Quote:
Originally Posted by Rich Hibner
fubar2 the pic of the dog was much better than the rest.
here's a lot that you have to factor into sharpness. the diffusion of your screen. the thicker the less sharp it'll be be, but deeper dof and better bokeh.
achromat FL. do you know what yours are?
try to move your achromat further or closer to the screen.
also, the type of lens you're using will increase or decrease sharpness.
i'm guessin you're using both achromats from the binocular. how are you stacking them together? flat sides together or the round side? i used two before and i put the flat sides together and had great results.
you said Dennis made the comment to zoom in closer. I can't argue with him and say that's a bad or good idea, but from my experience, the closer I got, the worse off i was.
i have an achromat you can have. it's 10x at 40mm diameter. to mount it i used step up rings and electrical tape. it's from a good supplier from Italy.
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Hi and thank you!
The FL of the achromat is 77mm. My focus screen is a Canon Ee-A.
I experimented with placement of the achromat and was intrigued at the differences I saw.
Dennis suggested that if I used a recommended 72mm achromat, I would require *less* zoom and thus the distortion might be less. I've been working on that idea with my collection of lenses to try to get an handle on what effect each of them has. My EOS tubes are only about, what, 60mm in diameter, so I can't use a 72mm achromat.
The binocular achromats - yes, I have tried them one at a time and both together. When used together I've had them round side facing based on Daniel's tutorial. Again I had to learn this from this group - I didn't actually know it made a difference such was the state of my knowledge. The binocular lenses seemed to provide the flattest image, but it was overly soft. I believe this to be caused by the very poor state of these lenses. I've been thinking of buying a new pair but decided it would be a better idea to try to understand the nature of the problem.
I very much appreciate the offer for your achromat, but right now I'd be very happy with information. Why is the image out of focus away from center? Why is it this way whether an achromat is present or not? And since it is present with and without an achromat, why does changing the achromat make such a big difference (and I have seen some very substantial differences in my experimentation)?