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Gregg MacPherson

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Everything posted by Gregg MacPherson

  1. I think the red knobs were just for turning the PL lock ring easier, and to clearly show the lock ring position.
  2. Pics of three PL/TS adapters... 1) The Les Bosher one..see my dropbox ACL II pics https://www.dropbox.com/sh/iv95oerahx3929f/AADPd-7BkrctDPv78WjwtDlDa?dl=0 and Les has a pic on his website... 2) The simplest and cheapest looking one. 3) Quite sophisticated. Heikki has it now so he can maybe answer questions about it.
  3. @Geffen You should show a link to the machinist on eBay. Info like that is useful...Do you have any factory made adapters for the ACL at the moment? I have photos of three different PL/TS adapters, but it won't help much. The TS end that mounts on the camera is mechanically very simple and it would be easy to make on a small lathe if one is good at cutting big coarse metric threads. If you have any PL/TS adapter you can just take off the brass flange, measure everything and make a drawing. There are some inexpensive PL adapters that could just trim and add the TS fitting. Gregg.
  4. I ended up getting a couple of eye cups from the Israeli eBay vendor (link as above https://www.ebay.com/itm/256311812732?hash=item3bad5fe27c:g:wRgAAOSwIuNhkNwa). The hole ID measures 28mm, not the 25mm quoted by the vendor. I was looking for an eye cup that would fit a Kinoptik orientable VF for the ACL, the recess on that is 32mm diameter. I don't have a VF here at the moment, but the rubber stretched easily over a 32mm tube. So for applications where the eye cup is not required to rotate easily in the recess, it may be a useful option. It would be handy to have a little table/ database of eyecups for the various cameras. For cameras like ACLs, with maybe various eyecups due to various VFs, it might help when trying to locate an adaptable Arri one etc... A good eyecup that immediately positions the eye (pupil) correctly can be very useful. Gregg
  5. Do you know what the internal diameter of the hole is? i have a hunch i have already asked Du-All and they didn't respond. I was looking for something with ID=32mm, or that might stretch. Gregg.
  6. Keep an eye open on ebay. I'm not sure who does the manufacturing. Maybe items like eyecups are commissioned from various manufactures in batches, or sold wholesale in batches. This chap in Israel said he produces them, but I'm not sure how to interpret that. They are cheaper than other versions I have seen...Internal diameter 2.5cm. https://www.ebay.com/itm/256311812732?hash=item3bad5fe27c:g:wRgAAOSwIuNhkNwa
  7. Can you measure the diameter of the recess that the eyecup fits into? Vernier is best. if the old rubber is really bad you may not like taking it off, but there is probably no other way. Gregg.
  8. The 80mm fronts that were commonly made for those MK I lenses...would that help? Otherwise you could have your machinist turn up a plastic spacer, put a split in it so it will clamp... Gregg Edit..sorry, that is in reference to the lens at the bottom of page 1...I lost my way.
  9. Rescuing this from eventual oblivion on the marketplace forum...
  10. Did the adapter ring have any optical elements? If not then a simple spacer shifting the VF mount away from the camera body would work..?
  11. Cheap V-lock batteries on Ali Express... Has anyone else wondered about switching to V-lock and using a voltage regulator? There are some really cheap batteries, chargers on Ali Express that might make the experiment reasonably inexpensive. 95Wh, USD43. Anyone tried them? Are they junk..(question 1)? (Edit: the V-lock batteries above, the shipping stated didn't match the shipping total in checkout, which was more. Almost USD100 to ship 2 batteries and a charger to NZ) I had seen a V-lock mount with 12v regulated output on Amazon which looked promising.. https://www.amazon.com/HEDBOX-UNIX-12V-V-Lock-Adapter-BREAKWAY/dp/B07JYG96DW Or I thought one could just add a 12V regulator.... Then I realized it would be better to have a higher voltage regulator, if these were easily available. Andrjez at AZ Spectrum gave 15.6V as the max actual V I think. So I thought a 14V or 13.8V might be the way, the voltage of a fully charged NiCad/NiMhi. Any suggestions on a cheap 13.8V/14V regulator..(question 2)..? Are most regulators for modern automotive use also rectifiers? So not suitable? Yes, big gaps in my education. I half remember some Kirchhoff theorems, but I can't read a resistor code. The idea of V-loc batteries brings up the ideas about how batteries are ideally mounted to enhance the mass distribution, hence balance on your shoulder. A multifunction base plate for rods, handles etc could also have a clamp/mount for a rod etc that went to the rear to support a battery. The ACL II has a lot of redundant aluminium in the base that a clamp or battery support could screw to. Gregg.
