Homemade 35mm Adapter

Filip Kovcin · March 16th, 2004, 04:33 PM

Jim,

very nice idea, but this will be very difficult with agus35, because of rotating GG, but maybe in static solution....

it looks that this is much easier to do there.

just a thought

filip

Bob Hart · March 16th, 2004, 07:45 PM

Jim.

Moving the screen with a rotating CD is a dead-easy option if you use three fixed screws as pillar bolts, springs and adjustment nuts to set backfocus and alignment by moving the motor mount plate. Just add a push button with it's own return spring (maybe an old switch with the back removed and an extension added to the shaft) so that when you press it in, it butts against the motor mount plate and pushes it in momentarily, moving the focal plane in the required direction on one side.

Agus.

I'm using Premiere 6. I have selected "always de-interlace, but have not been ssaving a pre-view or rendering out before adding the other effects. Maybe this is it. Thanks for the clues.

The difference between doing it in Premiere then extracting a sample frame and extracting an un-adjusted sample frame and then doing it in Ulead Photo Plus 4 is profound. Any problems I have had with Premiere 6 have always turned out to be my mismanagement of the software. I'm sure I am mismanaging it again but have not worked it out yet.

I'll make up a comparison .jpg and send it to Chris because that best shows what is happening.

Brett Erskine · March 17th, 2004, 03:48 AM

Jim why did you have to give that away. That is part of my design. I was hoping to surprise everyone. Oh well. Anyways yes it can be done but not too well with standard 35mm lenses. You'll need to step up to a medium format or larger. Although they do make a few tilt shift lens in 35mm. The problem with using a normal 35mm lens is that when you start getting into things like rise movements you need a lens that projects a image a fair size bigger than around 36mm by 24mm. Otherwise your going to run into major fall of problems. There are also other issues as well since our GG effected by the focal point of two lens (one on each side of the GG). Great thinking though Jim. Its funny more we work on this adapters more we come full circle to how a bellows camera looks and works.

Bob Hart · March 17th, 2004, 06:17 AM

RE: Bellows camera. I think I recall the term "camera obscura" used in one of the early posts. The bellows camera was a quantum leap forward from the pinhole camera.

I have emailed a comparison image set to Chris relating to the AP6 resolution problem I have experienced. This file will be "AGUSPROB2.JPG"

Would anyone be willing to accept a snailmailed .avi file or 42 minute DVCAM tape of raw non-inverted footage of the music video to experiment upon? I have the consent of the singer- songwriter-copyright holder, to post the footage or cause it to be posted.

The spec of the footage is :-

Running time 5 mins.
Head slate and tail slate.

Vision :-

Inverted, aquired via AGUS35
Electronic 16:9.
DVCAM PAL. (Sony DSR PD150P).

Defects in vision :-

Overexposed two f'stops due to changing light.
Some density variation and flicker apparent.

Sound.

48k 16bit Stereo.

Errors in sound :-

Location sound was amplified voice, distortion in beginning, guitar is clean. Camera manual record level was kept down to about -20db due to occasional loud spots in the performances.

If somebody is willing and able to exact the cure and perhaps make it web downloadable at a respectable resolution for the benefit of constructors, this would be appreciated. I will need to check again with Chris. My understanding is he would be willing to host downloadable motion footage at www.dvinfo.net

I am beginning to accept I might be a little undercapitalised and insufficiently skilled for this exercise. By the time I get my act together and have some AGUS35 motion origination people can make valid judgements upon, excessive time may have passed.

Agus Casse · March 17th, 2004, 11:02 PM

Hey bob, i never have the chance to thank you for the constant progress of the proyect... thank you very much..

btw are you still using a rotating ground glass ? i want to make a static adapter and test which one is better.

Bob Hart · March 18th, 2004, 07:05 AM

Hello Agus.

Re: Rotating groundglass.

Yes I am sticking with what I have for the present. I don't see the rotating groundglass and fixed groundglass as competing principles rather as tools for special purposes.

For less weight and small size, the fixed glass is better for small camcorders. Otherwise you defeat the very purpose they are made for, the convenience of light weight, simple operation and mobility.

A rotating glass versus a fixed glass for the same groundglass texture will always yield a superior image so any work done to improve fixed groundglasses is going to benefit the development of rotating versions. Getting the glass to run true requires a little care but is not impossible.

