Homemade 35mm Adapter

[Bob Hart]

Furthur to the above, I have sent another image of the modified mirror group arrangement. this will be "agusmr12.jpg".

The large mirrors (Group 2) can probably be trimmed even furthur across to the right to the left vertical edge of the path of Group 1.

In bright light, the images are sharp and clear but also heavily banded due to internal reflections in four layers of the thick mirror glass earlier mentioned.

[Filip Kovcin]

is it just me or what?

i can't find any new "miror" pictures on
www.dvinfo.net/media/hart

maybe another few hours... :)


filip

[Bob Hart]

Filip.

On page 63 Chris advises he will be posting them soon.

For alternative mirror material I tried cutting up some plastic "prison" mirror but the same internal reflection banding remains. Proper optical mirrors or prisms will be the only way.

If you are using this method, it is also best to position the small mirror as close to the CD groundglass as you can get without touching it.

For the CD case Agus constructors, a mirror or prism array could be made from tin can metal or light galvanised sheet with two side flaps soldered on and fastened to the outer circumference of the CD case with adhesive and short self tapping screws. There would have to be a clearance hole for mirror group one to enter the enclosure from the side. You might need to consider the 100 pack CD box

Relative to the camera, the case would have to be set lower about one inch (25mm) and to one side or another about one inch depending on which way you arrange for the mirror Group 1 to throw the image. A diagonal arrangement which sets the prime lens and camera lens centres centred vertically will require a larger mirror or prism size in Group 1.

For PD150 right offset may be best for handheld balance and for ground-level hand carry shots.

[Brett Erskine]

Thanks for all the work Bob. Perhaps Edmunds Scientific have the mirrors your looking for. Sounds like the same special coating they have on some of the better filters and high quality/pure optical glass.

Dont forget the two different prism combo I mentioned in one of my previous emails.

Thanks again.

[Chris Hurd]

Howdy from Las Vegas,

Bob's images are up (finally) at http://www.dvinfo.net/media/hart/.

[Bob Hart]

My last masking tests with mirrors fixed to a frame indicate the mirrors can be all 35mm x 40mm or prisms can be a pair of right angle prisms 35mm broad across all faces and 40mm long on the side faces. This is not set in stone and may not work with other camcorder-lens-macro combinations.

Brett.

Do you know of such a thing as a 5+ achromatic close-up lens or macro lens of 58mm filter thread mount. In my last tests, a 4+ and 1+ ( I presume this makes 5+ ) yielded a more convenient result in terms of keeping the assembly compact.

My imagining of making an Agus35 erecting version would be to design a one-piece folded mirror/prism mount as previously mentioned plus mount for either a piece of fixed glass which has been my test rig, or the CD disk in order to keep the whole thing stable enough.

This would be cut-outable from jam tin or light galvanised steel with scissors. Thin copper or brass sheet would be fine but unless found as scrap would be an expensive way to do it. If soldering was not the chosen method of joining corners and stays, other metals and adhesives as alternative to solder would suffice.

[Ignacio Rodriguez]

This is all so cool, I have enjoyed this thread... and I wonder: would it be possible to modify a DV camera so as to replace it's optics with a simple lens and a ground glass? What bothers me about the idea of adding a 35mm adapter and ground glass to an unmodified cam is the redundant optics which are lost in the camera not doing anything, just complicating things...

[Ignacio Rodriguez]

This is all so cool, I have enjoyed this thread... and I wonder: would it be possible to modify a DV camera so as to replace it's optics with a simple lens and a ground glass? What bothers me about the idea of adding a 35mm adapter and ground glass to an unmodified cam is the redundant optics which are lost in the camera not doing anything, just complicating things...

Or perhaps someone will sell us such a camera...
http://www.dvinfo.net/conf/showthrea...threadid=21387

[Bob Hart]

Ignatio.

If anyone does, it will be JVC. They have the runs on the board with their new DVD consumer camcorder which aims for high definition and their video cameras the KY-F32 and KY-F50.

As far as I can work out, these cameras use 1/3" 3 x CCD wedges but cleverly use optical relays to pick up 1/2" and 2/3" CCD sized images from the larger format lenses. They don't use a groundglass but the aerial images which the AGUS35 non-inverting layout does if you pull out the groundglass. These are of course not the 24mm x 18mm movie frame.

