Hello..i really have a simple question. I dont know if it is possible but here goes....I was wondering if the size of the 500mm objective is the same of the 345mm objective. I only have about 10 feet to the wall.Was wondering wich is the best. I have the 500mm...but could buy the 345mm.

I have lcd 15 inches full hd

400 watt hqi

Fresnel 220 mm and 630 mm


Thanks in advance...i have all the parts ...already done some tests ...hope i can put my results in the forum

You might want to download the focal calc program. It will give you screen sizes and distances based on your focal lens and fresnels.

Using your current equipment 550 objective and 630 fresnel you would get a 79" diagonal screen
Using a 345 objective you would need to replace your front fresnel with a 317 mm s15 fresnel (or one slightly larger). This would give you 125' diagonal screen at 10'.

It's all in the focal calculater. Check out this link. It has everything you need to get started. Help Me Help You, Tips to getting the right answer fast!

Xenotox has already been advised of what parts might be best for his build. All he needs to do is check out his older threads (like this one).

Xenotox, it would be best if you kept all of your questions in a single thread. This would make it easier for us to respond appropriately without repeating ourselves. It would also save us from having to go into every one of your previous threads to find out other information concerning your build.

You are using a 15.4 LCD. It's important to state this, because parts change when switching from a regular 15" LCD to a 15.4 widescreen LCD. You've been advised that you should not use the 345mm triplet with a 630mm rear fresnel. You don't say where you're buying your parts, but you want to make sure the fresnels you buy are larger (height x width) than your LCD.

Good luck on your build.

I am buying my parts diy beamer...less shipping costs. My question is if the 345mm lens and the 500mm have the same diameter to put in the box??


Thanks in advance

I suggest you contact the vendor you're going to purchase the parts from and ask them these types of questions.