Possible GG idea
 

I've been working with a gentleman that creates custom focusing screens. Unfortunately for me his materials have focusing circles in the center of them, thus rendering them useless for a GG. He has suggested another type of screen that may work. I've posted a link to a picture of the lens below for you to view. His description of the screen is as follows: "It's glass, flat and frosted on one side and convex and polished on the other. This screen measures 22 x 30mm." Any ideas on whether this would work or not? I've only seen the flat GGs made from glass or something like a Nikon D screen (although I don't know the actual shape of the elements in the D screen). If someone can tell me whether this might work or not I'd really appreciate it. Thanks everyone.

http://i3.photobucket.com/albums/y59...DSCN2827_s.jpg

I think its worth a try.

What is it called and where can i pick some up?

*edit*

is it something like this?
http://www.wolverinesports.com/mirrors.html

That would make for some very cheap ground glass + condenser... Unfortunatly its not glass... its the "Double Convex Acrylic Len"...

How bad is light loss for Acrylic?

I am just in contact with him personally. I will PM you with his email address.

I'll save you the effort and say it won't work. I've spoken with Bill Maxwell for a bit, and he, like Beattie, uses a custom optical acrylc process to make his screens. The grain is at best approaching somehting like WAO5 ground glass, but nothing like you'd need for a static adapter.

Now, if you could get your hands on an optical acrylic machine ($30k), that would be something -- you might be able to custom design your surface to spec.

- jim

Jim provided me with the email adderess of the guy who may have thies. When he replies we should have more information on the quality, and a price.

Hopefully it is glass, and a very fine grain. If the grain is too visible we could just have it vibrate.

I know very little about optics and/or ground glass, so I don't know if it's worth it. That's why I asked. :D

Now, Jim, you're saying that Maxwell uses a custom optical acrylic process like Beattie. From what I have read/heard/seen about these Beattie screens they are supposed to be rather nice for a static adapter. So wouldn't that make it higher quality? I'm just trying to understand all of this.

It's all relative. "Higher quality" than what? What is high enough? The Beattie provides a great image in many ways, but the grain is readily apparent in highlights. Watch the Holyzoo videos in Steev's "Ultimate Adapter" thread -- you'll see what I mean.

The Beattie and moreover Maxwell screens are probably great for oscillating adapters but pretty non-functional as static adapters.

Thanks for the info Mike.

The screen came out of a European 1950's era SLR camera, so i dont think there are any focus screens like it manufactured today. Ill keep an eye out for optics similar to this one.

I may try the acrylic optics just to see what kind of results i can get.

Good enough for me is a Nikon D screen but I can't find any. Very difficult to locate any source for those. I guess I will just keep looking.

Mike, B&H stocks them pretty regularly. If they're out of stock of the Nikon D's they should be in in a few weeks.

Thanks for the tip, but I haven't had much luck getting one from them yet. I've got them on my wishlist and I'm signed up to receive notification at three email addresses when they do come in. So, I'm hoping they do come in soon. :D Just hard to snag them before all of the other 35mmophiles get them.

Hey Mike, i just ran across a post at DVXuser forums...
http://www.dvxuser.com/V6/showpost.p...8&postcount=10

The Canon Ee-a or the Ee-s could be a good alturnative to the hard to find Nikon D. I dont think anyone has tested it yet.

That's what I love about this place. Everyone actively looks out for the other person. Totally cool.

Unfortunately I am aware of that thread (and have been actively participating in it) and there is some debate at the moment as to whether or not the screens have a small focusing circle in them. One of the guys has ordered two of both types and we are awaiting their arrival to determine whether or not they will be a good substitute. But thank you for putting forth that information. Maybe it will also point others in a better direction.

merging the gg and condenser is an old idea that some of us already implemented. It is a great solution but has a huge draback. You can not vibrate it, since vibrating a lens will vibrate the focal point too.

Vibrating the ground glass would blur the focus too, as your distance from the SLR lens would vary. You have to make it vibrate in a way that the condenser/gg moves only left-right or up-down. You can find some pictures of the Letus35, it has a good solution.

Just a quasi-update on the Canon Ee-A and Ee-S screens that Daniel mentioned a bit ago. A gentleman on DVXUser.com that I am in contact with has ordered the Ee-A screen and will be testing it upon arrival. When he spoke with Canon directly they told him there was no focusing circle. Several of us on DVXUser are anxiously awaiting the results of his tests, and I will post a link to them over here when they are available.

As yet another alternative, I have found a source for the Nikon B III BrightView screen that is used in the Nikon D2X camera. This focusing screen is supposed to increase the brightness of the image by a full stop, so we'll see if that helps in terms of its use as a GG or not. It's used in the D2X, which is a very expensive and high end digital camera, so I imagine the optical properties of the BIII screen will be at least up to par with the elusize D screen. I have my other parts ordered and will hopefully have things together within the next two weeks. I'll post my own results as I have them. I intend to post up my final design for anyone else to copy. The person that I got the plans from has since hidden them from the world and is planning on producing the adapter. But the adapter is based on several known designs anyway so I am going to post up as much info as I can about my design so if others want to they can make their own. It's really easy, and not very expensive either. Minus the lens, I should be assemble the entire adapter for just under $100. It is a static design, so it will have its limitations.

I have one of those one piece focusing screens too. Mine is even bigger than 36x25.
On most cams I`ve tried it it has more barrel distortion than Beattie and other frensel focusing screens.

One good thing with ground sided PCX is that you can re grind it`s surface to finer grade using usual methods mentioned many times here.

This kind of stuff is available from European eBays for around 5 to 40 EUR.

Something like this: EXA/Exakta Mattlupe for EUR 7,99

I'm not sure if anyone was following this or not, but the guy over at DVXUser.com that had ordered the Canon Ee-S screen found that it did in fact have a focusing circle in the middle. I thought he had ordered the Ee-A, but that's not the case. Apparently this won't be the "alternative" screen to the elusive Nikon D screen. I know that the frenzy is in full force over at DVXuser.com, as people are now spending upwards of $75 on the D screen on eBay. My B III screen is still on backorder, but when it arrives I'll test it out and let everyone know how it works as a GG. Better yet I'll post up screen grabs so you can judge for yourself.