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Filip, I intend to rather mount the camera *upside down* in front of the adapter.
This should flip the image just right, i guess. Given that this is a custom rig anyway, I see no problem making the camera mount that allows for such 180deg. rotated positioning of the cam against the GG. |
<<<-- Originally posted by Alex Raskin : Filip, I intend to rather mount the camera *upside down* in front of the adapter.
This should flip the image just right, i guess. Given that this is a custom rig anyway, I see no problem making the camera mount that allows for such 180deg. rotated positioning of the cam against the GG. -->>> the intention of this idea is not to put camera upside down, which is of course always possible, but to work normaly - with the picture on the flip out monitor in proper (upside down/flipped) position. as you know - it's already discussed many times - you can easily rotate image in post, but when shooting with camera in upside-down position - it's very tricky. i tryed that, and everything is in wrong place. with this solution (just a small mecanical or magnetic surgery in your camera) you can pan and tilt normally with no stress at all. the solution with the camera upside down is ok for NO POST. but during the filming.... hm... i will re- think that. just a thought. filip |
Flipping the camera around would be especially awkward when producing a video for hire. An upside down camera rigged to a tripod would not be to impressive to a client.
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Chemist way
Edit : This as to be done by a Chemist, don't try this at home.
I have receive a mail from a guy's in New Zealand, and he send me a recipe to make a GG .This sound pretty hazardous to me because I have absolutely no competence in chemistry, but maybe one of you... Maybe try this outside :~° Message: Just I can not make any post to the h**p://www.dvinfo.net/ maybe some technical reason from over there. Anyway I'd like to push some new idea for matting process of the Ground Glass -- chemist way: 1st recipe::: easy matt 1 part of Sulphuric Acid ---- H2So4 8 parts of potassium fluoride - KF 100 parts of Water --------------- H2O if substitude the Sulphuric Acid - H2So4 by -- Chloric Acid -------------------------- HCl, or by -- Acetic Acid --------------------------- CH3COOH, than use 18 parts of potassium fluoride ---- KF 2nd recipe::: more matt 100 parts of ammonium fluoride --- NH4F 20 parts of sulphuric acid -------- H2So4 100 parts of ammonium sulphate - (NH4)2SO4 100 parts of Water --------------------- H2O after approx 20-40 minutes just wash the glass, that's all... Edit: Read whit attention, From James Ball Acid Etching I'm a Chemist, I believe in better living through Chemistry and offhand believe this would produce better results than a mechanical method of making gg.... BUT Messing with fluoride can be dangerous. You'll be making hydrofluoric acid and it can not only etch glass, it can do really wicked things to your bones. HF can be absorbed through your skin to attack underlying tissues and exposure at low concentrations may not be immediately evident it may take hourse befor you notice you have a real problem. I also understand that it takes very special medical attention to treat a victim. HF exposure can lead to a very painful death. If I were going to do this first I'd read the Material Safety Data Sheet for HF http://www.chem.purdue.edu/chemsafety/Equip/hfmsds.pdf If the MSDS doesn't scare you away (it should) I'd also want a little more detailed recipe. For example, what order should you add the ingredients? Don't do it by order of occurance in the list!. You should add acid to water. Then I'd add the KF last. I'd also want to know if there is a commercial preparations available at low concentrations instead of making your own. You probably won't save much money over making up a batch yourself. You'll have less waste, and just dumping your left over chemicals makes you a criminal in some places, not to mention stupid, irresponsible etc. Also a commercial preparation will have its own MSDS sheet and will give you a better idea of just how hazardous the preparation is at the concentration you wish to use it. KF is chemically similar to NaF, the sodium monofluoride you'll see on your toothpast label. The NaFl you have in your toothpast is fairly dilute, here you'll be using the concentrated chemical. So in other words, don't make your own etchant. Buy a commercial solution and carefully use it as the mfg. recommends. |
I've read about acid etching, and it sounds like this could be very similar. As it ends up, acid etching (the stuff I read about) is only equivalent to 600-1000 grit. Since 3 micron is 8000 and 5 micron is 4500, the 1000 grit certainly wouldn't work for a static adapter. However, this new process could be very different chemically (even though the procedure sounds very similar) and provide better results. Either way, its certainly worth a try. Maybe 600-1000 grit was more a reference to how opaque the glass is as opposed to actual grain.
