Aapo Lettinen

design specs update, added features: - two trimmer potentiometers to easily fine tune the PWM values on the most critical mid range speeds (these are the 23.976, 24.00 and 25.00) . The fine tuning of the system on these speeds can be done with a screwdriver and no need to touch the code at all. The other speeds still need fine tuning to be really stable, especially the low speeds where high torque is generally needed - I will test off-the-shelf slot-type speed sensors to speed up the prototyping process a bit and standardize a critical part. If it works correctly, then a very common eBay sensor part can be used and it does not need preamplifier which makes circuit board designing much easier and would enable the end user to assemble all the mechanical parts of the system - function added to the program code which enables using a encoder disc with the system very easily. Just add the slot count of the disc to the code and it should work out of the box. I have more time for prototyping next month. I will probably make a dedicated test motor for this project with custom diy made encoder disc. this way it is easier to finesse the speed control functions. I will probably use a motor of 10A to 15A power draw range which also helps testing the power electronics of the system.

then you add a blimp housing to the camera ?

It would be possible to attach a potentiometer on the board which could be used for fine tuning these values. but not every one of them... maybe one or two of the speeds closest together like the 23.976, the 24.00 and the 25.00 . That would actually help 90% of the users. I will consider that option ?

at this stage I am not absolutely sure how accurate the current design can be when it is properly fine tuned. The first working prototype could maintain about 50rpm accuracy so the 10rpm is a good target for now. Part of it is that the analogue electronics are not properly tuned yet and the square wave conversion is not perfect which messes up the speed calculations a little. The Kinor motor also generates one pulse per revolution which is not optimal for this type of system. With a proper encoder with dozens of slots the speed accuracy would be much better in any case but it needs lots of testing to see how accurate it can be

what it practically means is that one needs to open the program code in Arduino IDE , locate the lines which set the PWM cycle low and high values separately for every frame rate and then manually fine tune the low and high values when comparing how stable the set speed stays when changing the values. I may do this differently in future versions so it might change. The speeds are rpm in this version (the "freqSetVal" ) :

I currently own three cameras which urgently need sync motors so I am primarily making the system for them. so small scale prototyping is not that costly and I have already done most of the hard work except the actual circuit board design (have to learn to use new programs so takes some time). The price point depends on how much the board needs customization or if the design I use fits the other cameras as well. Physical size is the most limiting factor if one wants to fit the whole system inside the existing motor housing. If an external box would do, then it would be much much simpler and cheaper. One of the factors is that the current code needs to be fine tuned per camera/motor type and the end user may need to do this by themselves. The current system is based on Arduino so the fine tuning is very easy to do but it may not be for everybody and will take some time. what will seriously take the cost up would be: - shipping cameras and motors back and forth, especially from U.S (installing by me instead of the end user) . By my opinion this should be avoided unless absolutely necessary - small physical size which is more demanding on the circuit board manufacturing technology. Larger boards can be made by me at home by simple means but very small boards will probably need to be custom made in manufacturing company which necessitates very precise designing and standardizing and a larger production run which is not economical for this kind of relatively early prototype - custom manufacturing mechanical parts like encoder disc fittings. this may necessitate shipping the motor back and forth

More like shadow lines or a blur as I remember

continuing the project little by little. My current specs: - rotary switch for selecting 6 preset speeds. The speeds are specified directly in the program code and can be changed there. - a LED lights up when the selected speed is reached - simple start-stop switch (can be wired to the original start-stop switch of the camera) - input for AC pilot tone signal with simple setup to turn the signal to square wave for frequency metering - the fine tuning of the speed control stability needs to be done setting the values directly in the code. this has to be done for every preset speed separately if the system is installed to different type of motor. basically testing how much the motor rpm oscillates around the set speed value and then manually tuning the pwm values to stabilise the rpm - the board contains a protected output for motor pwm signal but the power transistors actually driving the motor are separate (some motors have suitable metal surfaces which can be used as heatsinks so it is more handy to make the control board small and figure out the power electronics placement case by case - will add: output for using the frequency metering signal on external devices - will add: operational amplifier based, adjustable sensitivity input which could use optical and magnetic sensors for motor speed monitoring. - a possibility: dual operational amplifier inputs, both adjustable but one for encoder input and one with rectifier circuit to use with generators - might happen or not: a small display to read information. this requires lots more coding and I will finish everything else first before attempting this If anyone is interested in the project, please add comments and suggestions here or PM me. If there is a demand for this type of custom motor control electronics we can try to figure something out and maybe even do a small production run if it seems to be economically possible ?

