Homemade 35mm -- Edited Copy for Reading

Paul Bettner · November 24th, 2003, 02:13 AM

From the mini35 manual, it looks like the relay lens is something that goes between the DV camera lens and the ground glass, but in your set up it looks like the DV camera lens is just shooting the picture of the ground glass directly...

that's where I'm confused... it looks from your pictures like the DV camera lens is just sticking through the back of the box and taking a picture of the ground glass directly. Where is your "relay lens"? Is it a piece of glass that I can't see or is the relay lens just the lens of the DV camera itself?

Sorry about my confusion... maybe it's because the mini35 manual is for an XL1, which fits on the front of the camera directly instead of in front of a built-in lens like your camera?

Another question (Sorry, I should probably just wait for you to post more a more detailed website): How do you figure out the right distances between the back of the film lens, the ground glass, and the DV lens?

Finally: how did you fix the vignetting? I thought that required the use of some sort of fresnel piece?

paulb

p.s. it looks like eBay is a good place to find "real" ground glass. Just do a search for it and it turns up many results. With an 8x10 sheet of real ground glass and a circular glass cutter to make it the same size as a CD, maybe you can get a much better result (less light loss.)

Agus Casse · November 24th, 2003, 02:50 AM

Well, yeah you are right i am shooting directly to the ground glass, i use the term of "relay lens" just to undertand where it is positioned, sorry for that, my bad...

about the vigneting, you have to zoom in until it is gone, my cam has the manual focus broken (reason that i build the adapter!!) so to help the auto focus, i use a magnifying glass that i had from a wide conversion lens (the last glass magnify).

you can always get better ground glass if you buy it from a profesional, but my challenge was to build it with less than $10 (the cdrs box)... just to prove that the P+S adapter price is far overvalued, and you can get really good results with less, a lot less money.

I just shoot my self smooking a cigarette if you want to see, i can upload it in a couple of mins. (my baterries of the adapter are running low and it is 3am to go and buy another one, so you will notice that the ground glass speed isnt too fast) .

Paul Bettner · November 24th, 2003, 02:57 AM

Awesome... I will start experimenting soon! (Maybe tommorow?) Thank you for answering my questions!!

Is the magnifying glass required to make the set up work, or is that only in your case because of the broken manual focus? If it is required, where does it go in the setup?

I'd love to see more footage from the device. As much as you have! (I can host files for you also if you need bandwidth/web space - just let me know - paulbweb@hotmail.com)

paulb

Agus Casse · November 24th, 2003, 03:01 AM

Nah, it is not necesary to have the magnifying glass, i had the problem that when i zoomed it it went out of focus, thats why i used it... from there you should have no trouble at all.

Tomorrow we will shoot a TV spot with the adapter, lets see how it handle.... what i know for sure, is that i will need a lot more lighting equipment cause the ground glass loose a lot of light in the process.

Agus Casse · November 24th, 2003, 03:43 AM

http://altoque.tv/35mmAdapter/spotAdapter35mm.wmv

Some sample... hey.. i was bored... :)

Paul Bettner · November 24th, 2003, 03:55 AM

Oh man... I'm sure you feel the same way: that footage, even as simple as it is, looks just phenomenal coming from a TRV18... incredibly film-like, as they say. What else are you doing to that footage besides the adapter? It looks de-interlaced to me - does it have any other filmlook effects?

I'm very interested to see how this adapter handles in daylight.

Please keep us updated on how the shoot goes tommorow, as well as posting any more footage you have! I can't wait to get started building my own...

thank you so much,
paulb

Agus Casse · November 24th, 2003, 04:05 AM

I only use color corrector in premiere pro, in the daylight the adapter works perfectly, cause you have also the option to control the iris from the lens, that means less grain, i can underexpure and still get high light coming from the lens... it is a pretty tricky thing at first, but then you can have great control and excellent picture.

Cosmin Rotaru · November 24th, 2003, 04:11 AM

Hi Agus.
From the pics and your explanation I figured I could help you get better results...
"the ground glass loose a lot of light in the process"
A very fine GG will take away the vigneting but will also loose allot of light. A coarser GG will let more light to pass thorough, but you'll also gett allot of vignetting. You can get both a vignetting free image and also enogh light from the GG by combining a coarser (spinning, of course) GG and a fresnell lens. The fresnell lens, put in front of the GG (as close as posible) will even the light on the surface of the GG. (in front of hte GG - that is between the GG and the 35mm lens). Another thing to remember is that the fresnell lens, like any other lens, has its own focal point. The lens of the camcorder should be in that focal point of the fresnell, oherwise you'll not get rid of all vigneting. Now, depending of that focal distance, you'll need a "relay lens" so you can zoom in and focalize the camcorder on the GG.

Otherwise, with plenty of light, your footage looks great!

I hope you understand my bad english...

