You're a brave man Rob! No way would I be getting any further into that maze. Good luck with it - when you've done, I've got an old 500/5.6 no-name that needs a new rear element....
John Coyle Brisbane, Australia -----Original Message----- From: PDML [mailto:[email protected]] On Behalf Of Rob Studdert Sent: Thursday, 18 July 2013 5:00 PM To: Pentax-Discuss Mail List Subject: OT catching up Hi Team, I've been shooting a bit lately but I've had little time to post process the images or even check my PDML mail. School holidays, kids birthdays and a big burst of work came my way, the additional cash has allowed me to clean up a lot of loose ends. I have been doing repairs for work so I'm in repair and restore mode currently. I just finished fixing a few things in my car that had failed and I did some toy repairs, a phone touch screen replacement (a nightmare even for me) and a few computer repairs too. More car repairs to go but I'm much happier that the half dozen icons and messages have disappeared from my view whilst driving. After testing my 77ltd for flare performance against my old A50/1.2 a few months back and being totally disgusted with its contrast performance I decided to finally determine what is actually causing the problem. Contrast comparison: https://dl.dropboxusercontent.com/u/9304908/temp/77LTD%20contrast%20test%20IMG503059.jpg Test shot (jpg out of camera), still sharp just no blacks whatsoever: https://dl.dropboxusercontent.com/u/9304908/temp/IMG503052.JPG So I embarked on the task of pulling my 77 apart, not something that I had great enthusiasm for I must say. The last/rear element is fixed and comes away with the rear mount, that left me staring at the rear group, which I then unscrewed from the lens body. In this assembly the first two elements are cemented and the rear element of the group with an internal air-gap. Looking at the external surfaces there was no noticeable haze and looking into the group from the concave element that sits closest to the aperture it appeared very clear. https://dl.dropboxusercontent.com/u/9304908/temp/13488_pentax_77_bud.jpg However it was a very different story looking into the lens set from the rear, there was a definite haze visible and tilting the lens with a light shining through it was plain to see where the contrast was being lost. Not good, this means that the considerable haze is locked inside the sealed and aligned 5th and 6th elements, damn. So I now have to trek down a path that I was hoping not to have to and of course I can't locate my lens wrench so as soon as the shiny new one that I just ordered arrives I will set about setting free delicate glass elements in my currently expensive paperweight. I will let you know how it pans out, hopefully for the better. Curiously the chassis of the 77LTD is high density polymer :) https://dl.dropboxusercontent.com/u/9304908/temp/IMAG3228.jpg Cheers, -- Rob Studdert (Digital Image Studio) Tel: +61-418-166-870 UTC +10 Hours Gmail, eBay, Skype, Twitter, Facebook, Picasa: distudio -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
