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Yet another new hopeful

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  • Yet another new hopeful

    Hello everyone. Yes I am starting down this road like so many have done before me. I have a box of reels on top of my wardrobe and my desk is covered in electric motors, lenses, led's, arduinos and sundry parts from a Eumig projector.

    I read lots of stuff online but for some reason most of it was from 10 or more years ago. I think it was probably these old posts that led me to seek out an SPC880NC Philips webcam, they were very thought highly of it seems. Having got one and got it converted to an SPC900NC, I have to say that I am a little disappointed in its performance. I suspect that these old cameras may have been overtaken by better models in recent years. Perhaps someone could comment.

    I have a decent enlarger lens mounted on the projector and I have a motor ready for mounting as well. I could just go ahead and rip the existing lens off my webcam and try things out but I have heard that I need an infra red filter between the lens and the imaging sensor. If it has one at the moment I suspect it is incorporated in its standard webcam lens, so if I remove it I will have to work out a way of fitting a new one.

    Could someone tell me:- Do I need an IR filter? If so, how should I go about sourcing one and fitting it?

    I am very pleased to have found this forum. Some nice up to date info here.

  • #2
    Hi Barry,
    On my Wolverine/Hawkeye setup I tested different lenses and iR filter improves the image contrast somewhat. Obviously, different setups will have different results but in my experience I would go with the IR filter.
    You plan to use the webcam. The SPC900NC has an M12 lens mount which allows you to use the M12 lenses. My Hawkeye project also uses M12 lenses. One with 12mm FD and the other one with 16mm. Both of these lenses have built in IR filter. So, that could be one way for you to go. Obviously, you have to check that the magnification is OK for the sensor that you use. I can run a quick check for you if you decide to go this way.

    But, your post gave me some ideas that I could use with my DSLR project.

    Essentially, instead of going with the expensive DSLR and alternative could be a web cam or similar cheaper cam. The rig consisting of Wolverine film transport is an open platform that can accept almost any camera. I am thinking of cheaper camera with the C lens mount. The C mount lenses are superior to M12 and the selection is much better. With the camera running at 30 FPS and the rig running at 2 FPS exactly the two systems stay synchronized without any additional components and it is very easy to extract the relevant frames, 1 out of 15.

    OK, after thinking about this for a bit I see a big issue. I actually tried several cheaper cams, arducams etc and there is a big issue. In order to get enough magnification you have to use longer focal lengths such as 12mm and 16mm. Most of these cams are designed to work with shorter focal lengths and the longer focal length will give you pink glow.

    The image looks like this.

    It is very hard to correct for this issue. You can actually test it. Get a cheaper 12mm or 16mm lens and try it.

    Last edited by Stan Jelavic; March 21, 2021, 12:18 PM.


    • #3

      Thanks for your input.

      I was intending to use my enlarger lens as I assume it is of better quality that the standard lens fitted to the SPC900. I have already rigged up the lens mount for the 50mm enlarger lens. This lens is now the only lens in my system. In removing the standard M12 mount lens I have also removed the IR filter. So my question is, how to re-instate an IR filter.

      Perhaps I could try to remove the actual lens elements from a M12 lens so that only the IR filter remains. Has anyone tried this? Or maybe it is possible to buy an IR filter in an M12 fitting.

      Any help is much appreciated.


      • #4
        Have you taken any test shots with the 50mm lens. Any pink glow? The pink glow is caused by the sensor when a longer focal length lens is used with some sensors.
        I have some IR glass filters that should fit M12 holder if I can find them.


        • #5
          I read a bit more about your webcam Barry and it is popular in astro photography.

          That indicates that the pink glow may not be an issue. Here is some info on pink glow and CRA:

          The CRA of the sensor has to match the CRA of the lens. If not you get this pink glow or sometimes they call it shadowing. Some sensors are more forgiving than others.

          What I am trying to figure out is what the difference in CRA is when the lens is used with the telescope and when used for telecine (more like a microscope).

          Regarding the IR filter. I have several cheap old M12 lenses with the IR filter built in. You can get one of those or I can send you one.


