Jump to content

Recommended Posts

From what I've been told, they didn't make any money off the Logmar Super 8 camera. So how is not making any money a success?

 

The mere definition of "business" is financial.

 

Now I'm sure Kodak paid them to help develop their new camera, but I can't imagine it was very much.

 

They came out of nowhere, and within about a year, turned that into a deal for Kodak. I'm sure they were paid well for what they did for Kodak.

Link to post
Share on other sites
  • Replies 90
  • Created
  • Last Reply

Top Posters In This Topic

Tyler,

 

Pressure plate??? How is it different on a Super 16 camera vs Standard 16?

I think Tyler's confused, the pressure plate is the same, it's the gate that's different. (High speed SR mags have a different pressure plate design, but that's nothing to do with Super and Standard).

Link to post
Share on other sites

Dom, with the (non HS) SR I, II pressure plate, is there actually a slight clearance for the main plate, so that it isn't actually pressing on the film? The pressure being applied by the embedded pressure plate just over the gate area.

 

Later ACL pressure plates do exactly that. So a source of scratching is avoided for S16. The long pressure plates, I mean the main body of it, are not actually applying pressure over the S16 edge. The earlier ACL mags had a long one piece pressure plate, that I assumed might be less great in that respect. Talked to Bruce at Aranda ages ago, on English mags (single piece pressure plate), and he said they were fine for S16. So what do we really know?

Edited by Gregg MacPherson
Link to post
Share on other sites

I think Tyler's confused, the pressure plate is the same, it's the gate that's different. (High speed SR mags have a different pressure plate design, but that's nothing to do with Super and Standard).

 

Here is a standard SR magazine's pressure plate. You can clearly see the right edge nice and wide for "non-super 16" film stock. It will leave a small mark on the film, though it MAY not be noticeable depending on what you're shooting.

 

$_1.JPG

Link to post
Share on other sites

I've read that the SR main pressure plate has a much higher spring pressure than the "floating" centre pressure at at the gate. I'm busting to know whether this pressure is actually applied to the film, or if the litte posts at the corners of the pressure plate are controlling the pressure or in fact giving a clearance for the film.

 

If one had a spare gate, one could offer that up to a mag and find out. First fitting some film to probably the lower section of the pressure plate, and feeling if there was any friction at all. And or comparing that friction to that of the cetre "floating" plate.

 

Just to clarify. Though the main pressure plate may have a higher spring K (force per unit deflection), if its spring isn't deflected much the force on the plate won't be much.

 

I'm hoping Dom or someone can set us straight on this. I dont have SR mags here. I have some late ACL mags. Checked those and like I said they actually have a clearance to the film for the main pressure plate. So hats off to the humble ACL I guess. But maybe the SR is the same..and who did it first....?

Link to post
Share on other sites

The pressure plate must put ENOUGH pressure on the film to keep the focus perfect. On the non coaxial magazine cameras, where you have to thread the mechanics, the pressure plate isn't very stiff, but it's firm enough to hold the film of course. So I assume it's the same when you push a coaxial magazine pressure plate against the gate. It's nearly impossible to test this though because there is not enough room to pull film through the gate with the magazine in the proper place, without running film through the magazine, which of course adds a lot of friction.

Link to post
Share on other sites

Tyler, read what I wrote again, with care. There is, on both designs, a main presure plate and a centre pressure plate. The cenre pressure plate is the one that finally presses the film against the gate.

 

The overall pressure plate on the later ACL is just positioning the film in about the right place, with a small clearance, the centre "floating" plate is doing the work we normally associate with the pressure plate.

 

I'm just wondering if the SR plate is using the same concept. But it may be more sophisticated. There may be some presure from the overall plate. But it should be clear that the overall plate and the floating plate are doing different jobs. One could start trying to figure that out.

Link to post
Share on other sites

Ohh, sorry. You're referring to the part that pushes the film right against the exposing area. I've loaded a lot of SR and LTR/XTR cameras recently and I've pushed on that bit for cleaning purposes and there doesn't seem a big difference. I assume this puts slightly less pressure on that area. As a side note, the Arri/moviecam 35mm cameras, have a very light spring loaded pressure plate over the exposure area, but clamp down on the film firmly everywhere else. They can get away with that on 35mm because they have A LOT of space on the sides of the frame thanks to the double sprockets. They also don't have side rails on 35mm cameras.

Link to post
Share on other sites

Here is a standard SR magazine's pressure plate. You can clearly see the right edge nice and wide for "non-super 16" film stock. It will leave a small mark on the film, though it MAY not be noticeable depending on what you're shooting.

 

$_1.JPG

Show us a picture of a "Super 16 SR pressure plate", Tyler.