There are creative things you can do with a rotating CD groundglasses like varying the polish-back to create less dense patches in the surface. If the spindle centre is set off to the left rather than above or below the projected image frame, you can come close to the effect of the vertical varying density bands one sometimes sees in projected motion film if you adjust the spindle motor speed to almost strobe with the camcorder frame rate.

Testing which version is better is as simple as turning the spindle motor off. There is little if any difference to see but if you are not chasing an aggressive depth of field effect, you can close the objective lens aperture furthur before you see any defects from the groundglass surface.

Best practice seems to be to keep the objective lens open and use neutral density filters or gels to control the light instead of the aperture or the camcorder controls. Too much light onto the groundglass seems to spoil the contrast.

Slightly off-topic info follows. DVD-Video players which have to be a little more precise have an extra little trick you won't find on a CD player spindle motor though in most respects you will find little difference in the basic setup (still three Mabuchi style miniature electric plain-bearing motors).

To stop the spindle shalt jumping inwards and outwards in a cheap plain-bearing motor (end-float) they have come up with a cheap little low friction solution.

It is a small nylon vee-pulley which has a tiny stiff thin wire spring sliding in it. It has the added benefit of imposing a small side load on the shaft as well to take up chatter of the shaft in the bearing clearance which might be enough to throw off the tracking. One of the subjects I think I mentioned in earlier posts related to this being a cause of noise.

Matthew Johnson · March 18th, 2004, 10:29 AM

I was looking at this thread and let me say I'm very excited. However, I JUST started looking at it an there's well over 1000 posts (a bit overwhelming). I looked through the stuff for about an hour to see if Agus ever created that web page with a tutorial, or does any1 else have one. The idea is great, but I think I need a central place with a set of instructions in order to get this thing under way, and then i can sift through this thread and get ideas on how to improve it. So, if there is one, could you please direct me to it. If it's posted somehwre in this thread I appologize, but please understand at this point this thread is so big that it's a bit overwhelming and time consuming to search for a thing like that.

Frank Ladner · March 18th, 2004, 10:55 AM

Matthew: Yes, following these threads can be overwhelming. There's a lot of info to digest, as you know. I would almost reccommend reading in a back-to-front sort of manner, because there have been several improvements on the device, and you don't want to start building based on the first posts.

Here are some links to get you started:

http://ideaspora.net/agus35

http://www.metafilms.net/upload_images/agus35.gif

http://infrastructuredv.com/g35d/

Hope this helps!

Bob Hart · March 18th, 2004, 08:06 PM

RE: the music video with the Agus35, I have found that my version of Premiere will create a Netscape page which puts up a little screen which plays the video, one of my failed experiments in the steep learning curve.

The resolution is dreadful but apparently this is the case for all downloadable material. The file size is about 10 mb for an original 1 gb clip so something has to give I guess.

I will try to email this to Chris for posting here at dvinfo. In combination with stills it may give some indication of the Agus35 in practical use. The video is not complex, just a simple one camera take of the whole song outdoors.

Bob Hart · March 19th, 2004, 12:18 AM

If Chris is around, maybe he will see this message and advise me of a method of uploading an approx 10Mb Quicktime video file. It currently consists of a folder titled "export00" which contains another folder titled "upload to HTTP address" and four files which will each play at various resolutions.

They all look fairly crappy.

Matthew Johnson · March 19th, 2004, 12:53 AM

Is the distance from the rear lens element to the GG super cirital? I made the first part of the Agus35 today and tommorow I'm going to make the 35mm lens mount. I'll be using Canon's EF lenses. I know there is a certain distance it should be, but how ciritcal is it, cause I feel as though this could be the most challenging part (lining up the center of the 35mm lens to the ceneter of the DV lens and making sure the distance from the 35mm to the gg is the correct distance). Thnx

Bob Hart · March 19th, 2004, 05:45 AM

With a simple prime lens, you'll get away with the backfocus being a bit off but there will be problems, maybe with not being able to get infinity focus or confusing operating conditions if your lens is too close and you focus past infinity and the image softens again. If you use a zoom lens it will be pretty much useless unless you get the backfocus right.

If you just want to rough up a simple demonstrator of the principle then nothing is critical. What can be frustrating is becoming encouraged to take it to a higher useful level, then having to do some work over again when a little more initial care or time taken would have avoided it.