PS: You smoke to much! :)

Agus Casse · November 24th, 2003, 01:20 PM

<<<-- Originally posted by Jean-Philippe Archibald :

P.S.: Which "film lens" are you using? -->>>

I am an Minolta 50mm 1:2 lens from a SLR minolta camera, but i saw some 35mm lens from nikkon, with zoom, and focus control in like aprox $450 (reason that i willl shoot the video today, perhaps i could buy it if they take the ad)

Paul Bettner · November 24th, 2003, 05:13 PM

Agus, how did you figure out how far to place the 35mm lens from the CD and the CD from the lens of the DV camera?

paulb

Agus Casse · November 25th, 2003, 02:46 AM

Yeah, exactly, you get the picture upside/down, which it is a bitch to shoot, but you can correct it in post, today we shoot a xmas ad for a tv network with the adaptor, it worked prefectly, i will post some material when i get it edited...

i can get used to after a while, but still it is a bitch.... hehehe now... if i could get a pentaprism from a SLR camera, i could correct the image from the adaptor. just like the SLR camera...

I will make all plans in 3dsmax, with complete animations to download and step by step explanations and tips... remember.. this is a homemade version, something that you can make it fast and works 100% perfectly, from there you can improve it and therefore get better video (better ground glass, selective speed, correct image orientation...

A fast solution with the upside/down video is using a LCD monitor fliped out in the tripod, or the stabilizer... i will make some tests with my monitor soon as well.

Zac Stein · November 25th, 2003, 08:57 AM

just a question.

I have an old broken canon FD slr, if i removed the parts that run from the lens up to viewfinder, and blocked the light from other sections.....

well if i placed spinning ground glass at the end instead of the viewfinder ground glass... would that work... and then used say a diopater to magnify the image.... is that how the real mini-35 sort of works?

Zac

Agus Casse · November 25th, 2003, 02:05 PM

Yeah, give it a try... try first with a homemade ground glass... or the SLR camera ground glass... if it works, replace it with the spining one

Sebastian Scherrer · November 26th, 2003, 05:10 AM

I'm very much looking forward to your tutorial. I'll try to mount it to a XL1.

What modification would it require if it was to be mounted directly- that is without the
16x removable lense- to the cam?

Anybody been experimenting on this?
As for the XL1, it'd be much more practical, as the adapter could be made fit with the lense mounting mechanism!

Agus Casse · November 26th, 2003, 11:34 AM

I couldnt tell, i use a TRV18... but actually you should be able to mount it everywhere.

November 24th, 2003, 04:11 AM	#23
Cosmin Rotaru Major Player Join Date: Feb 2003 Location: Romania, Timisoara Posts: 453	Hi Agus. From the pics and your explanation I figured I could help you get better results... "the ground glass loose a lot of light in the process" A very fine GG will take away the vigneting but will also loose allot of light. A coarser GG will let more light to pass thorough, but you'll also gett allot of vignetting. You can get both a vignetting free image and also enogh light from the GG by combining a coarser (spinning, of course) GG and a fresnell lens. The fresnell lens, put in front of the GG (as close as posible) will even the light on the surface of the GG. (in front of hte GG - that is between the GG and the 35mm lens). Another thing to remember is that the fresnell lens, like any other lens, has its own focal point. The lens of the camcorder should be in that focal point of the fresnell, oherwise you'll not get rid of all vigneting. Now, depending of that focal distance, you'll need a "relay lens" so you can zoom in and focalize the camcorder on the GG. Otherwise, with plenty of light, your footage looks great! I hope you understand my bad english... PS: You smoke to much! :) __________________ Cosmin Rotaru

November 26th, 2003, 05:10 AM	#29
Sebastian Scherrer Regular Crew Join Date: Nov 2003 Location: Mainz, Germany Posts: 26	I second to that. I'm very much looking forward to your tutorial. I'll try to mount it to a XL1. What modification would it require if it was to be mounted directly- that is without the 16x removable lense- to the cam? Anybody been experimenting on this? As for the XL1, it'd be much more practical, as the adapter could be made fit with the lense mounting mechanism!

November 24th, 2003, 02:13 AM	#16
Paul Bettner Regular Crew Join Date: May 2003 Location: Dallas, TX Posts: 42	From the mini35 manual, it looks like the relay lens is something that goes between the DV camera lens and the ground glass, but in your set up it looks like the DV camera lens is just shooting the picture of the ground glass directly... that's where I'm confused... it looks from your pictures like the DV camera lens is just sticking through the back of the box and taking a picture of the ground glass directly. Where is your "relay lens"? Is it a piece of glass that I can't see or is the relay lens just the lens of the DV camera itself? Sorry about my confusion... maybe it's because the mini35 manual is for an XL1, which fits on the front of the camera directly instead of in front of a built-in lens like your camera? Another question (Sorry, I should probably just wait for you to post more a more detailed website): How do you figure out the right distances between the back of the film lens, the ground glass, and the DV lens? Finally: how did you fix the vignetting? I thought that required the use of some sort of fresnel piece? paulb p.s. it looks like eBay is a good place to find "real" ground glass. Just do a search for it and it turns up many results. With an 8x10 sheet of real ground glass and a circular glass cutter to make it the same size as a CD, maybe you can get a much better result (less light loss.)

