robin_odland Posted June 12, 2006 Share Posted June 12, 2006 How much exposure compensation do I need with an 87mm extension tube (Mamiya #2-for the RB-67)? Thanks for the advise Link to comment Share on other sites More sharing options...
ilkka Posted June 12, 2006 Share Posted June 12, 2006 Depends on the lens you mount in front of it. And the amount of focusing extension you use (ie. lens focused at infinity or to its closest distance). Link to comment Share on other sites More sharing options...
robin_odland Posted June 13, 2006 Author Share Posted June 13, 2006 I am aware of the compensation that is required due to the focusing bellows, which should simply be in addition to the compensation needed due to the extension tube, I would think. Does Mamiya produce a chart on this? Link to comment Share on other sites More sharing options...
jean-louis llech Posted June 13, 2006 Share Posted June 13, 2006 Here is the compensation table for Mamiya RB67 Pro SD, extension tubes and different lenses.<p> <a href="http://www.mamiya.com/products2.asp?id=1&id2=15&id3=40&id4=429&id5=431">Close-up table</a><p> The tubes are :<br> No 1 = 45mm extension<br> No. 2 = 82mm extension<br> No. 1 + 2 = 127mm extension<br> Probably the length of #2 is 82, not 87mm.<p> I have another document about RB67, RB67Pro-S (non-SD) extension tubes. It's the manual for these accessories. I'll send it to you soon.<br> Regards,<br> Jean-Louis<br> Link to comment Share on other sites More sharing options...
jean-louis llech Posted June 13, 2006 Share Posted June 13, 2006 The file has been sent. Link to comment Share on other sites More sharing options...
Ed_Ingold Posted June 13, 2006 Share Posted June 13, 2006 You can calculate the effective f/stop (a') as follows: a' = a*(f+e)/f where a is the nominal f/stop, f is the focal length and e is the extension with the lens focused at infinity, using the same units of measure (e.g., mm). Link to comment Share on other sites More sharing options...
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