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Old June 23rd, 2003, 05:30 AM   #46
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<<<-- Originally posted by Charlie Higgins :
I'll add one more thing: that adding any apparatus to a cam doesn't make it inherently more sensitive to light; it may, at best, increase the amount of light transmitted to the cam itself. This only means that the cam, once again, is the bottleneck of light sensitivity- you ARE stuck with the LUX rating of yer cam until you ebay it and buy a more sensitive one!
-->>>

Charlie, sorry for my insistance, but I'll ask again. It looks there is something basic that I don't understand.
On one hand you say that one can add something that increase the light coming to the cam. I mean something passive, not night vision tube or like.
Then you say, I'm stuck with LUX rating anyway.
I'm failing to connect these two statements. Could you please build a logic chain in between for me? I understand you have it in your mind, and it looks that Tom agrees with you, but I still can't understand.
Sorry for my ignorance, but I'd like to understand it. Is it at all possible without reading an optics textbook?
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Old June 23rd, 2003, 11:44 AM   #47
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Vladimir, I'm sorry.

My posts seem contradictory; my first assertions are based on scientific principles as related anecdotally to me by people who have forgotten more about optics, etc., than I will ever know. My latter post, the one to which you so perceptively refer, seems to undercut my previous posts because, and this is my again my fault, it seems more based on semantics ('the LUX of the camera itself is not altered, even if more light is introduced to its outer optics by an additive lens system' kind of argument). What I meant to say, and again please forgive my very basic understanding of what I was told by my collegues, is that any 'more' light that arrives at the front lens of a cam is absorbed by the lens glass, distance to the CCD, and various other losses that preclude a net gain of LUX in any cam. The cam itself, in order to become more light-sensitive, must be modified per my previous (and others') posts: i.e., modification or replacement of cam lenses, CCD, software or electronics. I am given to understand that the design and construction of a cam does not allow it to become more sensitive to light (LUX rating). One reason is that the lens dispersion and distance losses in both the attachment and the cam optics apparently absorb any incrementally increased light to the outer lens of the cam.

Now whether this is a theoretical or a practical limitation is what I don't understand myself. In other words, what about a huge Parabolic Mirror funneling light to the cam lens? Now, obviously, that would increase the light into the cam, no? Why doesn't this work on a smaller scale? Vladimir, I'm with you on this. I do not understand the (dis?) connection, if any, between one scenario and the other

I also wonder, and wish I'd thought to ask at the time, whether an attachment system such as 'Night Vision', an ACTIVE light amplification system of electronics and optics, might introduce light to the cam in such a way that would allow the cam, with the rest of its sytems intact and unchanged, to successfully record footage via the 'Night Vision' attachment.

Vladimir, I am at this point in optical water deeper than I can swim. I hope this helps in some small way, but if it doesn't, I understand, and my apologies!
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Old June 24th, 2003, 02:42 AM   #48
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I am pure amateur on this, but I think noone really cares if you can increase camera LUX or not, so to say... The practical thing is what it's of interest, so the real question is not if you can increase camera LUX (it's obvious you can not if you don't change the camera itself), BUT can one record at low lights with better results (with better image quality)? It's seems simple logic, that if you "attach" telescope in front of camera you can. E.g. recorded stars at night will appear much brighter and if you'd, say, point telescope to a city you'd get a much brighter city at night -- it's the telescope which collects light, camera per se does nothing new... So, wouldn't be possible to make lenses (prob. would be quite big), which would collect more light to pass to camera to say record at nights with good results even when light is relatively low...? Ohhh all this might sound stupid, I apologize if so...
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Old June 24th, 2003, 03:28 AM   #49
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Adding a tele and pointing it to a spot of light like a star isn't an example of decreasing LUX requirements with a cam.

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wouldn't be possible to make lenses (prob. would be quite big), which would collect more light to pass to camera to say record at nights with good results even when light is relatively low.
These types of lenses (or adaptors) are available at the cost of an average person's year's salary. It's good for about 15 feet and produces a nice grainy green colour. Sometimes you can see their use on CNN. I used to have a couple of links written down somewhere about them.
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Old July 9th, 2003, 04:44 AM   #50
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Hi

I've been away for a long time, I was amazed to see the discussion. The university professors had me worried though. I did some lecturing at uni once. First thing, only the guys with optical experience I would bother to ask, and only if they are paying attention and not just trying to get you out the door (as I said I have worked at university). One of my best freinds was the top electrical engineering student of his year (in the country) I wouldn't ask him anything about optical stuff though, just electrical/electronic. We both have simular intelligence (but not in spelling). I am a sickly computer scientist actually, and I wouldn't ask most IT people a single thing about optics.

