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Homemade 35mm Adapter
Note from Chris Hurd: This is an edited, locked version of the original "Homemade 35mm" thread located here. It has been edited by removing off-topic posts, meta-data (such as "great job!" etc.), repeated questions, and so on. This should make your reading of the entire relevant technical discussion a bit easier. If you'd like to add to this discussion, or post a question which has not yet been asked, please do so at the original thread located here. Hope this helps -- CH hello there, for all the "film look" fans... i have some news.. i have been experimenting for a while with a 50mm lens a homemade ground glass, a magnifying glass, and also a Dreamcast video game vibrator accesory... It works pretty fine.. the image comes from the lens and create the proyection in the ground glass.. which vibrates at high speed.. reducing a lot the grain from the ground glass.. from there i use the magnifying glass to capture more the of the usable part of the projection (you always will get a round shaped bright light coming form the lens) from there i capure it with my cheap TRV18 .... Open a new world to me in filming that will lead me to create a lot better video with a lot less money. The optics are great.. as soon as i finish up the box i will post up the plans so anyone that want to give it a shoot could pass all the troubles that i found with no problem. |
Ok, i have some shoots that i made with the adapter finished... it is all in testing stage at the moment.. but i can ensure you that with less than 30bucks you will get perfect 35mm quality DOF...
http://altoque.tv/test35mm2.mpg There is another test... it was shoot in the middle of the night with no aditional light....just a test.. the vigneting is caused because of the low quality ground glass... |
Ok...
i finish up the adapter.. you cant imagen how awesome optics and DOF i am getting now... here is a pic of the adapter mounted... http://altoque.tv/35mmAdapter.jpg The ground glass rotate at great speed inside so the grain disappear... i will post some footage as soon as i get it to the pc... I dont the following tests... focus pulldown, serious DOF density (background really blured), and some movements with the camera and the adapter... another thing is that you can still mount it in a stabilizer and move freely... |
Some frames
http://altoque.tv/test35mm2.jpg and http://altoque.tv/test35mm.jpg I have to apologize for the quality of the grain.. but i had low light and the adapter makes you loose a lot of steps of light as well... i will test it in outdoors soon, as soon as i solve some vibration problems and the optics aint that good now... These shoots shows the example of shallow DOF like you see first blur, in focus, and blur in the background |
http://altoque.tv/test35mm.wmv
There is another test the problem here is that tripod was moving a lot and there is some vibration ... i am still learing to shoot with the adapter.. but i think i will have to make some kind of support so i can tense all the system for now movement at all. |
Yeah that is my dad, he helped me a lot in this project..
i have great news... i download the mini 35 manual, and i discovered that i was missing a part... the relay lens... now i am making a homemade version of it... also i work more on the ground glass.... Just for an advance.. it is all in the ground glass... the fake cd plastic loose a lot of light... |
GREAT NEWS !!!
Ok, i solve the whole optics problem, now there is no vigneting at all.. i improve the ground glass, and change a little the design to reduce the noise and vibrations (need to build a metal skeleton to reduce them all to zero, the video shows vibrations from my hand adjusting the lens's focus) ... Check this video i finish it as soon as i could finish the problems mentioned before. http://altoque.tv/toy35mmtest.wmv Another Test with some color grading and "film look" filters http://altoque.tv/cigarros35mmtest.wmv |
Agus,
After a week, I've finally fixed my account so I can post again... Congratulations on your accomplishment!! The images are gorgeous. Is the grain in the image due to the ground glass grain or DV artifacting? If it is part of the ground glass, I can recommend a couple people who can improve the resolution of the grind. How noisy is the oscillator? Have you thought of rubber mounting it to your housing to eliminate vibration? This might help when you focus your image. Essentially, wherever your motor or ground glass touches the frame, you would insert a bit of rubber to minimize vibration. Anyway, keep us posted. I'm sure we'd all love to see a schematic if you're in a sharing mood! -Brandt |
I think that the most simple the design of the adapter is, the better it will work, what i need now is make the metal skeleton to eliminate all vibration and to secure the 3 parts of the adapter, the lens, the box, and the relay lens.