Establishing the back focus distance or flange to focal plane distance (same thing) is as easy as having the camera the lens came off and measuring the distance from the lens mount rear face to the focal plane. On the case of your camera somewhere there will be a little circle with a line through it. That's the focal plane.

Chris Hurd · March 19th, 2004, 08:35 AM

Bob -- I will try to get a temporary upload account established for you today. If you don't hear from me, please keep bugging me about it until it's done.

Note to all -- an off-topic side discussion involving email virus issues has been deleted. Thanks,

John Heskett · March 19th, 2004, 09:15 AM

Bob,
I got a similar email from our system administrator to my personal email. The RED FLAG, I'm the system administrator and I knew I didn't send any such email out. Our system was clean as well as my email account but the email sent to me was a virus. This is the reason I said what I did about the email possibility being a virus spoofing the network ID.

I know this is a little off topic, however I feel it is important.
FYI: I got some new information on a revised threat. It does NOT require you to open an attachment to spread.

"Alert to control the spread of PE_BAGLE.Q.
TrendLabs has received numerous infection reports of this malware spreading in Korea and Japan.

This new BAGLE variant is capable of infecting files. It propagates via email in two ways. The first is by sending emails,
which do not have an attachment. Instead it contains a link, which upon opening the email, starts a series of events that
eventually downloads this file infector into the system. The second is that the email may contain varying subjects,
message bodies, and attachment file names, just like its earlier
variants."

John

Bob Hart · March 19th, 2004, 08:09 PM

John.

Thanks for the reply. My habit with anything strange and different is never to open it but delete it. Can this thing propogate from within the in-box on being received or does it still have to be opened?

Because this machine is a W95B, no virus software seems to support it and the on-line virus screens now require Explorer 5 or better to come out and play. Mcafee stays home unless Explorer knocks on the door.

According to a nearby vendor, it seems the only way will be to extract the hard drive, make a temporary slave of it in a W98 machine and give it a scrub there.

That's my video machine. Will it go something like "TIIIIIIMMMMMBERRRRRRR" and that pretty sky blue screen with white Courier typeface show its ugliest face forever after?

March 17th, 2004, 03:48 AM	#1008
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Tilt/Shift Jim why did you have to give that away. That is part of my design. I was hoping to surprise everyone. Oh well. Anyways yes it can be done but not too well with standard 35mm lenses. You'll need to step up to a medium format or larger. Although they do make a few tilt shift lens in 35mm. The problem with using a normal 35mm lens is that when you start getting into things like rise movements you need a lens that projects a image a fair size bigger than around 36mm by 24mm. Otherwise your going to run into major fall of problems. There are also other issues as well since our GG effected by the focal point of two lens (one on each side of the GG). Great thinking though Jim. Its funny more we work on this adapters more we come full circle to how a bellows camera looks and works.

March 17th, 2004, 11:02 PM	#1010
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	Hey bob, i never have the chance to thank you for the constant progress of the proyect... thank you very much.. btw are you still using a rotating ground glass ? i want to make a static adapter and test which one is better. __________________ Agus35 - the ultimate tool for indie DV filmakers -

March 19th, 2004, 08:35 AM	#1018
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	Bob -- I will try to get a temporary upload account established for you today. If you don't hear from me, please keep bugging me about it until it's done. Note to all -- an off-topic side discussion involving email virus issues has been deleted. Thanks, __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

March 19th, 2004, 09:15 AM	#1019
John Heskett Regular Crew Join Date: Apr 2003 Location: Terre Haute Indiana Posts: 181	Bob, I got a similar email from our system administrator to my personal email. The RED FLAG, I'm the system administrator and I knew I didn't send any such email out. Our system was clean as well as my email account but the email sent to me was a virus. This is the reason I said what I did about the email possibility being a virus spoofing the network ID. I know this is a little off topic, however I feel it is important. FYI: I got some new information on a revised threat. It does NOT require you to open an attachment to spread. "Alert to control the spread of PE_BAGLE.Q. TrendLabs has received numerous infection reports of this malware spreading in Korea and Japan. This new BAGLE variant is capable of infecting files. It propagates via email in two ways. The first is by sending emails, which do not have an attachment. Instead it contains a link, which upon opening the email, starts a series of events that eventually downloads this file infector into the system. The second is that the email may contain varying subjects, message bodies, and attachment file names, just like its earlier variants." John __________________ Illuminate the Vision

