Kenko Auto Extension Tubes - AF Speed

[danster]

Hi, does anybody have any experience with the Kenko Auto Extension Tubes? What's the effect of the tubes on AF speed? Is it slower? Thanks in advance for your advice.

[deadpixel]

Originally Posted by danster Hi, does anybody have any experience with the Kenko Auto Extension Tubes? What's the effect of the tubes on AF speed? Is it slower? Thanks in advance for your advice.

It slows the AF down, but the speed lose depends on the max aperture of the lens and the number of rings you add. In some combinations, under less than ideal lighting, AF fails completely and you'd have to resort to manual focusing. I've been able to combine all three rings with a 50mm f/1.8 and still have the AF work properly (under good lights of course). This gives you a 1.47:1 macro effect.

[bcoolboy]

Originally Posted by danster Hi, does anybody have any experience with the Kenko Auto Extension Tubes? What's the effect of the tubes on AF speed? Is it slower? Thanks in advance for your advice.

Hi Danster,

Here's are some facts/issues to note when using Kenko's extension tubes: -

a.) That the extension tubes are incompatible with the Nikon AFS system and manual focusing is required.

b.) When using extension tubes the lens will not focus to infinity. The focus range will be greatly limited to a very close focusing distance.

c.) There is light fall off when using any extension tube, sometimes the equivalent of 3 f-stops of light is lost when using multiple extension tubes together. This light lost can affect the camera’s ability to auto focus. Manual focusing is recommended should the lens begin to “hunt” (not lock onto the subject).

d.) Nikon “D” information is not transmitted because the lens is focusing closer than its programmed to focus.

e.) Kenko’s Auto Focus extension tubes are designed with all the circuitry and mechanical coupling to maintain auto focus and TTL auto exposure with most Canon, Nikon, and Minolta lenses given there is enough light to activate the cameras AF system properly.

Hope this helps.

Regards,
bcoolboy

[danster]

thanks guys.

deadpixel, if you stack just 1 ring on the 50mm f1.8, do you see a noticeable fall off in AF speed?