Unfortunately the closet university, that has the relavent experience, is 3 1/2 hours away.

I saw a couple of flaws earlier on and that is the way the arguement went.

When you asked them about whereever puting a lense infront of the camera would increase it's lux sensitivity, did they think you were asking about a single lense and the light resolving factor, not the amount of light? I appreciate your comments though, it explains why the single lense won't work, something I thought might be the case, and needed a proper lense system to bend and foucus the light correctly at the front lense of the camera, so it passes through with minimal loose and hits the CCD correctly. I have tried a SLR lense (without adaptor) and have seen a increase in brightness (though I need a video card to prove the values), but at a slight telephoto :(. I had to dim the lights and put the old panasonic to 1/6000 of a second to keep auto iris at maxium to prove what could be seen at normal light levels, and pionted it at a white peice of paper with evenly reflected light off the the ceiling, took ages (eventually used frame capture button to compare 5% to %10 light). That is why I was unconvinced enough in it's accuracy to share it here (to much niose to be completely objective).


Of course, if it were not possible to increase the lux gathering power of the camera, then attaching it to the hubble telescope would produce little different image then pionting it directly (except for maginifaction with the same net brightness). Attaching a lense system to the front of the camera is infact changing the camera optical system by addition. My origional thought was that it would be an multi-lense engineering feet to get the light to come into the lense properly, so as to not loose light down the optical path through dispersion and "fractional" ansorption in the optics, this I would still like to know how to do.

Well thanks for all your comments they have been well thought out, correct in what they were talking about, and answers a few things.


Wayne.



<<<-- Originally posted by Charlie Higgins : Vladimir, I'm sorry.

I work as an instructor at a local University. I printed out this thread and took it to several trusted associates: Engineering Professors (and a Dean who is also a cutting-edge optics consultant); folks who, collectively, have over 100 years of experience and knowledge in Optical, Electrical, and Computer Engineering. They all gave me the same answer. Some professed being mystified at why there was a question about this in the first place.

Put simply, you cannot gain LUX without actually replacing the lens, the CCD, the electronics, or all three. You cannot ADD a lens, any lens of any design, and increase LUX sensitivity.

I suggest you go to a good University with this printed thread in hand. Ask someone in Optical Engineering, etc. to take a look at your argument. They will tell you, based on universally respected FACTS of physics, why this is impossible as you argue it.

-----

My posts seem contradictory; my first assertions are based on scientific principles as related anecdotally to me by people who have forgotten more about optics, etc., than I will ever know. My latter post, the one to which you so perceptively refer, seems to undercut my previous posts because, and this is my again my fault, it seems more based on semantics ('the LUX of the camera itself is not altered, even if more light is introduced to its outer optics by an additive lens system' kind of argument). What I meant to say, and again please forgive my very basic understanding of what I was told by my collegues, is that any 'more' light that arrives at the front lens of a cam is absorbed by the lens glass, distance to the CCD, and various other losses that preclude a net gain of LUX in any cam. The cam itself, in order to become more light-sensitive, must be modified per my previous (and others') posts: i.e., modification or replacement of cam lenses, CCD, software or electronics. I am given to understand that the design and construction of a cam does not allow it to become more sensitive to light (LUX rating). One reason is that the lens dispersion and distance losses in both the attachment and the cam optics apparently absorb any incrementally increased light to the outer lens of the cam.

Now whether this is a theoretical or a practical limitation is what I don't understand myself. In other words, what about a huge Parabolic Mirror funneling light to the cam lens? Now, obviously, that would increase the light into the cam, no? Why doesn't this work on a smaller scale? Vladimir, I'm with you on this. I do not understand the (dis?) connection, if any, between one scenario and the other

I also wonder, and wish I'd thought to ask at the time, whether an attachment system such as 'Night Vision', an ACTIVE light amplification system of electronics and optics, might introduce light to the cam in such a way that would allow the cam, with the rest of its sytems intact and unchanged, to successfully record footage via the 'Night Vision' attachment.

