DIY Ground Glass/Focusing Screen

N

noloc45

Active member
Ive searched and cannot find (maybe im blind??). I was trying to follow Daniel Schweinerts instructions for DIY GG, but its HARD!!! I cant get a perfect frost, I get and stuff like that. Anyone know how to make your own GG that can look good?? Maybe sanding?? HELP!!

Thanks!
 
Buy a focus screen...nikon or canon (or Beattie if you want to spend the cash). Hell I might even have one you can have.
 
Its easy,

Go to your local hardware place and buy a few cheap photo frames (the ones thats just a sheet of glass and some fibreboard behind it. In the UK an A4 sheet of paper sized photo frame is about a pound.

Take one and cut out your bit of glass, the size your final GG will be. Use the other one frame as a work surface. Pour out a little pile of aluminium oxide abrasive powder. You can get it from art shops and airbrush shops, its used in miniture sand blasting machines.

here

Put a little dribble of water on top of the pile of powder.

Now comes the hard work, put the bit of glass ontop of the pile of aluminium xide and rub it round in little circles, and the aluminium oxide will grind the surface down to a fine ground glass. You will find that patches of glass will start to frost before others. Dont worry about it, just move your pressure over the blank patches and keep going. Once a bit of glass is ground, it cant get any ground-er, so more rubbing wont make it any more frosted, so you can just keep going on the same patch and it wont change, so keep going until the whole bit of glass is evenly ground.
 
What about the effects the thin fresnel grooves that Canon Ee-A and Ee-S have?? How can I recreate that effect so I wont have a hotspot??

Thanks!
 
You should go over to the dvinfo.net forum for 35mm adapters. Lots of info for the diyer and the birth of a lot of our favorite vendors.
 
noloc45 said:
Maybe sanding?? HELP!!
Click to expand...
Over the past couple months I have been trying quite a number of methods.

Matte sprays, acid etching cream, acid baths, parrafin wax, sandpapers, powder abrasives, polishing compounds, abrasive paste, air abrasives.

In terms of uniform grain, the matte sprays, and sandblasting, and sandpapers have given the best.

Though the matte spray gives too coarse of a grain, the sandpaper takes too long, and very easily scratched. Sandblasting seems to be the way to go.

Though the acid treatments, are inferior due to not being able to get an even diffusion, becomes great one a big of wax has been added and melted.

Your best bet though with any is to use a big sheet of glass, then diffuse it, a somewhere in there you will have that perfect section to use for your focus screen.
 
noloc45 said:
What about the effects the thin fresnel grooves that Canon Ee-A and Ee-S have?? How can I recreate that effect so I wont have a hotspot??

Thanks!
Click to expand...

I bought one of Daniel's GG holders at jetsetmodels.info and tried also to make a DIY wax ground glass. It kinda worked fine, but the wax strangely frosted in different ways (parts with more grain).
As condenser lens, I am using a 50mm plan convex lens with 8 diopters (http://www.lupenshop.de/content/lup...4afce362742d43f47020674/Product/View/1841&2D2). I took of the motor from the gg holder and placed it on the other side (I had to cut a small part from the outer ring to fit the motor). On the now free site, I glued the condenser lens. Works pretty fine, I will try to post some shots in the next days.
Anyway... if you want to use it for professional reasons or just want to get the most out of your cam, I would strongly recomend you a SGpro (with the new steel nikon mount). The quality is much better than any DIY 35mm adapter.
 
This seems to be the crucial element in a 35mm adapter, not only the amount and pattern of grain, but also the bearings and hub it will spin on, (if it's the spinning type) to have no runout or wobble.

It took me about 8 hours of grinding to finish the gg I used for the last festival and I had time to think about it....

You know these places that do laser etching on glass? I haven't asked yet, but maybe they can etch a perfect diffuse pattern on a sheet, and cut it out too.
 
yeehaanow said:
maybe they can etch a perfect diffuse pattern on a sheet, and cut it out too.
Click to expand...

I thought about that some time ago, and visited several places that do that but found that the operators have no idea how to go about that. They basically just select their font and type in what they want to say and hit a button. They aren't exactly trained on how to use the software.

I have been thinking of trying these guys out:
http://www.crystalmagic.com/Custom_image_crystals.htm

Might not be the price you want to pay, but if you're planning on cutting your own you can get a few screens off a single piece of glass.

I use circles for my adapters, and fit them into empty filter threads and end up wasting a lot of area that can't be used. But if you're cutting smaller ones, you'll definately have a lot to use from a standard photo frame size piece of glass.
 
It's really not that hard to grind the glass. I use the http://www.snodart.com method and it takes about 12-15 minutes to grind perfect 5 micon GG.

I use the Nikon focus screens because they include a perfect condenser. No hotspotting at all.

That's the glass I sell in my line of BJ35 adapters. They're rock solid. I sell a static and vibrating model currently. Working on a spinner.
 
hoarp001 said:
Its easy,

Go to your local hardware place and buy a few cheap photo frames (the ones thats just a sheet of glass and some fibreboard behind it. In the UK an A4 sheet of paper sized photo frame is about a pound.

Take one and cut out your bit of glass, the size your final GG will be. Use the other one frame as a work surface. Pour out a little pile of aluminium oxide abrasive powder. You can get it from art shops and airbrush shops, its used in miniture sand blasting machines.

here

Put a little dribble of water on top of the pile of powder.

Now comes the hard work, put the bit of glass ontop of the pile of aluminium xide and rub it round in little circles, and the aluminium oxide will grind the surface down to a fine ground glass. You will find that patches of glass will start to frost before others. Dont worry about it, just move your pressure over the blank patches and keep going. Once a bit of glass is ground, it cant get any ground-er, so more rubbing wont make it any more frosted, so you can just keep going on the same patch and it wont change, so keep going until the whole bit of glass is evenly ground.
Click to expand...

I don't know what I do wrong, but just after few rubs the both glasses stick on each other like a cemented, so hard to separate them for further rubbing. And again: 2-3 rubs and they stick hardly again. I tried all the procedure many times from the zero, with lower or bigger amount of aluminum oxide/water, even I replaced the water with motor oil - absolutely the same result!!!
Please, any help, advice, idea...???
 
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