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Dom Jaeger

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Dom Jaeger last won the day on March 13

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About Dom Jaeger

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  • Occupation
    Other
  • Location
    Melbourne, Australia
  • Specialties
    Cinema camera and lens technician

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    http://cinetinker.blogspot.com.au
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  1. There are so many cinematography.com threads on this topic, but some diverge into abstraction.. we should have a sticky post that succinctly answers these questions. This recent one is worth a look: As simply as possible: 1. The shutter angle divided by 360 times the reciprocal of the frame rate gives you the exposure time. So for 24fps: 133/360 x 1/24 = 0.0154 or 1/65 sec. 2. You need to adjust the exposure reading by about a third of a stop to compensate for the light lost to the reflex prism. If using a meter in cine mode that assumes a 180 degree shutter you need to adjust a further third of a stop for the 133 degree shutter. There are several ways of doing this but probably the simplest way is to rate the film stock 2/3 stop slower, so for 100 ISO film set the meter to 64. 3. RX lenses do not compensate for the prism light loss, they only correct the optical aberrations that the prism introduces. 4. Plenty of good threads on this site about using a Bolex and shooting film in general.
  2. Well if all the other rolls are OK it's probably not something that happened in camera, maybe the roll got flashed and scratched during processing? In-camera scratches tend to be very straight, whereas yours looks wavy. I can't remember what causes a white scratch in a scan - a scratch in the negative base? Maybe a lab person can chime in.
  3. It could be that the shutter is a bit out of sync, exposing the film while it's being moved. To check, draw a wavy scribble along the emulsion side of some dummy film with a sharpie, load it and manually inch the film on while looking through the lens port (with the lens removed). You shouldn't see the film move at all. If you do see movement before or after the shutter closes, the timing needs to be adjusted. Unless you know for sure that it's working flawlessly, it's a good idea to have an experienced tech look over any camera that you buy before you spend money on stock, processing and scanning, but I don't know who to recommend in the UK.
  4. V and Gold mount batteries are almost all 14.4V, while SR3s need 24V. Even if you used a dual battery adapter that somehow worked with the SR3 on-board adapter it would be far too heavy for the on-board magnet attachment, so you'd need another system of attachment, and it would possibly supply too much voltage anyway when fully charged.
  5. You need to pull the lever out before it will move to change the shutter angle, then push it back in to lock a setting. A good copy of the manual is here: https://drive.google.com/file/d/0BxR_SVAX6J1ZWHdZSGFsZXh4Nmc/view If you've done that and it's still stuck, it needs a technician to look at it.
  6. You can use this close up lens calculator to work out what diopter strength gives you the right combination of distances: https://www.schneideroptics.com/software/Close_Up_Lens_Calculator.xls For example, if the taking lens is set to 4 ft with a +2 diopter close up lens, it will focus at 14 inches. So a +2 split diopter lens will let you focus at both 4 ft and 14 inches. Or 6 ft and 15.5 inches, 10 ft and 17 inches, etc. A +3 split diopter will let you focus at 4 ft and 10 inches, or 6 ft and 11 inches, etc.
  7. This site has a wealth of information in the archives: Older Arri mounts can be adapted to Aaton but the PL diameter is too large.
  8. Yikes! Yes soldering directly onto batteries is not a recommended practice, you should spot weld them or send them back to the seller.
  9. I think it would be fine to wind up and run the mechanism to check that it works. As a seller I don’t think you need to send the camera off to get serviced. Particularly if you send it to Bolex Switzerland, you will pay more than the camera can sell for. Leave that to a buyer. Some checks you can do to get a basic sense of the condition: Fully wind and run the camera all the way down with the lid off and the speed dial set to 24 (no higher). Note how it sounds, whether it seems to slow down at the end considerably or just a bit (which is normal). Check that the run plunger does not stick when depressed. Check that the take-up spindle (the bottom one in the chamber) turns smoothly as the camera runs. If it turns sluggishly or intermittently the camera definitely needs a service. Check the surface of the glass prism behind the middle lens port (you can unscrew the lens to check it). Check the lens for fungus (spider webs or tendrils visible on the glass surfaces), and whether the focus and iris rings turn ok. Check for any signs of corrosion. Note it all along with plenty of photos and put it on ebay or your selling site of choice.
  10. Aapo is right, you really need a depth gauge with a flat backing block in the gate to properly measure and set the flange depth. In theory your method could work, but it does require that the lenses you're using are perfectly collimated (ie back-focus set to the 52.00mm PL standard), and that the ground glass is perfectly set to the same depth as the gate (since you're checking the lenses through the viewfinder not at the gate itself). Then there is the question of how accurately you can judge focus on a wide lens. There may also be play in the lens threads adding further discrepancies. From your measurements, using a test projector, I estimated the 18mm needs to seat about 0.25mm closer, while the 12mm needs to be about 0.20mm closer. The difference of 0.05mm is substantial in terms of flange depth, which we usually try to set within 0.01mm. If you took the camera to a technician (at a rental house service department or repair facility) they could measure your flange depth and ground glass depth very accurately in about 10 minutes. The best way to set it is to machine the material about 0.10 mm under, and then shim back up to within 0.01mm. I'm curious what your "special" little camera is..
  11. Hi Todd, are you sure the Zeiss zoom is a Standard 16 10-100? It looks to me like it's been converted to 12-120 to cover S16. The zoom scale on the lens goes to 120. Some conversions changed the zoom scale ring but didn't bother with the front ring (that reads 10-100). If in doubt, you can always just mount the lens and check that it doesn't vignette in the viewfinder (with a S16 ground glass) at the wide end. A 10-100 would not cover S16 at that end. A S16 Zeiss 12-120 is quite a bit more valuable than a 10-100.
  12. Yeah they're pricey, but a good one will last forever, will be made to fine tolerances and should hold value. Let us know what TLS say.
  13. Hi Robbie, yes unfortunately most of the older adapters (or cheap eBay ones) made for Arri Standard lenses that need to rotate inside the adapter foul on the inner baffle of the PL throat of Arri's digital cameras. They work OK on Arri film cameras, but for reasons known only to Arri, they changed the baffle specs for Alexas and Amiras. I would email TLS in the UK to check first, but I believe their adapter (which is the same one Duclos sells in the US) should work with a PL mount Amira. https://www.truelens.co.uk/arri-standard-to-pl-adaptor?deptID=3&subID=8
  14. The advice is that the zoom motor does not in fact use the 3.6V centre tap. That only powers the iris motor. Since the OP mentioned that the auto iris works, as well as the camera run release which uses 7.2V, the battery itself is therefore not the problem. The issue is with the lens zoom motor or how it’s getting its power.
  15. If they're both the same nominal voltage, the only difference can be that the battery voltage is dropping under the current load of the camera (due to a bad or too low capacity battery) and setting off the sync warning, or the battery power cable has high resistance and the voltage is dropping across that.
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