The Close Up Len is better than Extension Tube作者: swl33338888 時間: 2010-5-20 01:30 PM
I have both and can share some experience with you. The close up lens (especially those two-element ones like Nikon 4T/5T) is very sharp with zooms/short tele without any loss of light. The magnification increases with the focal length of the lens which is nice. The extension tubes in theory should be sharper but you need to increase exposure to compensate. You also need more extension with longer focal length. I usually use the tube with longer focal length (e.g. 180AF) to move closer to the subject. To get 1:1 with tubes, you will need a lot of extension unless you restrict yourself to standard lens or so.作者: patshiu 時間: 2010-5-21 12:34 PM
personally i prefer extension tube...
i have both, but extension tube without optical element, thus will not affect the lens performance作者: moxfactor 時間: 2010-5-24 02:42 AM
a longer tube will not affect vignette nor lens quality.
a thicker front element will affect vignette, depends on which lens you use and your subject matter, sometimes more than 1 piece of close up lens will be needed.
more glass will affect quality of photo, as well as additional possible lens flare(which if not facing the sun or a strong light source could be avoided with a lens hood) and chromatic aberration, which cannot be prevented.
i do agree that wider lenses should use close-up and good teles should use extension tubes, since the loss of maximum focal range from wider lenses render wider lenses inefficient. if you intend to use a wide lens for macro, i can suggest a 3rd method, especially for inexpensive lens like 35mm or 50mm f1.8. a reverse ring, where the ring screws onto the filter threading, and the lens with the reverse ring is attached to the camera with the front end of the lens towards the camera. all controls will become manual, including f-stop, but it's quite easy to achieve beyond 1:1 ratio with almost no additional element or length. however, manual focusing a reversed lens might take a while to get used to.作者: moxfactor 時間: 2010-6-9 03:15 AM
after researching more on the topic, i should change my statement that extension tubes will not affect vignette. this is more correct...
an extension tube will affect vignette to a degree, but less horribly than multiple thick filter rings and cheap glass elements in front of the lens. choosing "pro" filters will cut down on vignetting because of their thinner ring, but they're also fairly rare in variety, most shops in HK only carry "pro" filters for CPL and generic UV/protect.作者: uaon99 時間: 2010-6-18 12:23 PM
學到嘢了作者: Hayms 時間: 2010-6-18 02:56 PM
Nice sharing, thanks a lot.作者: ssal 時間: 2010-6-19 01:05 AM
Anytime you can avoid putting another piece of glass in front of your lens, you should do that. If you're shooting with some expensive glass, no add-on is going to make the original better, only worse, just how much.
I prefer extension tube for my macro work. I have the very early version of Nikon rings which do not have any control. But in macro mode, I prefer manual focus so I can pin point the area I want to focus. I shoot aperture preferred, so the auto-exposure is right on. The dept control of with the extension tube is very effective.
Kenco makes some good extension tube set that is AF and AE compatible, but they are not cheap. For Canon, it is about US$150 for a set of 3.
