Built angus35..not working on dvx100 HELP!
 

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!

Diopter
 

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?

orientation
 

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?

Hoya
 

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

my opinion
 

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?

Re: Built angus35..not working on dvx100 HELP!
 

<<<-- 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!