November 24th, 2003, 02:50 AM	#17
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	Well, yeah you are right i am shooting directly to the ground glass, i use the term of "relay lens" just to undertand where it is positioned, sorry for that, my bad... about the vigneting, you have to zoom in until it is gone, my cam has the manual focus broken (reason that i build the adapter!!) so to help the auto focus, i use a magnifying glass that i had from a wide conversion lens (the last glass magnify). you can always get better ground glass if you buy it from a profesional, but my challenge was to build it with less than $10 (the cdrs box)... just to prove that the P+S adapter price is far overvalued, and you can get really good results with less, a lot less money. I just shoot my self smooking a cigarette if you want to see, i can upload it in a couple of mins. (my baterries of the adapter are running low and it is 3am to go and buy another one, so you will notice that the ground glass speed isnt too fast) .

November 24th, 2003, 02:57 AM	#18
Paul Bettner Regular Crew Join Date: May 2003 Location: Dallas, TX Posts: 42	Awesome... I will start experimenting soon! (Maybe tommorow?) Thank you for answering my questions!! Is the magnifying glass required to make the set up work, or is that only in your case because of the broken manual focus? If it is required, where does it go in the setup? I'd love to see more footage from the device. As much as you have! (I can host files for you also if you need bandwidth/web space - just let me know - paulbweb@hotmail.com) paulb

November 24th, 2003, 03:01 AM	#19
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	Nah, it is not necesary to have the magnifying glass, i had the problem that when i zoomed it it went out of focus, thats why i used it... from there you should have no trouble at all. Tomorrow we will shoot a TV spot with the adapter, lets see how it handle.... what i know for sure, is that i will need a lot more lighting equipment cause the ground glass loose a lot of light in the process.

November 24th, 2003, 03:43 AM	#20
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	http://altoque.tv/35mmAdapter/spotAdapter35mm.wmv Some sample... hey.. i was bored... :)

November 24th, 2003, 03:55 AM	#21
Paul Bettner Regular Crew Join Date: May 2003 Location: Dallas, TX Posts: 42	Oh man... I'm sure you feel the same way: that footage, even as simple as it is, looks just phenomenal coming from a TRV18... incredibly film-like, as they say. What else are you doing to that footage besides the adapter? It looks de-interlaced to me - does it have any other filmlook effects? I'm very interested to see how this adapter handles in daylight. Please keep us updated on how the shoot goes tommorow, as well as posting any more footage you have! I can't wait to get started building my own... thank you so much, paulb

November 24th, 2003, 04:05 AM	#22
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	I only use color corrector in premiere pro, in the daylight the adapter works perfectly, cause you have also the option to control the iris from the lens, that means less grain, i can underexpure and still get high light coming from the lens... it is a pretty tricky thing at first, but then you can have great control and excellent picture.

November 24th, 2003, 01:20 PM	#24
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	<<<-- Originally posted by Jean-Philippe Archibald : P.S.: Which "film lens" are you using? -->>> I am an Minolta 50mm 1:2 lens from a SLR minolta camera, but i saw some 35mm lens from nikkon, with zoom, and focus control in like aprox $450 (reason that i willl shoot the video today, perhaps i could buy it if they take the ad)

November 24th, 2003, 05:13 PM	#25
Paul Bettner Regular Crew Join Date: May 2003 Location: Dallas, TX Posts: 42	Agus, how did you figure out how far to place the 35mm lens from the CD and the CD from the lens of the DV camera? paulb

November 25th, 2003, 02:46 AM	#26
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	Yeah, exactly, you get the picture upside/down, which it is a bitch to shoot, but you can correct it in post, today we shoot a xmas ad for a tv network with the adaptor, it worked prefectly, i will post some material when i get it edited... i can get used to after a while, but still it is a bitch.... hehehe now... if i could get a pentaprism from a SLR camera, i could correct the image from the adaptor. just like the SLR camera... I will make all plans in 3dsmax, with complete animations to download and step by step explanations and tips... remember.. this is a homemade version, something that you can make it fast and works 100% perfectly, from there you can improve it and therefore get better video (better ground glass, selective speed, correct image orientation... A fast solution with the upside/down video is using a LCD monitor fliped out in the tripod, or the stabilizer... i will make some tests with my monitor soon as well.

November 25th, 2003, 08:57 AM	#27
Zac Stein Major Player Join Date: Aug 2002 Location: Melbourne, Australia Posts: 730	just a question. I have an old broken canon FD slr, if i removed the parts that run from the lens up to viewfinder, and blocked the light from other sections..... well if i placed spinning ground glass at the end instead of the viewfinder ground glass... would that work... and then used say a diopater to magnify the image.... is that how the real mini-35 sort of works? Zac

November 25th, 2003, 02:05 PM	#28
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	Yeah, give it a try... try first with a homemade ground glass... or the SLR camera ground glass... if it works, replace it with the spining one

November 26th, 2003, 11:34 AM	#30
Agus Casse Major Player Join Date: Jul 2003 Location: Guatemala Posts: 322	I couldnt tell, i use a TRV18... but actually you should be able to mount it everywhere.