ViewPoint

tube extenders

does anyone use them
and what are results

SonyA580 Loc: FL in the winter & MN in the summer

I think you are talking about extension tubes. I, as well as a lot of UHH folks, use them for close-up and macro photography. They magnify the image. The more extensions you use, the larger the image.

Apaflo Loc: Anchorage, Alaska

The results range from totally worthless to absolutely fabulous!

It depends on expectations and how tubes are used. So the question then becomes what is it you'd like to do? And what do you want to accomplish in doing that?

Are you looking for the ultimate macro setup and are you willing to seek out whatever it takes? Or are you looking for an inexpensive way to make use of some lens you found in a drawer? Both are valid topics that can lead to great discussions!

If you narrow it down people here can certainly help. But writing book length answers to over generalized question won't help... :-)

imagemeister Loc: mid east Florida

Tubes will allow you lens to focus closer - thereby, increasing magnification. When using the tube, you will loose light intensity to the sensor so that your exposures will be more than without them. The larger/more tubes, the more light loss - but also the closer you can focus(magnify).

Bugfan Loc: Toronto, Canada

As you move a lens away from a camera body you are able to focus closer and magnify more.

Extension tubes provide that capability. They have no effect on image quality, you'll always get high quality images within the limits of your gear because they are simply hollow tubes.

They come in two varieties, the old style that causes you to lose electrical connection with your camera and the newer ones that preserve the electrical connections. In the latter case you can usually focus and control aperture from the camera and your image stabilizer will work too.

The down side, they cost you potentially a lot of light. How much depends on how far you extend the lens from the camera and the focal length of the lens. So if you use an excessive extension make sure you have a lot of light to compensate with.

Tubes usually come is sets of three that add up to about 60 mm. You can add additional sets if you need more extension however the more you add the shakier becomes your stack and you may find yourself unable to get a sharp image because the stack will move in the breeze. Significant extensions also create vigneting.

I've used tubes to good effect and I tend to also use a bellows for magnifying evenmore. That's like an extension tube except it stretches out even more.

imagemeister Loc: mid east Florida

Light can reflect of the interior walls of the tube causing a loss of contrast to the image. Bellows are continuously variable and due to the way they are constructed, much less vulnerable to causing contrast losses. With bellows, you will be focusing at taking aperture because there is no mechanical or electrical connection to the lens.

Apaflo Loc: Anchorage, Alaska

That is often stated, and seems to be obviously true... but it is a myth.

Lenses are designed for a range of distances from the sensor. With lenses that are moved farther away to focus closer there are problems trying to optimize any number of aberrations, but the most significant problem is with astigmatism. The range of distances where astigmatism can be compensated for generally does not include close focus distances! It was once common to have macro lenses that were not sharp at infinity, but were sharp at 1:1. And most lenses that were for general purpose photography are fine at infinity, but suffer astigmatism at 1:1 due to close focus.

And then came what is called Internal Focusing designs. The lens does not move, and instead one or more internal groups of elements are moved. The lens is optimized to be at one specific distance from the sensor. This allows astigmatism in particular, but other aberrations too, to be better controlled across the entire focus range. But that is only true at the designed sensor to lens distance, and using extension tubes or a bellows will cause degradation of the image.

The effect of this can be seen in Nikon's change of marketing with macro lenses. Up through the Ai-S version of their 105mm macro lens this and other macro lenses only focused to 1:2 magnification, and Nikon sold a matching extension tube to get to 1:1. When that lens was replaced with an AF lens in 1990 there was no associated extension tube, because the lens was an Internal Focus design. It did go to 1:1 without help too. But Nikon was no longer recommending use of extension tubes for higher magnification, and instead recommended use of Teleconverters.


Actually the same reason that light loss is increased with added extension makes vignetting less of a problem. As the extension is increased the image is projected over a larger area at the sensor plane. Just the opposite of vignetting. What might be seen is lower contrast due to flare that results from a larger percentage of the projected image hitting surfaces other than the sensor and potentially being reflected.

ejrmaine Loc: South Carolina

Extension tubes work fine, considering the low cost. You can expect to get very good macro's using any lens in your bag. Have fun with it.

docshark Loc: Millersville, PA

I use 63mm of extension tubes with a Sigma "BigMA" 50-500mm lens on a CanonT3i.It allows me to magnify my zoomed shots of dragonflies quite well. They work for me.
-Doc

JimH123 Loc: Morgan Hill, CA

I might point out also that there are two kinds of extension tubes. The cheaper version provides no pass thru information between the camera and lens meaning the camera can't change the f-stop setting and can't auto-focus. You can typically find these kind on eBay for about $7.

The 2nd kind does provide pass thru information and the camera can adjust f-stops and auto-focus. Typically costs about 10X (or more) the above price.

Should point out that when you are using the extension tubes, most of your focusing is done by moving the camera. A focus rail is now one of the most useful tools you can use.

cbtsam Loc: Monkton, MD

Just a nit-picking fact check: I have an AF Micro Nikkor 105mm 1:2.8 D that goes to 1:1, and it is not IF; not sure when they went to IF, but it was after this D version.

Apaflo Loc: Anchorage, Alaska

Good catch, and my confusion was even worse than that. I said the 105mm, but described the 200mm Micro Nikkor!

The 200mm Micro Nikkor, which was the first IF design introduced by Nikon, was released in 1978. That and the Ai-S version released in 1982 would only go to 1:2 magnification, but instead of extension tubes Nikon recommended the TC-300 or TC-301 2x teleconverters for use with those lenses. The AF-D model released in 1993 goes to 1:1 without assistance.

the f/stops here Loc: New Mexico

Apaflo is correct and I would like to thank him for answering the question that was asked. I would also like to expand on another solution for doing close-up photography ... that being "close-up (diopter) lenses." They are very inexpensive, do not require additional exposure compensation, come in kits containing a #1, #2 & a #4 screw in lenses and do a respectable job of getting the lens closer to the subject. Neither the extension tube(s) nor the close-up lenses will turn a non macro lens into a true macro lens, but instead they will allow the photographer to get closer to the subject. They will work with fine results for many subjects but not for flat subjects such as stamps or small flat artwork. Simply put, true macro lenses are designed for flat field photography whereas a non macro lens is designed for curved fields. Keeping that in mind, enjoy taking close-up images, J. Goffe

cbtsam Loc: Monkton, MD

For many years, I used a set of extension tubes - Nikon K tubes - with a "Blowup Lens" (85mm 1.8). That rig could get me to 1:1, but I rarely used it at that extreme. I got very good chromes; indeed, some of my favorite images came that way. True, you lose light sometime a lot - but if you're shooting verrry closeup, you're probably well-advised to be on a solid tripod anyway. And, you'll lose a lot of light with a macro lens as well when you extend to very closeup. On the other hand, in bright daylight, with modern DSLRs giving good quality up to ISO 1000 and beyond, handheld closeups - not 1:1 - are quite doable.

Apaflo Loc: Anchorage, Alaska

Just be aware that the inexpensive diopter kits you speak of are somewhat less than stellar! :-) The cheap diopters are single element lenses that will have very poor correction for chroma aberrations. They might be almost sharp in the center, but universally get much worse towards the edges.

They do have one value though! You can, for only a few dollars, check out whether you like doing macro.

Good diopters are not inexpensive, but then again they don't cost as much as a macro lens either. Just make sure they are "multi-element" or "acrhomat" or something to that effect. Cost can be anything from $50 on up per lens.