Link to post
Share on other sites

You mean the one with the smaller bar on the right side, so the film doesn't get scratched?

 

I don't know, you're the one talking about different pressure plates for standard and super 16 SR mags. I said there is no difference, it's all in the gate. Rather than admit you might not know what you're talking about, you showed a picture of an SR mag pressure plate, describing it as for standard 16.

 

If you think there is such a thing as a S16 pressure plate, show us. Or stop posting misleading information with the confidence of an expert.

Link to post
Share on other sites

The market is there for a new PROFESSIONAL s16 camera. There are already plenty of options to amateurs with bolex, krasnagorsk, old aaton and arri cameras. If you want to sell you should be looking to make a camera that DOPs and production companies can trust and which works for them and gives them good results. There is a big market for a camera like that.

 

A new camera would have to outdo the 416 and be:

 

ultra lightweight (CNC'd titanium, carbon fibre)

fast (75-150fps top end)

modern production ready (an HD video tap with SDIs)

small (could consider 200ft loads but they aren't really available, but still wanting it to be at least as small as an aaton)

reliable (nanometer accurate pressure plate, pin registration, crystal sync, with self diagnostic sensors for loop, power, tension, sync, etc.)

and capable of powering accessories inc motors, monitors, etc.

 

you'd have to export R&D to china, because this project is really about miniaturising the mechanics with the latest brushless micro motor technology, and combining it with a seamless ultra lightweight fully CNC'd design.

 

if you can do all that for 2 or 3k USD you'll sell. hint: china.

Link to post
Share on other sites

Start Kickstarter, consult with Jean-Pierre Beauviala and run production ;-)

 

But yes moded Krasnogorsk is a killer. Scoopic is not good because crystal sync if brake needs new solution - found person who made new design with modern parts. Otherwise so nice camera.

Link to post
Share on other sites

Following the theme towards clarity and actually knowing things....me musing about the likely spring constants for the presure plate(s) is missleading. I'm guessing that the spring for the main pressure plate is preloaded, so the force is there even at tiny deflections.

Link to post
Share on other sites

To answer Gregg's question about the SR double pressure plate:

 

The larger plate with the long support rails has four posts which mate against the camera gate when the mag is fitted and create a film channel that is slightly deeper than the film thickness, so it exerts no pressure on the film. The spring pressure is to make sure it mates firmly and keeps the channel at a constant depth. The inner pressure plate has a much lower spring tension and exerts a light pressure on the film at the gate aperture.

 

Outside of the high speed mags this design didn't change during the various SR iterations until the last generation Timecode mags, which had a short length of the soundtrack area at the very top removed, but non-Timecode SR3 mags or earlier converted mags never needed the pressure plate altered to work with S16.

 

A S16 mag conversion consists of machining down the rollers, sprockets and guides, never the pressure plate.

Link to post
Share on other sites

If you think there is such a thing as a S16 pressure plate, show us. Or stop posting misleading information with the confidence of an expert.

First off, I never mentioned a specific camera in my initial post. I merely stated that the conversion from straight 16 to super 16, meant modifications to the gate and pressure plate. This is an accurate statement, as you don't want the film to be pinched right in the picture area between the gate and pressure plate.

 

Second, just because Arri never changed the pressure plates on the SR, doesn't mean they're "correct". The 416 has a smaller bar running up and down the soundtrack side. It ALSO shifts the center of the "inner" pressure plate to the center of a super 16 image, unlike the SR3, which is a slight variation of the older SRI/II pressure plate.

 

Third, there is absolutely force being pushed against the film on the rail edges. That's the reason they exist, to insure the film doesn't twist during exposure. The slightest movement will cause focus and stability issues in the image. So those two flat bars on the side of the pressure plate, squeeze the film between the gate and the plate. If this wasn't a problem, the whole pressure plate would be highly polished like the sides are and it would squeeze the image area just like the sides. Yet, they don't do that because they know, IT CAN SCRATCH THE FILM!!!!

 

Fourth, Not everyone works cameras in clean rooms. Dirt and derbies collect on those sides after only one roll of film. So that means DURING the roll, there will be a collection of dirt on those left and right bars. The film slides by those bars and guess what happens!!?!?!? The dirt scratches the film. Unless you're extremely anal with cleaning and pull the magazine off every few takes to re-clean those surfaces, there will be deposits on them at sometime during the running of film.

 

In summary, the pressure plate and gate should have an identical small little bar on the soundtrack side to prevent scratching when dirt builds up, outside of the image area.

Link to post
Share on other sites

if you can do all that for 2 or 3k USD you'll sell. hint: china.

