Originally posted by npc I guess everyone has seen the samples where DA* 60-250 "almost" covers FF with some dark corners.
But Pentax has a patent for a FF 60-250 lens so I thought maybe it is just the baffle at the back causing the dark corners.
So I finally got some time and disassembled mine to remove the baffle - and tested it on sony a7r. The results are pretty good! Dark corners were gone at all focal lengths.
I've noticed some light vingeting on some focal lengths wide open but no more than what I expect from any lens.
Resolution outside the APS-C zone is good as well, except maybe at 250 (but generally mine is somewhat worse at 250 than for example at 200 even on aps-c).
It is a pretty easy mod to do - just unscrew the mount (and make sure you dont loose those spring-loaded contact pins). The baffle is just a black tube that is glued (!?) with some spots of white glue to the back of the mount.
(I find it litte weird that the baffle is just glued that way - almost like it was not part of the original design and they just figured a way do add it later.)
Apparently the glue is not strong so you should be able to easily pry it out of the mount and re-assemble the lens without it. - And you'll have your FF lens ready.
Mod is fully reversible, as you can just glue the baffle back in its place. I guess it's purpose is to reduce internal reflections but I did notice any problems in that regard while testing.
I tested without the hood but I guess it should be fine at least in the 90-250 range.
Anyway, it looks like the FF camera is delayed again but I thought someone might find this information useful.
Hallo - I can confirm this text!
I'm from Sweden and phoned the official Pentax rapair-place.
I ordered the part (tube plus part for the SDM-contact glued at it as described above)
For heavens blueberries do not unscrew the whole bayonet. Just remove the SDM - contact thing (two black screws) and the three chrome screws
around on the bayonet itself - symmetrically placed in circle 180 degrees from each other - leave the other (one) screw sitting there.
OK - that's done - lift out the tube together with the "SDM-part". Loosen the glue - and you have the tube in your hands.
Now what I did - I took the tube and "dremmeled" (Search for "Dremmel" - grinder?) away the baffle from inside and out - in order to keep the full length of the tube - cleaned it with compressed air etc - and dropped it back after painting the grinded surface with matte black. Fits perfect! Now I did put on the "SDM-contact holder" and fitted it in. The three screws back on the chrome bayonet holding it - and last I did put back SDM-contact itself. Take care - it forks in to the SDM-bayonet contacts and you must be sure that the tabs fits the forks on the bayonet. Back with the two black screws.
(Before starting buy yourself a professional philips screwdriver set and make sure the screwdriver has "full fit")
Voila!
How it is on my K1 - just as it is the described by the thread starter!!!!! Wonderfull!!!!
If you want back the APC-feeling - just put on the Pentax 1.4-TC.
I'll look in here to see if you have any problems not understanding my explanation - as I'm not English native speaking.
By the way - what happened to my ordered parts from Pentax? They are still in the box - if I want to revert the above work and make it true original again.
Man - What a lens!!!!!!!
Now I love it even more!
I'll keep my K3 for serious tele-photoing, birdings etc
The K5 IIs is now for sale - cheap - anyone???