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Nico's Post
In reference to the post about the slide adaptor at:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3807276418&category=29964 There seem to be a lot of different versions of this item. This one in particular seems to have some sort of condensor lens on the end of it. As long as that was, and it worked out, wouldn't one only need to build an adapter to the front of that so that a 35mm lens could be mounted and project on its diffusion screen? Thoughts? |
cerium oxide
I just wanted to let you guys know that I went ahead and tried the cerium oxide. (My glass was first ground with 600 grit and then 5 micron white aluminum oxide.)
I felt pretty sure that it would polish the glass, but I wanted to really see what would happen. Anyhow, grinding with the cerium oxide is difficult. (A lot of catchy friction going on.) After a while, I did notice that I was getting a polished surface, so I went back and re-ground with the 5 micron. I still get grain with any AO I have tried. I can turn down the sharpness on my GL2, which helps, but the image becomes a little too soft. Now I'm thinking that microcrystalline is the way to go. ,Frank |
Acid Etching
I'm a Chemist,
I believe in better living through Chemistry and offhand believe this would produce better results than a mechanical method of making gg.... BUT Messing with fluoride can be dangerous. You'll be making hydrofluoric acid and it can not only etch glass, it can do really wicked things to your bones. HF can be absorbed through your skin to attack underlying tissues and exposure at low concentrations may not be immediately evident it may take hourse befor you notice you have a real problem. I also understand that it takes very special medical attention to treat a victim. HF exposure can lead to a very painful death. If I were going to do this first I'd read the Material Safety Data Sheet for HF http://www.chem.purdue.edu/chemsafety/Equip/hfmsds.pdf If the MSDS doesn't scare you away (it should) I'd also want a little more detailed recipe. For example, what order should you add the ingredients? Don't do it by order of occurance in the list!. You should add acid to water. Then I'd add the KF last. I'd also want to know if there is a commercial preparations available at low concentrations instead of making your own. You probably won't save much money over making up a batch yourself. You'll have less waste, and just dumping your left over chemicals makes you a criminal in some places, not to mention stupid, irresponsible etc. Also a commercial preparation will have its own MSDS sheet and will give you a better idea of just how hazardous the preparation is at the concentration you wish to use it. KF is chemically similar to NaF, the sodium monofluoride you'll see on your toothpast label. The NaFl you have in your toothpast is fairly dilute, here you'll be using the concentrated chemical. So in other words, don't make your own etchant. Buy a commercial solution and carefully use it as the mfg. recommends. |
Some grabs
Hey all,
I know there have been plenty of folks posting frame grabs since the start of this thread that most of you all wouldn't be interested in checking these out. I would like those who have successfully created a static adapter to give me some feedback and perhaps give me a hint on how I can fix my barrel distortion problem. I'm using a 60mm dia. 60mm F.L PCX lens with the flat side ground with 5 micron WAO. I did about 10 minutes of CEO grinding. This removed all of the minor scratches from the WAO grinding. The convexed surface of the condenser faces the video camera lens. I was considering using a longer F.L. PCX but I am worried that the hotspotting will return. Any ideas? Thanks, Joe http://www.paddlefilms.com/adapters/April 9 far focus mailbox.jpg http://www.paddlefilms.com/adapters/April 9 near focus mailbox.jpg http://www.paddlefilms.com/adapters/April 9 far focus.jpg http://www.paddlefilms.com/adapters/April 9 near focus.jpg |
Some grabs
Hey all,
I know there have been plenty of folks posting frame grabs since the start of this thread that most of you all wouldn't be interested in checking these out. I would like those who have successfully created a static adapter to give me some feedback and perhaps give me a hint on how I can fix my barrel distortion problem. I'm using a 60mm dia. 60mm F.L PCX lens with the flat side ground with 5 micron WAO. I did about 10 minutes of CEO grinding. This removed all of the minor scratches from the WAO grinding. The convexed surface of the condenser faces the video camera lens. I was considering using a longer F.L. PCX but I am worried that the hotspotting will return. Any ideas? Thanks, Joe http://www.paddlefilms.com/adapters/April 9 far focus mailbox.jpg http://www.paddlefilms.com/adapters/April 9 near focus mailbox.jpg http://www.paddlefilms.com/adapters/April 9 far focus.jpg http://www.paddlefilms.com/adapters/April 9 near focus.jpg |
impressiv
Bravo...
i am realy impress whit yours resault specialy whit the grain on near focus images... What about your SLR objectif => ??mm/f?? again bravo |
to joe
joe,
what kind of camera you are using? filip |
Wow Joe, those looked great - very very little grain in your GG.
