New 35mm Adapter & A great looking new short film - Page 2 at DVinfo.net
DV Info Net

Go Back   DV Info Net > Special Interest Areas > Alternative Imaging Methods

Alternative Imaging Methods
DV Info Net is the birthplace of all 35mm adapters.

Reply
 
Thread Tools Search this Thread
Old June 30th, 2005, 11:16 AM   #16
Regular Crew
 
Join Date: Feb 2005
Location: upton uk
Posts: 104
I think it may well be your monitor on the fritz. There is no loss of resolution, obviously the web version is heavily compressed and these artefacts do degrade the image considerably. I have checked this on broadcast montors, and my monitors have recently been calibrated so I am pretty sure its ok, but if anyone else notices this, please let me know, so I can do my best to resolve the problem. The camera is an XL1s and the movie was shot in frame mode 25fps. For all those who are wondering how the system works, I will do my best to explain more clearly. I will try to get some pics uploaded, but I am a bit busy at the moment. Think simple, ok here goes.

1. Take a big ass bearing with an internal diameter of about 55mm
2. Fix it into something, i used a piece of MDF with a hole in it, for weight reasons.
3. the outer wall is now fixed and the inner wall spinning freely and accuratly.
4. Fix you glass into the inner wall of the bearing.
5. Get a machine shop to make you a groved pully which also attaches to the inner wall of the bearing.
6. Fix your motor into a box, along with the unit i have just described.
5. Get a pully belt, and wrap it around the motor pully and around the pully which is now attached to your bearing.
7.Switch it on, and your inner bearing wall will begin to rotate.
Tinker, and Job done, you should have a rotating piece of ground glass.

Hope this helps.
Nicholas Bartleet is offline   Reply With Quote
Old June 30th, 2005, 01:30 PM   #17
Regular Crew
 
Join Date: Aug 2003
Location: hollywood , ca USA
Posts: 38
cyclone effect

Nicholas....

nice work....

i tried to dl the larger mov directly, but the link is messed up,,, ie it only goes to stream on the large file.... (you can dl the small version)...


the design that you used had a theoretcial flaw of spinning fast in the center and much slower on the outside edge....

i did not see this effect in the resolution that you provided... did you experience this at all at certian rpm's of the motor?? or was it noticeable with the better monitors???

thanks
skv
Sarena Valilis is offline   Reply With Quote
Old June 30th, 2005, 01:50 PM   #18
Regular Crew
 
Join Date: Feb 2005
Location: upton uk
Posts: 104
Sorry about that, I have sorted those links now, so you can download a larger version if you wish. It all works.

The problem you mention did not occur at any shutter speed. This is not an artifact present in the film. I am very particular about stuff like that. I used an excellent quality optical ground glass, which is paramount in making these things from my experiance. Diffusion paper, and sanded glass in my opinion can't provide the level of acuracy achievable with a good quality optical GG. I used a motor from a video player with 12v of power. Seemed to work very well indeed. The artifacts you mentioned were present having initially constructed the device, but with a bit of lubricant on the bearings and having left it on for an hour to break it in, the rpm was hig enough to not have any artifacts at all.

Hope that answers your question.

Nick
Nicholas Bartleet is offline   Reply With Quote
Old June 30th, 2005, 02:17 PM   #19
Major Player
 
Join Date: Nov 2004
Location: New Iberia, LA
Posts: 229
Quote:
1. Take a big ass bearing with an internal diameter of about 55mm
damn you beat me to it...about a week ago I started looking for the parts to do just that. I was going to use a Pillar block bearing...but that might be to heavy. Have a source for the bearing you used or was it a local source?

