Thanks to this form just posted a video of what I discovered when calculating

Lasers
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Thanks to this form just posted a video of what I discovered when calculating the focal distance of my lens and must say it was a bit of surprise! Later this afternoon will test it out and see if what I discover was correct and will post an another video! Thanks again to all for your help!
https://www.youtube.com/attribution_link?a=GNTOncaTm4M&u=%2Fplaylist%3Flist%3DPLInTrkIbj69kPO_UP81yxX-xov4SVyPlD

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Hi diy, don’t forget to take into account the distance between the light source and lens when calculating the focal length of the lens using the method you show. A true reading of focal length will only ever be obtained with an object at infinite distance from the lens. if the lamp is less than 1 meter from the lens then the result will be a few percent off. Here is a handy online calculator I found which shows the theory and can be used to calculate results too. http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/image.html
Kind regards, David.

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Many thanks David, the light source in this case was an easy 4 to 5 feet away. Also understand that I am focusing visible light too so I am simply guessitmating anyway. It was a fun experiment all Marc G’s fault as he gave me this link :slight_smile:

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@DIY3DTECH.com Your last posts have been block by the spam filter.
Please, to keep this page readable for all, do not overcharge it with link to your videos (including adds), I don’t mind a link to your channel once for all. Hopefully you will understand.

I try to limit the number of posts for clarity sake, don’t see here a censure, you are welcome to post and don’t hesitated to comments.

Thank you.

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Stephanie thank you for the feedback not sure what you mean when say page (I am a bit of Google+ novice) as I only see the link to YouTube and not body. Is there a better way to share as the only way I know is from the “playlist” share on YouTube. Thanks again for the feedback!