March 16th, 2004, 04:33 PM	#1006
Filip Kovcin Major Player Join Date: Dec 2003 Location: warsaw, poland Posts: 440	Jim, very nice idea, but this will be very difficult with agus35, because of rotating GG, but maybe in static solution.... it looks that this is much easier to do there. just a thought filip

March 16th, 2004, 07:45 PM	#1007
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	Jim. Moving the screen with a rotating CD is a dead-easy option if you use three fixed screws as pillar bolts, springs and adjustment nuts to set backfocus and alignment by moving the motor mount plate. Just add a push button with it's own return spring (maybe an old switch with the back removed and an extension added to the shaft) so that when you press it in, it butts against the motor mount plate and pushes it in momentarily, moving the focal plane in the required direction on one side. Agus. I'm using Premiere 6. I have selected "always de-interlace, but have not been ssaving a pre-view or rendering out before adding the other effects. Maybe this is it. Thanks for the clues. The difference between doing it in Premiere then extracting a sample frame and extracting an un-adjusted sample frame and then doing it in Ulead Photo Plus 4 is profound. Any problems I have had with Premiere 6 have always turned out to be my mismanagement of the software. I'm sure I am mismanaging it again but have not worked it out yet. I'll make up a comparison .jpg and send it to Chris because that best shows what is happening.

March 17th, 2004, 06:17 AM	#1009
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	RE: Bellows camera. I think I recall the term "camera obscura" used in one of the early posts. The bellows camera was a quantum leap forward from the pinhole camera. I have emailed a comparison image set to Chris relating to the AP6 resolution problem I have experienced. This file will be "AGUSPROB2.JPG" Would anyone be willing to accept a snailmailed .avi file or 42 minute DVCAM tape of raw non-inverted footage of the music video to experiment upon? I have the consent of the singer- songwriter-copyright holder, to post the footage or cause it to be posted. The spec of the footage is :- Running time 5 mins. Head slate and tail slate. Vision :- Inverted, aquired via AGUS35 Electronic 16:9. DVCAM PAL. (Sony DSR PD150P). Defects in vision :- Overexposed two f'stops due to changing light. Some density variation and flicker apparent. Sound. 48k 16bit Stereo. Errors in sound :- Location sound was amplified voice, distortion in beginning, guitar is clean. Camera manual record level was kept down to about -20db due to occasional loud spots in the performances. If somebody is willing and able to exact the cure and perhaps make it web downloadable at a respectable resolution for the benefit of constructors, this would be appreciated. I will need to check again with Chris. My understanding is he would be willing to host downloadable motion footage at www.dvinfo.net I am beginning to accept I might be a little undercapitalised and insufficiently skilled for this exercise. By the time I get my act together and have some AGUS35 motion origination people can make valid judgements upon, excessive time may have passed.

March 18th, 2004, 07:05 AM	#1011
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	Hello Agus. Re: Rotating groundglass. Yes I am sticking with what I have for the present. I don't see the rotating groundglass and fixed groundglass as competing principles rather as tools for special purposes. For less weight and small size, the fixed glass is better for small camcorders. Otherwise you defeat the very purpose they are made for, the convenience of light weight, simple operation and mobility. A rotating glass versus a fixed glass for the same groundglass texture will always yield a superior image so any work done to improve fixed groundglasses is going to benefit the development of rotating versions. Getting the glass to run true requires a little care but is not impossible. There are creative things you can do with a rotating CD groundglasses like varying the polish-back to create less dense patches in the surface. If the spindle centre is set off to the left rather than above or below the projected image frame, you can come close to the effect of the vertical varying density bands one sometimes sees in projected motion film if you adjust the spindle motor speed to almost strobe with the camcorder frame rate. Testing which version is better is as simple as turning the spindle motor off. There is little if any difference to see but if you are not chasing an aggressive depth of field effect, you can close the objective lens aperture furthur before you see any defects from the groundglass surface. Best practice seems to be to keep the objective lens open and use neutral density filters or gels to control the light instead of the aperture or the camcorder controls. Too much light onto the groundglass seems to spoil the contrast. Slightly off-topic info follows. DVD-Video players which have to be a little more precise have an extra little trick you won't find on a CD player spindle motor though in most respects you will find little difference in the basic setup (still three Mabuchi style miniature electric plain-bearing motors). To stop the spindle shalt jumping inwards and outwards in a cheap plain-bearing motor (end-float) they have come up with a cheap little low friction solution. It is a small nylon vee-pulley which has a tiny stiff thin wire spring sliding in it. It has the added benefit of imposing a small side load on the shaft as well to take up chatter of the shaft in the bearing clearance which might be enough to throw off the tracking. One of the subjects I think I mentioned in earlier posts related to this being a cause of noise.