I have been thinking a lot about postin the plans to build it, i think i will really soon, but i really want that the people remember that i build it first. About the grain, my camera is a TRV18, if you know the model, you will know it is the cheapest DV camera around, when you got low light and your exposure is on max, you get always grain. |
Here are the pictures of maybe the last version of the adapter.
http://altoque.tv/35mmAdapter/35mm7_0004.jpg http://altoque.tv/35mmAdapter/35mm7_0005.jpg http://altoque.tv/35mmAdapter/35mm8_0001.jpg http://altoque.tv/35mmAdapter/35mm8_0003.jpg http://altoque.tv/35mmAdapter/35mm8_0005.jpg The image now is almost perfect, i rapidly reduce the vibrations, and make a metal support that connects to the tripod hole, also the whole adapter can be detached with no problems with no screws at all... check 35mm8_0003.jpg. Check the phone cable attached to the battery box, i place it in the mic holder, if i need it to attach a light or another mic, i can detach it and put it in my pocket... it comes really on handy cause there you have the on/off switch, and you can remove some weight to the camera using a stabilizer I will post a video sample soon. About the plans, i need to make the webpage, and take the pictures and explain how to build it. |
This is great, but I am a little confused... Doing the cd rotate or not? If it doesn't what is the need for all of that? Also I'm glad to hear you will be putting a "how to" together. Rougly when do you think you'll have this up by? I'm only asking because i'm so eager to get started on my own.
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Of course,
you need to rotate the cd so the grain will disappear. i will put in raw instructions how you could build the basic version of the adapter, while i start making the plans and taking some picture in how to build a better working version. 1.) Buy a 25 spindle CDR pack... 2.) Drill 2 holes (see the picture) from one you put your Camera lens and in the other you put your dv camera, 3.) Take a electric motor from a toy (those $ 0.99 stores are your best allies in this project) and put it in the center of the spindle, you need to drill another hole. 4.) Take one of the fake cds, those thar look like cristal glass, and from one side you take some 600 sandpaper, and carefully you start scratching one side of the fake cd... (this is your ground glass) 5.) Basically now you just put your pieces together, the lens, the cd spindle box, with the fake cd rotating inside thanks of the electric motor, and in the other side you dv camera.. you will notice that the lenses is making a projection in the groundglass, when you start rotating it, you will check that it is like a hologram floating in the air.. that is the what you got to film with the dv camera. |
Fantastic Agus, that looks like almost enough to start experimenting on my own.
A few questions: What is the "relay lens" and where is it in your set up? What is that piece that connects the film lens to the CDR spindle case. Is that the relay lens? What did you use for the battery pack? Did that come from the toy also? What toy did you use? (im trying to determine what speed motor I need - i.e. how fast to spin the ground glass.) What did you use to connect the pieces together? Epoxy? Thank you SO much Agus, your project is really going to help me out. I can't wait to see your new video sample! paulb |
The relay lens is where you put your Dv camera,
The piece that conect the film lens to the CDR spindle case is just a plastic tube with the same diameter (i took it from a flash light in the latest model of the adapter, so i can turn it and remove it to change lenses), i use 2 AA, about the speed of the ground glass (the fake cd) it could be said that it should be like the shutter speed... you will get it as soon as you build yours, you the first step is to get the projection in the ground glass, then you can start experimenting a lot. I use one of those plastic guns, the ones that you put silicone tubes and they get heated and liquified (i got lots of burns with it) TIP: There is a center circle in the hard plastic of the spindle, use that to center the electric motor, that is esential, as well as when you will stick the ground glass, it has to be perfectly centered, or you will start getting vibrations that will screw your footage. |
I recomend you to dowload the mini35 digital manual, there you will see the order of the pieces... my model is a homemade copy of that device... it works the same, but more basic, also remember that the fabrication of the ground glass is the hardest part, that will depend your quality of video and grain... i will for example make a glass version, cause the plastic from the cd loose a lot of light steps.
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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.) |
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) . |
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 |
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. |
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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 |
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.
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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! :) |
<<<-- 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) |
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 |
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. |
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 |
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
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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! |
I couldnt tell, i use a TRV18... but actually you should be able to mount it everywhere.
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I have been trying to make this work with a 35mm lens and I can't seem for the life of me to get a good image that is not croped. I zoom but my camera (pd150) can't keep the focus
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You'll likely need a close-focus diopter on the front of your lens.
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man o man, I cant wait for this tutorial!
in the meantime what do you guys recommend for a Film Lens? 35mm ..50mm? Brand? |
I will have the footage of the ad as soon as i finish it adding the 3d animation.
Thanks you all for the interest in this adapter, it is a great thing indeed... i have been working all this week, and the results have been superb so far. I want to make the better ground glass next week. Peter Sciretta, i solve it using an magnifying glass from a wide conversion lens that i have, the first piece will manify the image without ruining it. John Gaspain, my best advice would ask for photographer about it, but i found that 50mm lens doesnt actually make closer or farther the image, the 35mm will make it a little up wider, me for example i am using a 50mm minolta lens, but i want to try up 35mm... once you build the adaptor, try to find photographer that let you try some type of lens, then you choose which you preffer. |
I reckon I can get one of these on to an XL1s..
