Arri IIc flare problem

[GeorgeSelinsky]

To all who have posted here,

 

I want to thank you all very much for contributing your knowlege and taking the time out to post pictures of your own setups!! I haven't been able to continue my tests all this time but today I will hopefully get back to this and start deducing what the trouble is. Perhaps with this body of knowlege on the web about this camera's problems, others with the same or similar problems will be able to get it fixed or at least have good starting points.

 

There IS one thing wrong with my shutter, the bottom of one blade is somewhat chipped, looks like somebody put the wrong lens on it at one point or was careless somehow. Still, the bottom edge of the blade is fine, the side is painted black. Maybe the paint is too shiny, though. I have to grab a digital still of this and forward it.

 

- G.

Edited January 10, 2005 by GeorgeSelinsky

[John Sprung]

There IS one thing wrong with my shutter, the bottom of one blade is somewhat chipped,

<{POST_SNAPBACK}>

Aha -- that sounds like it could be the problem. Look at the film frame by frame, and if the flare is in every other frame, it's 99.999% sure to be shutter related.

 

 

 

-- J.S.

[GeorgeSelinsky]

The possible culprit:

 

 

 

Any ideas how to fix this problem on a budget, w/o having to buy a new shutter?

 

Thank you to all for the advice as always!

 

- G.

[John Sprung]

There does indeed appear to be a reflection of the emulsion on the shiny surface of the black paint. Reflections work both ways, so this could be it. All you have to do is get the gloss off of it. A fine grit emery cloth or sandpaper -- say 200 or so -- wrapped around a Q-tip might do it. Depending on what kind of paint it is, denatured alcohol on a Q-tip might also dull it down. Replacing a mirror shutter in any camera is to be avoided if at all possible. The precision required is extreme and therefore expensive.

 

 

 

-- J.S.

Edited January 10, 2005 by John Sprung

[Rolfe Klement]

It looks to me like the shape of the 2nd shutter is deformed slightly. I am looking at the image on a laptop so it is difficult to tell. So I would be interested to know if the reflection is the only issue - fingers crossed it is easy to fix

 

Have you got a list of lenses that you put on the camera - I was told to be very careful about which lenses go on a 2C - and in fact I was told (but I forgot) that when you put any lens on you should manually inch the shutter around to check for bumping.

 

I own Zeiss primes 16, 25 and 40 and have never put anything else on the camera - and maybe I should be really careful that I only put certain lenses on

 

Quick question for John - How did the ground glass stay in if you took all the baffles out - cause I am interested in getting rid of the baffles if I can - cause my Video Assist always looks weird with these 2 lines down the middle - and how do you get rid of them

 

thanks

 

R

Edited January 11, 2005 by Rolfe Klement

[GeorgeSelinsky]

Have you got a list of lenses that you put on the camera - I was told to be very careful about which lenses go on a 2C - and in fact I was told (but I forgot) that when you put any lens on you should manually inch the shutter around to check for bumping.

<{POST_SNAPBACK}>

 

I only ever put 3 pieces of glass on that camera, the three Cooke lenses I listed previously. The shutter was apparently damaged when I got the camera. Now that it's been over 2 years the warrantee is way out.

 

I'm going to try to fix the paint gloss issue, and also see if I can apply some tape to the back of the shutter in order to correct that indentation.

 

By the way, here is a simple question, the lens mount that the arrow is pointing to is a bit different than the other two, is this some reinforced mount for zooms or something?

 

 

- G.

[GeorgeSelinsky]

More images:

 

The shutter, a better view. Note the paint job done by Visual products...

 

 

The healthy shutter blade casts a straight shadow from the flash...

 

 

The unhealthy shutter blade casts a slightly crooked shadow from the flash...

 

 

- G.

[GeorgeSelinsky]

More exploration...

 

I opened the gate and taped a piece of regular paper on the area of the film plane. Here the normal shutter is about a third open. The camera has a 75mm Cooke lens which is pointing into a desk lamp, that is facing the camera. Notice the shutter paints a straight line.

 

 

Here we see the damaged shutter about a third closed. Notice the leftmost corner, where you can see a chipped blade.

