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First post and hoping someone may have run into this issue. I'm building a 16mm frame by frame telecine video capture unit. I used an old B&H projector, stepper motor, microswitch trigger, and a Nikon D3100 with a macro lens. It captures the picture well. But when I put them together, I get some flashing. So the exposure is different for each shot. It could be some exposure setting on the camera but it seems I have everything turned off and am shooting in manual mode. I'm using a LED bulb but it is powered by 110v AC, possibly I need to convert to a DC power source. Anybody have this issue before? Any ideas?
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Sample of exposure variations... -
Most likely the cause is the 60 Hz because the source is not filtered. Try with the bright flashlight to see if this fixes the issue. If it does then any baterry powered bright white light source will do.Comment
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That's a great idea. I'll give that a try first thing on Saturday when I can work on it again.Originally posted by Stan Jelavic View PostComment
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What's the camera's shutter speed? That might be the cause as well.
But also check your light source too.
My home brew setup uses 12V DC LED lamp as the light source. No flicker found so far.
Being DC light source make it possible for me to capture at 1/1300s shutter speed, and still no visible flicker/banding.
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Thanks. Your setup looks nice. I'm not sure about the shutter speed as I tried many. I'll make the led changeout and go from there.Comment
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Thanks guys, I swapped the light source over to a DC LeD and it works well now. On to figuring out the audio capture.Comment
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Good work Larry.Comment
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I've been trying to make it KISS for years - and I think I've eventually achieved that.Originally posted by Larry Bell View Post
Projector modification.
- Replacing its original drive motor with geared motor running from external DC source. So I can dial in to the maximum possible running speed without dropping a frame.
- Using DC LED light source as mentioned earlier.
- Enlarging the aperture to get entire frame plus some surroundings.
Trigger system.
- The simplest trigger approach ever - a reed switch & a magnet, hooked up directly to a wired remote shutter release. No electronics, no arduino, no plc. Nothing whatsoever, just two passive components and that's it!
The camera.
- Typical mirrorless camera, an outdated Panasonic G7 in this case. No modifications need at all - it works well even with its kit zoom lens. As long as all settings are kept strictly manual and with electronic shutter mode it will work just fine.
Even at low 3.5 Mpx resolution setting it seems more than enough, and it works relatively fast at around 2 fps too. If going down to lowest setting at FHD 1920*1080 pixels, it can run at pretty fast speed - 3fps. It will get a 50 ft super 8 film within just 20 minutes.
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Agree that is the simplest DIY way of getting a good quality transfer. I had that several years back, hall sensor and geared motor. My main issue with the setup was access to the gate. You really need enough optical magnification and for that the lens has to be relatively close to the film gate. An alternative is to keep a part of the original lens that works together with the camera lens. Not sure what your optical setup is Nantawat but in any case for me that part took some time.Comment
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Can't remember where I've got this little dirty secret, but I had great success with this setup for years.
Nothing particular, just replacing its original projection lens with a very typical 16mm projector lens 1:1.6, 50mm and that's it! This lens will act as a "loupe" magnifying the image large enough to work comfortably with camera's normal lens. Speaking about collimator lens principle...
For camcorders this will work right away, as most would have long enough zoom lens to fill the entire frame. For DSLR/mirrorless it's a bit trickier. But I managed to use the camera's digital teleconverter function (1:1 pixel readout I guess
) with 50mm taking lens to capture at 3.0 megapixel resolution, to fill most of the frame with some extra margin for additional later cropping.
And no, I don't shoot RAW. 3 megapixels of jpeg seems almost overkill for me.
This setup is, in theory, NOT ideal. In practice I've found it more than good enough to my eyes. Unless I've found another breakthrough, I'd stick to this setup for the time being.
PS just found this YouTube video.
Although 35mm, but this is EXACTLY the same in principle to what I'm doing. So it could be done, for sure.
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You essentially use a condenser lens in between the camera and the film. That is a compact version of the old condenser lens trick that consisted of a large condenser lens placed some distance like a foot from the projector. That system had lots of issues with alignment and vibration. Your version should not have these issues because it is compact and everything is close together. I have seen many solutions similar to yours.