the gel filters are handy if wanting to shoot with very small lenses like the 25/1.4 switar, or when shooting with fisheye/wide angle lenses. I like to use a Chinese c-mount 8mm lens on my H16RX for wide angle shots (extremely compact lens and pretty OK optically) so the gel filters may became handy in these situations though they are a little pain to work with because they collect dust so easily

visible scratches and marks on gel filter may affect the image easily. If it's not possible to test them then it would be wiser to just replace the filter or use the glass one like the OP suggested. I personally like to use 3x3 filters with clip on matteboxes if possible (the 3x3 tend to be cheaper than 4x4 and are more compact as well)

It is a very common misconception that using an old lens would automatically and magically turn the image technically inferior but nice looking and interesting at the same time. It is almost like saying that shooting with an old camera body would automatically turn the image old looking even when the lens and the film are modern.(I know lots of these people too...) Most of the lenses manufactured in the last 100 years are surprisingly high performing and will most often be a disappointment for persons who expect very clearly visible "vintage look"(whatever that means) by just attaching a random old lens to the camera and keeping everything else the same. There is differences of course but if not talking about coating performance you will generally need to shoot wide open to see enough difference to justify the use of a "vintage lens" instead of a higher performing more modern one. This limits their use to certain type of scenes and effect style shots. As always, there is some exceptions. For example I have shot some stuff with oct18-mounted Lomo 28/T2.3 on a slightly larger than S35 sensor and the weird focus curvature cannot be replicated easily with any other equipment and one can also easily see it stopped down. Basically your focus point and depth of field changes from center to edges very clearly because the retrofocus front elements are originally designed for Academy format and the edges are thus not corrected all the way.

// edit: ninjaed.... replying to the original post, not David's. the lens projects the image as multiple very small points of light. Also the sensor reads millions of small areas separately. So no, it does not work that way. IF the sensor only had one pixel in it AND the lens would be totally out of focus only projecting a single point of light, then it would be another matter

I became interested in microcontrollers a while ago and I am considering a DIY sync sound motor for my Kinor 2m camera. I also have other cameras which could use a stable speed motor (for example my 35mm Soyuz-US3N camera and the rheostat motored Konvas 1KCP. This is because there is no available motors of any kind for Soyuz and the rheostat Konvas never had any sync motors made originally) . I started with the 16mm Kinor motor last month and I'm refining the analog control electronics and fine tuning the code now. I was just thinking, is there lots of people out there who could use a customisable sync sound motor on their camera and if so, which exact camera models would be the most in demand? If there seems to be some common interests then I could take them into account when developing my own motor project and it might be easy to make custom solutions for other persons cameras as well. --------- What would be the absolutely mandatory specifications for this type of motor? I am aiming for +/- 10rpm accuracy at the moment but we will see how accurate the diy solution will be when it is fine tuned for the specific motor and camera model. That 10rpm accuracy would be about 1 frame drift for every 2.5 minutes of footage shot which should be usable for sync sound uses in indie films which have relatively short takes (a minute per take for example). My current design for the Kinor16 motor will have 6 different preset speeds and it uses the original pilot tone generator just like the Olex crystal sync modification does though my design is not as sophisticated or accurate (one gets what one pays for :) the Olex motor is better and my design is cheaper). - what type of camera and "wild" motor would most urgently need a digital speed stabilising system like this one? - how accurate the speed needs to be. how much it can drift to be usable? I am talking about minimum specs which would enable practical use of the system, NOT about how much would be nice to have :) - how much it can cost, in case there seems to be so much demand that it would be doable to do for example a dozen or so of these? - how much the end user can assemble by themselves? is a parts kit with pre drilled circuit board enough (needs soldering and a little bit of tuning) or only fully assembled board would do? - it is very clear from beginning that this type of product needs to be user installed to be a viable option. It would not be economical to ship cameras and motors back and forth between continents, that would ruin the whole point of this type of motor solution - what kind of inputs for the encoder which is attached to the motor. My current design uses the pilot tone generator signal coming from the Kinor motor but for other cameras I will use either a encoder disc or magnetic sensors for rpm feedback.

