im working already
 

I got my first Job with the COLONIA35MM

the adapter i just made myself.

go to the site www.bobflash.com.br

choose the city RECIFE-PE

on the site theres a session called BOBCAM, where i go to parties and film everything.

check out the two last clips from a xmas party. i made the two with the 35mm lens, 50mm, 1.4.

it is wonderful, altought i had some problems to focus, with the light of the place, etc. im still learning. and i was drunk too, etc...anyway, tell me what you think of it.

im just waiting your review.

thanks

ciao

all static is the way.!!!!!

ciao

Ground Glass info
 

Daniel, do you know where I can get the type of ground glass you're using or what it's called?

The camera I'm using will be VERY hard to have a spinning CD. Thanks, Corey

gg
 

It is a gg from an old zenit photocam.

clean, without anything. i think the fresnel that comes attached to it its the best thing ever. makes the diference.

ciao

Do you have any idea which model? If not, could you maybe post a photo of the camera so if someone were to find it online it would be easier to identify by sight? Thanks, Corey

help everyone here
 

i will help everyone in here.

for sure.

on moday i will go to the same store and buy ALL gg from these cameras.

the guy from the store has a lot of them, they are old.

they are silver.

i will send a pic to everyone.

ciao

Cool
 

Thanks for replying so quickly. I knew there had to be some sort of grainless type ground glass out there. I know the movietube thing coming out uses a non moving grainless ground glass from what they told me in an email. This will be so much better than having to use moving parts.

I have a question about it though. How is the brightness? I'm guessing it's probably better than using a CD. Corey

...
 

brightness?

i think i loose 1 f stop by the way.

dont know excatly.

and if i close the 35mm lens exposure to 4f , it gets dark and i can see the ground grass a little. so im using the lens all opened to 1.4f and adjust the exposure in the TRV18, so i dont get any grain at all, even if i close all the exposure.

sometimes i just cant believe it...

i just have to grip the box so i dont vibrate when focusing

ciao

Have experimented with a microscope slide using loose aluminium oxide grit 600 grade lapped on a sheet of glass. Glass is a much more controllable medium to work with than the CD disks which seem to get injured at the drop of a hat. The result across the glass is also totally consistent.

For those thinking of the fixed glass option and can't get the Zenit screens, the microscope slides are almost 16:9 frame. Used with a large or medium format camera lens and videoing the larger image across the whole slide, you could look forward to a good blemish-free result. I'm not sure how good the light from the lens will be as the image is spread over a larger area thus dimmer.

The frosting texture with 600 grade aluminium oxide might still be a bit course but the light transmission is heaps better than the plastic CD lapped with the 600 or pressed with 600 grade silicone carbide paper. With glass, the frosted surface is not injured by encounters with finger sweat or cleaning cloth.

Have tried the new groundglass as a stationary screen. Method = Pringles chip can, slots for glass slide to fit through it. PD150 videocam, with close up lenses x4 + x2 + x1 stacked, looking in from one end, 55mm Nikon f3.8 lens in other. Lens is crudely secured in end by rolled up sock cuff, video camera secured in end by rolled up sock cuff (True, the socks did have no heels left - honest and were washed).

In bright daylight which would require f16-f22 with ASA 320, the Nikon lens wide open, there does not appear to be any difference in the quality of the image at centre from that of image into PD150 direct. Contrast and colours remain the same though blue seems perhaps a little truer. This effect is reminiscent of late seventies 16mm Agfa neg stock.

There seems to be a slight diffusion of highlights. White objects like a flying moth seem a bit fuzzy.

There is a bit of a hotspot over 80% of the image from centre with the corners seeming about two f-stops darker.

Granularity becomes apparent in these darker corners. If the Nikon lens is stopped down, the granularity becomes apparent across the screen. The dark corners might be because I can not zoom close enough to the screen before focus crashes in the last 10% of the zoom range and I am covering an area larger than the 35mm camera frame.

There is a greater depth of field effect but nothing I cannot replicate with a close-up lens on the DP150 direct. However with a close-up lens, one cannot pull focus to infinity, so there is the bonus to using the Agus35 principle.

