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09-19-2016, 01:19 PM   #106
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Somewhere else I read the maximum / optimum values are 20 by 30 mm and this will fit in to the tube, the inner diameter of the tube shoud be 30mm.
Maybe that your calculation are much more accurate, but is it a good idea to calculate so sharp, or will there be side effects by the light hitting the edges?

09-19-2016, 02:30 PM   #107
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QuoteOriginally posted by bdery Quote
For those interested, I've gone ahead and made the calculations as to what's needed to cut a rectangular window. The long axis of the rectangle needs to be 2.83cm in length (I went all in on significant digits...) and the short axis needs to be 1.89cm. If you can cut this shape, aligning it correctly with the flange (maybe using the foot and plane surface as a reference) then there's no need to remove the whole flange.

Note : the opening won't look like a rectangle at all, but like a circle with triangles protruding from it...

I'm still undecided on this. If anyone wants to tackle the proposed test I wrote above, let me know!
For what it's worth, I think people are way overthinking this.

Since the modification, I have taken and processed multiple pictures with the modified lens on both the K3ii and K1 and cannot appreciate any unintended consequences. I would do it again in a heartbeat.

Last edited by riseform; 09-19-2016 at 02:31 PM. Reason: spelling
09-20-2016, 04:56 AM   #108
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QuoteOriginally posted by joergens.mi Quote
Maybe that your calculation are much more accurate, but is it a good idea to calculate so sharp, or will there be side effects by the light hitting the edges?
I calculated the maximum rectangle that should fit into the circle. Just so interested people can build themselves a jig to remove only what's needed.

QuoteOriginally posted by riseform Quote
For what it's worth, I think people are way overthinking this.

Since the modification, I have taken and processed multiple pictures with the modified lens on both the K3ii and K1 and cannot appreciate any unintended consequences. I would do it again in a heartbeat.
I might be overthinking, that's entirely possible. A part of me is worried at hacking away part of a 1000$+ lens. And being an optical designer myself, I appreciate that we rarely include useless components into our designs. So before modifying my lens, I want to know as much as possible about the consequences.
09-20-2016, 07:14 AM   #109
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QuoteOriginally posted by bdery Quote
I calculated the maximum rectangle that should fit into the circle. Just so interested people can build themselves a jig to remove only what's needed.



I might be overthinking, that's entirely possible. A part of me is worried at hacking away part of a 1000$+ lens. And being an optical designer myself, I appreciate that we rarely include useless components into our designs. So before modifying my lens, I want to know as much as possible about the consequences.
I for one, appreciate the work you did to figure that out. I am seriously considering this lens for my k-1 rig and have been following the thread. Seems like the most legit mod to me.

09-20-2016, 08:05 AM   #110
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QuoteOriginally posted by bdery Quote
For those interested, I've gone ahead and made the calculations as to what's needed to cut a rectangular window. The long axis of the rectangle needs to be 2.83cm in length (I went all in on significant digits...) and the short axis needs to be 1.89cm. If you can cut this shape, aligning it correctly with the flange (maybe using the foot and plane surface as a reference) then there's no need to remove the whole flange.

Note : the opening won't look like a rectangle at all, but like a circle with triangles protruding from it...

I'm still undecided on this. If anyone wants to tackle the proposed test I wrote above, let me know!
I'd like to try this route when I get my lens back from repair. I'll definitely report back what I find if/when I do!
09-28-2016, 04:36 AM   #111
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QuoteOriginally posted by bdery Quote
I calculated the maximum rectangle that should fit into the circle. Just so interested people can build themselves a jig to remove only what's needed.
I'd remove it completely so that composition adjustment via sensor movement works without vignetting.
09-28-2016, 04:59 AM   #112
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QuoteOriginally posted by indykpol Quote
I'd remove it completely so that composition adjustment via sensor movement works without vignetting.
The calculation I made was in order to fit the largest rectangle possible inside the circle. Using composition adjustment (if at all possible with the modified lens) would not be influenced by removing more, if there's a problem it will come from the corners anyway.

09-28-2016, 12:38 PM   #113
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QuoteOriginally posted by jatrax Quote
I would like to thank @npc, @Gutta Perka, @Fenwoodian and the others in this thread that figured out this mod and how to do it. I am just going to lay out in detail the instructions with pictures for what they figured out.

NOTE: Do this at your own risk. You are working on a 'DA*' lens worth maybe $1,000. Think carefully if you want to take the chance of ruining your lens!!!!!!!!!

Here are some detailed instructions:

  1. First, there is no need to remove the bayonet. Just the smaller plastic ring that holds the SDM contacts.
  2. Locate the SDM contacts and remove the two small black screws there.
  3. Gently pry out the black plastic SDM mount with the two gold contacts. These are slip fit connectors, like electrical connectors, so just gently pry on each side back and forth until it lifts out.


