APS-C Cam on Scope - with or without objective? (1 Viewer)

Hi Guys,
after i tried to make pictures with a cheap 500mm lense and a 500mm Mirror lens which are resulting in poor quality i decided to use a scope. A Swaro or Kowa is a bit to expensive, so i bought a Celestron Regal M2 80. The 20-60X EP comes with a adapter ring for T2 thread.

Now I connected my Samsung NX300 with a NX-T2 adapter direct to the scope. Yes, I can focus, but only the center of the image is sharp. If I zoom in it's looking a bit better. As next step I mounted a 15mm T2 between to bring the sensor more away from the eyepiece. With that I'm "looking" more only to the sharp part of the picture, but the field of view is getting small. The picture quality seems also not to be the best.

So my question: is it better to use the camera with an objective or is the direct connection without also good?
If an obejctive would be helpful makes it sense to try the 16-50mm small lense (150EUR) which is relative new on the market? My try with the old kit-objectives (18-55 and 50-200mm) has shown that i cannot close enough to see the full picture. Or should I better invest the 150EUR for a small digicam instead of the objective where I not know if its working?

Would be nice to get some answers here.

Normally you should use only the camera body when connecting with a T2 adapter. The length of the adapter should set the sensor in the correct place to get "full frame".

However, it sounds like you are getting image distortion from the eyepiece on the scope. One of Opticron's eyepieces (the original SDL) showed a similar issue when used without a field flattener/corrector - sharp central image but soft and distorted all around the edges.

Have you set the zoom on the eyepiece to minimum (20x)? If yes, maybe try zooming up a bit (25x, 30x) to see if that helps.

If you can post some images, that will help to show where the problem lies.

HTH

Cheers, Pete

Okay, I've made some pics perpendicular to the side of the neighbor house.

from left to the right:
1) 20x zoom, camera direct connected with t2-nx adapter
2) 40x zoom, camera direct connected with t2-nx adapter
3) 20x zoom, 15mm t2 elongation between cam and t2-nx adapter
4) 40x zoom, 15mm t2 elongation between cam and t2-nx adapter
5) 20x zoom, picture with 18-55mm objective on camera trough the EP. Objective in 18mm position. (Going to 55mmm will make the visible picture smaller because the length of the objective is increasing..)

What kind of effect are we seeing here? Think the picture with objective is the sharpest overall. Will I get a better view with the 16-50mm which seems to be shorter so that the lens comes closer to the EP? Or is there any chance to get a sharp picture with the direct connection?

The first four images are what you will always see with this method of eyepiece projection. Eyepieces don't project a flat image which is why only the middle area is in focus. Eyepieces are only designed for looking through and the human eye never sees the out of focus area.

There are a few specially designed flat field eyepieces but I've never tried any to see what they are like. I doubt there are any for your scope anyway. Old fashioned orthoscopic eyepieces project a fairly flat field. Magnification with the eyepiece projection method is generally too high though to be of much use for day to day photography.

Photographing through the eyepiece with a lens on the camera is always better than the projection method. A fixed magnification eyepiece will usually produce better results than a zoom eyepiece. A zoom eyepiece has a lot of glass in it so there is more that can go wrong with the image quality. A fixed length eyepiece is much more precise, it's designed to give a good image at one fixed length. You could try projection method with a fixed magnification eyepiece too and it should be better than the zoom with regards to sharpness and how much of the image is out of focus.

Paul.