 

 

Here is a closeup of the normal shutter:

 

 

And the damaged shutter:

 

 

Looks like this little indentation may be causing problems, too. The edge of the indentation is shiny somewhat. It is also exposing the film longer, which means every second frame must be getting slightly more exposure in one area.

 

- G.

Edited January 11, 2005 by GeorgeSelinsky

[John Sprung]

By the way, here is a simple question, the lens mount that the arrow is pointing to is a bit different than the other two, is this some reinforced mount for zooms or something?

<{POST_SNAPBACK}>

It's the Arri steel bayonette mount. It takes the ordinary Arri mount lenses, too. You're right, it's intended for heavy zooms.

 

I wouldn't worry so much about that corner chip. The shiny paint on the bad edge is likely to be your only real problem. The tiny extra exposure from the damage is very unlikely to be detectable, even with a good densitometer, let alone by eye.

 

 

 

-- J.S.

[Guest Sean McVeigh]

wow, that shutter is quite banged up.

I'm not even sure what to suggest in terms of rebuilding that. Tape might help, but tape can also fall off at 720rpm and make a much worse mess.

That shutter looks like it's been ground down to hide some troublesome chip and then just repainted I presume.

I guess your choice of action is going to come down to weighing the cost of replacing the shutter vs the cost of winding up with flickery footage (and of course, the gnawing suspicion that it could happen at any time again in the future if you cobble a fix together). Still, you can always call Visual Products and gripe.. the worst they can say is that they won't fix it.

 

Good luck with it though :) (and yes, you've got one of the turrets with a single Arri-B mount on it as John points out).

 

Sean

[Rolfe Klement]

If you want to wack this together into some kind of doc I can host it on my site - if you need the space - cause this is great info

 

Fingers crossed it works with a simple paint job

 

If you got the camera like that - I know Visual Products are great guys - can they do nothing to help (although I see their point - it has been 2 years so...)

 

thanks

 

R

Edited January 12, 2005 by Rolfe Klement

[GeorgeSelinsky]

One member of this forum was kind enough to email me privately and tell me that s/he had a very similar problem with their IIc, it turned out to be related to the shutter timing gear. How can I troubleshoot and fix this problem, if that is the case? Anyone have any ideas?

 

Thank you all once again for your enthusiastic help (and yes, if someone wants to put up a page devoted to this problem, by all means you can use my photos, my words).

 

- George.

Edited January 13, 2005 by GeorgeSelinsky

[John Sprung]

, it turned out to be related to the shutter timing gear. How can I troubleshoot and fix this problem,

<{POST_SNAPBACK}>

It's fairly easy. Thread up a scrap of raw stock, pull the lens and inch the shutter open. Draw a big "X" or box or something on the frame in the gate with a sharpie. Inch the camera back and forth very slowly from the frame before the "X" to the frame after. Watch carefully to see if the film is still moving when the shutter opens, or starts moving before it closes. The "X" is to make that movement easier to see. I've never had that problem, so I can't tell you how to take it apart and re-mesh the gears to get it right.

 

However, from the images you posted of the flare you're getting, this is very unlikely to be the problem. This shutter sync problem is called a "travel ghost", and it results in a vertical smear of extreme highlights near the top or bottom of the frame. These smears are very straight up and down, not rounded like the ones you have.

 

 

 

-- J.S.

Edited January 13, 2005 by John Sprung

[Webster Colcord]

George, I think your chipped shutter blade is definitely the problem. I've had "out of phase" problems like John is talking about above, with an old Wall animation camera with a worn gear. After reading through the postings I think my less severe 2B flickering artifact is happening because the black paint has worn off one blade of the shutter. You could try the tape fix or supergluing a tiny sliver of blackwrap onto the edge. Aluminum dryer duct tape (metal with an adhesive backing) is stiff enough for this job, and would probably never come off- the adhesive is really strong. You could cut a thin sliver and stick it to the black side of the shutter to replace the missing chipped area, then paint it black (or paint it black before cutting the sliver, then touch it up after).

[GeorgeSelinsky]

Hello everyone,

 

Looks like I've come closer to the cause of the problem.

