guys I followed the tut on line and I now have the whole project made ...problem is I get the dark edges around my image on the lcd screen...what should I use to make the GG image bigger so that the dvx lens does not have any dark corners? I bought a +1 +2 and +4 Diopter from the local camera store but this still does not get the GG image big enough ...HELP!


thanks a bunch!

Obin,

bad news about the DVX... its a bit harder to get rid of the vignetting than other cameras. The macro focus is just not sharp enough to zoom in close enough as is... so you need a really powerful diopter as opposed to other cameras that use weaker ones for this purpose. +4 wont work. I have two +7s on there and they just barely do the trick. If this was the static ALDU35 version you were making then in addition, you would need a condenser lense between the ground glass and the SLR lens (or between the gg and the camera depending on who you ask). That will spread the light out and correct the hotspot. I just use a PCX macro flipped so that the flat side is facing the camera. You can either grind that flat side or lay your ground glass flush against the macro's flat side. The first option of just grinding the flat side of the macro is a better choice since you eliminate an extra piece of glass that light has to pass through and thus improve image quality and light loss.

I'm gonna be posting verisons of my ALDU35 soon... it's the static version, but concept is pretty similar, especially from the DVX to the gg. I don't know how exactly you would correct the hotspot issue with the AGUS since I'm not sure the best way to mount a PCX condenser infront of the spinning gg so that it's close enough but not actually touching... I've heard people talk about fresnel lenses, but those are supposed to degrade image quality in a use such as this. www.surplusshed.com has a variety of PCX lenses for really really cheap (like $4 a pop). some of them are really powerful and since they aren't mounted in filter rings, you could conceivably secure that PCX so that the flat side is really really really close to the spinning GG without it touching.

John

so who can I buy 2 +7's from? not my local camera store...and I am not sure I follow you about the hotspot issue or should I say how to fix the issue.. got any pics to show me what you mean?

also I really feel that the GG spinning is way better then static because it is so clear and grainless!

what is a PCX ??

Ok I now know what pcx lens is, what size do I need to buy for the dvx angus35 project? also do you mount it with the flat side to the GG? and this spreads the light out? this does not mess up the image that the 35mm lens is projecting on the GG?

wow do I have to spend $500 just for 2 century optics +7 diopters?!?! any other sources?

Actually the two macros on my setup are supposedly +10 but I'm not totally convinced that they're +10 since they don't actually say +10 anywhere on the ring... I think they're something a bit weaker so I just assumed +7... according to some of the users in the ALDU discussion two +10s should be more than enough so that's why I think I actually got something a bit less. The correct amount to be able to focus on a 24mm area of the GG (which is what you need to focus on in order to get the correct DOF) is about +13 for the DVX... someone in the ALDU discussion did the math... so that's why I think the macro's I have are something like +7.

Here's a diagram of the setup:

SLR - (l - gg - (l - (l - DVX100

in other words:

(SLR) - (PCX condenser) - (gg) - (+10 macro) - (+10 macro) - (DVX)

If the condenser is too far from the ground glass then yes it will change the magnification of the image, but the closer the GG is to the PCX (or Fresnel for that matter) the less magnification. And if the GG is flush up agaist the PCX or is the ground flat surface of the PCX as it is in the ALDU design there is no magnification.

Have you had a chance to try some of the glass grinding tequniques talked about in the ALDU discussion. The idea is to grind the grain smaller than the DVX's CCDs can register... then there would be no difference between the two designs except in the way they are built. There are some members of that discussion who have achieved amazing results. I haven't begun the grinding process yet, so I can't give you my opinion on it yet, but from what others have succeeded with I'm pretty confident that my completed static design will also be grainless as far as the DVX's chips are concerned.

will this work with a +4 on the front?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3815589464&category=30040

wow so you think that you can get the grain down below the viewable size? that would be amazing! I would just remake the design I guess and make a static one...I am using the spinning CD design now and it looks GREAT but for the "hotspot" and the dark corners...do you think I should giveup and make a static unit?

Those are the one's I'm unsing... and like I said, I'm not confident that they're actually +10. They're also definitly not proquality (check the aldu discussion to learn a little more about the difference between high quality macros) but they were so cheap that they were good for experimentation. If they aren't +10 but something weaker, then no, a +4 won't give you the +13 rating that you need to really get in there.

