Nikon Extension Tubes

The BAT · Post by **The BAT** » Tue Jun 15, 2010 3:05 pm

Hi Guys,
While in the field, I find myself constantly trying to 'screw' my lens/extension tube combination tighter into the camera mount all the time to make sure that the camera lens metering combination is fully operable. I know that the Kenko extension tubes that I am using are at fault and that it is a well known problem. However my set of tubes are just over a year old and are 'taped' together with gaffers tape and shouldn't yet be showing signs of wear? I'm also worried that the constant screwing/tightening of the lens will damage the mount.
I am wondering if it is possible to get my Nikon PN-11 extension tubes 'chipped' so that they will provide electronic metering?
BTW, I am using a Nikon D90 which doesn't allow for lens info to be manually input into the camera's system, unless anyone of you knowledgeable gentlemen know of a suitable 'hack' ???
TIA,
Bruce

morfa · Post by **morfa** » Tue Jun 15, 2010 10:55 pm

Hi Bruce,

I haven't had time to look carefully into it and I don't know if it's compatible with the D90 but I think the new "dandelion chip" seems interesting: http://filmprocess.ru/nikon_spec_en.htm

According to this site the dandedlion chip appears to be compatible with D40/D90: http://ongabonga.wordpress.com/2010/06/ ... municator/

Some installation information: http://www.leitax.com/conversion/Chip/index.html

***Edit: Here it is on eBay with some additional info:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 656wt_1139

One thing that concerns me considering your purposes is that while this allows for communication between the camera body and the chip, there is no digital connection to the actual lens.

PaulFurman · Post by **PaulFurman** » Wed Jun 16, 2010 6:54 am

Note that the camera won't be able to meter anyways if things are too dark, due to stopping down and or high magnification. It will say Lo, as in 'low' for the shutter speed and will try something but maybe not correct. Frustrating because you can't see what it has chosen, just Lo, so have to take the shot & read it on the LCD in preview. That's for a D700, and I think D200 also.

The BAT · Post by **The BAT** » Wed Jun 16, 2010 7:20 am

morfa wrote:Hi Bruce,
One thing that concerns me considering your purposes is that while this allows for communication between the camera body and the chip, there is no digital connection to the actual lens.

Hi John,
Thanks for the links mate. Unusual that this technology comes from Russia, but I'm definitely glad that someone has actually done something.
What is your concern about the lack of a connection to the actual lens?
I'm thinking that being able to manually input the lens focal length into the camera via the 'Daffodil' that this should eliminate major problems?
My question would be when entering the lens' focal length would be, do I include the actual length of the extension tube as well as the lens' focal length or the lens' length alone?
I suppose I should also ask if I include the lense' 'starting' length or the actual length when being used at 1:1 seeing as most lenses shorten their focal length when brought right in to 1:1 ??
Thoughts fellas ???
Bruce

ChrisLilley · Post by **ChrisLilley** » Fri Jun 18, 2010 2:20 pm

Dandelion is intended to add a CPU to a lens that doesn't have one. Its similar to the CPUs offered by Bjørn Rørslett, except built into the contact block.

What seems to be needed here is two sets of contact blocks and a pass through cable; to be used with a lens which already has a CPU. The easiest way would seem to be to cannibalize some Kenko extension tubes to get the contact blocks and cables, adding these to the PN-11.

And indeed that is the approach taken at this site:
http://damien.douxchamps.net/photo/pn11/

Well, even easier than that would be to change your D90 for a D300 so it would use the mechanical aperture coupling provided by the PN-11

but like you, I haven't done that and still have the D90.

AndrewC · Post by **AndrewC** » Sat Jun 19, 2010 5:17 am

Something else you can do is look out for a nikon TC-20 teleconverter with damaged glass on eBay - strip out the glass and you've got a nice extension tube with contacts.

The BAT · Post by **The BAT** » Sat Jun 19, 2010 5:05 pm

Hi Chris,
Great idea and thanks for the link.
I've read it twice now and I'm still not quite sure about my own abilities with the handyman stuff when it comes to precision work with delicate equipment? I would love it if I had a local 'go to' man for my photographic problems. . .

Hey Andrew,
Thanks for the suggestion, I hadn't thought of that.
Funny thing, Craig Gerrard contacted me earlier about a Nikon TC-20 that's for sale in Melbourne (Oz), but it is brand new in box. I have been looking for one for ages to use as a converter and there have been some pretty shi**y ones that I have said no to. . . .bugger

Anyone interested in helping out a simple-minded colonial with either some parts or some 'handiwork' ???
PM me and we can chat. . .

Thanks fellas,

Bruce