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11-27-2010, 09:54 PM   #1
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Made my own extension tube

But having a problem now. When I first made it, it was working great. Then yesterday and today while shooting my usual macro shots of flowers, I noticed a look to the flowers like their taken at the end of a tunnel. Black circle around the outside of the frame. What causes this?

11-27-2010, 11:23 PM   #2
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First guess: something moved?

What lens, what aperture, how much extension, what diameter is the tube, is lens hood appropriate length/width, photos of home built rig, etc.?
11-28-2010, 12:03 AM   #3
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That was my first thought, that something moved. But there really isnt' any moving parts, per se.

I used a toilet tissue roll which I first cut in half, then both halves, I cut in half lengthwise.

I measured out to fit 52mm. Then using black electricians tape, I wrapped the three sections together, forming the tube. I wrapped the outside and inside of the tube, so it's black outside and inside. So now I have a 2 inch long tube. On one end I taped a step up ring so I could attach the tube to my lens I am using, Pentax 18-55mm DA L ll. On the other end I taped my closeup lenses, screwed together, to the tube.

No lens hood.

The first was taken two days ago. As you can see there is no black ring on the outside of the photo and I didn't crop this, it's as shot:


This one was taken today, same no crop, just as I shot it.


I'll see if I can get a photo of the tube. Right now it's apart cause I was trying to figure out what moved.
11-28-2010, 12:22 AM   #4
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Here is a photo of the homemade tube:



11-28-2010, 12:34 AM   #5
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QuoteOriginally posted by photolady Quote
On one end I taped a step up ring so I could attach the tube to my lens I am using, Pentax 18-55mm DA L ll. On the other end I taped my closeup lenses, screwed together, to the tube.
Lenses on both ends of the tube isn't how it's meant to work. The tube should be mounted between the camera body and the normal lens. No additional close-up lenses or other optics required.
11-28-2010, 01:01 AM   #6
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QuoteOriginally posted by openyourap Quote
Lenses on both ends of the tube isn't how it's meant to work. The tube should be mounted between the camera body and the normal lens. No additional close-up lenses or other optics required.
Oh, that's why it was working to start with through 26 day of photos, but because I didn't do it the way you said, it's stopped working. HUH? That doesn't make sense. My question was why am I now getting a black ring, when two days ago with this rig, I wasn't. And my photos in my album titled Single in November prove it's working.

Last edited by photolady95; 11-28-2010 at 01:14 AM.
11-28-2010, 02:13 AM   #7
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aperture change

did you change the aperture of the taking lens. If you did this may have caused the vignetting. You are less likely to vignette with a wider, or faster aperture, but if you closed down in the search for more depth of field, this may have caused the problem. HTH
11-28-2010, 09:02 AM   #8
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That's it. When the top flower was shot I was using f22, the bottom flower at f27. Thanks.

I'll just drop back down to f22 or lower. Depending of course on what I'm shooting.

11-28-2010, 09:08 AM   #9
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Another thing: this might work ok with longer focal lengths but not the shorter ones as these have a wider FOV which is blocked by the tube.
11-28-2010, 10:05 AM   #10
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Thanks jolepp. I might try this setup on my Sigma lens after the SiN is over with.
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