Thorlabs Achromats doublets

Yes your tube/fixture/casing/ whatever. You'll need to start with the size, then you'll need to know how much magnification.
 
How does one go about finding the correct magnification? Say the image size is
34x22, not quite 36x24, inside a 52mm tube?
 
We have achromatic lenses that can be paired to have a high magnification like the +7 Achro Diopter. Diopter is the inverse of focal length (1/meters). So a 7 Diopters corresponds to a 142.9mm focal length.

That's a quote from someone over at Edmund optics. And they're comparing that to the Century Optics +7.
Hope that helps. It answered my question about an achromat.
 
Cool. That makes finding the right achromat easier but, I guess my question
still stands... is it really necessary to use a +7 achro for a 36x24mm size on
ground glass?
 
Lens

Lens

Well, how did it go and what were the results?

Which lens did you get and from where?

Do you have part numbers for the lens?

I'm interested in putting together the Ed35 V2 but would like to low the cost of the lens.

Sincerely,
James Cori:dankk2:
 
I never bought one from them. I did buy one from Wanye Kinney. He has a spectacular Achromat. I hope he stills sells the one he sold to me, I'd like to buy another one. I know he's rolling out an HD one soon.
 
Hello,

We will soon be making the SGpro's r2 HD achromat available as a seperate item for £99 ($194). It is be in a black anodized 72mm threaded ring (male and female) and fully Anti reflection coated. It is the same achromat used in the SGpro r2 units, and has been tested with the HVX200 and HD100. Its strength is roughly +8 (little stronger the the CO +7)
 
Be careful on direct focal length vs diopter ratings....a rough guide is indeed 1000/diopter rating, however the equivalent actual measured focal length will vary. We now have very high quality 72mm HD achromats made in several strengths, depending on intended use. Although achromats do reduce CA, they aren't perfect, so max image quality with respect to both spherical and chromatic aberration is achieved using the minimum strength achromat required for your application. Keep in mind too, that tolerances on the outer 10% of most lenses are not within spec...meaning using a 72mm achromat will guarantee you are using the sweet spot of the lens.

Pick up a cheap set of close up macro filters from ebay, in 58 or 72mm flavours (under $50). You can use these stacked in different configs to estimate your needs...then get the achromat required after.
 
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