Vladimir, I am at this point in optical water deeper than I can swim. I hope this helps in some small way, but if it doesn't, I understand, and my apologies! -->>>
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Old July 9th, 2003, 01:56 PM   #51
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I also wonder, and wish I'd thought to ask at the time, whether an attachment system such as 'Night Vision', an ACTIVE light amplification system of electronics and optics, might introduce light to the cam in such a way that would allow the cam, with the rest of its sytems intact and unchanged, to successfully record footage via the 'Night Vision' attachment.
This alters the light so the cam will only capture a grainy green not much more than 15 feet in front, plus this thingy costs a fortune.

Regarding adding a lens to increase LUX, with these small cams you cannot add a lens, an adaptor, yes, but not a lens. Furthermore, these small MX cams come with a fixed lens which have been designed for their CCD. Panasonic explains that if a larger CCD where used, a physically larger/wider lens would be required.

Quote:
Now whether this is a theoretical or a practical limitation is what I don't understand myself. In other words, what about a huge Parabolic Mirror funneling light to the cam lens? Now, obviously, that would increase the light into the cam, no?
And if you add more light, whether from a light bulb, the sun at high noon (compared with dawn) or a mirror, obviously you will be increasing the light (LUX), however, you are changing your original question/lecture---the parameters of your argument. In scientific terms, you are adding another variable. The argument is if whether or not an adaptor is able to add more light to the CCD/s, so that the cam will perform better in lower light. This is what you originally wrote (1st post):

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Hi I am looking at buying a cheap consumer camera. Does any body know of a way to increase their low light performance and the light range it can work over (at set aperture and gain)?
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Old July 14th, 2003, 12:54 AM   #52
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I thank you for your graciouse reply Frank.

<<<-- Originally posted by Frank Granovski :

And if you add more light, whether from a light bulb, the sun at high noon (compared with dawn) or a mirror, obviously you will be increasing the light (LUX), however, you are changing your original question/lecture---the parameters of your argument. In scientific terms, you are adding another variable. The argument is if whether or not an adaptor is able to add more light to the CCD/s, so that the cam will perform better in lower light. This is what you originally wrote (1st post): -->>>

Which from first post (parabolic mirrors quote, Charlie Higgins post, light bulbs etc others) is what I was interested in, to increase performance with the existing lighting. The adaptor basically, in semantrical terms, becomes a part of the camera's equation through being an extension to the camera. I have allways had the assumption that, most likely, it needed an adaptor to correct for dispersion of light, chroma and other abreviations, to balance out, which, in part, has been verified (I think by the professors). With hindsight, if I look at an SLR lense system (I bought a nice one to try) it focuses image at a set piont behind the SLR lense, over an area much bigger than most CCD's. Before, during and after that piont the rays are not entering the camera lense on an natural angle, which makes it hard to focus (with light dispersion etc) as the camera lense system was not designed to handle this. Meaning that at least an adaptor lense/system that takes SLR output light and bends it to suit my camera's (most likely individual) lense system is needed. I have gotten it to focus, I believe only in Macro up close, and believe I have gotten an brighter image form it (around 50% to double), but it is slightly telephoto (which for certain situations is undesirable). More robust testing wil have to be done when a new camera is decided upon. I think it would be much harder with the mini35 35mm movie lense adaptor though. This adaptor works by rotating ground glass projection lense/screen dispersing light in all directions, so some of it will likely miss the collecting lense completely.

I have recently gotten Scott Billups book on "Digital Movie Making". Thumbing through it I notice that he states that Beta SP is actually a good format, because some Beta SP cameras have better CCD's etc than some modern 'professional' Digital cameras, and a 3:1:1 luminance to chrominance ratio. I still remain unconvinced though, I have seen side by side comparision reveiw between a BetaSP camera and a VX1000 and could see little (at captured image magnification) resolution difference (picture was close too) between the two, and the VX1000 is not the greatest dIgital camera. I will have to research this further, as I'm certain I have seen old SP camera's for simular to 953 prices (over here), but the price of a good capture card is likely going to cost a bit too, and it is going to be a used and worn camera. Still waiting to see the GS100 also (and MX7000, if it exists).

