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Phil Rhodes

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Everything posted by Phil Rhodes

  1. Everything you say is absolutely right, with the possible exception of this. Most LEDs are light and fast, but the really big, high-power LEDs are getting pretty chunky. A full Aputure 600C kit weighs more than twice what an Arri 575W HMI fresnel does, although the HMI doesn't come in a nice padded rolling case. The 600C does a lot more but it is not a featherweight either in the lamp head or the ballast. Part of this may be due to Aputure very clearly beefing up its build quality, probably in the knowledge that these things are much more targeted at a higher end market. Of course it's also less than half the price of an Arri D5, which is an increasingly absurd reality.
  2. Ah, yes. I tried very hard not to miss what I was missing, but I missed that. Very good spot.
  3. That looks far enough away to be effectively infinity. What sort of camera and lens was this? If it's a reflex viewfinder, is the problem visible in the viewfinder? Is any part of the viewfinder image sharp? This can arise from a number of sources: - The flange focal distance is perhaps not correct. Simply put, the lens has to be an extremely precise distance away from the film for focus to work as expected (to within something like the width of a human hair). The mounting surface on the back of the lens and the lens mount on the camera must be very accurately positioned. Is there anything stuck to the mount, any damage? Did anything get stuck between the lens and the mount? What sort of mount is it? Was it properly and firmly attached? You can test this to an extent by verifying that the lens accurately (and I mean accurately) focuses to the expected distance otherwise. This will require a measuring tape to establish. Do it at a wide aperture to minimise depth of field and measure a few distances. Make sure you're measuring from the right point, which is where the film is inside the camera body. - Is this a zoom lens? Some zoom lenses have internal controls to set up tracking, which ensures the lens stays in focus as you zoom in and out. Normally that's a problem with broadcast TV lenses, though. Zooms can break in other ways which cause focus problems. If it's a zoom, does the focus appear to change as you zoom in and out? It shouldn't. Again, test. - The lens may be allowing the focus to move beyond infinity, which means nothing will be in focus. If you look at the markings on the lens barrel, do they appear to let things move beyond infinity? That can be an issue; infinity is not necessarily just a matter of turning the ring as far as it goes. In an ideal world, the lens should mechanically prevent this from happening, but sometimes they don't. - Was this shot at a very high f-stop? I see it's a day exterior presumably with lots of light. What film stock did you use, and what sort of filters, if any? Lenses have a diffraction limit which can mean fuzzy pictures at very high f-numbers. That does have a fairly specific sort of look to it, though, and this does look more like a conventional focus problem. - Did you shoot anything else with similar problems, whether set to infinity or not? - Did you use any diopters (close-up lenses) on any part of the shoot? Is it possible one of them was left in place? That might cause this. Notice several of these problems would imply a problem with the lens, so if you can only send one thing off to be looked at, send the lens off. I know it's ruinously expensive but if you can do some tests on film to make sure someone didn't make some sort of daft mistake on the day, test again to make sure this is really happening and is a repeatable problem. Once you're convinced it is, it'll have to go off to be fixed. Has this camera and lens been maintained recently? Phil
  4. I have some Aputure 600-watt LEDs available right now, so if you want any measurements done I'm happy to oblige. Generally they seem powerful because, with the high-gain reflectors, they are effectively PARs. It's a high-efficiency layout. They do quite well with the spotlight adapter, too, because the profile lens tube is pretty well designed and nicely put together. There is an argument that Aputure's fresnel isn't quite large enough and perhaps fails to capture as much of the light output by the COB as it could, though it's not clear how much difference that makes compared to a 575W HMI with its small lens. It's worth noticing that all of these things are actually more to do with the adaptors that go on the front than the light itself. The point is that it's relatively easy to gather all of the light that comes out of the LED module because it isn't radiating light into a near-spherical pattern. It's easier to push the photons in a useful direction. The system is less lossy. As such, these modern LED designs are all likely to be more efficient, watt for watt, than HMIs, for no reason other than that they let people create more optically efficient designs. The absolute efficiency of an LED with reasonable colour quality is probably not that much larger than an HMI, although for me the deciding factor has to be cost. An Arri D5 575W HMI PAR with ballast is more than twice the price of an Aputure LS 600C, and the 600C is a full colour mixing, dimmable, interchangeable-modifier light that can in a pinch be run from batteries. Expensive batteries, sure, but it can be done. I would also say that the 600D Pro (which is the beefier, better-built, roadworthy version) and the 600C Pro are both reasonably representative of Aputure upping its game and targeting a higher end clientele. On that basis, I wonder if some of the big players in this industry will go the way of, say, DaVinci, which gurgled down the plughole with a shriek of "but we're high end, this can't happen to us!"
  5. Depends what you need. ProRes, raw from various cameras, SDI, HDMI, 1080, 4K? Get something used, maybe.
  6. No, didn't have any idea about it. I guess I could find a reason if they'd have me.
  7. So where do I find this COFDM thing? As far as I was aware the Amimon tech is a QAM approach with clever allocation to minimise the impact of errors. P
  8. Ah, Nyrius! Mine died a while ago but served well for a while. I have a Bolt 4K 1500 here if anyone wants me to run any tests. Can't remember how much power the transmitter pulls.
