[lalung]

Tamron AF 28-75mm f/2.8 SP XR Di LD ASL IF Macro (A09) Zoom 變焦 是否代表不能調教光圈,只得f/2.8???

[Cosplay]

佢係恒定光圈 f/2.8，最細可以去到 f/32

依到有講。
http://www.dcfever.com/lens/lens.php?lensid=223

[williamhychan]

lalung:


支Lens一樣可以較細光圈

一般Zoom Lens會因應焦距改變,而改變光圈大細

Example: Tamron AF 28-200mm F3.5-5.6

恆定光圈: 不論焦距改變, 用家設定了光圈都不會改變

Example: Tamron AF 28-75mm F/2.8 (你問那支Lens)


我都剛剛上星期買o左,給兩幅試機相看看!!

ISO:100 焦距:28mm


F22光圈


F32光圈

[ohayoking]

你買左幾錢呀??

[williamhychan]

成成價HK2,850.xx

但我 (12分期) HK$238.xx (Each Month)

[lalung]

恒定光圈 有甚麼好處 /壞處???能否用光圈先決???
請指教!!
當場點check Lens有冇走焦??

[lalung]

恒定光圈 有甚麼好處 /壞處???能否用光圈先決???
請指教!!
當場點check Lens有冇走焦??

[wlachan]

During the manual focus era where you cannot alter the aperture through the body, constant aperture zooms are easier to work with if you do flash photography, or using a handheld meter. Nowadays, f2.8 zooms are often superior optically against other consumer zooms, with a few exceptions.

Checking the BF/FF is not that easy on the spot. If your camera can take a split screen, use it. Do a few AF at different distances and focal lengths, and see if it agrees with the split image. Otherwise, you will have to do the test at home and inpect them on computer. Just be aware that AF is never 100% accurate. Sometimes they miss, especially with wide angles near infinity.

[williamhychan]

lalung

兩幅試機相

我正是用(光圈先決)影