Quote:
the design that you used had a theoretcial flaw of spinning fast in the center and much slower on the outside edge....
Even if you do come across this problem shooting off center should solve it (only the center in essense does not move...the difference in speeds on good glass shouldn't be noticable)
Matt Champagne is offline   Reply With Quote
Old June 30th, 2005, 02:32 PM   #20
Regular Crew
 
Join Date: Feb 2005
Location: upton uk
Posts: 104
It is a very robust and simple design.
For the bearings, Local source, I don't know about the states, but over here in the uk, there are hundreds of bearing suppliers. Give one a ring, tell them what you are looking for and 'bob's your uncle', Job done.
Nicholas Bartleet is offline   Reply With Quote
Old June 30th, 2005, 05:52 PM   #21
Major Player
 
Join Date: Dec 2003
Location: United Kindom, England
Posts: 290
Cool!, thanks for the reply,

Have you thought about using an XL2 on your next project? (or maybe sony FX1/Z1 that would be great for blow ups!)
Anhar Miah is offline   Reply With Quote
Old June 30th, 2005, 06:44 PM   #22
Major Player
 
Join Date: Jan 2005
Location: (The Netherlands - Belgium)
Posts: 735
>>>>1. Take a big ass bearing with an internal diameter of about 55mm
<<<<<
Should I check the doctor for that?

Besides the technical part, which is great, the film and story have high quality.
Oscar Spierenburg is offline   Reply With Quote
Old June 30th, 2005, 07:51 PM   #23
Regular Crew
 
Join Date: Aug 2003
Location: hollywood , ca USA
Posts: 38
gg

thanks for fixing the links.....
i wanted to dl it and burn to dvd and see it on the bigger tv screen.....



""""I used an excellent quality optical ground glass"""""


could you expound on that just a tad as to the grain or ????

thanks ,
skv
Sarena Valilis is offline   Reply With Quote
Old June 30th, 2005, 11:07 PM   #24
Regular Crew
 
Join Date: Jan 2004
Posts: 31
Very nice. I also would like to know the details about the ground glass you used. Where did you get it? What are the specs of the glass?

And how'd you avoid having a hotspot?
Jef Bryant is offline   Reply With Quote
Old July 1st, 2005, 01:02 AM   #25
Regular Crew
 
Join Date: Mar 2005
Location: Perth WA
Posts: 103
Excellent video, very impressive and very inspiring!

I did a search for Nick's other posts and it looks like he's using a Knight Optical 40 micron GG and a macro to get rid of the hotspot? I ordered a GG from Knight Optical, it was only 5 micron finish, too much grain, but the annoying thing was it came with a flaw in it. Not impressed. I recommend Optosigma.

Cheers
Andy
Andy Gordon is offline   Reply With Quote
Old July 1st, 2005, 03:16 AM   #26
Regular Crew
 
Join Date: Feb 2005
Location: upton uk
Posts: 104
Thanks Andy, for your kind comments.

I am using a ground glass from knight optical. I have to say, if you want a custom job, give them a call and they will try to get you whatever you need. They also replaced a £40.00 gg, free of charge, because it cracked duiring heavy use. Just to clear things up for people, a macro will not get rid of the hotspot, the macro is merely to allow your camera lens to focus on the screen which is very close to the camera.

A condenser, much like the ones used on focussing screens can be used to help eliminate a hotspot, however it will reduce your image size. I have done numerous tests with this, it seems the main way in which this works is by utallising the brighter cental part of the image, and essentially magnifying it in size. If you take a nikon viewing screen apart, you will see this is the case. i.e, if you buy a 28mm lens, you won't see all of your fov.

The best way, to eliminate the hotspot, which is incidently what I have had to to, it to use a gg without any condenser, and buy very good quality fast lenses. I have been using nikons. I made the mistake of buying a fast vivitar, 24mm, and thought i had a bargin. Next to my nikon 28mm with the same apeture, the vignetting was incredible. The apeture on the vivitar, f2 was about 3mm wheras on the nikon at f2 it is about 40mm. I'm sure someone knows the reason for this on here, and this could be causing a problem for some people.

It doesn't matter how good your adapter is, without good lenses, it will always look crappy.

