Nikon Extension Tube with Full AFS Contacts

[Bjørn Rørslett]

Many true telephoto designs do not respond well to added extension. One has to experiment to learn whether results are worth the efforts.

However, for lenses that are useful with extension, adding a working TC to the extension is worth while to try out. As to the 105E, one indeed needs something in between in order to make any TC fit.

[Bjørn Rørslett]

Born curious, this morning I ventured outside in the half-light and heavy wind to snap some shots in my front yard. In a corner there is a small Sorbus koehneana (Chinese Rowan) shrub that tends to get nice autumn colours. Not this year though as the temperatures have stayed far above the freezing point so far. Still, an easily available target is handy, and I verified that AF works well with the 25 mm extension Erik made for me, plus with a genuine TC14E.2 in working order attached. Any background simply melts away using such a combination.

Shot at effective f/2.1 with Df at ISO 1600.

[Bjørn Rørslett]

Near by, there is a large Athyrium filix-femina Lady Fern again not getting its autumn colours this year. However, the delicately laced fronds make a good test subject for the AFS 105E with extension and TC14E.2 added to it.

The very shallow depth of field and the manner in which bokeh is imparted to the background makes explorations of these ferns an enjoyable experience.

For the Lady Fern fronds, I stopped down a little more, to effective f/2.8. Df as before.

[Frank Fremerey]

I use a modified TC-20E for the longer focal length like the 300mm to really make a difference - However not all lenses react equally well to extension! Unit focusing lenses usually works quite well but not most IF designs,,, Voting is still out for the 300mm AFS
You send me a TC-14E, TC-17E or TC-20E and pay 100€ plus return post via PayPal 

I just bought a 20E in mint condition for 186 Euros insured and shipped.

So total costs will be a little north of 300 Euros.

Looking forward to it.

Does it make sense to drive other G and E lenses trough such a long extension?

My 85/1.8 is and IF design IIRC.

What about a future 105E?

[Bjørn Rørslett]

A modified TC20E might be on the longish side for the 105E, but probably will do good service on the 300 mm class lenses.

[Erik Lund]

IMHO the 300mm AFS 4 PF don't take extension well, see the last posts in this thread:

http://nikongear.net/revival/index.php/topic,2077.msg71376.html#msg71376

[Pistnbroke]

If you are in the UK  and don't have a lathe I can take out the middle for you ..just get in touch   ..no charge.
Personally I find unless you are stacking 3 Kenco tubes there is minimal play,

[Erik Lund]

If you are in the UK  and don't have a lathe I can take out the middle for you ..just get in touch   ..no charge.
Personally I find unless you are stacking 3 Kenco tubes there is minimal play,

The thru hole of the third party extension tubes are too small a diameter for most applications.

The shell of the TC is very thin so you need to disassemble it first, you cant just clamp down on it on a lathe.

A complete disassembly is needed to get rid of any chippings also to not cut the flex-board.

[Pistnbroke]

Well the offer is still there if you are in the UK and need something turning.  I always buy cheap petal lens hoods  ( $4 ) and turn off the threads and bayonet to my Nikon lens . I keep the expensive originals for the re sale.

[chris dees]

....
However, for lenses that are useful with extension, adding a working TC to the extension is worth while to try out. As to the 105E, one indeed needs something in between in order to make any TC fit.

I have a Kenko 1.4x TC that fits and works on the 105 E

[Bjørn Rørslett]

Interesting. Do you have any pictures taken with this combination to share? I assume the optics of the Kenko don't protrude in the same manner as with the Nikon TC 14 then?

[Akira]

This is the picture "of" the Kenko x1.4 TC:

http://www.kenko-tokina.co.jp/imaging/eq/4961607601273_l.jpg

[PeterN]

I was wondering what the magnification effect would be of a converted 1.4 or 1.7 TC. Initially I could not find the info but after searching again, I found some info. If it is not correct, perhaps someone could provide the correct info.

The basic formula is magnification = total extension divided by focal length (M = TE / F). Without extension tube the total extension would equal the internal extension (IE). Since most vendors list the magnification ratio, this internal extension can be calculation easily: IE =  M x F.

When you add an extension tube, the formula would be M = (IE + EE) / F. EE being the length of the extension tube (External Extension).

Examples:

For the Nikon 105 1.4E the given magnification ratio is 1:7.7 or 0.13. So the internal extension (IE) is 105 x 0.13 = 13.65
When you add a TC-14 as tube with a length of 25mm, the Total Extension would be 13.65 + 25 = 38.65mm. Hence the Magnification ratio would become M = 38.65 / 105 = 0.37 or roughly 1:3

Adding the same tube to a Zeiss 135mm (with a magnification ratio of 1:4 or 0.25x) the outcome would be 0.44 or roughly 1:2.2

Hope this helps for other dummies like me. If not, it helped me. ;-) which probably says a lot about my level of knowledge in this field.


source: http://photo.stackexchange.com/questions/5603/how-can-i-calculate-what-the-effect-of-an-extension-tube-will-be

[Bjørn Rørslett]

Modern optics are more complex than what assumed by these simple equations (for the case of a 'thin' lens). They at best give ballpark figures.

It is best to to try with a ruler what kind of magnification you get. Such tests will also show to what extent the increased field of curvature, commonly emerging by adding extension, causes of issues including more chromatic aberrations.

Never fall prey to the widely circulating myth that extension "has no glass hence will not influence image quality". This is entire wrong, simply because the added extension pushes the conjugate distances out of their design range into uncharted terrain as it were. Lowered image contrast, loss of sharpness, more field curvature, spherical and chromatic aberrations, are the usual responses even of high-end lenses. Some do behave better than the pack and in general, the better lens one starts with, the better output will result.

[Frank Fremerey]

I have a Kenko 1.4x TC that fits and works on the 105 E

Full AF and Aperture control?

The picture Akira just posted does not show the contact block.