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Dom Jaeger

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About Dom Jaeger

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    Melbourne, Australia
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    Cinema camera and lens technician

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  1. P&S Technik announced their Technovision lens series in 2018, they are already available to the public: https://www.pstechnik.de/lenses/technovision-lenses I think the custom lenses Greg mentioned are just the close focus 40 and 50mm. Some history about Technovision and P&S Technik's involvement: https://www.fdtimes.com/2018/12/18/technovision-classic-anamorphic/ The founder and creative vision behind P&S Technik, Alfred Piffl, died in 2019, but I'm glad to see the company is still continuing his legacy.
  2. I know the feeling Greg! For years now I’ve been collating a database of image circles for every lens I come across, with caveats about how this lens covers Alexa Open Gate if you don’t stop down past T8, or this zoom covers DXL 8K down to 29mm or this lens series covers Arri LF 1.78 down to the 40mm etc. Some of our Panavision lenses have been modified with expanded optics to allow them to be used on larger formats, or they’ve been individually modded by having a baffle or front mask removed to cover just a tiny bit more. Some lenses cover a larger area than they were designed for but th
  3. Proper fluid heads like these are not easy to service. You need to be trained on them or it’s very easy to make them worse, and you can spend many, many hours overhauling one. Note that they contain special fluid, which is sticky and viscous, and needs to be drained to work on the pan and tilt drag systems, which are seperate to the counterbalance mechanism, among other difficulties. There is a Vision 30 Vinten service manual online, which gives you an idea of the complexity, and may be of help with a Vision 20 model: http://www.used-broadcast-equipment.co.uk/i/3259_9.pdf I’ve wo
  4. I get the feeling Stuart, that fact-based responses by experienced cinematographers like yourself and Satsuki are somehow not welcome in this thread. Well, points for self belief I guess.
  5. The example I have seems quite sharp to the corners, but I can't project it past 20 ft. That infinity image looks softer than it should to me, perhaps have it checked by a tech.
  6. What size sensor did you use to capture the still image? The 28mm Zeiss Standard Speed has about a 36mm diameter image circle - depending on how much of that circle you use the edges will have deeper depth of field. I can't say if it's normal or not just from one mainly out of focus image of a field, but I took some pics of a test projection of one I have here to show the defocus characteristics. Here's the lens focussed a few feet in front of the screen: It's a bit low res due to the low file size allowed, but you can clearly see the difference between the defocussed centre and
  7. Zeiss Standard Speeds are very well known T2.1 cinematography lenses, they have been used on movies for decades. They were an earlier cine lens design compared to the T1.4 Zeiss Super Speeds. There are several iterations, the first date back to the 60s, but the optical formula remained the same. Google them.
  8. What I think you’re seeing isn’t necessarily field curvature but increased depth of field at the edges. The plane of focus is set quite near, with only the very bottom of frame in sharp focus. With many older lens types, the way the focus falls off is much steeper in the middle of the frame, with the edges defocussing much less, which is what’s happening here. If you were to take the lens to a rental house with a lens projector and project it slightly defocussed, you would see that the test pattern is more defocussed in the centre than the edges. Have a look at the lens projecti
  9. It’s more likely that the battery cells just reached the end of their lifespan, but that can happen sooner if a charger is not suited to the battery. Some batteries are more finicky about the charger than others. I mean it’s probably safest to use the same brand charger with smart batteries, but lots of people don’t. Does the Hawk Woods charger specs say it’s compatible with IDX batteries? How you store batteries and how deeply you drain them can also affect battery life. I’m sure a battery specialist could give you more specific advice.
  10. Rental houses use battery testers to discharge a battery at a nominal current and measure how long it takes for the battery to be depleted. Once a battery drops to around 70% of the spec capacity they get retired. In the absence of a battery tester you could just compare how long a battery lasts compared to a new one running the same appliance and retire them once they drop to below 60-70% of the run time. Or if you know the current draw you could roughly calculate the capacity based on the time it takes to run down and compare it with the battery specs. Some batteries are rated in Amp- h
  11. The thing is, if you have an eye for composition, you would probably frame the same scene differently given a different aspect ratio. Cropping a well-composed image into a different aspect ratio is not the same thing as an original composition. Sometimes cinematographers have to compose images with two separate aspect ratios in mind, knowing that there will be different release formats, but usually one is the better composition.
  12. So you have the eyepiece type with a lock screw rather than a locking ring. When you say the lock screw won't tighten do you mean it keeps turning? Because that would suggest the threads are stripped and the unit needs replacing (or perhaps the threads could be repaired with a helicoil).
  13. That's actually a really good possibility, it was simply the mean of the two most extreme aspect ratios commonly in use.
  14. Sure, it's easier to picture the shape of an aspect ratio using decimal ratios relative to one. I was just pointing out the mathematical derivation of most aspect ratios, not promoting a different terminology. Though personally I don't have a problem with integer ratios. It just describes the relationship in a different way, and illuminates a different aspect of it. Your position is basically saying that fractions are too confusing and should be replaced with their decimal conversions, but there are good reasons to keep using fractions. Arguing for clarity in communication is a valid s
  15. Nothing more than tradition and maybe existing workflows or equipment.
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