I have a Tamron AF 70 - 300 mm F/4-5.6 Di LD Macro....which captures some decent shots. It is rather a heavy lens....Can i use it with the Kenko extenion tubes in the normal mode to do some macro photography as buying one more lens is not in budget at the moment. I am planning to buy the extension tubes if I can at least use any of my existing lenses either the 35mm(not recommended as it needs to be pretty close to the subject) or the Tamron lens(i hope it works). Would really appreciate if anyone can advise. Thanks in advance.

Link to earlier question.Macrophotography using Nikkor 35mm and Tamron AF70-300mm

  • \$\begingroup\$ Thanks for answering. By normal mode, I meant the way an extension tube is attached to the lens and not by reversing the lens. So when you said that a 25mm tube can be used, should i take it the way that an extension tube can be attached to the Tamron lens....? The objective of using the tamron and not a 35mm lens is to gain some distance and not venture too close to the subject. I think. \$\endgroup\$
    – Adi
    Commented Nov 15, 2015 at 22:25
  • \$\begingroup\$ The way you gain magnification in macro photography is by allowing closer focusing. This allows your subject to fill more of the frame. The problem with using extension tubes with longer lenses is that the reduced focusing distance (as measured from the film/sensor plane) needed to achieve 1.0X magnification is not as long as the distance from the physical front of the lens to the film/sensor plane... That is why you rarely see a true macro lens with a focal length greater than 100mm. \$\endgroup\$
    – Michael C
    Commented Nov 16, 2015 at 3:13
  • \$\begingroup\$ It is also why you rarely see zoom lenses with true macro capability. The lenses are generally longer than their prime counterparts. \$\endgroup\$
    – Michael C
    Commented Nov 16, 2015 at 3:19

1 Answer 1


The Tamron 70-300mm f/4-5.6 Di LD Macro, though touted as a macro lens, is nowhere near a true macro lens. It has a maximum magnification of 0.25X or reproduction ratio of 1:4. With a 25mm extension tube you can increase the MM to about 0.4 or 1:2.5. Extension tubes are much more effective with shorter lenses than longer ones. A typical 35mm lens that has a MM of 0.25X can be combined with a 25mm extension tube to yield a true macro 1.0X MM or 1:1 reproduction ratio.

It is unclear what you mean by "normal" mode in your question.

With macro lenses it is usually best to shoot in manual exposure mode using manual focus. This is especially true when using extension tubes. Even if you have a set of extension tubes that allow for auto focusing, the extremely narrow depth of field obtained at such short focus distances often places the camera's shot-to-shot standard deviation from perfect focus outside the range of the depth of field obtained when shooting macro. Exposure issues are similar, as the focal length of the lens effectively changes when focusing at close distances. This makes the "effective aperture" narrower than the aperture number the lens is set at.


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