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Joe,
I just ordered a 50mm diameter, 50mm focal length lens from Edmund Optics, but after reading about your barrel distortion with a 60mm focal length, I'm hesitant to use my 50mm (it will be worse). How bad is the distortion? I see the left side of the mailbox bends a little bit, but still looks okay. Can you post a still frame of your adapter focused on a grid to show how much distortion there is? I'm afraid I may end up trying to get two 100mm focal length lenses. That's supposed to decrease the barrel distortion but still diffuse the hotspot as much as a 50mm (two 100mm FL lenses in series equal one 50mm). |
Joe: Great job! I am also curious as to what video camera you're using.
I think this will be my last framegrab post for a while, as I think I've got my ground glass about as refined as I can get it. Looks like the next step is to figure out how to use microcrystalline. Actually, I need to get a regular uv filter to grind, as I am currently using a linear polarizer, which is dark like a ND filter. This is probably not helping the grain situation much. The only post I did on these was curves (warmed the images a bit) and letterboxing. (Honestly, I pulled back on the zoom a bit to try and get less grain, and in doing so I revealed the edge of the adapter. This may be a good tradeoff. I'd have to use the 16:9 guides when shooting, though.) Another thing: I'm shooting this with a GL2 w/ the sharpness turned quite a bit. www.frankladner.com/images/t3_01.jpg www.frankladner.com/images/t3_02.jpg www.frankladner.com/images/t3_03.jpg www.frankladner.com/images/t3_04.jpg www.frankladner.com/images/t3_05.jpg www.frankladner.com/images/t3_06.jpg Thanks! |
Joe Holt
That look good , but still some grain in the last image.
What are your slr lens, 1.4, 2.0 ? I have a 1.4 and 2 and there is a big difference in grain, whit 1.4 I have no grain but whit 2, I start to see the grain. For the distortion, in my experience I have notice that the distance betwen the macro lens and the camera lens as a influence. I know that the closer the better, in my case. Alain |
Thanks for the feedback
All,
Thanks so much for the positive feedback. It means a lot coming from you all. I used a Minolta MD mount 50mm F1.4 lens. The lens was wide open for those shots. I used a sony PD100A (that's the little Sony DVCAM before the DX10) I had the camcorder on full auto (except focus) I didn't do any fix in post except to orient. What you saw was what was on tape. My set up doesn't use a dipoter lens. I just point the video camera lens at the condenser. My condenser is a 60mm dia. 60mm F.L. PCX from surplusshack.com Here's a crude diagram: [SLR] [)ground pcx [Sony] I zoom the Sony in until the lens won't focus on the GG and then I back off a hair. If I zoom out too far, I get severe vignetting. I was wondering if I should try to find either a slightly longer focal length lens such as 60mm dia. 65mm FL or get two 60mm 120F.L. lenses and grind just one of them. (]{) {= GG Unfortunately, I'm comitted to 60mm dia. due to design reasons. I would have to do a major rebuild to change that. Nicholi, Have you tried surplusshack for your lens first? Their prices are great. Usually $4 for a PCX. Much better for experimenting than Edmonds' prices. I'm curious to see your results. I say you should have better results than mine with the barell distortion because you will use more of the 50mm dia. lens with your image than I did with my 60mm dia. If you look at a PCX lens, the convex is more severe at the center and tapers as you near the edges. I believe this is why I got the distortion. The 36mm x 26mm image I'm shooting only utilizes roughly 65% of the PCX. Oh well, give it a try and let us know how it works out. Frank, Your images look great too. There is definately some vignetting going on. I've noticed that it is more noticable with bright subjects but with a bright subject, you can zoom in a little on the GG because the grain will be "burned out" more. Are you using a fast lens? F1.4 seems to be a requirement for low grain with these static adapters. You can also try opening the iris on your video camera (without turning on gain) and slightly over expose the GG. Than you can drop the luma in post. Try that and turn your sharpness back up in your camera and you may get a completely different look to your images. Just a suggestion. Thanks again everyone for your kind words. Any ideas about the barell distortion would be appreciated. Joe |
Joe: Thanks! I'll have to try what you recommended. That sounds like it would work, so long as I don't blowout to complete white w/ no detail. Excellent tip!