It would be pretty pointless doing groundglass with these cameras if you could. As I mentioned they are 1/2" and 2/3" format so little advantage would be gained and much resolution lost as the groundglass texture would be more apparent due to the smaller image frame and higher magnification to the same TV screen. But having gone there up to a point, JVC already have the experience of building and selling such a product and it would not be such a leap for them to build a relay lens set for the larger movie frame.

The problem is marketplace. If P+S Technik could sell enough of their Mini35s, economies of scale would make it possible to set a lower price. Price keeps the marketplace small. Its a sort of Catch 22.

My imagining of such a product would be a low cost single chip camcorder with fixed groundglass, non-inverting with the CCD itself inverted, possibly marketed as part of a digital still camera range and able to use those lenses. I don't think you will see it as a prosumer camcorder option any time soon.

[Dino Reyes]

hey any XL1 folks, anyone out there yet have a proven version of the Agus35??? just curious. i am sooo close to completing my version, but getting the correct close-up attachment for my relay lens is driving me batty... my master lens and spinning gg (that's real glass) looking the best i've seen so far. tonight i've tried stacking a +4, +2 & +1 closeup lens but my magnification seems a tiny bit cloudy (that could be cause they are stacked) and i can only magnify up to just about 6 inches away. I need to magnify more like 2 inches so i can complete for fine tunning. i'll be trying to find a +10 tomorrow and see if that works, but if anyone has any thoughts or prototype they want to show, i'd be curious... thanks.

[Bob Hart]

Dino.

If you eventually go the prism or mirror, image erector route to get your images upright, you may find you don't need any more than 5+. I'm only guessing because I don't know the XL1.

As for cloudy images, first silly question is, have you painted the interior of your Agus housing with flat black paint to stop internal reflections, second silly question is, have you dressed the outer circumference and inner hole edges of your glass disk with fine emery to make them non-reflective or are they still bright and shiny as cut.

Additionally, some flat black paint on these edges and on the portions of the disk which do not contain your projected image, may also help. Non reflective COATING (not finish) on the shiny side of your disk may be needed. Is the groundglass side of the disk facing the camcorder or the prime lens. You may find it better to project the image through the disk onto the ground surface rather than look through the disk at the ground surface.

Even with the defecits you have encountered I'm sure you have found the glass disk worthwhile so far.

[Bob Hart]

Dino.

Please be sure to read a correction I made to message above - the word "COATING" replaces finish. I don't want anyone to try dressing both side sof their groundglass disk because that definitely won't work.

[Matthew Campbell]

Hey , i've been following this whole thing for a while now and i was wondering if agus or anyone has posted the steps on the how to make an Agus35 because i got the supplies to make my own but i don't know if it is going to work. I have a Sony Digital handicam DCR-TRV250, a 50 pack spindle and the 1.5-3v motor and battery hookup along with the clear cd, sandpaper ect... i also bought a magnafying glass but i just want to know how to put it together the absolute correct way to put it together. if anyone could help me out that would be awesome. thanks

[Dino Reyes]

Thanks Bob, the interior coating is something i forgot about, I'll address that also, it should help. I still have a problem though and for the life of me i can't figure it out. my relay lens is a Nikkor 55mm f1.2. my problem still is to get the lens focus distance closer than 6-7 inches, at that rate, my spinning gg unit and master lens will extend out almost a foot. i'm not sure if its the lens itself or i am doing something wrong with the close-up +7 (that's a +4, +2 and a +1) lens. i even tried a reversal attachment, that get's me around 4.5-5 inches but it also is too microscopic.

i just did a rough test, just shooting though the gg and i get no vingnetting. what occurred to me is that maybe i need a +10 macro, as i have heard that number being thrown around on the thread. i'll run out to b&h tomorrow and see about picking one up. another thing, if you or anyone may have insite on, is that my gg picks up such a beautiful image, but the sweet spot is such a small portion in the center-it's too bad i can't really utilize more of it. Is there something i might be able to try to get more of it, or if my master lens (currently a 50mm f2) were a wider angle, i would assume that's how i could get more image and the rest is pretty much fixed because the ccds shoot in such a straight direction. thanks again...

dino

[Brett Erskine]

Dino and Matt RMPP.