The PD150 will tolerate being operated upside down and the viewfinder can be positioned to display correctly if the combination is used at waist height like an old-fashioned box Brownie or medium format camera with top window viewfinders. With the eyepiece jammed into the stomach, the whole thing can be held quite steady. (An ample gut helps).

In low light levels, with the 600 grit fixed groundglass, I have shot a couple of comparative tests also one test in good light. I'll send these images to kennelmaster Chris to see if he can post them.

The groundglass test pattern seems softer yet on closer inspection, resolution seems to be the same across both test patterns in poor light. The groundglass image is about a half-stop darker, a slight lowering of contrast and there is a faint fawn coloured tint.

Camera gain was left on automatic for the low-light tests. It's probably not a valid test except it might be more representative of practical low-light conditions where you want every bit of gain you can get. Defects on the groundglass visible in strong light were not apparent in low light.

Some slightly darker streaks were apparent in some of the bright light images. These came from oils in the can lining from the crisps it once contained.

Dressing the groundglass surface with a hint of some sort of oil or wax might be an option for better contrast. The oily bits seem to contain light spill from adjacent areas.

I read on the large format camera forum that one thing to do is smear vasoline on the ground side of the glass, then wipe clean with a soft, smooth cloth. The vasoline will fill in the holes and provide a "wet" look to the glass, and improve brightness. I haven't personally tested it, but it might be worth a try.

Just read all 41 pages in a row:D

Looks great...
Has anyone made an adapter for the GL2/XM2? would love to see some footage made with the agus35 and the GL2, and even better, the GL2 in frame mode with the agus35:D.

Chris, you said a few weeks ago you were going to make a agus35 for your GL2, i was just wondering how its going?

Thanks:)

Richard, claps to you for doing your homework! Some people drop in on the last few pages and ask questions that have already been answered - like this thread needs to be any longer! I've been working on an adapter for my GL1 and have recently gotten my camera back from the canon repair shop. Come early next week (Tues/Weds) I should have some test footage up with the traditional design - 50mm lens > fresnel > spinning frosted cd > macro lens > camera. I'll be sure to post pics and other info....I've also been on the hunt for someone who's made an adapter for the GL1/2!

GREAT NEWS!

I've discovered where to get pre-frosted CDR's like Agus uses -- Maxell's 48x/700mb 50 spindle has it!

I found this on sale at Tower Records today ($15.99), and since I just ripped the label in order to open the pack, here's an idea of what it looks like:

http://ideaspora.net/agus35/frosted.jpg

- jim

<<<-- Originally posted by Jim Lafferty : GREAT NEWS!

I've discovered where to get pre-frosted CDR's like Agus uses -- Maxell's 48x/700mb 50 spindle has it!

I found this on sale at Tower Records today ($15.99), and since I just ripped the label in order to open the pack, here's an idea of what it looks like:

http://ideaspora.net/agus35/frosted.jpg

- jim -->>>

Great news!...now Im gonna have 200+ CDR's laying around.... ;)

Thanks Devin, Look foward to seeing your final design and footage:D

Daniel,

Are these the clips you speak of at bobflash.com.br:

Clip 1

(bobcam-natalbarrozo-01.wmv -- 4.07mb)

Clip 2

(bobcam-natalbarrozo-02.wmv -- 3.47mb)

?

For future reference -- when posting clips, please include the file name and/or size in your post -- that way we know we're getting the right material.

- jim

If having trouble getting the CD disk to run true, three solutions - (1) Use the whole of the CD spindle system including the pressure plate which clamps from the opposite side. This is supposed to let the CD find its correct position through gyro effect with the inner hub acting more like a clutch and centre rather than an alignment. The motor remains hard mounted. (

2) If this can't be done because of limited space and you have to mount the CD rigidly to the spindle, try making a diaphragm mount for the motor if the motor is of face-mount Mabuchi style construction. Make a little thin disk or square out of something really light and pliable. Shim steel would be best. Ice cream or milk container is okay but it will deform out of position in time. Face-mount the motor to this. You'll need to be able to precisely drill 4 holes through it, one for the motor spindle shaft, three for the screws.

