[Cyril_K5]

I would like to thank @npc, @Gutta Perka, @Fenwoodian

After brief testing I can say that most, but not all of the, vignette has been removed. Unfortunately it is dark and overcast today so difficult to do good testing. From what I see there is no vignette below 85mm and only a slight darkening in the corners above that. This is at f/4. The sharp circular vignette is completely gone and I do not think the lens is much worse in the corners now on FF than it was on APS-C.

Thanks a lot mate. I just did the modifications as you suggested step by step. Worked like a charm for me ;-)


---------- Post added 10-01-16 at 01:14 PM ----------

Hi, all.
I just want to toss in my 2-cents worth. I also removed the baffle and the result is quite good with my K-1. There is very slight vignetting at 250mm/f4.0 and barely noticeable at 250mm/f5.6. Nothing noticeable from f8.0 and up. Curiously, the angle of view to my LCD monitor (the computer's, not the K-1's) is critical. Initially, I did see more vignetting, but when viewing exactly normal to the screen the vignetting all but disappeared. The monitor is a Samsung 28" 4K model at 3840x2400.

A tip: if you decide to "dremel" the baffle I suggest using a slow speed. Initially, I used high speed but progress was slow and control was poor. I lowered the speed to "2", what a difference. Cutting was much quicker and control was much improved. Also, use flat paint from a can, not from a spray can. The paint in the spray is very thin. I used Rustoleum's "Camoflage" flat black. Oh yeah, let the final assembly de-gas for an hour or so to eliminate any fumes.

Bests,

Dan

Thanks mate. Mine worked too but I kept the original baffle (cardboard and black flocking material for telescopes).

I did a few tests and I noticed something strange with my K-1. When I zooming in the longest range and I shut the aperture to say f/9 in Av mode, I get an overexposed picture of about 2 stops. Not sure if it is the modification but it is something I never noticed before.

*** Edited message ***
Found the culprit. It was my "Cardboard baffle" that was a tad too wide and was exercising some pressure on the aperture mechanism and preventing the lens from shutting the aperture. I have fixed it now and it works.

Lesson learned: if you choose to go for the homemade baffle vs dremmeled one, make sure you measure it to the millimeter and test that the mechanism is still working inside the lens.

---

Last edited by Cyril_K5; 10-01-2016 at 08:39 PM. Reason: Situation changed

[mattb123]

Well I took the plunge. Once I got in there I just decided to dremel away the flange and it all seems to work again. I used some Testor flat black model paint that comes in a pen to touch up the bare metal parts. Got it back together and it looks good!

Thanks for all the contributors who figured this out and tested it!

Test shot, 250mm at f/4

[sbh]

Matt, does the lens hood make a difference in vignetting?

[npc]

No, the hood is fine on FF. In theory I think there could only be vignetting in the 60-75mm range on FF (since it's the same hood on the DA* 50-135), but even there I have not noticed to make any difference

[mattb123]

Matt, does the lens hood make a difference in vignetting?

Not in my unscientific test. I'll keep an eye out. That test shot was with the hood.

[jcsnyc]

Going to try this out over the weekend - likely via the Cardboard route. Probably a dumb question, but has anyone investigated this technique for the 50-135 2.8?

[bdery]

Going to try this out over the weekend - likely via the Cardboard route.

Can I suggest taking a before/after picture in a controlled environment? For instance, set your tripod somewhere, take an interesting subject, and repeat after the test? Make sure the light doesn't change, if at all possible, and take pictures wide open, at 60, 135 and 250mm.

[link81]

Going to try this out over the weekend - likely via the Cardboard route. Probably a dumb question, but has anyone investigated this technique for the 50-135 2.8?

i don't believe the 50-135 has the same baffle set-up. i'd have to look at mine to check though.

[bjdavey]

Can anyone tell me what size Philips screwdriver should be used. I've just got a K-1, and am keen to do the modification this weekend.

[bjdavey]

Can anyone tell me what size Philips screwdriver should be used. I've just got a K-1, and am keen to do the modification this weekend.

Worked it out - bought a set of JIS precision screwdrivers, and it was the #000 that did the trick perfectly, so it's a JIS screw head, and not Philips. So I've joined the baffleless club, whole procedure was quick and easy, no more than 5 minutes - many thanks for the guidance to the predecessors on this thread. The lens is working fine on both my K-3 and K-1, and vignetting on the latter is much reduced. Interestingly, my removed baffle tube also has the circumferential scratch as can be seen in the pics posted by Jatrax in this thread. There must be something in the assembly process that causes that scratching.

[adrienbarrieau]

My test shot at 250mm with the 60-250 on a K1

[joergens.mi]

I joined this club, and I'm satisfied.

I'm missing a 12-24 (28) f4 and a 24-70 f4 all sharp - all over - beginnig with F4, light, small, WR that would be an excellent set up for hicking and landscape photography.

[Jacquot]

I like the idea of grinding away the flange and keeping the original tube, but do not really feel comfortable doing this myself, and do not have a Dremel tool or work area for grinding, not to mention any experience doing grinding. Is anyone offering to do this modification? If I did it myself, I'd have to choose between the remove/replace with cardboard or nothing options. I too love this lens, and just bought a K-1.
David

[jbondo]

Is anyone offering to do this modification?

I will consider this after doing mine sometime in the next week. I have a well equipped shop (end mill, lathe, etc..) to do a precise job. I'll let everyone know then if I will offer this. Thanks.

[jcsnyc]

In the meantime the cardboard is working well for me. Bought some that seemed to have somewhat clean edges from an art store and it is working fine.