I cannot figure it out.

[tevans9129]

This is strictly technical, it is not about the subject or composition. It may be necessary to enlarge the image to see the squiggly (??) lines but they are there...many of them.

D800e, PB6 bellows, 20mm AIS f/2.8 reversed, 1/8, f4, ISO 200 using Stackshot and Controlmynikon, 90 slices, 8 microns.

This happens with an old Mamiya 50mm 2.8 also but not quite as pronounced. They are there when the bellows is fully opened or fully closed but not there when I use a Nikon 200 f/4 with a PN-11 extension nor any other combination that I have tried using what is currently available to me.

This is all new to me so what am I doing wrong? Am I trying to use a flawed combination?


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[Beatsy]

The squiggly lines are caused by dust on your sensor. As each frame is realigned for stacking, the dust spots (which are "in focus" in every frame) move slightly and produce the trails you see. Clean the sensor and the problem will be gone.

[tevans9129]

The squiggly lines are caused by dust on your sensor. As each frame is realigned for stacking, the dust spots (which are "in focus" in every frame) move slightly and produce the trails you see. Clean the sensor and the problem will be gone.

Thanks for the suggestion Beatsy, it only recently came back from Nikon and I am very careful with it but I cleaned it and will test it tomorrow. Would you say that it only shows up on the reverse lens setup because of the higher magnification? Thanks again.

[rjlittlefield]

Would you say that it only shows up on the reverse lens setup because of the higher magnification?

Yes. At higher magnification you probably have a narrower effective aperture, which makes the dust spots more sharply defined. In addition, the dust trails essentially measure how much the subject moves around in the frame as you step focus. Whatever lateral play there is in your focus stepping system, higher magnification will result in more movement of the image and hence longer trails.

You can confirm that this problem is due to dust by checking your original source frames. What you'll find is that each source frame contains a single small black dot corresponding to each trail in the stacked composite image.

--Rik

[microman]

When you change the extension on the bellows the dust gets pushed around and it will get on the sensor. Expecially on a horizontal setup. Its not a huge problem if the bellows is in a set extension but if you extend and contract the bellows while camera is mounted the dust will get on the sensor for sure.

I had the same problem. Some use a teleconverter between to shield the sensor from dust. I ahve been thinking of using a clear filter but it might get reflections.

[tevans9129]

Thanks to all for the comments...yep, it was dust on the sensor. Perhaps it was due to the old PB6 bellows as the D800e had recently returned from Nikon and the problem had not been evident until I began using the PB6. All is well now, thanks again. Ted