DA* 60-250 mod for FF

bdery · 01-03-2017, 12:15 PM

Originally posted by Jacquot

Is anyone offering to do this modification?

I wouldn't mind doing it for others. I haven't done my lens yet, but after reading what others have posted, I don't foresee any problem. I modified a Vivitar series 1 70-210 in the past (the aperture tab protection was too large for DSLRs).

**jbondo** · 01-08-2017, 04:00 PM

I've started my project on this. Made the "Before" shots and am starting to shoot the video of the procedure. While making the "Before" shots, noted the following: Worst vignette case is 250mm at infinity. To my surprise, focusing closely at 250mm lets significantly more light in at the center of the frame than when focused at infinity.

I'll post the video and matched Before/After photos when project is done. It would be a piece of cake to just enlarge the diameter of the opening on my lathe, but I am thinking I want to use the end-mill to mill a rectangular opening because I want the baffle to still function optimally. I'm going to make a template/fixture for the end-mill machining. I've been unusually busy with work so it may take me another week. I'll decide about offering this as a service when done.

joergens.mi · 01-08-2017, 04:16 PM

make the rectangular window a little bit wider, exactly cut tmax 3.2 window seems to vignette.

**jbondo** · 01-08-2017, 09:25 PM - **5 Likes**

OK, made prototype jig to do more of these and did the initial mod on mine. I'll have to wait for daylight clear skies to see if got the geometry right or if it will need refinement.
(I purposefully did it without separating the SDM contact ring from the tube. - if I got it right, I'll use the SDM contact ring to create a key on the jig, so all future ones will be identical.)

Edit: I removed photo with incorrect alignment so as not to confuse anyone. See my later post with the correct alignment.

Attached Images

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Last edited by jbondo; 02-05-2017 at 02:04 PM. Reason: Removed photo of innacurate alignment.

**mattb123** · 01-08-2017, 09:32 PM - **1 Like**

Originally posted by jbondo

OK, made prototype jig to do more of these and did the initial mod on mine. I'll have to wait for daylight clear skies to see if got the geometry right or if it will need refinement.
(I purposefully did it without separating the SDM contact ring from the tube. - if I got it right, I'll use the SDM contact ring to create a key on the jig, so all future ones will be identical.)

That looks great. I wanted to do that initially but just took an easier route. I don't have precise enough tools.

**UncleVanya** · 01-08-2017, 10:01 PM

Originally posted by jbondo

OK, made prototype jig to do more of these and did the initial mod on mine. I'll have to wait for daylight clear skies to see if got the geometry right or if it will need refinement.
(I purposefully did it without separating the SDM contact ring from the tube. - if I got it right, I'll use the SDM contact ring to create a key on the jig, so all future ones will be identical.)

That looks fantastic!

joergens.mi · 01-08-2017, 11:45 PM

That looks excellent, mine is nearly the same after the refinement.

Cyril_K5 · 01-09-2017, 04:22 AM

Originally posted by jbondo

I've started my project on this. Made the "Before" shots and am starting to shoot the video of the procedure. While making the "Before" shots, noted the following: Worst vignette case is 250mm at infinity. To my surprise, focusing closely at 250mm lets significantly more light in at the center of the frame than when focused at infinity.

I'll post the video and matched Before/After photos when project is done. It would be a piece of cake to just enlarge the diameter of the opening on my lathe, but I am thinking I want to use the end-mill to mill a rectangular opening because I want the baffle to still function optimally. I'm going to make a template/fixture for the end-mill machining. I've been unusually busy with work so it may take me another week. I'll decide about offering this as a service when done.

Where are you based? I would be very interested by your services

**Jacquot** · 01-09-2017, 04:27 AM

Nice work jbondo... Looking forward to your test!

bdery · 01-09-2017, 05:47 AM

Originally posted by joergens.mi

mine is nearly the same after the refinement.

Nearly? Other posters suggest there is no difference.