Ages ago I got a cokin P-series adapter, which I've not used a great deal as I've since got some tiffen screw-in filters that meet most of my needs. Anyway, the cokin set came with a 72mm adapter designed so that you could slot the P series mount over the top. They do a whole range of them, which step up whatever screwthread you have to the P-mount slot size. If you were to make a 72mm diameter hole in the cd-spindle then you could put the cokin adapter ring on the other side and then screw it into the camera, holding your adapter firmly in place. The only problem is that you need something larger in diameter than your average cd spindle in order to be able to have a motor spinning at the centre point... However, a cd should be just about the right size to project the image on to.. If you're using something other than an XL1s, this would probably be the best, cheapest way to secure the adapter to the camera, and you can get these rings from camera stores for about £5.. I'm going to have a go at making one when i get back home from Uni.. A couple of questions for you Agus, could you take a still of what the projected image looks like with no zoom on the camera? Also, have you tried mounting the lens at various distances from the "ground glass", how does that affect the quality of the projection? and last of all, did you get the motor out of a dreamcast vibration thing? it's just I'm sure I've got a N64 rumble pak lying around somewhere that would probably make a good motor... Thanks, Kieran PS A link to explain the cokin adapter thing (I'm suggesting that at stage one in the diagram you put Agus' wonderful device between the camera and the ring, and then secre it to the camera via the ring through the whole in the cd spindle): http://www.cokin.com/ico1-p2.html and a chart for getting adapter rings: http://www.cokin.com/ico2-p3.html |
The motor was actually from a cheap toy, i found it very useful cause i also remove the batery compartiment, and the on/off switch from it.
There are several ways to make the adapter, i think using a 25 spindle, will be the best one, cause the spindle have all the exact measures, and you only need to paint it so the light wont contaminate the image built in the ground glass. Also you only have to drill hole in the center, which almost all electric motors found in cheap china toys will center almos perfectly... that is why i choose it... also you have the choice to unmount the cap, in case you need to change the ground glass... it is very practical, easy to build, and useful.. I have been working on a Xmas ad, and i have to tell that for the first experience it was great, but i loose too many light steps and my cheap trv18, make a lot of video noise, i am workin now on remove it, but dont be scare, cause in daylight or in a very illuminated scene, with 4 steps down from the max exposure, you get perfectly video noise clean image... something really great. Kieran, i would definitely, insist in building it with a 25 cds spindle. |
How would these plans adapt to larger lenses (on the DV Camera side). Like the 58mm on the Sony VX2000 or the 72mm on the Panasonic AG-DVX100?
Also, where did you put the fresnel/magnifying glass? Between the lens and ground glass or between the ground glass and the DV camera? Sorry for all the question, I was able to make the ground glass with spinning mechanism and also able to mount the lens, but I don't know where to mount the fresnel/magnifying glass. Thanks for all your help! |
between the ground glass and the DV camera,
Show some pictures of the adapter built !!! i would love to see the second mini35 Homemade Adapter. |
It's not finished yet, still testing focal lengths and what not. Unfortunately I don't have a fresnel lens that fits so I am going to hunt for it sometime this week. Here is what I have so far
Ghetto35 Digital Adapter on the VX2000 :) http://infrastructuredv.com/g35d/ Thanks again for all your work, Agus! |
WAY too cool !!!
i am going to be famous !!!! :) hey dude... put some creditin the adapter... make it with a knife... hehehe j/k I am sooo glad that it worked for you and those pictures looks really great... !!!! No noise at all... Cool man... really cool ... i loved this part "This adapter is a modified version of the ORIGINAL made by Agus Casse." HEHEHE ok dudes... i will post this tutorial next week with full plans !!! BTW did you get too much noise from the motor, also, who is the vibration doing, i had to use some homemade pieces from the motor to the ground glass, but let me tell you this tip... It is almost imposible to make it Zero vibration, try puting a tape in the center of the ground glass cd, and then put in the motor, this way, if the cd is kinda of loose, the self spining force will center it with no vibration and reduce increible the video noise. I am really glad that you well able to made it, and it worked for you... now we are two owner of a Mini35 adapters for less than 10 bucks !!!! ISNT that GREEEAAAT ?? Tomorow i will put my adapter to the task, i will shoot a Gokarts race. that will be exciting. |
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