What is causing streaks - top right

NewForestTel · Post by **NewForestTel** » Mon May 23, 2016 5:35 am

I have been learning from this forum over the last 18 months and it is really appreciated. Rik pointed me towards the setup for a full frame camera when using a 160mm tube length with a reversed Raynox 150 lens and a Nikon 10 Plan objective. I have tried that and it works with minimum vignetting.
The attached image is taken with a full frame Canon 1Ds Mk3 and a MPE65mm macro lens at 2.5x. I consistently get streaks in images with this lens and with the microscope objective setup. I have seen an explanation on the forums but cannot find it in a search. Can someone point me in the right direction please?
This is my first post with an image so hopefully I have used the correct procedure

naturepics43 · Post by **naturepics43** » Mon May 23, 2016 7:49 am

Looks like a dirty sensor to me. To verify, take a photo of a clear blue sky or white paper. Set aperture to f/16. Doesn't matter whether the shot is in focus or not. Sensor dirt will show up.

NewForestTel · Post by **NewForestTel** » Mon May 23, 2016 12:24 pm

Thanks for your reply.
Why didn't I think of that? I was thinking that it was something to do with the alignment of camera and subject during stacking.
Best wishes

Pau · Post by **Pau** » Mon May 23, 2016 3:40 pm

I was thinking that it was something to do with the alignment of camera and subject during stacking

The dust trails are due to the actual dust particle on sensor remaining at the same place while the subject magnification changes during the focus stacking. The stacking software adjusts the frame to the subject as it should do so the dust spots moves radially at the frame.
The camera is well aligned: the trails pointing radially certifies it.

NewForestTel · Post by **NewForestTel** » Tue May 24, 2016 1:12 am

Thanks Pau
I have learned something else. It is nice to know that camera alignment is correct and nice to know how you have confirmed it.
Thanks for your reply. Much appreciated