Hoya sells a +10 macro that I know for sure is +10 (cause Hoya is a reputable company vs. the Ebay dude I bought mine from). It's only $60. If you get two of those suckers you're good to go in terms of focusing on the GG. The only problem is that they don't sell them in 72mm ring size... I think 58 is the largest they have. So you'll need a stepdown ring... the macro's I got from Ebay are defintly not pro quality lenses but they are 72mm... which make up for their lack of quality. 58mm macros will come with some blurring on the edges and distortion problems if you're not carefull how you set it up.

John

I think you should spend a few hours reading the ALDU posts... I'd say that for me it really got interesting at around page 44... that's when the idea of using acid to grind the glass first appeared (apparently gets an amazingly fine finish)... there's also a really fantastic design that has begun to catch on using nothing but filter rings... very clean and optical looking. Every distortion, magnification, and hotspot issue you can think of has been covered and solved to some degree in that discussion. I think it's fantastic. I'm not gonna suggest which one you build... I can only say that for me the idea of moving parts, batteries, vibration, humming, not to mention bulk was just too much of a deterrent.

John

john what size pcx do I need to order from that site you gave me the link to? also how close does it have to be to the spinning cd?

<<<-- Originally posted by Obin Olson : guys I followed the tut on line ->>>

When you say tut is there one speicific tute? or did you wade thru a million posts?

Ok John been readin the posts...so I guess my last question is what size pcx do you think I need for my spinning augus35? I have no idea what to buy at this point...can you give me a link? thanks a million

ben here:
http://www.dvinfo.net/conf/showthread.php?s=&threadid=25542

great tut for building!

John, here is the design I made:

http://www.mediachance.com/dvdlab/dof/index2.htm

so you can see what I am working with and give me some ideas how to mount the lens I need

I would say something wide enough to cover the 24mm x 18mm image area that you're gonna be focusing on... I'd say any lens with a diameter of around 50 + would be fine. What's the radial measurement of a CD gg. I guess something a little bit smaller than that. In terms of Focal Length, people on the discussion boards have been saying that if you use a PCX with a focal length close to or exactly the same as the SLR lense you're using that's best (so if you've got a 50mm lens attached then you should get a PCX with a 50mmFL)... but I'm just using one of those EBAY macros you saw, and it works fine for correcting the hotspot. Of course you couldn't use one of those for your design since the filter ring wouldn't allow you to place the lense close enough to the GG.

As for how close... I guess as close as you can without the spinning CD touching it. Obviously if it starts touching it, it'll scratch the lens... a problem you don't have to worry about with the static version.

John

I will be using a 28-135 slr zoom...how can I get one for that?

how will the ring not allow me to get close enough to GG??

How about a 4th board with a hole drilled exactly the size of the PCX you end up purchasing. That board should be able to be moved as close to the spinning CD as possible and then locked into place using additional nuts. It would probably be a tight squeeze, but you should be able to do it. The only things that would be keeping the lens from getting really really close would of course be the nuts themselves creating a space between the spinning CD and the board as well as the little CD spinner that does actually protrude a bit from the middle of the CD when it's attached. Maybe you could glue two or three smaller pieces of wood where the hole would be and then drill through all three, creating a tube that actually protrudes out a bit from the the board that the nuts hold in place. That woudl allow you to move that board back a bit and still get the lens right up close... it would give you a little more space to actually tighten the nuts and also allow you to get past the CD spinner protrusion. I could draw something up and post it if that doesn't make sense.

John

Cause I don't know about other macros, but those macros you saw on ebay are the one's I have... and I can say for sure that they're set in the ring about four millimeters down. So unless you filed down that ring or poped the lens (and I have no idea how you could... I've looked) that extra bit of metal will always keep the flat side away from your spinning model's GG. And in addition to that you won't be able to have the filter rig itself flush upagainst your gg so if you had to keep the linse in its filter, you probably wouldn't be able to get the flat side closer than 7mm or so... and I think that may be to far. In the static version, you can either just grind the flat side, or just take the glass out of a UV filter ring grind it and then place it flush upagainst the flat side or at worst a couple millimeters away.

John

ok I got it ,,,cool so it 's not like you need the lens AGINST the GG just as close as you can get it...I will make it work! thanks a million!

everything is on order...maybe I should sell the dvx100 and get the 100A?? would that be a much better cam to make this adaptor for?

Not having to use diopters to focus on the GG will help with distortion as well as light loss. I have the 100 and I have to use those two macros, and to be honest it's a pain. But I've gotten it to work. There are other reasons to get your hands on a dvx100A. Colorbars, autofocus, better cinegamma, digital squeeze... no question it's a better camera.