te1221

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發表於 2010-5-17 11:04 PM | 只看該作者

[問題] Extension Tube & close up lens 一問

請問 Extension Tube同close up len, 邊樣會比較好, 對相片質素影響最少, 煩請指教

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moxfactor

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發表於 2010-5-18 02:27 AM | 只看該作者

我個人認為extension tube會比較好啲, 主要因素係因為始終少塊鏡. 第一係最簡單, 少塊鏡少啲幾會有lens flare, 雜訊, 等等. 另外, 鏡頭同機身接駁位同鏡面/filter面鏍絲位比較起上嚟, 應該係機身接駁位比較耐用, 而且裝上/拆除比較容易, 當然, prot/uv filter比例上係唔值錢, 但係如果你有試過filter駁filter, 你就知道其實都幾煩, 鏍絲位亦好容易壞. 太緊難拆, 太鬆易跌. 如果同一支鏡有機會用嚟影唔同subject, 一時換close-up filter, 一時換grad. ND, 一時換CPL, 個filter ring唔壞致奇. 加上filter用多過一個(就算係一個厚身既prot/uv filter), 就好容易出現vignetting(黑角). 第三, 唔係賣廣告, 但Kenko套extension tube, 一套3個, 可以加上加. close-up當然都可以, 但每多一個就多塊鏡片...多兩面機會黐塵...

以上為個人愚見~~

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te1221

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發表於 2010-5-18 01:58 PM | 只看該作者

多謝指教

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te1221

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發表於 2010-5-18 02:03 PM | 只看該作者

我見到鴨記有大陸tube（有測光），around$500, 唔知好唔好

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rayaries76

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發表於 2010-5-19 10:21 PM | 只看該作者

The Close Up Len is better than Extension Tube

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swl33338888

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發表於 2010-5-20 01:30 PM | 只看該作者

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.

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patshiu

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發表於 2010-5-21 12:34 PM | 只看該作者

personally i prefer extension tube...

i have both, but extension tube without optical element, thus will not affect the lens performance

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moxfactor

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發表於 2010-5-24 02:42 AM | 只看該作者

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.

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moxfactor

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發表於 2010-6-9 03:15 AM | 只看該作者

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.

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uaon99

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發表於 2010-6-18 12:23 PM | 只看該作者

學到嘢了

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Hayms

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發表於 2010-6-18 02:56 PM | 只看該作者

Nice sharing, thanks a lot.

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ssal

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發表於 2010-6-19 01:05 AM | 只看該作者

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.

.

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