  12. Nice as it is to have self leveling viewfinders, I remember coping quite well without one. Most of the time with an ACL on sticks I was leaning over it, the VF rotated 45 to 90deg and my head the same, to level the image. The young, unspoilt directors also seemed fine with it...
  13. Thank you David. Searching Schmidt–Pechan prism on google is a fine start point to understanding how the Kinoptik and Ang VFs on the ACL work. I wish you had pointed to that sooner. Hope your S16 camera devpt is gong well. Gregg.
  14. Hey Walt, On the main page showing all the sub forums there is >Cameras Systems and Formats>Eclair...quite an active group with a couple of electronics guys and maybe some Cameflex knowledge..Show the photo there... (Edit: the marketplace forum has high traffic and you will be lost downstream in a day or two.) https://cinematography.com/index.php?/forums/forum/76-eclair/
  15. Hey Jon, I didn't mean to seem critical. I just wasn't sure what you meant. Cheers.
  16. Hey Jon, David Jean's sample i thought looked very pretty (1st clip). It doesn't look like it's trying to show the sharpness. But if you look through you find parts that suggest the sharpness...the walking boots... the blond hairs, bright against black. I think maybe the sharpness needs to be carefully measured, maybe on the lens projector. Not sure what you mean about the film grain..?
  17. Oh I see. Please send it if it's easy, or put it in your Dropbox etc. But I don't have much skill with digital to examine the frames carefully. Gregg.
  18. Thanks Boris...that answers that question. Was there originally a special service tool to set the alignment, gear clearance for the mag dive assembly (325E)...? When aligning the mag drive assy did you have the mag mounted on a camera? I may remember doing that. How were you adjusting the gear clearance? Were the screws loose enough to adjust the clearance by feel, then check the noise and amps? No cigarette paper between the dry gears or some arcane thing like that? The gear clearance for the transmission shaft assy (52E), driving the shutter shaft, in contrast has very precise adjustment with the wedge, but I wondered how the gear clearance was chosen. Again, for this one also, were there special tools, or some precise criteria, or is it by feel, checking the noise and amps? Gregg.
  19. I think we need to be precise about what phenomena we are observing. The word flicker perhaps masks several discrete phenomena. In an ideal case we might observe them in isolation and find causes. In real life, one or more may present in concert, making observations more difficult. Does anyone have ideas about Aapo's case? I'm tempted to challenge him on the neg density (brightness), the lack of variation across the frame. How was that measured. Not because I disbelieve him, I just want a bit more precision. Regarding resonance in mechanical systems. The oscillating frequencies of separate elements /assemblies can resonate to give extreme elastic deformations. It can happen with aircraft during design/development. Example..(normally a fatal error, but not in this case) https://youtu.be/kQI3AWpTWhM The obvious element in the camera that could allow large variation in angular velocity is the rubber drive coupler.
  20. More puzzling things. The small drawing on one of Boris' pages that shows the mirror, shutter and the driven link rod. It's a schematic like mine, with the mirror spindle and MIN83E orthogonal to the drawing plane. It looks like it shows the effective mirror radius. I assumed for now that it was to scale and copied it into 2D CAD. I discovered that the position of the driving ball end on 83E was not plausible if the mirror was in its dwell position (A). The dwell position for the mirror would be 23deg further to the left. So I think the drawing is not to scale...ha. There's a pdf here that will print the image 1:1 at full size or 100%..... ACL mirror, shutter, rod, 83E copied to CAD from maint docs.pdf
  21. Hey Boris, Glad you came. I continue... In terms of what is observable on the neg or scanned frame, I'm assuming that there is more than one kind of flicker. I have to try categorising them... 1) Even exposure across each frame, but variation in brightness in alternate frames. A 2 frame cycle. 2) Variation in brightness across the frame, with brightness to the L and R alternating. A 2 frame cycle. 3) A shadow on the top corner or side edge of the frame, on every second frame. 4) Scattered light from a leak in the body. Not sure what that looks like. Anyone, feel free to add to this list, or remove one if it is fictitious. Type 1 flicker, I don't get yet how it could be due to mis-timing. If the mirror sweeps into frame while the shutter is open should we not have some variation in neg density across the frame...? Type 2 flicker, makes sense that it is the mirror and shutter out of phase. Mis timing. I don't know what all the possible variants could look like. Type 3 flicker, with the mirror at positions A,B, let's call them the "dwell" positions, if the mirror partly shadows the aperture there must be a dark area every second frame, no? The only explanation I can come up with is the link rod length. Beyond that, I still wonder about elasticity in the system, and resonance. At the very least we need the opinion of someone who was solving flicker with new rubber drive couplers in the 80s, 90s. Is there a reason why Aapos N16 mirror dwell positions are so asymmetric? Is that common, or has someone fitted a S16 link to that camera? The dwell positions favour a S16 frame. I'm speculating a lot. Perhaps we should start with simple but precise observation of one particular case, and try to find an explanation. Aapo swears that his sample frames have even density across the frame, and alternating density, a two frame cycle. Does anyone have an explanation for that? And so it continues...
