Ground Glass Info at DVinfo.net

Cory Cone · July 28th, 2005, 05:31 AM

Hi everyone, I have done a lot of reading about peoples plans on how to make mini35s and it's a pretty simple idea from what I understand, the only problem is that this "ground glass" that everyone is trying to make.

I read that you can do it by sanding down a UV filter with sandpaper or you can use wax, but why can't you just buy a focusing screen and use it? If you can could you not just buy a cheap one like the one at the following link: http://www.bhphotovideo.com/bnh/cont...ughType=search

I know it's a stupid question and I'll probably get bashed but someone please enlighten me.

Thanks,
Cory Cone

Frank Ladner · July 28th, 2005, 08:48 AM

Hi Cory!

The big reason not to use a focusing screen from a camera is because most of them have markings...and if you find one without markings (like the one posted), it still likely won't have a fine enough grain.

The first couple of ground glasses I made were from UV filters. Then I learned I could use 50mm glass from 99 cent picture frames just as well...and I saved a bunch of money.

The best results I've had were with microcrystalline wax: http://70.147.193.182/mwtest

...however it is a bit more tricky than glass grinding.

I still think the best solution, if you have the money & equipment, is a moving ground glass - You'd get as much light as possible and grain wouldn't be an issue. I've made some very low-tech attempts at this, but nothing near as good as what Les Dit, Dan D., Ori, and some of the others have done.

Hope this helps!

Leo Mandy · July 28th, 2005, 02:32 PM

Is that a field lens sitting in front of your GG Frank? Or just a condenser? (the rounded rectangular glass piece)

Cody Dulock · July 28th, 2005, 10:25 PM

the screen could work if you vibrated it.

Cory Cone · July 28th, 2005, 11:29 PM

Thanks for the info guys.

So the GG does not need to be perfect if you can vibrate it? Or does it need to be spun?

Cory Cone · July 30th, 2005, 07:21 PM

One more question, when I'm sanding the glass with 600 grit, I read somewhere to use oil, should I use any oil? If so what kind? If not do I just sand with straight sand paper?

Thanks

July 28th, 2005, 05:31 AM	#1
Cory Cone Regular Crew Join Date: Jan 2005 Location: Saskatoon, Saskatchewan, Canada Posts: 41	Ground Glass Info Hi everyone, I have done a lot of reading about peoples plans on how to make mini35s and it's a pretty simple idea from what I understand, the only problem is that this "ground glass" that everyone is trying to make. I read that you can do it by sanding down a UV filter with sandpaper or you can use wax, but why can't you just buy a focusing screen and use it? If you can could you not just buy a cheap one like the one at the following link: http://www.bhphotovideo.com/bnh/cont...ughType=search I know it's a stupid question and I'll probably get bashed but someone please enlighten me. Thanks, Cory Cone

July 28th, 2005, 08:48 AM	#2
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	Hi Cory! The big reason not to use a focusing screen from a camera is because most of them have markings...and if you find one without markings (like the one posted), it still likely won't have a fine enough grain. The first couple of ground glasses I made were from UV filters. Then I learned I could use 50mm glass from 99 cent picture frames just as well...and I saved a bunch of money. The best results I've had were with microcrystalline wax: http://70.147.193.182/mwtest ...however it is a bit more tricky than glass grinding. I still think the best solution, if you have the money & equipment, is a moving ground glass - You'd get as much light as possible and grain wouldn't be an issue. I've made some very low-tech attempts at this, but nothing near as good as what Les Dit, Dan D., Ori, and some of the others have done. Hope this helps!

July 28th, 2005, 02:32 PM	#3
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	Is that a field lens sitting in front of your GG Frank? Or just a condenser? (the rounded rectangular glass piece)

July 28th, 2005, 10:25 PM	#4
Cody Dulock Major Player Join Date: Sep 2004 Location: arlington, texas Posts: 420	the screen could work if you vibrated it.

July 28th, 2005, 11:29 PM	#5
Cory Cone Regular Crew Join Date: Jan 2005 Location: Saskatoon, Saskatchewan, Canada Posts: 41	Thanks for the info guys. So the GG does not need to be perfect if you can vibrate it? Or does it need to be spun?

July 30th, 2005, 07:21 PM	#6
Cory Cone Regular Crew Join Date: Jan 2005 Location: Saskatoon, Saskatchewan, Canada Posts: 41	One more question, when I'm sanding the glass with 600 grit, I read somewhere to use oil, should I use any oil? If so what kind? If not do I just sand with straight sand paper? Thanks