Would this work with the 550mm fresnel?
http://cgi.ebay.com/AMERICAN-OPTICAL-22-TR...1QQcmdZViewItem
My guess would be that EFL is the "effective focal length". And 22" equates to about 558.8mm. 3dlens.com has the 550mm fresnels. So if I'm understanding this all right, I want the triplet focal length to match the fresnel focal length as much as possible. And this should be a good match.
I missed out on the last batch of LL PRO Triplets, and I can't seem to find any other sources out there. So I'm hoping this triplet on eBay will work for my 1080p setup.
Full Version: Triplet On Ebay
QUOTE (orificium @ Feb 20 2007, 08:01 PM) 
Would this work with the 550mm fresnel?
http://cgi.ebay.com/AMERICAN-OPTICAL-22-TR...1QQcmdZViewItem
My guess would be that EFL is the "effective focal length". And 22" equates to about 558.8mm. 3dlens.com has the 550mm fresnels. So if I'm understanding this all right, I want the triplet focal length to match the fresnel focal length as much as possible. And this should be a good match.
I missed out on the last batch of LL PRO Triplets, and I can't seem to find any other sources out there. So I'm hoping this triplet on eBay will work for my 1080p setup.
http://cgi.ebay.com/AMERICAN-OPTICAL-22-TR...1QQcmdZViewItem
My guess would be that EFL is the "effective focal length". And 22" equates to about 558.8mm. 3dlens.com has the 550mm fresnels. So if I'm understanding this all right, I want the triplet focal length to match the fresnel focal length as much as possible. And this should be a good match.
I missed out on the last batch of LL PRO Triplets, and I can't seem to find any other sources out there. So I'm hoping this triplet on eBay will work for my 1080p setup.
Use the LL pro fresnel at 650mm. You want to fill the back of the triplet with light. If it's at the focal length the light will be focused to a tiny point. Which is not what you want.
it's definetely not good. 
. Front fresnel"s EFL should be bigger than LCD distance - Fresnel gap, otherwise the triplet cannot focus on
. Front fresnel"s EFL should be bigger than LCD distance - Fresnel gap, otherwise the triplet cannot focus on
QUOTE (orificium @ Feb 20 2007, 07:01 PM)
Would this work with the 550mm fresnel?
http://cgi.ebay.com/AMERICAN-OPTICAL-22-TR...1QQcmdZViewItem
My guess would be that EFL is the "effective focal length". And 22" equates to about 558.8mm. 3dlens.com has the 550mm fresnels. So if I'm understanding this all right, I want the triplet focal length to match the fresnel focal length as much as possible. And this should be a good match.
I missed out on the last batch of LL PRO Triplets, and I can't seem to find any other sources out there. So I'm hoping this triplet on eBay will work for my 1080p setup.
http://cgi.ebay.com/AMERICAN-OPTICAL-22-TR...1QQcmdZViewItem
My guess would be that EFL is the "effective focal length". And 22" equates to about 558.8mm. 3dlens.com has the 550mm fresnels. So if I'm understanding this all right, I want the triplet focal length to match the fresnel focal length as much as possible. And this should be a good match.
I missed out on the last batch of LL PRO Triplets, and I can't seem to find any other sources out there. So I'm hoping this triplet on eBay will work for my 1080p setup.
I would also be interested in what its field size is, since they don't all take in an image wide enough. I would instead check the trading post for a Beseler lens or wait for a Pro - those would do the job for sure. If it doesn't give any field image sizing, I would not buy it.
QUOTE (sfij @ Feb 20 2007, 05:39 PM)
it's definetely not good. . Front fresnel"s EFL should be bigger than LCD distance - Fresnel gap, otherwise the triplet cannot focus on
. Front fresnel"s EFL should be bigger than LCD distance - Fresnel gap, otherwise the triplet cannot focus onWhy should the front fresnel's (collector?) FL be larger than the LCD distance? How does the light path change making it not focus correctly? Are you saying that (LCD distance) - (Fresnel gap) < (collector fl)?
That being true, exactly how does the layout work? I followed the layout steps here and I came up with a LCD distance that was too large as you describe it.
QUOTE (tkal @ Feb 21 2007, 04:51 AM)
Why should the front fresnel's (collector?) FL be larger than the LCD distance? How does the light path change making it not focus correctly? Are you saying that (LCD distance) - (Fresnel gap) < (collector fl)?
If the light coming from the bulb hits the aperture of the triplet unfocused, then you won't get a decent projection. - actually will some kinda, but with a very big light loss.
So you are saying that the triplet lens should be before the focus point of the collector?
Any idea how the calculation is worked out on the focal calc II? It is the last piece of the puzzle for me.
Any idea how the calculation is worked out on the focal calc II? It is the last piece of the puzzle for me.
QUOTE (tkal @ Feb 22 2007, 05:03 AM)
So you are saying that the triplet lens should be before the focus point of the collector?
Any idea how the calculation is worked out on the focal calc II? It is the last piece of the puzzle for me.
Any idea how the calculation is worked out on the focal calc II? It is the last piece of the puzzle for me.
Ideally, The focal point of the front FL should be in the centre of the triplet. This is the main role of the front FL: focus the light into the triplet's aperture.
focal calc ii is taking into account triplet's beahviour only. If you go split, then it computes with the virtual image of the LCD, since in case of split the triplet can project the virtual image only.
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