Showing posts with label gg. Show all posts
Showing posts with label gg. Show all posts

Saturday, April 14, 2007

How not to do a Vibrating Ground Glass

The static is fine for web videos but leaves much to be desired for full DV. At low light like indoors shooting the grain shows up around the edges. So I try to convert the simple static to a full vibrating ground glass. Unfortunately I am not successful yet.


Notice something wrong? The adapter was a full centimeter short! One of the spacers is too short. This wreaked havoc with the infinity focus.



I started with the 52mm tube and cutout a plastic card. I carefully cut a rectangle the size of the Nikon Type D for mounting the ground glass. I tried it alone inside of the tube as a static but it wasn't stable. So I try using a 52mm filter in reverse and that held the ground glass well. Trial fitting the motor I found that there wasn't much room to mount it vertically as it should. So just for kicks I try it horizontal. It doesn't work.



Not one to give up, I sacrifice some of the focus screen's visible area by mounting the motor vertically against the fastening tab on the Nikon Type D. The vibrations are more quiet but I can't see the grain moving. There isn't enough play in the rectangular cutout nor the plastic card to allow the grains to move.

I ask the kind folks at DVInfo Alternative Imaging what kind of stupidity I've delved into and I'm told that my arrangement wouldn't work. The horizontal was moving in the wrong direction. It was also loud because it was turning the card into a diaphragm. Meanwhile my vertical was too tight on the tube to allow the movement necessary to blur the grain. Just for kicks I'm taking the vertical setup to the seaport for some test shots.

Thursday, March 15, 2007

The Wily Frosted Maxell CD-R ground glass

Supposedly there are nicely frosted fake CDs in the 25pk Maxell CD-R cakeboxes. Maybe maybe they were more abundant in 2004. But it's now 2007 and I had a hard time finding one.

I used to have those frosted plastic disks that protected CDs/DVDs in a cake box. Just last year I threw out my empty spindles with those non-crystal blanks. Little did I know that I might want them a year later. In desperation I tried to sand my own ground glass from some crystal DVD-R blanks. Not having any 1500 grit wet dry sandpaper handy, I used a sheet of metal sandpaper that was lying around from repairing some car rust. This was Norton brand from the Home Depot with no grit rating on it. It was marked "fine" which I guess is about 100-200grit. Apparently, "fine" wasn't fine enough as I tested my poor groundglass. The light loss was horrendous.

So I scoured several stores to find the elusive ground glass (gg). Walmart had 25pk Maxell CD-R but these were the 'printable' type. Looking through the top I couldn't tell if there was a frosted there. This was not to be mistaken for the CD-R Pro with its gold surface and no frosted cd. There were several cakeboxes by Memorex, Sony, TDK, and Imation but none of them had it. Once I got fooled by the milky translucent look of the Memorex 15 pack so learn from my mistake. The best bet is to look for silver top CD/DVD. The clear cakebox is an even milky color but the frosted blank will make it look rough and spotted. It will look like it has dust particles around it but its somewhat evenly spaced and distributed.

Best Buy, Circuit City, CVS, RiteAid, Radio Shack, Target and the local supermarket saw me inspecting every brand they had. Even among Maxell brands you must beware. I think the trick is to find a place with old stocks of CD-Rs. So I went to a lonely FYE near a huge Barnes and Noble. In a corner mixed in with white and blue-green 50pk Maxell CD-Rs was one cakebox of its older stock. Instead of the 56x, I grabbed the 40x all green 50pk Maxell CD-R box. The cover was a bit dusty so I had to really examine the top against the light. Seeing the small white dots and bumps told me it had a frosted CD.

Back home there was a cheap Durabrand CD player. Little did it know its life as a portable entertainment device was coming to a close.

Frosted vs Sanded