2X teleconvertors with telescopes,how is image quality? (1 Viewer)

C

cango

Well-known member

• Aug 21, 2012

• #21

Very neat and professional looking!

 

DanC.Licks

AKA Daniel Bradley

• Aug 21, 2012

• #22

Thanks, Carlos.
There is a Sunagor coming up in 4 1/2 days on British ebay. Let me know if you want to bid on it so we don't bid against each other. There are lots of old Canon 100-200s around, and so far it seems to be pretty good.

 

Tord

Well-known member

• Aug 21, 2012

• #23

DanC.Licks said:

The old Nikon 14mm and 25mm extension tubes arrived, and it was a snap mounting the Canon TN inside the 14mm. I stripped out the guts of the tubes, trimmed down the TN mount a little on my mini lathe, and screwed it in. Works fine and is much closer to the body than just stuffing it inside the T2 tube. It gives 1.55x, and 2x with the 25mm tube in between.

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The result looks very professional, I am impressed. Is the TN lens symmetrical by the way, or in what direction should it be fitted?

 

DanC.Licks

AKA Daniel Bradley

• Aug 22, 2012

• #24

I don't know, but Paul might. I put it in "right side up". Easy enough to turn around, so some day when I don't have anything to do I will give it a try.

 

Tord

Well-known member

• Aug 22, 2012

• #25

I meant symmetrical with respect to optical plane, i.e. if concavity/convexity is same on both sides of the lens.

 

P

Paul Corfield

Well-known member

• Aug 22, 2012

• #26

Tord said:

I meant symmetrical with respect to optical plane, i.e. if concavity/convexity is same on both sides of the lens.

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I think as a rule both sides are slightly concave and some are flat on the front while concave on the back. I found they can be mounted either way round without affecting the photo quality. You can do that with barlows too. The TN's are quite similar to barlows in their optical design and they can be used as very good barlow alternatives on the telescope with an eyepiece as long as you can mount them ok.

Paul.

 

DanC.Licks

AKA Daniel Bradley

• Aug 22, 2012

• #27

I understood you, Tord. As I said, Paul is the man who would know. Have to give it a try the other way around. Just from looking at it it looks symetrical, but I really don't know enough about it.