Nikon D50, 18-200VR, & Kenko Tube

[Not Here]

A little technical help please; and/or opinions from anyone who has tried the

Kenko tubes on similar setups.

 

I'm attaching a photo taken today with the D50, 18-200 VR lens and the new (?)

Kenko N-AF Uniplus Tube 25. I'm somewhat disappointed in that I can't seem to

obtain a tack sharp focus, at any given f-stop. Let me give the specifics of

this photo: ISO200, RAW, matrix meter, 1/1.6s, f10, mod.exp. -0.7, 200mm, UV

filter, remote release, and tripod. I've sized this down to 500p for posting,

but feel it adequately represents the full size. Oh yes, the subject is a single

Kalanchoe bloom that is approximately 5/8-inch across, manual focus - VR off

(auto and VR on was tried with same results).

 

Is this the quality I'm to expect? If so I may have wasted $80 for this tube.

Thanks in advance for your opinions and/or experiences... Mike

[ron_hiner2]

You should be able to get great results with the tube... but I've never tried my tubes with a zoom lens. Do do you have a prime to try?

 

Skip the UV filter... they never add quality, they can only take it away. The sensor is already proteced from UV, so you are probably using it to protect the lens. This protection can take away IQ -- don't use it if you don't need it.

 

I've used my canon 500D close up filter on zooms with great success.

[Peter_in_PA]

An extension tube will NOT work with that lens.

[Not Here]

Ron - Guilty, I have a habit of using the UV for protection only.

 

Peter - Is it because it's a zoom (as questioned by Ron), or something to do with the VR function (even though I turned that off)?

 

Thanks for the replies guys! Mike

[frank_skomial]

I have the Kenko set of 3 latest version tubes, and they have the AF screwdriver shaft/drive extension and a bunch of electrical contacts, transferring AF-S and D and other information (VR perhaps - though I never used VR on tripod), from the lens to the camera.

 

See how many electrical pins/contacts your tube has. Perhaps you may need to know what lens information each of the contacts carries from the lens to the camera. And what commanding information pins convey from the camera to the G - type aperture, VR, and AF-S. Once you know that you can assure yourself seeing if it workes for you tube. Just try it.

 

Chances are that your tube has the AF-S pins needed for your lens, and the G-Aperture pins, as well as the rest of them?, unless you have a very old Kenko tube.

 

Your lens is in no way a macro lens, no matter how many tubes you put on it. The picture shown is perhaps good for the lens in very close focus, and there is no obvious focus problem that I could see. If you need sharper pictures at macro distance, you need a better suitable lens for it.

[Not Here]

I think Frank that you have hit on the answer I was expecting... get a macro lens. :-) However, since my last post, I dug out the box and it does say this is a "Kenko Unipulstube 25DG for AF extension tube" and also says "for digital". It appears to focus well, and all modes appear to work, it's just not as sharp as I thought it should be.

 

Oh yes, it has 7 pins, just like the camera; but the lens has 10 pins.

 

Thanks to all for your help... if you think of anything further or if anyone else has info, I'd appreciate it.

[mark_chappell]

I think your problem is simply this: you are forcing your lens to do something it was not

designed to accomplish. An 18-200 zoom range necessitates optical compromises even

when used at the distance it was intended for, and you shouldn't be surprised it's not

super-sharp when forced to focus a lot closer than that.

 

The long exposure (1/1.6 s) may also have caused problems. What happens if you shoot

something in bright light, or with a flash, so that exposure time is a lot shorter?

 

To summarize: if you want really excellent results in macrophotography, follow the path

of least resistance and buy a real macro lens.

[Not Here]

Mark... As I noted to Frank, I feel you are entirely correct about the macro lens. I'll give this thing a few more tries with a shorter exposure, but that may necessitate a higher ISO; not the dread it used to be with film, but I do like to use the lowest ISO possible. I'm coming to the conclusion that this tube will be gathering some dust from lack of use! Again, thanks for your input... Mike

[david.elliott]

I was looking into macro lenses as well, but decided to get the 50mm f/1.8 nikkor and a set

of extension tubes. It seems that lots of people have had success with that route (searched

this site and normal google search). You may want to just purchase that lens for ~$100.

 

I'm an absolute novice though so hopefully somebody else can chime in regarding this

suggestion. :)

 

Good luck!

[Not Here]

David... Thanks, and that does sound more appetizing to my budget. I'll check that route out also. Mike

[Peter_in_PA]

To quote Thom Hogan at http://www.bythom.com/18200lens.htm

 

"The optical design of the 18-200mm means that almost any extension would put the

focus point inside the lens--I assume you don't want to focus on the fifth element. TCs

also pose multiple problems, including loss of autofocus and potential damage to the rear

element of the lens. In short, the only thing you can add to this lens are filters (including

things like a Canon 500D close-up lens)."

 

Forget Extension tubes with this lens.

[Not Here]

Thanks Peter, a very informative article; and I've already decided to scrap plans to use the ET on this lens.

 

I think this will close this discussion, at least for my original question. Anyone that has information or personal knowledge with the 50mm and ET combination proposed by David Elliott would be most appreciated.

 

Thanks again... Mike

[Peter_in_PA]

Michael.

 

Glad we could help.

 

I would, if I were you, look carefully at perhaps getting a 55mm f2.8 or f3.5 micro instead.

They are AMAZING for close work, better than the 50mm f1.8 (which I think should ALSO

be in every Nikon camera bag, though...)

 

georgeury.com has a 55mm f3.5 at a great price right now. You will have no AF or

metering, but I've found I don't care about either for close-up work. This photo was taken

with a D50 and 55mm f3.5 micro. Blown up it's just as sharp!<div></div>

[david.elliott]

regarding the 50mm f/1.8 option---

 

General google image results:

http://images.google.com/images?

q=50mm+f/1.8+nikon+extension+tube&hl=en&client=safari&rls=en&um=1&ie=UTF-

8&sa=N&tab=wi

 

Other links that may prove helpful:

http://forums.dpreview.com/forums/read.asp?forum=1034&message=12462668

 

http://www.flickr.com/groups/bokeh_/discuss/72157594175043300/

 

I'd try to find more, but I'm in class right now. Hope that helps a bit.

 

 

--

 

I agree with Mr. Hamm. I think that a true macro lens would be the best option.

 

The reason I went with the 50mm and extension tubes is that I own the D70 with kit lens

and thats it. I figured that the 50mm f/1.8 would let me do other work and not just

macro. I still wanted to do close-up work though so I am getting extension tubes to go

with it.

[Not Here]

Thanks Peter, I'll keep that lens in mind.

 

David - some good info there, thanks!

 

Thanks to all, again! Mike