March 18th, 2004, 10:29 AM	#1012
Matthew Johnson New Boot Join Date: Mar 2004 Posts: 5	I was looking at this thread and let me say I'm very excited. However, I JUST started looking at it an there's well over 1000 posts (a bit overwhelming). I looked through the stuff for about an hour to see if Agus ever created that web page with a tutorial, or does any1 else have one. The idea is great, but I think I need a central place with a set of instructions in order to get this thing under way, and then i can sift through this thread and get ideas on how to improve it. So, if there is one, could you please direct me to it. If it's posted somehwre in this thread I appologize, but please understand at this point this thread is so big that it's a bit overwhelming and time consuming to search for a thing like that.

March 18th, 2004, 10:55 AM	#1013
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	Matthew: Yes, following these threads can be overwhelming. There's a lot of info to digest, as you know. I would almost reccommend reading in a back-to-front sort of manner, because there have been several improvements on the device, and you don't want to start building based on the first posts. Here are some links to get you started: http://ideaspora.net/agus35 http://www.metafilms.net/upload_images/agus35.gif http://infrastructuredv.com/g35d/ Hope this helps!

March 18th, 2004, 08:06 PM	#1014
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	RE: the music video with the Agus35, I have found that my version of Premiere will create a Netscape page which puts up a little screen which plays the video, one of my failed experiments in the steep learning curve. The resolution is dreadful but apparently this is the case for all downloadable material. The file size is about 10 mb for an original 1 gb clip so something has to give I guess. I will try to email this to Chris for posting here at dvinfo. In combination with stills it may give some indication of the Agus35 in practical use. The video is not complex, just a simple one camera take of the whole song outdoors.

March 19th, 2004, 12:18 AM	#1015
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	If Chris is around, maybe he will see this message and advise me of a method of uploading an approx 10Mb Quicktime video file. It currently consists of a folder titled "export00" which contains another folder titled "upload to HTTP address" and four files which will each play at various resolutions. They all look fairly crappy.

March 19th, 2004, 12:53 AM	#1016
Matthew Johnson New Boot Join Date: Mar 2004 Posts: 5	Is the distance from the rear lens element to the GG super cirital? I made the first part of the Agus35 today and tommorow I'm going to make the 35mm lens mount. I'll be using Canon's EF lenses. I know there is a certain distance it should be, but how ciritcal is it, cause I feel as though this could be the most challenging part (lining up the center of the 35mm lens to the ceneter of the DV lens and making sure the distance from the 35mm to the gg is the correct distance). Thnx

March 19th, 2004, 05:45 AM	#1017
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	With a simple prime lens, you'll get away with the backfocus being a bit off but there will be problems, maybe with not being able to get infinity focus or confusing operating conditions if your lens is too close and you focus past infinity and the image softens again. If you use a zoom lens it will be pretty much useless unless you get the backfocus right. If you just want to rough up a simple demonstrator of the principle then nothing is critical. What can be frustrating is becoming encouraged to take it to a higher useful level, then having to do some work over again when a little more initial care or time taken would have avoided it. Establishing the back focus distance or flange to focal plane distance (same thing) is as easy as having the camera the lens came off and measuring the distance from the lens mount rear face to the focal plane. On the case of your camera somewhere there will be a little circle with a line through it. That's the focal plane.

March 19th, 2004, 08:09 PM	#1020
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	John. Thanks for the reply. My habit with anything strange and different is never to open it but delete it. Can this thing propogate from within the in-box on being received or does it still have to be opened? Because this machine is a W95B, no virus software seems to support it and the on-line virus screens now require Explorer 5 or better to come out and play. Mcafee stays home unless Explorer knocks on the door. According to a nearby vendor, it seems the only way will be to extract the hard drive, make a temporary slave of it in a W98 machine and give it a scrub there. That's my video machine. Will it go something like "TIIIIIIMMMMMBERRRRRRR" and that pretty sky blue screen with white Courier typeface show its ugliest face forever after?