the filters: the advertising will suggest that stacking the filters is how one attains more magnification, which is correct, but doing so also can create more optical nightmares in many shooting scenarios, especially apropos Flare and or Optical Vignetting.

Also stacking will obviously exacerbate any general optical deficiencies of the Filters.

It seems to me that one of the man uses for a set of Close Up Filters is for Cameras with a fixed lens that has limited close up optics.

WW

PS - I just love Dan's macro work.

Compliments of the Season, to all.

[DanK]

Bill,

thanks very much.

BTW, I too have started using a 12mm tube in front of a converter, in my case between my 100mm macro and a 1.4x converter. It is a nice combination, although heavy.

And a wonderful holiday to you as well.

Dan

[William W]

You're most welcome and most deserving.

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. . . I too have started using a 12mm tube in front of a converter, in my case between my 100mm macro and a 1.4x converter. It is a nice combination, although heavy.

Returning to my previous – as I already mentioned I don’t usually need “macro” but I do find "close up" very handy.

This is my typical “quick and easy ‘close up’ set” on any digital camera:



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Here’s a result used on a 5D, same 50mm lens, x1.4 Extender and 12mm tube:

(Student Exercise) F/13 @ 20s @ ISO 50
Used a low power LED 'Flashlight' for Light Painting

WW