  4. Locate the three silver screws holding the black ring in place. There are four screws in the ring. Three located at 120 degrees from each other and a fourth just to the right of one of the others. Of the pair you want the left one. Remove these three screws. I used a rear lens cap to put the pieces in to keep them safe. These are very small screws. They are also JIS so make sure you do not strip them.
  5. Now with the screws out the black SDM ring and the baffle will just pull out in one piece.
  6. The baffle is glued with something like rubber cement to the SDM ring. I used an Exacto razor knife to cut the glue away, but it was soft enough I think you could just break it. Note the scratches on the black baffle, these were present on the baffle when I removed it and were not caused by anything I did. Not sure if they are from manufacturing or if something was rubbing on it inside.
  7. Now the baffle and the SDM ring are seperated, clean up any glue residue on the ring. I just used the razor knife.
  8. Now we need to remount the SDM ring. Place the ring back in position, aligning the two rectangular holes with the two gold female SDM contacts. Replace the three silver screws.
  9. Now gently replace the SDM contacts by pressing them slowly back into the female connectors. Replace the two black screws that hold the SDM contact plate in place.
  10. Now insert the cardboard replacement baffle. Dimensions of the original are roughly 30mm wide so you need a cardboard strip a bit smaller than that and long enough to wrap around itself. I just rolled it up slightly tighter than needed, inserted it and let it unroll in place.

  11. The project is done, put the lens on the camera and test. I gave myself nearly a heart attack as mine would no longer auto-focus. I forgot I had the camera in manual focus.


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 for the pictures.... I kind of lost it at step 10:
"Now insert the cardboard replacement baffle. Dimensions of the original are roughly 30mm wide so you need a cardboard strip a bit smaller than that and long enough to wrap around itself. I just rolled it up slightly tighter than needed, inserted it and let it unroll in place."

what is the "cardboard replacement baffle"?
09-28-2016, 01:40 PM   #114
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QuoteOriginally posted by LFLee Quote
what is the "cardboard replacement baffle"?
The metal tube that you removed serves as a light 'baffle' to stop reflections from bouncing around inside the lens. Perhaps it does something else besides but that is beyond me. Anyway, we just removed that in order to open the projection circle to nearly a FF diameter. The "cardboard" replacement baffle is just a sheet of matte, flat black cardboard or heavy paper that is curled up and put back to serve as a replacement for the light baffle function of the tube that was removed.

I am not certain that this is necessary, some people have done the mod without putting a baffle back in. However, if there are stray light reflections bouncing around inside it could produce some flare or reduced contrast in the image. Whether this is the case I do not know for sure. I put one in because I did not want to reopen the lens to put it in later if I needed it. If you have the time you might experiment without it and see if it makes any difference.
09-28-2016, 01:51 PM   #115
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QuoteOriginally posted by jatrax Quote
The metal tube that you removed serves as a light 'baffle' to stop reflections from bouncing around inside the lens. Perhaps it does something else besides but that is beyond me. Anyway, we just removed that in order to open the projection circle to nearly a FF diameter. The "cardboard" replacement baffle is just a sheet of matte, flat black cardboard or heavy paper that is curled up and put back to serve as a replacement for the light baffle function of the tube that was removed.

I am not certain that this is necessary, some people have done the mod without putting a baffle back in. However, if there are stray light reflections bouncing around inside it could produce some flare or reduced contrast in the image. Whether this is the case I do not know for sure. I put one in because I did not want to reopen the lens to put it in later if I needed it. If you have the time you might experiment without it and see if it makes any difference.
I see... so this "baffle" that you put in, where did you get it? is it the original tube with the baffle removed?
also, is it no longer glue to the SDM ring? will it move around in the lens?

Sorry, I am a little confuse....
09-28-2016, 02:00 PM   #116
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QuoteOriginally posted by LFLee Quote
I see... so this "baffle" that you put in, where did you get it? is it the original tube with the baffle removed? also, is it no longer glue to the SDM ring? will it move around in the lens?
The replacement is just a strip of paper. I provided rough dimensions that you could use to make one. You need a strip about 30mm wide and as long as needed to curl into a tube that is the same diameter as the metal tube you took out. Just flat back construction paper. It is not part of the original tube. I kept the original tube intact in the parts box in case I want to reverse this modification.
09-28-2016, 02:18 PM   #117
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QuoteOriginally posted by jatrax Quote
The replacement is just a strip of paper. I provided rough dimensions that you could use to make one. You need a strip about 30mm wide and as long as needed to curl into a tube that is the same diameter as the metal tube you took out. Just flat back construction paper. It is not part of the original tube. I kept the original tube intact in the parts box in case I want to reverse this modification.
ahh... okay. Make sense now. thanks!
09-29-2016, 05:29 AM - 1 Like   #118
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QuoteOriginally posted by LFLee Quote
Sorry, I am a little confuse....
Just to be clear, there are two options for this mod:

1-separate the baffle and tube from the rest of the assembly, and replace the tube by something else (cardboard in this case).

2-grind the baffle and put the tube back in place.

Option 1 is reversible but might add dust to the inside of the lens (from the cardboard), plus the cardboard might not protect some internal elements as well.

Option 2 is permanent (unless you purchase back the tube and baffle, at apparently 25$ USD) but retains the original tube.
09-29-2016, 06:14 AM   #119
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QuoteOriginally posted by bdery Quote
Just to be clear, there are two options for this mod:

1-separate the baffle and tube from the rest of the assembly, and replace the tube by something else (cardboard in this case).

2-grind the baffle and put the tube back in place.

Option 1 is reversible but might add dust to the inside of the lens (from the cardboard), plus the cardboard might not protect some internal elements as well.

Option 2 is permanent (unless you purchase back the tube and baffle, at apparently 25$ USD) but retains the original tube.
And option 3. Remove the baffle and do not replace it.
09-29-2016, 03:44 PM   #120
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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
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