Thanks

Wayne.
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Old July 14th, 2003, 01:15 AM   #53
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There is no MX7000, just like there is no VX3000 or GL3---not yet, anyway. The GS100 is a Japanese Domestic, and according to Pana Japan, there are no plans to make this cam available outside of Japan.
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Old July 15th, 2003, 07:54 AM   #54
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<<<-- Originally posted by Frank Granovski : There is no MX7000, just like there is no VX3000 or GL3---not yet, anyway. The GS100 is a Japanese Domestic, and according to Pana Japan, there are no plans to make this cam available outside of Japan. -->>>

Your probably right, I have read comments that the MX7000 is the GS100, and that Supervideo got the translation mixed up. We got the MX500 (mx5000) over here resonably quickly, the price of the GS70 is so near to the discounted price of the MX500 model I suspected that the 500 might have been replaced soon with the GS100. If not, stuff, I'll have to wait until they discount the vx2000. I suspect they will replace that 24p camera with a high def model before they introduce a cheap HI-def, but it would have been a nice dream anyway (GS7000 now rather than a couple of years).

Thanks, have a good night Frank (well morning over there).

Wayne.
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Old April 18th, 2004, 02:28 AM   #55
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here's my 10c:

if you were a kid playing with lens and focusing the sun (burning stuff) you'll know that size matters a lot.
There's no way you can tell me that you "loose" the light in the more glass.
but ... talk is cheap, please.. someone .. just TRY IT =) and post the pics =)
how hard can it be?
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Old April 18th, 2004, 06:21 PM   #56
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if you were a kid playing with lens and focusing the sun (burning stuff) you'll know that size matters a lot. There's no way you can tell me that you "lose" the light in the more glass.
You can start fires not only with a magnifying glass but also with the opposite type of glass, which pushes everything further away. Perhaps get a wide angle adaptor, hold it under the sun and see if it will light some paper on fire. I'll give you a cigar if you can. :-))
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Old April 18th, 2004, 10:27 PM   #57
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lettme get a match.... hold on...
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Old April 21st, 2004, 09:16 AM   #58
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I thinkith that this thread has been greatly carstrated since last year, pity there were some interesting technical discussions. I was amazed that it went on for so long after Ieft.

On the threads past history: I have observed a general mixup in terminology in threads dealing with optical science (everywhere on the web, apparently). I offer no advice on resolving this, but this, that what a person means is the most important thing what ever terms they use rightly (the hearer mixes it up) or wrongly (the writer mixes it up) to describe it. For example, you will notice that I said "hearer" rather than the more proper term "reader". In a philisphical forum (not here) that should not lead into an arguement that the arguement was not right because you can't "hear" a written text, the intent is the same (though people tend to read text internally to themselves, so you could say they are infact hearing it, sort of). So it is really a matter of seeing deeper to what the person is actually meaning. And why this ever got mistakenly put into a Panasonic forum, I don't know. It never was about the Panasonic cameras, they were only passingly mentioned as an example of the cheapest possible 3CCD target camera.

The same with lense systems, to one person a light "gain" means that the lense is manufacturing light, which is impossible nowdays (though somebody could theorectically, one day, make a futeristic lense that is fed external energy that is then used to amplify the light coming through it, can I now take a patent on that). To the other person it is meaning that the light gathering ability of the system is increased resulting in a more light reaching the target (the 'gain" so to speak). In the above discussion the intent was allways to gather and deliver more light to the target. The larger lense though, also can distort the optical properties and result in light loss off the sides of the imaging plane, and a decreased feild of veiw. See the holographic diffuser dicusions in the 35mm adapter threads at the Alternative Imaging forum. I thought I made a post where I tried it on (a now dead) camera and received increase in image brightness. Actually over in those threads some people would have whopping big glass lenses, and I have read of somebody getting great increase in brightness, but reduced angle. Actually in this thread there was links to a Wide angle adapter that seemed to do the same thing, is that post still here?

George, to get your free cigar ;), I think if you face the front towards the sun it will condense it down like any magnifying glass, but if you use the other end it should spread the light instead.
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Old April 21st, 2004, 01:17 PM   #59
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Actually in this thread there was links to a Wide angle adapter that seemed to do the same thing, is that post still here?
It should be here if they were posted, unless they where on an other thread.
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Old April 23rd, 2004, 08:59 AM   #60
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Yeah there it is:

http://www.tiffen.com/digital_lenses.htm

My apologies, now I know why the pages look wrong, I have change my posts per page preference.

I should post the information on the lense I used. It is a old Minota, 58mm and f1.4, must have been worth a packet in it's day. Now to search for a lense that is 50mm and f1 or less ;) Actually I would like to try a medium format lense (around 70mm film) but what is the equivalent focal length to get neutral perspective look in this format (it's 50mm in 35mm SLR).
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