  9. Has anyone used the wheel accessories for modern remote heads and gimbals? Are the skills transferable? One would have hoped so.
  10. Or hit the charity shops* for old bits of cut glass tableware. * Thrift stores, Americans
  11. Spare chandelier parts! http://www.uk.thechandeliercompany.com/section.php/911/1/crystal-and-glass-pieces
  12. If someone has an F3 and the SD card I'll look at it. Might end up inadvertently destroying both, of course...
  13. Crikey, lugging 16mm around on a documentary in 2022! That's dedication. Well, I guess what you lose in batteries you make up for in stock. Not to nitpick, but is the time lapse at about 20 seconds going backwards?
  14. I think a lot of people are basically doing that because there's almost no other cost-effective solution. This is what LTO is for, but LTO is too expensive for many situations. I am constantly dismayed by the failure of the LTO people to make it more popular than it is, which would mean addressing the cost of entry in a way that would mean restructuring the whole way they market the thing. As a technical writer I get a lot of announcements of new ideas in this area, none of which ever seem to make it to productisation. The problem people should be aware of is that hard drives are not designed to be, and are not very good at being, a long-term archival storage medium.
  15. If you accidentally delete something from a RAID, you're not protected. If you have it on another storage medium, you are. RAID is not backup.
  16. I recently had a look at a Fuji X-H2S which has IBIS on a sensor that will do 6.2K at video rates. Seems to me like a pretty high performance design.
  17. I'll reiterate what Heikki said. RAID protects you from hardware failure - to an extent. It does not protect you from human factors and simple mistakes. RAID is not backup. LTO tape might be backup.
  18. Well, it's a photographer's studio, isn't it. Those are nonpaying clients, presumably. I once shot a short film set in 1911 which required our actress to wear an outfit - with a jacket over the top - markedly like the one worn by the woman in the first image. Corset, long skirt, way too much tight-fitting velvet, and feathers in the hat. She did not enjoy it.
  19. That works when the lighting flickers at the local mains frequency, which assumes the use of magnetic ballasts for fluorescent or other types of discharge light or, sometimes, LED lightbulbs without much circuitry in them. Magnetic ballasts have largely been replaced with electronic ones, to the point where electronic ballasts are also increasingly obsolete, with discharge lighting itself is being rapidly subsumed by LED. It's certainly not impossible to find street or industrial lighting that flickers at 60Hz, but a gas discharge light which does will likely be a rust-encrusted, decades-old installation at this point. I have some metal halide lighting which uses electronic ballasts and I've measured those at 150Hz (though they're square wave devices, like an HMI ballast in "flicker free" mode, and they are indeed highly flicker free - a casual test with my cellphone's 900fps mode reveals not a twitch). LED lightbulbs can sometimes flicker at the mains frequency or at double the mains frequency. They may also use much more elaborate drivers that can either cause no flicker, or flicker at almost any frequency the designer found convenient. Sometimes they may flicker very quickly, quickly enough to create venetian-blind effects on rolling-shutter cameras. LED video walls invariably use pulse width control and will more or less all flicker unless special measures are taken to synchronise with them. I've been around a few virtual production stages recently and taking photos of them on a cellphone generally requires trimming the exposure to create a slow enough shutter speed for reasonable integration of several PWM cycles. Either way, again, the electronics that drives them has nothing to do with the mains frequency. The sad reality is that classic ideas around picking specific degree shutter angles to avoid lighting flicker are as obsolete as iron-ballasted fluorescent tubes at this point. Image below shows a virtual production stage video wall shot on a cellphone. Exposure time was 1/160s. Overlook the moiré; the horizontal bands are the residual timing error between the display drive and the shutter timing.
  20. I hate to fall into my accustomed role here, but if you're struggling to afford to scan your film, should you really be shooting film?
  21. Well, they can, though it's usually an artefact of the backlight rather than the LCD panel itself. What makes me comment, though, is that LCD video walls are rare. What we might be talking about is LED video walls, which use a fundamentally different technology and can absolutely flicker terribly. Can we clear that up?
  22. Split diopter. Notice the slight curve evident on the glass itself.
  23. These days, more or less anything will do that, from a video-capable stills camera to a Venice 2. I have a Fujifilm X-H2S stills camera here right now, on demo, which will shoot 6.2K ProRes to internal storage with decent dynamic range. If that's not enough for almost any purpose, I'm not sure what is. As such, usability, ergonomics and other practicalities quickly become the deciding factor. You need to demo some things and shoot short projects on them and figure out what you personally like. Phil
  24. Seconded. Rent cameras. Buy everything else! If you need to buy something, go get yourself an FS700 or something. 240fps raw 4K, extremely compatible lens mount, and the price it is now? Still hard to beat.
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