( A quick and dirty cheat for making a template is to place an identical motor face down on the platen of a scanner or photocopier. The spindle shaft will have to have been removed though some photocopiers or scanners will accurately scan an object up to half an inch away from the platen. - So you'll probably have to have a second motor to dismantle for this. Slide-tray CD players often
have similar motors for tray and transport drives so these could be used. Print the scan and check the distance between the holes against the motor. Glue the print to the metal or plastic you want to drill, mark or centrepunch through the paper then drill through it. Printing to a sticky label makes the job even easier.) Mount the plate or glue it to the case. When the CD runs up to speed and straightens out, the motor will be seen to be vibrating slightly.

(3) Make a foam rubber sock out of hotwater pipe
insulation. Fix your spindle motor inside this and mount the foam inside a piece of plastic pipe glued to the case. It may be harder to keep the motor is position though as the material will slump in time.

For Aussie visitors, with Chris kennelmaster's help, there may soon be a .jpg of a partly assembled early prototype of the Agus35 non-inverter rotary groundglass principle, using Australian standard PVC plumbing bits for case and lens tube structure, plus a Decor potplant saucer as a soft motor mount. (Yes the sock will be there).

Once the motor and disk image plane positions have been tied down by testing, the lens tube will be shortened to accept a proper lens mount for the objective lens and some sort of attachment, probably 58mm filter thread for the PD150 at the other.

There will be observed a cut-out in the lens tube insude the enclosure. This provides assembly clearance for the motor and disk mount which clips into place. The enclosure case comprises two riser caps and a short piece of pipe inside one purely as an internal guide sleeve for case assembly.

The disk sits ahead of the orange saucer driven by the motor mounted behind - not fitted in this illustration. The battery holder will fit in the rear enclosure with the motor and the switch will be mounted to the rear cover which will be the removable cover for maintenance.

Fixing of the covers will be by long pillar nuts and screws as used to mount circuit boards.

bob sounds great... looking forward to seeing it.

I have some webspace, just email me zac@mindfreeproductions.com

Zac

jim
 

yeah,

these are the clips

i just told about the clips, xmas ones, 24th ones.

thanks

ciao

Bob Hart's images now online at www.dvinfo.net/media/hart.

By the way, I've finally edited a boiled-down version of this thread which you can read at http://www.dvinfo.net/conf/showthrea...threadid=18950 -- but continue to post responses to this one, please.

The edited version has been chopped down to about half the size of the original, but if anyone sees more stuff in it that can afford to go away, please let me know. Hope this helps,

In relation to using fibre-optics for image inversion I enquired with Electrophysics Corporation in the US who make the Astroscope line of camcorder image intensifiers and have received advice which indicates fibre-optics would not suit our application.

Their representatvie was most co-operative and gave a prompt response even though I was not in the market for their product.

An extract follows :-

"""
Clearly the prism/mirror approach would be lower cost and better performance. There is no existing production of image twisters having 35mm format. In addition, performance will be degraded in several areas:

1) There will be a significant reduction in effective F-number from the coherent fiber bundle (they usually have about 30% transmission);

2) Resolution (MTF) will be significantly reduced due to the limited size of each fiber;

3) They will be costly.

""""
(End quote).

Therefore, it's back to the lenses, mirrors and prisms. Well it was worth a thought.

Wow, that's really cool that they were so informative.

For those of you who are looking to build an Agus35 for your GL1/GL2, I'm in the final stages of mine (read: sanding epoxy down and applying the last coat of black paint).

I had it up and running a moment ago and the image is stunning -- the pre-frosted disc makes all the difference in the world, and using a CD motor makes this quieter than a whisper.

Here are the pics:

http://ideaspora.net/agus35/final/front.jpg

http://ideaspora.net/agus35/final/rear.jpg

http://ideaspora.net/agus35/final/motor.jpg

http://ideaspora.net/agus35/final/disc.jpg

http://ideaspora.net/agus35/final/full1.jpg

http://ideaspora.net/agus35/final/full2.jpg

Footage up later today.

- jim

<<<-- Originally posted by Jim Lafferty : GREAT NEWS!

