You have to remember, 650,700 and 750 have already been proven to be too long (via lumenlab). Please! 550 or 600 MAX!
I would prefer 550.
Hey Rox, you build a projector yet that your recommending focal lengths?
I would prefer 550.
Hey Rox, you build a projector yet that your recommending focal lengths?
Size is critical
I agree that either 550 or 600 mm focal length can work very well in an unsplit design. But a split design puts the field fresnel at least 50 mm closer to the projection lens. I think a 550 mm fl fresnel would work much better in a split design for this reason.
But Rox is absolutely right that either one will work with a little bit of lamp adjustment. There are some problems with using the 450 mm fl triplet still being sold by one or two DIY projector stores, but there are other lenses that can be used. It is also possible that the supplier could change the design of this triplet to give our community a lens with a wider field. In any case, 450 mm fl is about right for a long throw projection lens.
The most important feature of a new fresnel will be the size: It has to be large enough so that everyone building a long throw large format projector can use it. If you make it too small, then 3dlens will lose some of the potential customers.
I agree that either 550 or 600 mm focal length can work very well in an unsplit design. But a split design puts the field fresnel at least 50 mm closer to the projection lens. I think a 550 mm fl fresnel would work much better in a split design for this reason.
But Rox is absolutely right that either one will work with a little bit of lamp adjustment. There are some problems with using the 450 mm fl triplet still being sold by one or two DIY projector stores, but there are other lenses that can be used. It is also possible that the supplier could change the design of this triplet to give our community a lens with a wider field. In any case, 450 mm fl is about right for a long throw projection lens.
The most important feature of a new fresnel will be the size: It has to be large enough so that everyone building a long throw large format projector can use it. If you make it too small, then 3dlens will lose some of the potential customers.
OK!
To satisfy with everyone in building 15", 17" and 19", I decide to change the size to 400mm x 310mm. I think the size is big enough for everybody.
What focal length is good for the size? 550mm or 600mm?
To satisfy with everyone in building 15", 17" and 19", I decide to change the size to 400mm x 310mm. I think the size is big enough for everybody.
What focal length is good for the size? 550mm or 600mm?
Re: Size is critical
Sincerelly i doubt it. (it would bee great if they could do it, but if they change the FOV angle, then i guess they need to change the EFL also( so they keep the same housing) so it won´t be 450mmEFL.
JCB; Having the enough knowledge of projectors design should be just enought to understand what elements are needed there. Don´t you agree? Didn´t you told me you had 55cm separation between lcd and triplet's rear? (this means 55+2+6=63cm field fresnell works fine on your setup) but maybe you plan on larger throws for future designs...
I don´t care being 550mm fresnell, it will work nice for me. (but i think it has sense all this i am saying)
Guy Grotke said:
Sincerelly i doubt it. (it would bee great if they could do it, but if they change the FOV angle, then i guess they need to change the EFL also( so they keep the same housing) so it won´t be 450mmEFL.
JCB; Having the enough knowledge of projectors design should be just enought to understand what elements are needed there. Don´t you agree? Didn´t you told me you had 55cm separation between lcd and triplet's rear? (this means 55+2+6=63cm field fresnell works fine on your setup) but maybe you plan on larger throws for future designs...
I don´t care being 550mm fresnell, it will work nice for me. (but i think it has sense all this i am saying)
jimhuang: how long would you expect it to take to get this future item in stock when you decide on the specs. I want to be the first to order!
Jimhuang,
please let me know when the panels are available for sale. Iwill need one for a 15.4" widescreen panel.
Thank you.
please let me know when the panels are available for sale. Iwill need one for a 15.4" widescreen panel.
Thank you.
550mm please
I'm splitting for keystoning and 550mm would be perfect for me. +600mm will also work but i don't like the uglier longer box
I'm splitting for keystoning and 550mm would be perfect for me. +600mm will also work but i don't like the uglier longer box
I would say 550 is a great focal length for the fresnel. Higher than this will work but is not necessary at all.
With 550 you can use 15, 17, and even 19 inch screens if the fresnels are large enough. So for 3Dlens producing one single 550 especially for DIY projectors will be the best option.
With 550 you can use 15, 17, and even 19 inch screens if the fresnels are large enough. So for 3Dlens producing one single 550 especially for DIY projectors will be the best option.
Update on the new fresnel. 3dlens.com has finalized the specs. It will be 400mm x 320mm in size with a focal length of 550mm. It is now in the design process.
Rox, there is no word yet on the time frame. Hopefully all will go well with the development and we'll have a lens in less then 2 months.
I'd really like to get my hands on the new fresnels. I hope the delay is from some perfectionist hard at work...
Time passes...
Time passes...
Once they settled on the size and focal (which they have) they should have the first batch run off within 3-6 weeks. And as I'm sure they'll run off quite a few I'm willing to guess more along the lines of 6 weeks from the time they settled on the design.
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