  22. But the ideas may be useful, so scale is not an issue. When I think of making an adjustable length link rod I assume using cheap chinese tap and dies, not cutting super fine threads on my old lathe. For RH thread at both ends, the thread pitch increment to give a 1 deg shift in the mirror per turn would be about 0.1mm. The "tube" could be aluminum but the rod needs to be steel or titanium. Oh, unless it was bigger diam. Gregg
  23. Adjustable mirror link rods Adjustable length might be very useful if they can be light enough. Ditto for adjustable ball cups. I have seen adjustable ball cup screws that went in axially, but I can't yet find a reference. An old, very faded, ACL I manual shows adjustable ball cup screws (I think) that screw in radially. Versions of an adjustable length rod that could be made simply seem possible. Just need to make them light enough for 75fps, which may be a fatal problem. The solution to accurate link rod length may be to accept the plastic and find a way to machine a simple cup positioned super accurately. Or just buy one from Les B if he is makes them. He probably would make them in a batches, assuming he thought this was a solution to something. Here is my doodle on an adjustable length rod with (acetal) plastic cup halves. Better version may come quickly to mind.. .
  24. Duncan, Great stuff! I have done a near full tear down on 2-1/2 English 400' mags. Some of the parts look identical, and others are a different design. A toothed belt shifts power across the mag body to the take up arm drive spindle from where another toothed belt drives two little rubber tyres that run on the film. And the footage counter is a complicated little mechanical number counter with complicated drive system. And the take up arm spring tension adjustment has machinery and needs some deft handling. So there could be grounds for separating that one. I started a thread on those to bust some common myths about them and made a patchy attempt to document some of the tear down.. https://cinematography.com/index.php?/forums/topic/91664-english-acl-400-mags-facts-and-myths/ Back to the here and now.... I'm going to use the part names and numbers in the parts pdf, I'll just list some below and note your terminology in " ". I may use some shorthand, like dwg for drawing (not the file type) and assy for assembly. - 315E, in the 200' mag dwg is the feed sprocket assy. (Duncan..."thumbwheel in the take up side"). In the 400' mag dwg it is 730E but it doesn't show in a parts list. I think Duncan spotted that there is a page missing or something. - 325E, magazine drive assembly (Duncan..."drive spigot"). - 325, called driving axel bearing in the parts pdf, I'll call it the mag drive assy housing (Duncan..."the solid machined piece") Re the mag drive assy housing (325) being wiggly, not positioned precisely by the design engineering...I don;t remember the Eng mags being so, but it was a while ago. I do have a disassembled donor magazine here that is a mongrel...French throat, english body, take up system. This particular mag also has an imprecisely positioned (wiggley) mag drive assy housing. it looks like the machined surfaces should fit precisely in the chanel in the body, but no. I did notice that the loose fit of the screws was more on the ones further from the gear, so when you wiggle the housing the part near the gear is moving less. There is a good chance that my donor mag has been fiddled with. Some simple explanation may be there, like the Eng and French parts being different, and were swapped. I will at some point service the French mags I have, so will solve this riddle then. Meantime, if anyone knows the answer already, please spill. Gregg. PS: a correction re the transmision to the take up arm drive spindle above is in italics...
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