HA! The R&D alone would cost upwards of half a million.

 

China is only good at making plastic and electronics. So sure, them making the HD camera, no problem. All the precision metal and glass components, they'd struggle to make. Even Arri sourced from other manufacturers who were MORE specialized then they were at making mechanical bits.

 

Now Japan is a different story, but they're not much cheaper then the US or Europe in todays market. They could easily churn out a brilliant camera, but it would be very expensive.

 

Unfortunately, cameras are expensive to design and manufacture, especially one's that use precision glass optics, which is what Logmar removed from their $5,000 USD camera. If they HAD a real viewfinder, it would cost a lot more money.

Link to post
Share on other sites

Tyler, did you miss that idea that the main part of the pressure plate is leaving a small clearance so it is not actually pressing on the film. It positions the film. The little floating pressure plate at the centre is pushing the film against the gate.

 

Re emulsion build up or crud in the gate. Nothing wrong with pulling the mag to clean the gate now and again, especially if you have a problematic film stock. That's not anal, that used to be quite comon didn't it. File that one with your recommendation of white cotton gloves for loading?

Link to post
Share on other sites

Tyler, did you miss that idea that the main part of the pressure plate is leaving a small clearance so it is not actually pressing on the film. It positions the film.

The pressure plate does push the film against the gate, or it wouldn't work. .01mm of flex and the camera is not in focus anymore.

Link to post
Share on other sites

First off, I never mentioned a specific camera in my initial post.

 

Yes you did. To quote:

"I recently worked on a friends SR that only had the gate widened and ground glass replaced. I was horrified to see the pressure plate was standard 16 and it was squeezing the film where the soundtrack was, that's now picture."

 

Second, just because Arri never changed the pressure plates on the SR, doesn't mean they're "correct".

Seriously? You're backtracking to the point where you'd rather say Arri was wrong than you don't know what you're talking about? Was there millions of feet of scratched S16 footage shot on SR3s during the 90s and 00s? Are SR3s renowned for scratching film? You talked about being horrified by a standard 16 pressure plate on your friend's SR, a distinction which doesn't exist. Now you want to pretend you were right all along because Arri should have made a Super version, despite any evidence that it was necessary.
The initial fact remains, there is no such thing as a "pressure plate for standard 16" on an SR, which is the only point I really wanted to make.

Third, there is absolutely force being pushed against the film on the rail edges. That's the reason they exist, to insure the film doesn't twist during exposure. The slightest movement will cause focus and stability issues in the image. So those two flat bars on the side of the pressure plate, squeeze the film between the gate and the plate. If this wasn't a problem, the whole pressure plate would be highly polished like the sides are and it would squeeze the image area just like the sides. Yet, they don't do that because they know, IT CAN SCRATCH THE FILM!!!!

 

The long plate with polished rails does not press on the film, it creates a channel just a little deeper than the film thickness, so the film can slide through unimpeded but held fairly close to the film plane. Only at the aperture does the small inner pressure plate exert pressure, and it's not much. This surface is against the backing, and is highly polished.

 

On the gate side, which is in contact with the emulsion, the soundtrack edge support rail is machined down so it does not touch the expanded S16 area. Some early S16 conversions did not machine this rail down, but proper S16 SR gates have the narrower support rail.

 

The system works extremely well, as evidenced by the millions and millions of scratch-free feet shot on S16 SR2s and 3s over the last few decades.

Link to post
Share on other sites

It's a botched design, laziness on the part of Arri. They fixed it on the 416 for a reason.

 

New cameras, maintained by professionals, don't scratch film. Since those cameras now have millions of feet run through them now, since those cameras are dinosaurs with little to no support, they will start to scratch film as those wear surfaces loose their high polish. A design change that only touches where there is no image, would have resolved that issue for the future.

 

I frankly don't believe the pressure plate doesn't pinch the film on the sides by a tiny amount. It sure does on my Aaton. It sure does on my Bolex. It sure does on my K3. It sure does on all the 35mm cameras I've run over the years. It's hard to test on the SR's because you can't thread the film through the magazine without going through the sprockets, unlike those other cameras.

Link to post
Share on other sites

You can believe what you like, happily it has no bearing on reality whatsoever. :)

 

It's actually quite simple to verify what I'm saying about the fixed film channel. You remove the gate from a camera (8 screws) and the pressure plate assembly from a mag (2 screws), and you press them together. You'll see a gap that's just wide enough to slide a piece of film through. Only at the aperture will the little pressure plate proper push slightly against the film.

 

By the way, 35mm cameras like Moviecam/Arricams also create a fixed film channel when the movement block is closed, the film isn't pinched at all. Something else not to believe!

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...