Hi everyone, and merry christmas to all my friends on here. Just a simple question about my extension tubes I just got. I ditched my other cheapo ones and went for the kenko extension tubes. The cheap ones I bought last year, I kind of was nervous putting them on and off my macro lens because they just were soooo terribly tight that I was afraid I was going to damage either my camera or my lens. Anyway, just got the kenko tubes and while they are much easier getting on and off, I am finding that I can't manual focus. It won't let me turn my focus ring on my 105 macro. It feels like I need to force the lens to focus,,and I don't want to do that. It sounds almost like a grinding sound. I made sure I had my lens set to manual focus, so that isn't the problem...Not sure what else to do. It will let me manual focus if I have only 1 of the tubes on, but not with two...I didn't even try it with all three...Any ideas?
Sat 22-Dec-12 08:58 PM | edited Sat 22-Dec-12 09:12 PM by Leonard62
Hi Darlene, I think you're going to have to figure this out by the process of elimination. The first thing I would do is to remove the tubes from your D90 body. Then one by one add the tubes to the lens and see if the focus ring turns freely while it's off the body. You should be able to see if one of the tubes is binding. If everything turns freely off the body then attach the tubes and lens to the D90 and see if it focuses. Make sure the little AF/MF switch is turned to MF.
I have the Kenko tubes and a D80 which should be close enough. But I don't have your lens. My AF 105mm f2.8 lens manually focuses just fine when the lens is set to MF. It turns quite freely with all the tubes attached and mounted on the body. In my case I don't have to set the body switch to MF but you may have to.
edit: I forgot to ask. Is your lens HSM or screw drive? I assumed it was screw drive.
You know that's one thing I don't know. If it's hsm or screw drive. I looked at the lens, but it doesn't say....and I looked online, but one says hsm and one says screw mount. But I will try the elimination process. I know the lens focus ring turns freely with nothing added, and I will start adding one by one, see if that shows anything....thanks
If its HSM then it doesn't even use the screw drive. HSM lenses have their own focus motor built in them. The pictures of the sigma 105 macros with HSM on them all had the lettering HSM on the lens.
Like Len said, your going to have to do trial and error. Try each extension tube by itself on the camera with that lens and see if it works. This will tell you if it is just one tube and which one it is. BTW, I have had my kenko extension tubes for about 6 years and I have yet to ever need to use more than one at a time.