          • #6

            Here is one of the first frames of the first reel of film that I have tried. Its horribly out f focus but I think that was down to my dads lack of filming skills rather than anything at my end. I dont see a pink glow, so perhaps I am ok.
            Can you suggest any free capture software, and also, what is the best file format to use? A used SharpCap to get this image but .png files are one of the few options available.Click image for larger version

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            • #7
              That looks very promising Barry. I just got one SPC900NC from ebay and will try it today. My plan is to use it in video mode with the 12mm or 16mm M12 lenses. Then I save the individual images from the video stream with ffmpeg utility. Then select the good images and recompile the video. The selection of good images is easy because the video stream FPS is a multiple of the Wolverine FPS. For frame-by-frame the camera has to be triggered and I will have to look in into it since I am still not very familiar with the cam features.

              BTW - when done with the telecine I can still use the camera with my telescope. Bought the 16mm to T adapter for that purpose.


              • #8
                Tried the webcam and had to use a custom installation procedure for Windows 10. Got it working with SharpCap 3.2. The video is only 600x400 resolution and the FPS fluctuates quite a bit so not sure if the video mode will work well with the 2 FPS Wolverine.
                For image capture, an external trigger would have to be implemented somehow.


                • #9
                  I have managed to get 640x480, I was told to use version 3.0 specifically with windows 10. Maybe this could explain why you only get 600x400. I want to capture frame by frame and it seems that I can only get still pictures in .PNG or .FITS formats, are either of these formats ok for my purposes?

                  I am setting up an external trigger system using a hall sensor wired up to an old mouse via an arduino nano. I have set up an experiment with these components to see what trigger signal is needed and also to see how fast I can capture frames. So far it seems that the trigger pulse needs to be longer than 10 milliseconds, and that 3 frames per second is about as fast as I can go. As it happens, the top speed of my motor is about 3 fps, so thats ok but I must admit, I was expecting to be able to capture frames faster than that. Oh well, early days.

                  I will also need to simplify my power supplies. At the moment I have plenty of different voltage requirements.

                  LED lamp 9v (current needs to be variable)
                  DC motor 17.5V
                  Fan for led heatsink 12 V
                  Arduino/s 9V


                  • #10
                    My bad, Using Vlounge I get 640x480 for video and 1280x960 for image capture.
                    Click image for larger version

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                    The old mouse trick should work OK for frame-by-frame. With rigged up Wolverine it should be pretty easy. Just use the interface board and an old mouse and run the left button switch from the interface output.
                    Barry, you can make a simple regulator board with a 24V in.

                    Use on-board regulators for all of the voltages that you need.


                    • #11
                      Vlounge! I had never heard of it before your last message. At first I thought it was great. Very simple and it seemed to be able to capture more frequently than SharpCap, Venue and other products that I have tried but then I realised that I was not able to set the exposure time. In fact SharpCap is the only one I have tried that permits this.

                      My hall sensor trigger system seems to work ok at about 1 fps but when I speed it up I get a lot of black or partially black frames. This made me think that the hall sensor was not sending trigger signals at the correct time. I set up an experiment that flashed my led light source for just 1millisecond every time a trigger signal was received, a strobe to freeze the position of the shutter disk. It worked well and revealed that the trigger signals were well timed. Any thoughts on what the problem may be? I think I read a post somewhere suggesting that long wires could be a problem, could this be true?

                      As soon as I get this problem sorted out I will be shooting thousands of frames and I will need to learn about the next stage of the process. What format should my frames be? With SharpCap my only options are .PNG or .FTS.

                      Any advice is welcome.


                      • #12
                        Suggested Vlounge because that was the only one with the 1280x960 capture. The possible usage is to se set up the camera using some other app like SharpCap and then the cam memorizes the settings and then use Vlounge just for capture.
                        But I think I will use this webcam with my telescope only because it is just not good enough for the 8mm scan based on my latest tests.
                        I used my Wolverine open rig for testing. Set up the webcam on the adjustable stand and tried both the 12mm and 16mm Hawkeye lenses with it.
                        The good news is that there is no pink glow as we already know, but the the optical resolution is way too low.
                        Click image for larger version

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                        Here is the comparison with Hawkeye.


                        • #13
                          Click image for larger version

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                          • #14
                            The black frames can be caused by SharpCap. Have you implemented the mouse click? If so try VLounge. As I suggested earlier, preset the camera with SharpCap, close SharpCap and then run VLounge and set the capture to 1280x960. It outputs JPG format only which I think is quite OK considering the low rez of the camera. I tested it around 10 FPS and did not get any dropped frames.
                            BTW - the cam is a VGA cam but the shapshots get interpolated to 1280x960.