Comments on: Sigma classic 400mm tele quick rechip http://www.photoclubalpha.com/2009/03/06/sigma-classic-400mm-tele-quick-rechip/ Search this site - over 170 articles on Alpha system topics! Subscribe to our magazine too! Mon, 22 Feb 2010 17:11:52 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: admin http://www.photoclubalpha.com/2009/03/06/sigma-classic-400mm-tele-quick-rechip/comment-page-1/#comment-2042 admin Fri, 29 Jan 2010 16:38:24 +0000 http://www.photoclubalpha.com/?p=1323#comment-2042 The old chip has no further use. There are no electrical functions in the lens. It's all mechanical. The chip just provides identity, the camera knows where the lens is focused by doing calibration - that's when you switch on (and off) it sets the focus to infinity before doing AF - it's telling the camera what lens is fitted, then the camera gets the 'reading' at infinity, and uses the number of rotations of the drive to work out what's happening. Of course with modern SSM (focus motor in lens) designs there's a lot more feedback, same goes for eight-pin contacts and chips (xi and D lenses). But the original 5-pin chip like this does not actually get any data from anything happening in the lens. David The old chip has no further use. There are no electrical functions in the lens. It’s all mechanical. The chip just provides identity, the camera knows where the lens is focused by doing calibration – that’s when you switch on (and off) it sets the focus to infinity before doing AF – it’s telling the camera what lens is fitted, then the camera gets the ‘reading’ at infinity, and uses the number of rotations of the drive to work out what’s happening. Of course with modern SSM (focus motor in lens) designs there’s a lot more feedback, same goes for eight-pin contacts and chips (xi and D lenses). But the original 5-pin chip like this does not actually get any data from anything happening in the lens.

David

]]> By: Maggy http://www.photoclubalpha.com/2009/03/06/sigma-classic-400mm-tele-quick-rechip/comment-page-1/#comment-2041 Maggy Thu, 28 Jan 2010 20:15:01 +0000 http://www.photoclubalpha.com/?p=1323#comment-2041 I'm sorry but I do not understand. Shouldn't you solder the cable from the old chipboard onto the new chipboard in order to have functioning AF and aperture control? I’m sorry but I do not understand. Shouldn’t you solder the cable from the old chipboard onto the new chipboard in order to have functioning AF and aperture control?

]]> By: tgigreeny http://www.photoclubalpha.com/2009/03/06/sigma-classic-400mm-tele-quick-rechip/comment-page-1/#comment-1780 tgigreeny Fri, 10 Jul 2009 01:02:13 +0000 http://www.photoclubalpha.com/?p=1323#comment-1780 Hi there. Great post. Do you have any idea which chip to order from James' page? I really need to get my 400mm rechipped, but James' page is a little impenetrable for mere mortals like myself! Tom Hi there. Great post. Do you have any idea which chip to order from James’ page? I really need to get my 400mm rechipped, but James’ page is a little impenetrable for mere mortals like myself!

Tom

]]> By: admin http://www.photoclubalpha.com/2009/03/06/sigma-classic-400mm-tele-quick-rechip/comment-page-1/#comment-1680 admin Sat, 28 Mar 2009 15:06:31 +0000 http://www.photoclubalpha.com/?p=1323#comment-1680 I have now updated the link again - the new one I found failed shortly after putting it in place. Also, I have corrected a typo - James Lao not Loa! David I have now updated the link again – the new one I found failed shortly after putting it in place. Also, I have corrected a typo – James Lao not Loa!

David

]]> By: admin http://www.photoclubalpha.com/2009/03/06/sigma-classic-400mm-tele-quick-rechip/comment-page-1/#comment-1675 admin Wed, 25 Mar 2009 01:38:03 +0000 http://www.photoclubalpha.com/?p=1323#comment-1675 The URL always worked for me and was redirected by the owner to a new domain. I have now changed the URL to the new domain. David The URL always worked for me and was redirected by the owner to a new domain. I have now changed the URL to the new domain.

David

]]> By: johnbscot http://www.photoclubalpha.com/2009/03/06/sigma-classic-400mm-tele-quick-rechip/comment-page-1/#comment-1667 johnbscot Tue, 10 Mar 2009 11:57:09 +0000 http://www.photoclubalpha.com/?p=1323#comment-1667 Thanks David. Do you have a working link to James Lao? The link in your text does not work. Regards John Thanks David.

Do you have a working link to James Lao?
The link in your text does not work.

Regards

John

]]> By: braeside http://www.photoclubalpha.com/2009/03/06/sigma-classic-400mm-tele-quick-rechip/comment-page-1/#comment-1658 braeside Sat, 07 Mar 2009 15:31:26 +0000 http://www.photoclubalpha.com/?p=1323#comment-1658 Thanks for the report on the lens David. Please Sigma UK, can I have that lens I sent to you that you couldn't rechip for me back now please? - Actually having seen the results optically I don't think I would bother ;-) I'll stick to the 70-300G and crop. Thanks for the report on the lens David.

Please Sigma UK, can I have that lens I sent to you that you couldn’t rechip for me back now please? – Actually having seen the results optically I don’t think I would bother ;-) I’ll stick to the 70-300G and crop.

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