I've discovered where to get pre-frosted CDR's like Agus uses -- Maxell's 48x/700mb 50 spindle has it!

I found this on sale at Tower Records today ($15.99), and since I just ripped the label in order to open the pack, here's an idea of what it looks like:

http://ideaspora.net/agus35/frosted.jpg

- jim -->>>

Hey there Jim, i bought the same spindle,but the label is green, and unfortunaly it didnt came with the frosted CD inside...

Try up finding the blue label ones instead.

Agus Casse

The label on mine was blue with a green tint -- sort of a deep aqua. Dunno why yours didn't have a frosted CD? I'll pick up another spindle next week and let you know.

- jim

Well, I thought I'd have footage up tonight, but I've just come home and there's a long render ahead. It's 12am and someone's waiting upstairs for me :)

However, as proof of the improved imagery I've grabbed some full-res stills from the footage I shot around the house today. Be aware that it is not "well lit," and was intentionally so -- I wanted to see what the adapter would produce under "normal" circumstances.

Also, there can be seen some minor vignetting in a shot or two -- this is because my adapter is still without a rail setup and consequently there is noticable movement when the focus ring is adjusted on the 50mm lens -- the adapter will occasionally slip out of alignment, bringing vignetting into view. Hopefully I'll have the rod setup done by week's end.

This room is lit by minor exterior light and two 60 watt bulbs. I shot it at 1/60th, f/2.0 on my GL1, with gain set to 6 (yes, I'm aware of grain produced...)

Here you go:

http://ideaspora.net/agus35/teststills/

- jim

Those looks really nice, dont worry about the grain and lowlight... if you light up more the scene, you will be able to reduce it, same happens with the TRV18, i need to put it like 5-6 steps before the max exposure to get some low grain image.

Also, you can underexposure and then light it up in post.

GG substitute
 

Hi all, I just started reading this thread so I apologize if this has been brought up already.

There is an optical concept where if you wave a stick up and down very quickly with your hand and wrist (like swatting a fly)you can project an image on the plane that the stick passes through. the image appears to be visible in mid-air. My observation is that if you had 2 or maybe 4 propeller-like white arms at 90 or 180 degrees to each other, and had them spinning fast enough, the image would appear on the plane where the arms were spinning. An easy way to test this yourself is to take a slide projector or LCD projector or film projector and hold a piece of paper about 5 feet in front of the lens and focus the image on it. Then remove the paper and while moving the stick up and down rapidly, you will see the image where the paper used to be. The optical principal is called Persistence of Vision.

I will attach the sicence part of this as JPEG's for chris to post.

David Mesloh
just lurking on this one.

I'll attach

Found the frosted CD in the same maxell 50 pack at my local STAPLES... they had a ton of Maxcell cd packs... this rang in at 9.99... for 50 cds, thats not a bad deal anyways

below is a link to a better picture of the packaging and cd(s)

http://www.orfilms.com/cd.jpg

The problem with this is that it's not so much generated by light in and of itself, it's because of the way your eyes work. Meaning, it wouldn't really help with what we're trying to do. A camera CCD and your eye don't work in quite the same way. Also, if you tried the spinning shutter like you mentioned, all you would end up with is a very flickery picture since the response time for bright lights is much faster on the CCD than it is for your eye, which is what creates the persistence effect.

Jim Lafferty...
 

...was the grain in your images due to the frosted plastic, or to the gain in your GL1?

Probably low-light and gain. I'll start really running my setup through its paces once I've got my rod assembly up and running.

- jim

Jim Lafferty...

What are you using to magnify the frosted cd?

hey jim, do you think you can post pictures of how you are attaching the cd spindle to your GL1? i also have the same camera and was wondering the shape you cutted out.. thx

Your shots look good on your gl1 jim, i look foward to making an adapter when i get hold of my GL2/(XM2).

Look foward to seeing some footage still!:)

Ok, so maxell with bluel label have frosted cds, are they 50 packs, be careful, i bought the GREEN pack, and it didnt have one.

Oh and Happy new year to all! (when it comes) :)

Happy New YEAR ! from Guatemala to all the world!!