Minimum focus distance

[alain_hogue]

If we add an extansion tube on Nikon 500mm or 600mm, what is the

minimum focus distance we can get. I would like to buy one of those

big lens but I enjoy using a blind and I want to be sure that I will

not miss to much opportunity.

[bill_horn2]

Alain,

 

The MFD varies with the amount of extension you add, but with a 500-600, you might reduce it 2-3 feet. Be aware, you lose light and may lose AF depending on the brand of extender(s) used. Also, DOF is reduced, so use fast film.

[derek_franks2]

How about you just keep more than one lens in the blind with you?

[kelly_krabbenhoft]

I'm not sure what extension tubes Nikon has, but when I use an EF25mm tube on my Canon 400 5.6L, I change the MFD from 11.6 ft to 5.8 ft. One-half the distance. I just bought the 600 f4 IS with a MFD of 18 ft and I expect that to be 9 ft with the EF25mm tube. How can you say that it will only decrease it by 2 or 3 feet? This wouldn't be worth the light loss that you mentioned and lack of autofocus (which you still get with Canon). Take the lens into a dealer and try different tubes and check the MFD so you are sure.

[robert_p._boner]

Kelly, if you read the specs that come with the lens and ext tubes, I think you will find that MFD with 600 IS and EF25 is more than 9 feet. Check the archives. I think Bob Atkins posted a formula for finding the approx. MFD with different extensions a couple years ago.

[kelly_krabbenhoft]

I found the formula Richard. Thanks. All I was trying to get across was that it was more than 2 feet. One can stack extension tubes to get even closer. Start adding converters and this is really a mess. Have fun shooting.

[don_baccus]

Kelly - I frequently use both a 25mm and 12mm extension tube on my EF 600/4. If you use atelextender in addition to the extension tube, remember that the telextender mounts to the lens, the extension tubes to the telextender, then the camera on the end of all that.

 

Also, folks, read your camera manual when using an extension tube, you may lose certain metering modes. For instance, my EOS1 and 1N lose their spot metering mode (but retain all others, including the partial mode).

[bob_royse]

Kelly, the poster was saying that you get an additional 2 or 3 feet of additional MFD - not focusing down to 2 or 3 ft.!

<P>

As Don says, with Canon EF lenses, it's best to put the tube between the camera and teleconverter to maintain AF capability, but with manual Nikkors, it's best to put them between the lens and teleconverter since less extension will give better MFD. i.e. it takes less extension to get a 600mm lens down to, let's say, 15 ft. than it does for a 840mm lens.

<P>

In any case, there are no probems using an extension tube to get you close up for photographing from a blind with a 600mm lens.

<P>

<P>

<I>In other words

<UL>

<LI>

For Canon EF: lens, TC, extension tube, camera body

<LI>

For manual Nikon: lens, extension tube, TC, camera body

</UL>

-- Shun Cheung

</I>

[bob_royse]

Sorry, I misread what Kelly was saying.

 

A 600mm lens with a 25mm tube will give about 5 ft. of extra MFD.

[alain hogue]

Correct me if I am wrong. Is it true that the simple fact to use a tele-extender already reduce minimum focus distance. In other words, the telextender act also as an extansion tube.

 

Alain Hogue

[bobatkins]

No. The minimum focus distance is NOT changed when you use a TC.

[lars]

Well it is often stated that TCs leave MFD unchanged but it is nevertheless NOT true (at least not with Nikon TCs, I belive others behave similarly). You can easilly exemplify this by setting your tele on a tripod focused on something really close by (like the MFD). When you now add a TC the subject will still be in focus BUT your film plane will be farther away - by excactly one (1) TC length! This is not much but still significant at close range. The TC has worsened (extended) the MFD by one TC length. Best regards,

[erick_lamontagne]

So I guess that would mean MFD changes but MWD (minimum working distance) stays the same.