October 15th, 2004, 06:15 AM | #181 |
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I was wondering about the whole prism (rotate image) question. Doesn't the prism and mirror steal F-stops??
Because on the XL-1 you can simply flip the eyepiece to the other side and the image is corrected. Then in post you can just use the: http://www.leadtools.com/SDK/Multimedia/Direct-Show-Filters/Multimedia-DirectShow-Rotate.htm during capture (without loss I hope). If this is true then I would rather avoid bothering with prism and mirrors. Or am I wrong??? |
October 15th, 2004, 07:21 AM | #182 |
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We can sell the relay lens for Euro 900,- (round $ 1.115,-)
We found a cheaper one, but i dont know how good it is. We check it next 2 weeks A mount adapter (to connect the lens to the Canon) cost Euro 198,- ( $ 245,- ) BTW: only with this lens (without the other GG adapter parts) you can make good night shoots. ( F stop = 0,95 ) Anders, yes, the prism "steal" a little bit light but. In F-stops? I think only 0,05. The prism is a expensive part, because you need a "big on" with inside more than 40mm diameter and it must be color corrected. I will check out the best price till next week Without the prism you need 10cm more distance. |
October 15th, 2004, 07:54 AM | #183 |
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I don't understand why it needs to have 10 cm more distance!
In a normal still-camera the lens is only about 5 cm from the film... I can see that without the prism and mirror the light will travel a shorter distance but... I'm sure that you are correct but could you explain it to me? I would properly be interested in buying a colorcorrected prism then - So it would really like to know the best price you find. In the PDF file showing the PRO35 there is something called "Schutz glas" - Is that a fresnel?? Thanks |
October 15th, 2004, 08:13 AM | #184 |
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schutzglas means protective glas
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October 15th, 2004, 08:13 AM | #185 |
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The way through a prism is longer than the prism outside. A still-camera have also build in a prism. So the way in a still-camera is also more then the outside dimensions.
But in different to the still-camera prism, you need a bigger one, because the relay lens have more than 30mm light circle. Thats why you need the big prism and thats why it take more distance. Okay, you can mount a macro lens in front of the relaylens to reduce the distance, but than you will have some distortions. The "SCHUTZ GLAS(S)" is only a clear glass to protect (SCHUTZ=protection) the inside parts for dust and dirt. To reduce (elimate) the hot spot there is a convex lens with the plan side very near behind the vibration GG (sorry last day i call this condenser, thats wrong) |
October 15th, 2004, 10:15 AM | #186 |
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That's a little over $1700 American. Still, at 1/5 the price of the Mini35, if it works, it wouldn't be too bad an investment.
My biggest problem with the idea of buying the Mini35 (I've rented it, but I really, really don't like renting equipment - I like to own so that I can spread out cost over years and keep individual production costs down) is the idea of putting $10,000 worth of equipment on a $3,000 camera. For that kind of investment, I would just as soon buy a better camera. |
October 15th, 2004, 10:45 AM | #187 |
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You say that the prism is expensive - what are talking here, $100 ? $500??????
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October 15th, 2004, 02:40 PM | #188 |
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I can't help but believe that there has to be a slightly less expensive way to do this--- yeah, 1700 bucks isn't as bad as 5000 but still we are talking about a fairly simple idea here.
I've used the Mini-35 with some pro 35mm lenses myself (had a client pay the tab for renting it) and loved what it gave me and have to believe there is a way to do an Agus35 for under a grand. Maybe I'm out of touch (which might be so) but I have seen others do them for lesser cameras for next to nothing. |
October 15th, 2004, 04:08 PM | #189 |
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Im with you Kevin.
This lens is not the only way to go. What it affords us is this: c-mount (which can be converted to xl mount) very fast at f.95 (all i can say is, wow) and wide enough at 25mm to capture 24x18mm frame moderately small min focus distance the downside is that it is $1100. if we can find a lens that isnt quite as fast, but is wider (able to capture the still 35mm frame) and has a mount that can be coverted to xl, then we are in luck. OR, we can continue to test building from scratch, ie the info I got from the optical engineer at optosigma, using a achromatic doublet as our relay lens (24mm) and a pcx as our condensor, and a gg, with a simple mount in front of the gg. this may be the way to go if cost is an issue. all of these items are obtainable through optosigma website. I also found out that you can return optics to optosigma as long as they are in good condition, that way we have the ability to use trial and error. the gg that you can buy from them is 1500 grade, probably better quality than I can make by myself, it costs $24. All of the other parts are cheap, between $20-50. We could probably get a mount made at a local machine shop using the cap that came with our camera, have it reversed machined or whatever. The most difficult thing I am foreseeing is constructing a system to make accurate at fine tunings to distances, and having an effective method to measure that data. This could be more difficult to to than the lens itself. stephen |
October 15th, 2004, 09:36 PM | #190 |
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now you are talking... I would love it if I had the money to drop on a more expensive solution but if that was the case I'd just breakdown and buy a Mini-35 but I doubt that I can talk the wife into selling off a kidney or a second mortgage for that sort of thing.
