Firstly I assume you have successfully using the PST visually with an eyepiece to see the chromosphere – although solar activity has reduced recently there is a reasonable group at the moment which even produced a flare this afternoon. So if all is OK using the PST visually this indicates that you have correctly wavelength tuned the telescope. If it off-band you will just see a featureless disk a bit like in your image.
The difficult part of using a DSLR or indeed any other type of camera with a PST is obtaining focus. This requires using a Barlow lens (which you appear to be using) or an eyepiece lens to bring the focal plane of the DSLR closer to the PST eyepiece holder. I suggest you perform a Google search using ‘PST and DSLR’ without the quotes. There you will find videos and other information (e.g. https://www.youtube.com/watch?v=RYDzdYkVbGM). Note there is no need to modify the PST eyepiece holder itself.
Yes thanks one of many I saw, I have come back to Imaging, had a PST years ago, sold it and re bought, I did image before, in fact Patrick Moore was a good friend of mine and used two of my images, I did use a Starlight Express camera (I was told they would not work but it did), I have been told that the fact that a DSLR has a IR blocking filter is a problem and I should use a solar camera (I have a Celestron NexImage 5) will be better.
What you see is an Astro Imageing Magnimax, on the camera.