,Frank |
post production removal of hotspot
Obviously an optical solution would be better, but here's an idea for those who don't mind doing a bit of post processing to get acceptable results.
Shoot an evenly illuminated white background. Now you can use this frame in your NLE to adjust the luminance of all the frames in your movie. Everyone's NLE or Compositing software will handle this differently so direct your specific questions to the appropriate software forum. Or course a lot of people here can field general questions. Is this perfect, no. Will you have the full latitude (grayscale range)as before, no. But it may work for a lot of you. The same thing could be done printing an inverted image to positive slide transparency and placing it on the 35mm lens side of the GG. The transparency could work as a gradient neutral density filter with the most dense part of the filter in the center. |
there is also another possibility - you can use filter called hotspot, with VIrtualDub program. both are free.
filip |
xl1s testing
here is some footage of a new updated version of my lens, i finished off the inside with flat black paint, more fine tuning. the codec i used on this version cut about +30% of the color saturation of original uncompressed-so the uncompressed footage is very juicy in terms of color and depth.
i had originally planned on shooting a dv version of short in-camera edited film we were working on at a closed bar in midtown new york, but due to many time constraints i wasn't able to. the footage you see here [sorry it's upside down still] are some actors waiting at a bar before their scene and some others going through a walk through of parts in the background... http://www.dinoreyes.com/images/test11B.html i think VERY promissing overall... -d |
Glass etching cream.
http://www.glassmart.com/etching_cream.asp
http://store.artcity.com/arp-150xxx.html Here is a safe alternative to HF and H2SO4 based etching solutions. It's about $7 to $10 Do a vivisimo or google search on glass etching cream to find more. http://www.rhoadescameras.bizland.com/Camera%20Creation/Ground%20Glass/ground_glass.htm is an example of a piece of glass treated with some cream. |
http://www.greatlakeslaboratories.com/cne1.htm#Coverage
has a MSDS sheet for the material. It is phosphoric acid based so all you need is proper ventilation, goggles, gloves, and water nearby to rinse off should you get spattered. From what I've been reading you must clean the glass very well and leave the etching cream on a long time at the proper temperature to get an even etching effect. I would wash using ammonia in a sonic bath (jewelry cleaning bath) if you have access to one. Otherwise just let it soak overnight. Then remove the glass holding only by the edges with latex gloved hand. Rinse with tap water then add the cream. I'm going to be trying this out soon. I'll let everyone know how it works. James the Chemist |
Cheap, Easy, and Good GG Alternative
Hey All, hope the addiction is treating you well-
I thought I'd pass along a discovery. I was frustrated with the amount of grain in my ground glass, so I was trying some other materials. One of the batch was a 10-pack of "Clear Project Files" from Office Depot. they are 8 1/2" x 11", Item #741-341. Office Depot brand. These are translucent files for putting paper in. I used my ground glass (removed from the holder) as a template and found the cleanest, scratch-freeless spot on one of the folders and traced my ground glass. I carefully cut it out with scissors, giving me two circles of this translucent plastic the same size as my GG. I put both circles into my holder, put the retaining ring back in and tried it out. Its significantly better than my ground glass, and I can't see any grain. It actually showed me that I have scratches on my condensor which I didn't know I had (next problem, I guess)... At any rate, it was good enough for me to say I'm sticking with this instead of my GG. The ten-pack of folders was around $5 It's super cheap, super easy - might give it a try and see if you get similar results. Just passing it along. Enjoy :) |
DVX100 - DOF test
http://homepage.mac.com/dvx100/iMovieTheater1.html
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Hey Jonathan, can you post some footage of your static adapter using the Clear Project Files translucent material?