I seem to see the big problem as being finding a cheap adapter to go from the XL mount to a standard (relay) lens mount. I don't have the brain cells left to start reading through the several thousand post long Agus35 threads here but when I have I see people will very practical skills at figuring out focal lengths and solutions--- I think we need to invite a few of these brainy folks to advise us on this. There are plenty of folks out there with XL1, XL1S and XL2's that would be interested in this sort of project--- we just need to get them in here and helping out! |
October 15th, 2004, 10:58 PM | #191 |
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What would be good, is if we could consolidate the xl1 35mm adapter threads. As of today, there are 3 active ones.
wonder if a moderator could merge them. There simply isnt enough resources to split up our efforts. I cant order them right now, I may have to wait a week or so, but here are the lenses needed in case someone else wants to start: relay lens (achromatic doublets) 20mm and 25mm http://www.optosigma.com/miva/mercha...matic+Doublets condensor lens need to figure out what focal length http://www.optosigma.com/miva/mercha...herical+Lenses ground glass 50mm diameter (1500 grade) http://www.optosigma.com/miva/mercha...+%26+Apertures prime lens mount and housing is something we need to figure out how to do, as pvc is somewhat limited in its adjustability. I encourage everyone to try and participate in this process and not just wait for me to succeed. Achieving a solution will be much quicker that way. stephen birdsong |
October 16th, 2004, 07:48 AM | #192 |
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Okay... here's the deal. I'm starting a "Consolidated XL1 35mm Adapter Thread".
I would ask that folks here copy over the relevant posts (with the name of who posted them originally) and we can get things rolling along in one single thread. |
October 16th, 2004, 07:50 AM | #193 |
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Consolidated XL1 35mm Adapter Thread
Since we've got three different threads covering the XL1 and creating an adapter for it we decided we wanted to move it all over into one.
At this point (I believe) the place to start off is with an adapter for a relay lens to the XL mount. I ask everyone copy over any relevant posts into this thread so we can keep rolling on this and make some progress. |
October 16th, 2004, 07:53 AM | #194 |
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Hi.
Since we've got like 3 or 4 threads going on the XL1 adapter issue and I think things are starting to move forward toward an organized option I'm starting a "Consolidated XL1 35mm Adapter Thread". I would ask that folks copy over the relevant posts (with the name of who posted them originally) from the assorted threads and we can get things rolling along in one single thread. |
October 16th, 2004, 09:50 AM | #195 |
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here's a couple of the recent posts from Stephen Birdsong:
----- 1. We need to figure out what focal length we need for our relay lens. 2. we need to figure out what focal length we need for our condensor lens (hot spot issues). our options for relay lens are: a. using a standard 35mm lens with some sort of mount adapter b. using an achromatic doublet and fashioning our own mount system. I did some research today. My first concern is to figure out what focal length relay lens we need. If I had taken a geometry class, I would be able to solve this very easily, so maybe I can get some help. if we know the angle of view of various focal lengths, and we know approximate distance from film plane, than with the angle of views, we can calculate the focal length. here is the info I have: in 35mm fl 14mm-81 degrees 17mm-70 degrees 20mm-61 degrees 24mm-53 degrees 28mm-46 degrees ---------------------------------- if we can find a lens that isnt quite as fast, but is wider (able to capture the still 35mm frame) and has a mount that can be coverted to xl, then we are in luck. OR, we can continue to test building from scratch, ie the info I got from the optical engineer at optosigma, using a achromatic doublet as our relay lens (24mm) and a pcx as our condensor, and a gg, with a simple mount in front of the gg. this may be the way to go if cost is an issue. all of these items are obtainable through optosigma website. I also found out that you can return optics to optosigma as long as they are in good condition, that way we have the ability to use trial and error. the gg that you can buy from them is 1500 grade, probably better quality than I can make by myself, it costs $24. All of the other parts are cheap, between $20-50. We could probably get a mount made at a local machine shop using the cap that came with our camera, have it reversed machined or whatever. The most difficult thing I am foreseeing is constructing a system to make accurate at fine tunings to distances, and having an effective method to measure that data. This could be more difficult to to than the lens itself. ---------------------- What would be good, is if we could consolidate the xl1 35mm adapter threads. As of today, there are 3 active ones. wonder if a moderator could merge them. There simply isnt enough resources to split up our efforts. I cant order them right now, I may have to wait a week or so, but here are the lenses needed in case someone else wants to start: relay lens (achromatic doublets) 20mm and 25mm [url]http://www.optosigma.com/miva/merchant.mv?Screen=PROD&Store_Code=OS&Product_Code=pg49-52&Category_Code=Achromatic+Doublets[/url condensor lens need to figure out what focal length http://www.optosigma.com/miva/mercha...herical+Lenses ground glass 50mm diameter (1500 grade) http://www.optosigma.com/miva/mercha...+%26+Apertures prime lens mount and housing is something we need to figure out how to do, as pvc is somewhat limited in its adjustability. I encourage everyone to try and participate in this process and not just wait for me to succeed. Achieving a solution will be much quicker that way. |
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