Here is one example:
https://player.vimeo.com/video/20950590
My concern with this approach is that the optical system is custom and you could get image distortions. One of them that really bothers me is corner color aberration. But looks like you are pretty happy with the result which is encouraging. Definitely have to use a good quality condenser lens as a start.
In the link that you posted no condenser lens was used. But keep in mind that a camera was used instead of the projector. The camera lens is different, so no condenser was needed and besides that was a 35mm film that needs less optical magnification.
Overall it does look like one of the best solutions from the price/performance point of view. Good work.
Note: The system optics is one of the most important components of the system. For Hawkeye we use a good quality 16mm lens and nothing else. Adding additional lenses etc can only degrade the optics.
Also it is important to run the SMPTE resolution test. Here is the test result for the 16mm lens and ImagingSources camera:
https://photos.app.goo.gl/GgLvWkRD45PyXzjE6
That gives a uniform 80 line resolution anywhere within the frame.
The image that you sent Nantawat is lower rez and fuzzy when you zoom in. Can you share the full size.
Last edited by Stan Jelavic; August 31, 2021, 11:45 AM.Comment
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Actually it is "magnifier" lens setup, not "condenser" setup.
Those condenser/relay lens as used in those old school telecine system would need at least 3 optics (projection lens, condenser lens, and camera lens) and some workspace to setup. And LOTS of patience to do the alignment work - probably not what I'd like to do.
This magnifier setup is probably a lot simpler as only 2 optics involved (projector lens & camera lens). That projector lens is for "enlarging" the image large enough to work with using normal camera lens. I even tried coupling this with the camera's kit lens - mediocre 14-42 compact zoom.😝 When zoomed all the way in I can almost fill the entire frame at 3 megapixel resolution setting with the help of Digital Teleconverter function on (1:1 pixel readout I guess).
The actual capture is obviously inverted vertically - not a problem inverting it back to upright position in editing software.
Will it give the sharpest possible output? Probably not!
But since the capture resolution is 3 megapixel and the output is still at HD 1920*1080 pixels, this is more than enough. My customer seems pleased with the result.
Since their other option is Wolverine scanner, and while other scanning house is still doing the job at SD resolution (and charge twice as much as mine
) no wonder why they still keep coming back.
With all factor weighted in, this seems to give me the best quality/cost ratio at the moment. So I would stick to this for the time being.
(Well I should have my own topic by now lol. Maybe soon.)
PS 1: another scanning house, as far as I know, uses modified projector with analog cctv camera slapped on doing only real-time capture, and charge $30😨 for 50 ft reel. Does not sound right to me.
PS 2: I remembered that Janice did post her similar optical setup a while back. Can't find that post at the moment.Comment
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OK you mentioned on an earlier post that you replace the projector lens with the 50mm lens. Missed that.
The optical resolution (not pixel resolution) definitely seems to be noticeably lower than Hawkeye. But looks like that is good enough for you and your customers.
A better solution in my opinion is to use a true macro lens with the camera (attempted that years back) but in my setup I could not get close enough to the film gate due to the projector design.
Just recently we attempted that with the open frame Hawkeye with some very good results.
https://8mmforum.film-tech.com/vbb/f...0-hawkeye-dslr
The downside is the cost and complexity. Is it worth it? Perhaps it is to some people.
Perhaps use your setup with the macro lens and DSLP camera (Canon, Nikon)
https://8mmforum.film-tech.com/vbb/f...0-hawkeye-dslr
Or 60mm 2.8 macro lens for the Lumix.
This type of the lens may be able to access the film gate. The optical magnification is high enough to cover the full frame camera frame.
Quite expensive however.
Another thought... use reverse mount with your lens without the 50mm lens. The working distance may not be long enough for required magnification but may be worth a try. It may give you better optical results than what you get with two lenses.
Last edited by Stan Jelavic; September 01, 2021, 12:55 PM.Comment
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Thanks!Originally posted by Stan Jelavic View Post
Here's the working unit now. I'll be playing with speed and focus but it works pretty decent.
https://youtu.be/z65Z3DsYQG0
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