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I'll try and put something together later tonight -
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Re: DVX100 - DOF test
<<<-- Originally posted by James Webb : http://homepage.mac.com/dvx100/iMovieTheater1.html -->>>
James, That looks fantastic! I would love to see a larger res file of you test! I am considering getting the DVX100 and want to build a static adapter for a short I'm working on. Could you give us more information on your adapter? Perhaps post some pics of the camera with adapter or a brief explanation of your approach. Or email me with some info? I was very impressed with your results. Thanks, -Dana |
File Folder Clips
I put up some clips of the File-Folders-As-Ground-Glass as requested by Ernest.
At the very top of my adapter page is a link to my own server. Not sure how well this will work, and these are also first attempts at encoding clips for the web, so there's lots of potential problems here :) Let me know if any of it doesn't work for y'all. http://home.austin.rr.com/aqua99/adapter/ Follow the link at the top to ALTERNATE GROUND GLASS MATERIALS: and (hopefully) you'll get a page with some links to the movies at the bottom. I'm hampered by both my out-of-date gear and my experience level :) but there ought to be enough here for you to decide whether to drop $5 on some file folders or not. Enjoy- By the way, these tests showed that the file-folder may work for some projects, but bloom the heck out of highlights. Not the right 'look' for everything. I might try some drafting mylar sheets next. |
Your "bloom" maybe the result of using 2 layers of the folder material. You may want to try only one layer, perhaps supported by the glass from the uv filter ring.
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Re: DVX100 - DOF test
Thanks Dana,
I'll put some info together soon. I consider the images to be very good (@f1.8) although the grain on the GG becomes pronounced @ about f4-5.6. I think the GG is about as clean as I can get it (WAO 5) but I can still see a few tiny specks (e.g., dirt, scratches). Not sure. I haven't had the time to check to see what they were. Maybe on the condensor. I've found that the GG is the key. I'll definitely continue to search for the best material for the GG. |
Thanks James,
I am really looking forward to your information! What lens are you using in that demo? Are you changing your aperture (on your SLR lens?) or are you leaving it wide open? I can hardly wait to hear more details! Ooh, and pics :) -Dana |
Dana-
Yeah, I was changing the aperture on the 35mm lens from f1.8 to f4 or f5.6 (I don't remember exactly). The iris on DVX remained wide open @1/25. My lens is an old (50mm) Konica. I'll try and put some stuff together by the weekend. -J |
Myler no good
Just tried Myler sheets; its a no go, the grain is too large
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DVX100 - Static Adapter
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Looks great! Could you post some full resolution shots with the camera?
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DVX100 images
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Looks great James!
Just a few questions... Are you using the original DVX100 or the "A"? I could see some grain in your blacks (that's where you're going to see it), but I didn't see any vignetting. Are you zoomed into a smaller than 36mm x 26mm image? I thought most DVX100 users were using +7 diopters instead of the x10 you're showing in your diagram photo. Have you tried using just adding a +2 to one of your 5x? It could be that I don't know what I'm talking about as I don't have a DVX100 but am interested because I plan on getting one to replace my Sony soon. With my Sony, I zoom out until I start to see vignetting and then I tap the zoom lever just a pinch to get the largest image possible without vignetting. Can you do that with your DVX100 or do you have to keep the camera wide with the macro adapters? Keep forging ahead. There are lots of us eager to see your results. The DVX100's Cinelook color technology coupled with the 35mm DOF should make a very impressive combination. Joe |
aldu35
your aldu35 was made the same as mine I think this is the best design .I sent chris some photos of the rig . my filter rings are 52mm a 50 mm plcx fits inside. it is fitted with the internal threaded filter ring washer this also is used to hold the ground glass. and to get the just right focal length the washer can be used as a spacer . a local camera store had a bin of scratched
filters, and a cannon 50mm 1.4 lens.... thanks to everyone it looks so simple now ,but it took a lot of work by a lot of people to get to this point. I wish i new a place that I could tell people to buy blank filter rings for 2 or 3 dollars .some factory has to make these things |
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