sounds like you live in very humid climate. I have never had any fungus problems with lenses here. I am normally storing them in clear plastic storage boxes to avoid dust but no desiccant packs needed ever. If storing them in basement or garage then there could be fungus issues of course but never had them when storing lenses in normal room temperature and humidity

I tested the 12-120 T3 on my friend's Aaton LTR and it covers S16 on 12 - 30 range if focused between 3m and infinity. between 30 and 120 it covers S16 at all focusing distances. These are the same results I got with my S16 modified Kinor earlier but I wanted to confirm with another camera because my Kinor is N16 centered. So the Lomo covers S16 but you have to live with some annoyances like the poor lens speed and focusing distance limitations. It is very affordable lens though, you get a usable S16 capable zoom with the PL adapter and caps for about 150 bucks or so

there is Arri-B mount Illuminas available on eBay. Apparently the manufacturer made changeable mounts. Maybe it was a later production run and not available when they first came out https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=optar+illumina&_sacat=0

It's been years since I tested this on sr3 but I remember clearly that most of the lenses including S4 did not have viewfinder clearance issues. The ones problematic were Ultra Primes where the lens barrell comes very very close to the viewfinder tube (they are "fatter" from the rear part than most 35 lenses even when they are otherwise smallish lenses). Though they could still be used, at least the ones I tested. There was just about 1mm or so of free space between the lens and the finder

Richard please! Why don't you just learn some French to make the Telefilm people like you more? would be much easier than raging on forums about their attitude and it would be useful when traveling as well ?

If she is interested in robots and programming it would be possible to start early on. Arduinos and similar microcontrollers are easy to learn for example (you will get results in couple of hours even) and one can do almost anything with them when being able to write one's own programs for them. It is best if you both learn to build and use them so that it is easy to resolve issues and learn faster

I would not want to work in a place where they inspect one's genitals and skin color in the job interview to confirm that they surely hire the right type of person ? it will become even more messy if it is taken into account that there is more than two genders. Yes, positive discrimination will easily get messy very quickly. I have understood that the best approach against both negative and positive discrimination is anonymous hiring where the applicant's background or gender cannot be seen so that it does not influence the hiring decisions. I don't know how possible that would be for HODs but it works very well in other industries so it is at least something to think about

With 16mm it is a little bit easier because you have perforations only on one side. The easiest it to check that the perfs are on the same side than on the projector sprocket teeth and the roll is starting with the correct shot so its not reversed accidentally. The emulsion position depends on the film you project (print or camera original). Winding direction does not matter that much on 16 unless you have a projector with rewind function you want to use. The film can be a little bit more stable if running from the feed reel counterclockwise depending on the projector. From Kodak page: "There is no preferred emulsion orientation for 16 mm and 8 mm films since they are used in both emulsion positions. Original reversal films, such as those used in cameras, are wound emulsion out. Prints from negatives and reversal dupes are normally wound emulsion in. "

if you will want to load the film to a spiral tank for diy processing, then I would recommend watching some tutorials first and practicing with a dummy film to make sure you are able to load it properly. when loading Lomo spirals there is some tricks to make it a bit easier (or to make it possible in the first place). If you can't find a good tutorial we can make one for you :) If you wanted to ask about preparing the rolls for sending to a lab, then it is pretty easy to advice the process if you tell a bit more of what you want to do with the rolls and how they are shot, how they are intended to be developed and how you want them to be transferred

load the film to what kind of reel? Do you mean a spiral tank for diy processing? or preparing the film for sending it to the lab for processing? or making sure the roll order is correct to ensure easier telecine?

the characteristics curve is of most interest for you when exposing the film. the exposure change is presented as log values which are "common 10 base log" values. to convert these to f-stops I do the following: read the curve points which interest you. check how much this is on the log exposure scale on the graph (we call this value X) calculate 10x to return the exposure change as a value (for example if the X was 2 the value change is 100) calculate how manu f-stops the value change is (remember that one f-stop is the value doubled or halved? for example if the change value was 100 then the change is in f-stops.... 2, 4, 8, 16, 32, 64, 128 which is 7 stops )

there is documents explaining this very easy way: https://www.kodak.com/uploadedfiles/motion/US_plugins_acrobat_en_motion_newsletters_filmEss_06_Characteristics_of_Film.pdf