Originally posted by jbondo

OK, made prototype jig to do more of these and did the initial mod on mine.

I can't wait to see your comparison, that looks impressive!

joergens.mi · 01-09-2017, 06:48 AM

Originally posted by bdery

Nearly? Other posters suggest there is no difference.

First I made a cut to the maximum 2:3 rectangle possible, it was much better than before

, but there was a heavy vignetting, then I expanded the field a little bit to all four sides and it improved heavily.

ChatMechant · 01-10-2017, 07:04 PM

Originally posted by jbondo

OK, made prototype jig to do more of these and did the initial mod on mine. I'll have to wait for daylight clear skies to see if got the geometry right or if it will need refinement.
(I purposefully did it without separating the SDM contact ring from the tube. - if I got it right, I'll use the SDM contact ring to create a key on the jig, so all future ones will be identical.)

That looks great! Thanks for sharing. I will likely be attempting a hack-job version.

**jbondo** · 01-11-2017, 03:57 PM

ok, folks, don't use my previous photo as a reference for the rotation angle to cut yours. I had the wrong rotation. The good news is that I only have to re-glue the tube to the SDM contact ring at the correct angle and it should be good.
I'm still busy with work and the band so it may be a few more days before I post. Thanks for your patience.

joergens.mi · 01-13-2017, 10:33 AM - **1 Like**

this one works and is correctly aligned.

**jbondo** · 01-29-2017, 07:03 PM - **3 Likes**

Thanks for your patience. Been busy with work and the bands. Re-aligning the barrel ended up being trivial compared to cutting it. Used an old film body to confirm exact alignment. (Now I can key the fixture.)

Here are the before and after shots under very carefully controlled conditions.
60-250 mod - Vignette before and after shots.

01-08-2017, 04:00 PM	#137
jbondo Loyal Site Supportaxian Join Date: Sep 2013 Location: Texas Photos: Albums Posts: 503	I've started my project on this. Made the "Before" shots and am starting to shoot the video of the procedure. While making the "Before" shots, noted the following: Worst vignette case is 250mm at infinity. To my surprise, focusing closely at 250mm lets significantly more light in at the center of the frame than when focused at infinity. I'll post the video and matched Before/After photos when project is done. It would be a piece of cake to just enlarge the diameter of the opening on my lathe, but I am thinking I want to use the end-mill to mill a rectangular opening because I want the baffle to still function optimally. I'm going to make a template/fixture for the end-mill machining. I've been unusually busy with work so it may take me another week. I'll decide about offering this as a service when done. Last edited by jbondo; 01-08-2017 at 04:57 PM.

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01-03-2017, 12:15 PM	#136
bdery Pentaxian Join Date: Mar 2008 Location: Quebec city, Canada Photos: Gallery Posts: 9,362	Originally posted by Jacquot Is anyone offering to do this modification? I wouldn't mind doing it for others. I haven't done my lens yet, but after reading what others have posted, I don't foresee any problem. I modified a Vivitar series 1 70-210 in the past (the aperture tab protection was too large for DSLRs).

01-08-2017, 04:16 PM	#138
joergens.mi Veteran Member Join Date: Jan 2012 Posts: 408	make the rectangular window a little bit wider, exactly cut tmax 3.2 window seems to vignette.

01-08-2017, 09:32 PM - 1 Like	#140
mattb123 Site Supporter Join Date: Apr 2010 Location: Colorado High Country Photos: Gallery Posts: 10,873	Originally posted by jbondo OK, made prototype jig to do more of these and did the initial mod on mine. I'll have to wait for daylight clear skies to see if got the geometry right or if it will need refinement. (I purposefully did it without separating the SDM contact ring from the tube. - if I got it right, I'll use the SDM contact ring to create a key on the jig, so all future ones will be identical.) That looks great. I wanted to do that initially but just took an easier route. I don't have precise enough tools.

