Eyepiece Projection with the Olympus E-series cameras (1 Viewer)

[erniehatt]

Eyepiece Projection, someone already started a thread about this,
but deserted it after two posts, why is a puzzle to me.
I have had success in the past using the Canon A640, and the Panosonic FZ50.
So this is the next step up since I got into the Olympus E series cameras.
I had difficulties using them at Prime Focus, and could not work out why,
but since playing with this system I am beginning to work out why.
I have a number of two inch eyepieces namely 26, 30,40, and a 75mm, the first three are ok, but need so much extension to get it down to 10meter near focus,
it starts to become impracticle, the image below was taken from 10m with the 40mm eyepiece, the subject is only 3" from beak to tail, the overall length between the camera body and the diagonal is 200mm, with the 75mm I had to add another 3" and still could not get focus, so that one is out. so it looks as though I will have to buy another eyepiece say a 50mm, I am just a bit worried as to whether it will be a waste.
I have got an adapter to be able use the 1.25 eyepieces, but these will
probabley give me the same problems.The more extension you use the less light that gets to the censor.
It seems that the cause of the problems is th 2X crop factor that the E-series has, Ive been told that my WIlliams Optics Scope at 545mm, now becomes 1090mm,
so the 600mm Skywatcher will be next to useless.
Anybody have any idea how a focal lenght reducer would go. Ernie

 

[Paul Corfield]

The only reason I "deserted" the thread as you put it was because I couldn't beat my usual prime focus methods for overall image quality. Plus I had run out of eyepieces to experiment with so there's no point just posting images over and over with the same eyepieces. Your own posted image has all the same optical problems that I had with my own projected images. With what's possible with an astro telescope it's not a step forward but a step backwards in terms of image quality and it's more awkward because you need a 45° or 90° erecting prism.

Paul.

 

[erniehatt]

Ok Paul,point taken, agree its not the best solution, but it does produce good indentification images, with the 90 degree diagonal there appears to be less strain on the focuser, than I expierianced with prime focus, the extra long extensions seemed to pull down on the focuser much more. The image shown shows far less edge softness than the ones you posted. Ernie

 

[Paul Corfield]

The lack of edge softness is probably down to the Olympus having a smaller sensor. I can eliminate edge softness by moving the eyepiece about 5mm to 10mm further away from the sensor on the Canon. This means by the time the projected image has reached the sensor the image circle is bigger and only the centre and sharpest part of the image is kept.

Paul.

 

[cango]

"had difficulties using them at Prime Focus, and could not work out why,"

I use an E-3 in prime focus with a 80mm extension tube, with no problem. Please let me know if there is somthing I could help you with.
(tried eyepiece proj, but haven't had any good light here (sweden/stockholm) to really test it, but due to the 90 diagonal it's quite a pain. I have a 30mm superview (telescope service) )

 

[erniehatt]

The lack of edge softness is probably down to the Olympus having a smaller sensor. I can eliminate edge softness by moving the eyepiece about 5mm to 10mm further away from the sensor on the Canon. This means by the time the projected image has reached the sensor the image circle is bigger and only the centre and sharpest part of the image is kept.

Thanks Paul, that has thrown a little light into my shadow areas.


I use an E-3 in prime focus with a 80mm extension tube, with no problem. Please let me know if there is somthing I could help you with.
(tried eyepiece proj, but haven't had any good light here (sweden/stockholm) to really test it, but due to the 90 diagonal it's quite a pain. I have a 30mm superview (telescope service) )

Cango, thanks for the reply here, I appreciate any help that comes my way.
I had another play around this morning with prime focus, using the Williams Zenithstar 80mm ED Apo scope, and the E410, I am using this instead of the E520 untill I am happy with the setup.
I attached a 2X barlow to the end of the 2" to T2 adapter fitted directly into the camera, this gave me an extension of about 2. 1/2" i added to this a Williams extender, which gave me an overall extension after minor adjustments of 5. 1/2". Near focus measurement was approx 7 1/2 meters. The image of my test piece was at 10m shutter speed was 1/320s, ISO 400, there is a little noise in there but not enough to worry about only adjustment was resizing. Ernie