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Old June 17th, 2004, 01:53 AM   #46
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I'm not sure which focusing screen to get. I'm thinking of the Beattie Intenscreen that posts have referred to earlier. What's your take? Best-Frank
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Old June 17th, 2004, 06:28 PM   #47
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I have no experience with focus screens. I used a GG that I made myself. Worked great.
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Old August 23rd, 2006, 09:16 AM   #48
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Winston Vargas Medium format adapter

Quote:
Originally Posted by Joe Holt
Jay,
Keep the ideas coming. Here are my thoughts...

1). A medium format lens would work to increase the image size and hence would reduce the grain (static adapter) I agree with Brett about the magnifyer. I don't know of anyone who has made an adapter based on Medium format lenses though. My guess why is because these lenses are much more expensive and harder to come by than 35mm lenses. If you have one laying around, I'd love to see some images with a medium format rig.

2). Why use a two way mirror at all? Couldn't you use an optic quality surface coated mirror? The mirror would be mounted at an angle that would project the image directly onto the 3M reflective surface mounted just above the opening for the SLR lens. The video camera would be mounted on a higher plane than the SLR lens. The 3M surface could be mounted at a parallel angle with the mirror keeping everything in the same focal plane. The problem I see is the video camera's need to be perpendicular to the reflective surface for proper focus. This would probably require the video camera to be mounted at an angle perpendicular to the 3M surface. This would work with smaller video cameras but would be quite challenging with larger models like an XL1.



.......3M/.......[]Video Lens
SLR[ ]...../mirror

This might be a nice grainless option for the new prosumer HD cams just now hitting the market. Let me know what you think. Joe
I have the medium format adapter, if you like to see it check out my website.. www.freewebs.cm/wvargas/ The medium format lenses are a bit more expensive, but not by much any more. Check out the photos of the adapter.
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Old August 23rd, 2006, 09:18 AM   #49
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Winston Vargas Medium format adapter

Quote:
Originally Posted by Joe Holt
Hey Jay, or anyone one else interested. I found this Med. Format lens on ebay. It might be ok for adapter making. It's currently at $12 and ends in 2 days. Just in case you wanted a lens for testing your design. Joe

http://cgi.ebay.com/ws/eBayISAPI.dll...EBWA%3AIT&rd=1

Description
This is a Mamiya No. 27972 lens 1:3.5 C series 645mount lens,it is being sold as a parts lens only, the iris is sluggish and is not guauanteed to work. The lens is being sold as is and buyer pays 5.00 shipping in the lower 48, please use paypal if you want the fastest shipment.


Check out my medium format adapter and if you have any questions about it please email me.

www.freewebs.com/wvargas
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Old August 23rd, 2006, 09:31 AM   #50
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the Medium format adapter

Quote:
Originally Posted by Nicholi Brossia
I'd thought about this idea too, but don't know anything about medium format cameras other than the film being 6cm x 6cm. A 60mm frame would cover a lot more area (grain) than a 35mm without having to be magnified, therefore preserving the medium format's DOF. That would be pretty neat (granted I don't know the difference between 35mm and medium format DOF... from your description it sounds too shallow?).

Currently, with 35mm, a 4:3 frame requires a 50mm diameter focusing screen (ground glass) and 16:9 requires 42mm diameter. That's just about perfect for these prosumer camcorders. A 6x6 frame would require an 80mm diameter focusing screen at 4:3 and 70mm for 16:9. That would be great as far as overall grain coverage, but the adapter would end up huge. Although it may work out super well with the DVX100's 72mm threads, which would be awesome. Any ideas Brett?

Joe, I also like the prism block idea that you've drawn in your Idea 3 design. I'm not optical engineering inclined, but it sure looks like a good idea from my standpoint. The only thing I'd be worried about is splitting the colors up... like the "Dark Side of the Moon" album cover. Again, that may or may not apply.

Check out my medium format adapter using Mamiya 645 lenses. I decided not to use prisms or mirrors because of the increase of surfaces which just collects dust, but more important is the light loss, check out my website www.freewebs.com/wvargas
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Old August 23rd, 2006, 09:45 AM   #51
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Wow, Winston, you actually built one. Do you have any footage or stills of the images it produces?


-j
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Old August 23rd, 2006, 12:53 PM   #52
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Very Cool

Nice looking device, nice price, any footage? Low light performance will be THE challenge with medium format.
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Old August 23rd, 2006, 10:07 PM   #53
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70mm adapter

Quote:
Originally Posted by Jay Silver
Wow, Winston, you actually built one. Do you have any footage or stills of the images it produces?


-j

Yes I have them ready and I can send you a DVD. I have sent out a lot of them but I have been disappointed at the lack of feedback, the ones that I have gotten have been very good.

Winston
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Old August 23rd, 2006, 11:17 PM   #54
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Any footage? How do we get this DVD? I am also curious about the light loss
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Old August 24th, 2006, 03:39 AM   #55
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Winston are you charging people for your dvd? It's been beaten to death but for some reason you won't post any footage from your device. Take the easy road and give some people a little footage.
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Old August 24th, 2006, 12:06 PM   #56
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He is not here to aid the community, just to pimp his device... 90%+ of his posts are just linking to his site...



ash =o)
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Old August 24th, 2006, 02:00 PM   #57
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Too true. He did it in this thread too (http://www.dvinfo.net/conf/showthread.php?t=52175). He's done it on other forums as well (most notably dvxuser.com). I don't understand why he doesn't just post footage and let people decide for themselves.
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Old August 24th, 2006, 02:01 PM   #58
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I don't think anybody would pay a single cent until they've seen some footage.
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Old August 25th, 2006, 03:26 PM   #59
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Framegrabs from Winston 70mm adapter

Quote:
Originally Posted by Jay Silver
Thanks for the responses. I agree that the medium format lens idea isn't very cost-effective but it might not be a total dead-end - I think I didn't explain myself very well in that first post, so here's another go.

Click for a diagram:
Medium Format Idea


And in the meantime I've had another thought along the lines of my two-way mirror/3M tape idea.

Another handy diagram:
Idea 3


More for the pot.


-j

Finally got some framegrabs from my 70mm adapter on to the website, please check it out..

www.freewebs.com/wvargas

Thanks
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Old August 25th, 2006, 04:39 PM   #60
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Winston,

I'm not trying to be a jerk here, because I'm inclined to believe that maybe as far as web stuff goes you might not be too savvy. While the frame grabs are a step in the right direction they appear to be very grainy and interlaced. They are not sharp at all and give us no indication of the adapters strengths. I tried to save a picture so that I could deinterlace it in photoshop to get a better idea as to what I was looking at. Unfortunately your website wouldn't allow me to do so.

Right now as it stands the only thing those pictures tell us is that you can achieve a shallow DOF with the adapter, but every adapter can do that, that's the point after all. So we aren't really seeing what the adapters strengths and weaknesses are. As it stands those stills are not going to help people determine the quality of your adapter.

I hate to point the finger without offering a solution. So, If you were so inclined, you could send me a CD/DVD with a raw DV stream I would be more than happy to extract stills and encode video for decent web presentation, and then send them back to you. I am very curious about your adapter myself.
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