01-08-2017, 10:01 PM	#141
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,458	Originally posted by jbondo OK, made prototype jig to do more of these and did the initial mod on mine. I'll have to wait for daylight clear skies to see if got the geometry right or if it will need refinement. (I purposefully did it without separating the SDM contact ring from the tube. - if I got it right, I'll use the SDM contact ring to create a key on the jig, so all future ones will be identical.) That looks fantastic!

01-08-2017, 11:45 PM	#142
joergens.mi Veteran Member Join Date: Jan 2012 Posts: 408	That looks excellent, mine is nearly the same after the refinement.

01-09-2017, 04:22 AM	#143
Cyril_K5 Forum Member Join Date: Jun 2013 Posts: 73	Originally posted by jbondo I've started my project on this. Made the "Before" shots and am starting to shoot the video of the procedure. While making the "Before" shots, noted the following: Worst vignette case is 250mm at infinity. To my surprise, focusing closely at 250mm lets significantly more light in at the center of the frame than when focused at infinity. I'll post the video and matched Before/After photos when project is done. It would be a piece of cake to just enlarge the diameter of the opening on my lathe, but I am thinking I want to use the end-mill to mill a rectangular opening because I want the baffle to still function optimally. I'm going to make a template/fixture for the end-mill machining. I've been unusually busy with work so it may take me another week. I'll decide about offering this as a service when done. Where are you based? I would be very interested by your services

01-09-2017, 04:27 AM	#144
Jacquot Loyal Site Supporter Join Date: May 2008 Location: Sun City Center, FL Photos: Gallery Posts: 2,544	Nice work jbondo... Looking forward to your test!

01-09-2017, 05:47 AM	#145
bdery Pentaxian Join Date: Mar 2008 Location: Quebec city, Canada Photos: Gallery Posts: 9,362	Originally posted by joergens.mi mine is nearly the same after the refinement. Nearly? Other posters suggest there is no difference. Originally posted by jbondo OK, made prototype jig to do more of these and did the initial mod on mine. I can't wait to see your comparison, that looks impressive!

01-09-2017, 06:48 AM	#146
joergens.mi Veteran Member Join Date: Jan 2012 Posts: 408	Originally posted by bdery Nearly? Other posters suggest there is no difference. First I made a cut to the maximum 2:3 rectangle possible, it was much better than before , but there was a heavy vignetting, then I expanded the field a little bit to all four sides and it improved heavily.

01-10-2017, 07:04 PM	#147
ChatMechant Pentaxian Join Date: Jun 2010 Location: Matsuyama Photos: Gallery Posts: 1,284	Originally posted by jbondo OK, made prototype jig to do more of these and did the initial mod on mine. I'll have to wait for daylight clear skies to see if got the geometry right or if it will need refinement. (I purposefully did it without separating the SDM contact ring from the tube. - if I got it right, I'll use the SDM contact ring to create a key on the jig, so all future ones will be identical.) That looks great! Thanks for sharing. I will likely be attempting a hack-job version.

01-11-2017, 03:57 PM	#148
jbondo Loyal Site Supportaxian Join Date: Sep 2013 Location: Texas Photos: Albums Posts: 503	ok, folks, don't use my previous photo as a reference for the rotation angle to cut yours. I had the wrong rotation. The good news is that I only have to re-glue the tube to the SDM contact ring at the correct angle and it should be good. I'm still busy with work and the band so it may be a few more days before I post. Thanks for your patience.

01-29-2017, 07:03 PM - 3 Likes	#150
jbondo Loyal Site Supportaxian Join Date: Sep 2013 Location: Texas Photos: Albums Posts: 503	Thanks for your patience. Been busy with work and the bands. Re-aligning the barrel ended up being trivial compared to cutting it. Used an old film body to confirm exact alignment. (Now I can key the fixture.) Here are the before and after shots under very carefully controlled conditions. 60-250 mod - Vignette before and after shots.