Focusing Problems with B&H 346A

Post by **videoguy326** » Mon Sep 27, 2004 2:30 am

I bought a Bell & Howell Super 8 projector model 346A off of eBay. I'm having trouble focusing the picture though. I think it has something to do with the way the 4 little glass lenses that make up the lense are arranged. If anyone knows how thease pieces of glass are supposed to go I could use the help.

Post by **Winston** » Mon Sep 27, 2004 2:52 am

Focus knob?

Post by **videoguy326** » Mon Sep 27, 2004 2:56 am

There is no focus knob. I believe I focus it by twisting the lens. The lense is the issue.

Post by **Winston** » Mon Sep 27, 2004 3:05 am

I'm sure there's a focusing knob. The knob will rotate the whole lens barrel. Does it have a zoom lens?

I don't hear of a projector lens going bad by itself. Is it clean?

Post by **videoguy326** » Mon Sep 27, 2004 3:47 am

The lense is focused by physically rotating it. There is no focus knob per se.

Post by **videoguy326** » Mon Oct 04, 2004 12:39 am

Can anyone tell me how the pieces of glass that make up the projector lens are arranged?

Post by **super8man** » Mon Oct 04, 2004 3:49 am

Instead of repeating yourself, give us more clues...do you have the individual elements in your hand? If so, then, consider it a parts donor.

Otherwise, many of those projectors had NO focus knob - you simply focused by carefully pulling and pushing the lens in and out. I think. I may be mistaking it with a zoom model.

Anyhow, the ONLY other option is that the lens it turned/rotated to achieve focus. Again, if you have taken apart the barrel itself, then I think you have a parts donor.

Need more info. Does not compute.

Good luck though.

Post by **videoguy326** » Tue Oct 05, 2004 4:40 am

The lense can be detached from the projector for cleaning. The glass pieces that make up the lense can be taken out of the lens and re-arranged. My problem is that when I got the projector I accidentally loosened the lens and the glass pieces fell out.

I never had a chance to test it before than. So I don't know if it was messed up when I got the projector or if I put the pieces back in incorrectly. There are two circlular pieces that go in the back of the lense. One is belved or curved on one side and the other lense is thicker and curved on both sides. Next there is a metal tube that keeps the previously mentioned pieces of glass in place. After that tube there is another curved larger piece of glass and than after that there is the main lense which is unscrewable from the rest of the lense barrale. I'll try to post some pics later if that would help. Thanks for the help.

Post by **super8man** » Tue Oct 05, 2004 5:45 am

Wow - now we're talkin! OK, well, I stand corrected, you DO have a bunch of elements in your hand. Well, I am out of luck. About the only advice I can give is to search the web (I am thinking of the "citynet" "fodder" website in my links section) and look for any and all pictures of proejcteor lens setups (like they show for 35mm camera lenses like at the nikon website). You may just get the idea of how the light is bent and changed through the course of travel until is hits the screen.

Here's a hint: the rear element will have a totall flat side with hopefully some grunge so you can tell it was exposed to air, etc. The fornt most element will convex with the curve pointing out so that the light leaves the projector in a diverging way so that the image gets bigger twoards the screen.

Seems to me that that would leave you with two lenses and about 4 combinations of possible fitting inside the barrel.

Good luck.
m

Post by **videoguy326** » Wed Oct 06, 2004 2:28 am

I got it to work. The picture can now be focused properly and it looks great. Thanks alot Super8 Man. Your input saved me weeks of trial and error.

Post by **super8man** » Wed Oct 06, 2004 2:58 am

Glad to be of help...

As Red Green used to say, if the girls don't find you handsome, at least they can find you handy!

Filmshooting

Focusing Problems with B&H 346A

Focusing Problems with B&H 346A

How do I arrange the lenses