Hope this helps
Nicholas Bartleet is offline   Reply With Quote
Old July 1st, 2005, 07:38 AM   #27
Major Player
 
Join Date: Dec 2004
Posts: 749
Thanks for the info, but I found what you say not to be necessarily true. Using my Canon 50mm 1:1.8, hotspots during the day and there is not a step down mechanism on it, so I am stuck with that aperature. BUT on my SEARS cheap 1:2.0 lens, there is a step down and I get the same hotspot with it. So maybe the condenser is a necessary evil?

BTW, I have a couple of extra lenses lying around that when looked through make the image smaller - are these condensers?

Last edited by Leo Mandy; July 1st, 2005 at 07:53 AM.
Leo Mandy is offline   Reply With Quote
Old July 1st, 2005, 08:27 AM   #28
Regular Crew
 
Join Date: Feb 2005
Location: upton uk
Posts: 104
I can not really comment on your design or the issues you are having, as I havn't seen it first hand. The fact that you are comparing 2 questionable lenses with eacholer, will of course lead you to draw your own conclusions, and without looking at your GG, lenses etc, i couldn't really comment on your hotspot problem. It may well not be the lens in your case, it could be the GG etc.

I am however comparing a 28mm nikon 1.4 lens, with an £800 retail value with that of a 24mm f.2 vivitar with a £80.00 retail value, both set to F2 and I can assure you, there is no hotspot with my setup using the quality lenses, where there is with the lesser ones. Again, this is with a well built adapter. I am not sugguesting buying an £800.00 lens for your rig, as your problem may well lie elsewhere. Therefore, the condenser is only really a necessary evil, if you are to use cheaper lenses, or you have a problem elsewhere in your design, and I can assure everyone from my own experiance, that this is the case. If you have seen my film, and feel that a condenser is a necessary evil, than you are sugguesting that I have a hotspot on my short, which doesn't appear to be the case, this why I am confused with your argument.

I appreciate your opinion, and can understand the appeal of using a condenser, for ease. I would however also not choose to use a condenser for another reason, as it does blur the image towards the edge of the 35mm image plane. This i would imagine is due to the different focal distance between the center of the condenser, which is closer to the macro lens and the outer edge of the condenser, which is further away.

Hope this helps make my point a little clearer. I'm sure there are numerous different designs which all work equally well, however this is the best result I have found, and as I have said can only talk from my own experiance.

Nick
Nicholas Bartleet is offline   Reply With Quote
Old July 1st, 2005, 08:47 AM   #29
Major Player
 
Join Date: Dec 2004
Posts: 749
Nick,
You are right about the cost of the lenses. I am using a charity shop cheap lens that I found with a Canon EOS 750, so I think it is not in the range of $800.00, so in that case, you point is well taken.

And no, I didn't see any hotspot on your film, it looked great (as I stated earlier), the dark shots looked great, with lots of brightness.
Leo Mandy is offline   Reply With Quote
Old July 2nd, 2005, 11:53 AM   #30
Major Player
 
Join Date: Jun 2005
Location: Brighton, East Sussex, UK
Posts: 938
Hi Nicholas,
Firstly, great short, very inspiring. Been through all your website as well, very nice stuff.

I am also from the UK (Brighton in the South East), so finding a good source for ground glass is hard.

I see you got ya ground glass from Knight Optical. Could you tell me which type you used from them?

http://www.knightoptical.co.uk/acata...ssDiffuser.htm

they have Ground-LEGB, Ground-B270 and Ground-UV fused silica

Do you think they would be able to custom cut a cd shape for me? I emailed them but get no reply.

Cheers,
Wayne.
Wayne Kinney is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

B&H Photo Video
(866) 521-7381
New York, NY USA

Scan Computers Int. Ltd.
+44 0871-472-4747
Bolton, Lancashire UK


DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Special Interest Areas > Alternative Imaging Methods

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



All times are GMT -6. The time now is 05:26 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network