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Zak Ray

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  • Occupation
    Cinematographer
  • Location
    New York

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  1. I've been working on an iOS app with lens specs, coverage charts/image circles, and some basic cinematography tools, and I'm happy to say it's finally finished. A few people here helped out with the specs (especially hard to find panavision specs) and with some depth of field math, so thank you for that! https://apps.apple.com/us/app/lenskit-tools-for-filmmakers/id1523521746 Full disclosure, the Panavision specs are still not complete, and there's also a few lenses from various manufacturers that don't have an exact image circle, but for the most part all the lenses have all the specs. Hope this tool can be of good use. If anyone has any suggestions or spots any errors, please let me know!
  2. I've read that some of the old Z Series cover S35 and some cover FF. Same with the Standard Primes from the '60s. Anyone happen to know which ones cover which?
  3. Thanks to you both! And yes I've already been through the Panavision site and also David Stump's book. I also tried calling Panavision directly but they got cagey pretty quick 🙂
  4. I'm working on a lens database app, and I'd like to include what year each lens series came out. Hoping someone here might be able to chime in. Doesn't have to be exact, even the right decade would be helpful. Here's what I'm missing: -Primo classics -Close focus / macro panatar -Primo anamorphic -Super high speed anamorphics -Various spherical zooms (LWZs, STZ, Z5S/Z6S) -Various anamorphic zooms (AWZ, ATZ, ALZ) I'm also coming up short on what the anamorphic squeeze is for the following: -B Series -Close focus / macro panatar -Primo anamorphic -Super high speed anamorphics -T series -Various zooms (AWZ, ATZ, ALZ) P.S. I'm also looking for weight and length specs on a lot of pana lenses... if you have any tips (beyond the Motion Picture Lens Database) let me know!
  5. PCam appears to use 0.021 for S35 1.78.
  6. Thanks Dom, that's very helpful. The reason I keep pressing for a formula is because I'm working on a DOF calculator and I thought it'd be useful to allow users to plug in their own numbers. But I appreciate the futility of trying to narrow it down to multiple decimal places, fair enough. It's good to know that there's some talk about updating the standard for modern cameras. Does anyone else have an opinion on what that "updated standard" might be?
  7. Thanks David, I agree they should only be used as guidelines, but broadly speaking, I would think the CoC for theatrical projection vs. a home television would be noticeably different; for most people, the movie screen fills up a larger amount of the field of vision, and so the need for precision is greater. Or are you saying even then the difference is negligible? Simon, I agree that human vision has to come into the equation, which is why the "visual acuity" parameter is part of the formula. My (admittedly shaky) understanding of why visual acuity = 1/1000 is derived from here. I could be totally off base here, but thats why I'm asking for the formula 🙂
  8. Thanks Simon. My understanding was that besides lens design, it's also necessary for DOF calculations, and in order to select the right value, one has to consider the size of and distance to the final screen. For example, this post... ...gets at what I'm trying to achieve; specific CoC values for different presentations. I want to know how those values are calculated. I'm not quite sure I understand what you mean by the medium affecting the result.
  9. I get the concept behind CoC, I'm just trying to wrap my head around the formula. I've seen the simple approach ("d/1500") but I want to actually plug in different values for screen size. My understanding of the full formula is this: CoC = (Visual Acuity * Viewing Distance) / (Display Diagonal / Camera Sensor Diagonal) I know the "standard" CoC is 0.001". I assume that's for Super35 1.78, which is a diagonal of 27.54mm. I don't fully understand the visual acuity part, but from what I've read it should be around 1/1000 for normal vision? So with that information, I can reverse engineer the formula to be: (1/1000 * 52') / (57' / 27.54mm) = 0.001" (obviously after converting all the units) 57' seemed like a reasonable diagonal for a theater screen, and 52' was the required viewing distance to get to an answer of 0.001". Is this anywhere near correct?
  10. I'm working on a new app for cine lenses -- if anyone wants to try it I'd love the feedback. Main features will be specs and sensor coverage but general tools like lens matching, FOV, DOF etc will likely be added. If you're interested here's the link: https://mailchi.mp/8fe94682fa6a/lenskitbeta
  11. Thanks Adrian, yes I would love to have some bulbs with high TLCI but it's impossible to find manufacturers that test for it, short of TV/film manufacturers like Quasar. That said, I have noticed that most lights with high TLCI also tend to have a high CRI. So I might take my chances with those bulbs and see what happens.
  12. Here's a few interesting options: 5500K, 93 CRI: https://www.bhphotovideo.com/c/product/1403778-REG/alzo_2000_55_04_di_fs_8w_joyous_spotlight_dimmable.html 5000K, 90 CRI: https://www.bulbs.com/product/LED9A19-81L-950 3000K, 92 CRI: https://www.bulbs.com/product/E12A19DLED930-JA8 2700K, 91 CRI: https://www.bulbs.com/product/F8-5A19DLED927-JA8
  13. Reviving this thread if I may. Anyone made any new discoveries? I was excited about the Quasar A-series, but they took them off the market due to overheating issues.
  14. Thanks guys. So the consensus is I shouldnt be trying any sort of beam angle compensation, meaning in terms of the Aputure light, itd be fair to say that its a 1.5K equivalent. I just have to factor in that its a smaller beam angle. Right?
  15. Thanks Adrian. I hear what you're saying re: measuring the center of the beam, but wouldn't the center naturally dim as the beam angle increases? I might indeed end up renting some lamps to test, but at the moment I'm just comparing a lot of them online to gauge what's in the ballpark of what I'm looking for. And yeah, I know marketing deparments can go a little wild! (I remember the Litepanels Sola 6+ being marketed as a 1600W HMI equiv-- ended up being closer to a 650W tungsten)
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