 

Using that white piece of paper in the film gate, I pointed the camera with the 50mm Cooke at my white bulb again. I started twirling the shutter. As the damaged blade was closing (or opening, forgot the proper orientation but it doesn't really matter here), lo and behold I discovered a nice white flare that suddenly appeared. It didn't happen with the normal shutter blade. That, I am sure, is the cause of the problem. Something on that chipped shutter is causing a sharp reflection back onto the film when it is nearly closed. It's VERY tough to spot, you have to make sure the light and camera is in the correct position for you to see it clearly - the bulb in the frame has to be a bit low (in reality high, since the image you see is upside down). You can't see it through the viewfinder, only the film gate.

 

I started sanding the shutter paint with 220 grit sandpaper. It doesn't get rid of some shine, so I think I will have to resort to using a better paint. I purchased 322 foil tape at Home Depot and experimented with it. I'm going to have to locate a durable paint that will not reflect back into the gate.

 

While it's still too early to definitely say, it looks to me like the Arri IIc has a very fickle mirrored shutter.

 

I'll keep everyone posted on progress. Thank you all one more time for your assistance and collective brainstorming, I'm very grateful for the time you all put out!

 

- George.

Edited January 14, 2005 by GeorgeSelinsky

[GeorgeSelinsky]

More experimentation...

 

Okay, here's what I did now ->

 

I still need to find the best paint for the aluminum tape, but what I did instead as a test was cut a thin slice of gaffers tape and placed it on top of the damaged blade edge.

 

 

When I tested this combination out, the flare disappeared. Actually, I now discovered that the other normal shutter blade also gives a little flare. Looks like I should take care of both sides just to be safe.

 

It seems now that the problem is that the recessed chipped away shutter was not shielding part of the film plane. As the mirror was closing, the reflection of the white source could have knocked back into the rear element of the lens, creating a reflection that hits the film just as the shutter is nearly closed (meaning the mirror is in the correct position, completely reflecting the bulb). This would explain why the flare varies with camera and light position, it doesn't just happen in one region of the frame.

 

I'm very glad I have that nice white piece of paper acting as my film, saves me a lot of $$$ in tests!

 

- G.

Edited January 14, 2005 by GeorgeSelinsky

[GeorgeSelinsky]

Some more thinking.

 

The reason why I have gotten more flare with my 50 and 75mm Cookes versus my 25mm is because the surface area of the rear element in the 25mm is about half the size of the other two lenses. This means that when the mirror starts reflecting the light, there is much less reflection from the 25mm than from the 50 and 75mm lenses. Also, the 50 and 75 are Ser II, the 25mm is a Ser III, I'm assuming this means a more advanced coating system on the 25mm, thus making it less prone to flare from the outset.

 

- G.

[John Sprung]

The reason why I have gotten more flare with my 50 and 75mm Cookes versus my 25mm....

<{POST_SNAPBACK}>

I doubt that it's as complicated as a two bank shot from the shutter to the back element to the film.

 

With the shutter open, light comes through the lens to form the image on the film. When a good shutter blade passes through that light, it casts a simple shadow. When the blade is chipped a little, the light reflecting off that chipped edge changes direction, but only by a small amount, maybe something like 5 - 30 degrees. You get a lot more specular reflection at those steep rakes. That moves the light over a fraction of an inch, and throws it out of focus. When that light is from a very bright area, say a practical in frame, and it gets moved to a dark area, it produces enough extra exposure in the wrong place to show up as a visible flare.

 

The reason you see more of it with a long lens than a wide angle is that the image of the practical is larger, and the light rays forming the image are closer to perpendicular to the film plane. The more divergent rays of a wide angle spread the flare out over a larger area, making it dimmer, and therefore less likely to produce a visible exposure.

 

In any case, if dulling the paint doesn't work, the foolproof thing to do is make a sharp knife edge for the shutter, like an Eyemo has, so there's no area for light to glint off of. Of course that's a lot more work, and you also have to think about the weight you're adding. At 720 RPM and up, you don't want to get too far out of balance.

 

Another thing to think about is whether you can add a variable shutter to this camera. If the damaged edge is the one that the extra disk extends from, that could solve the problem. But it would take a tech who knows more about the 2C than I do to determine that. Clairmont does a lot of mechanical work and customization on their rental stuff. If all else fails, maybe they'd work on it for you.

 

 

 

-- J.S.

[GeorgeSelinsky]

Hello again everyone,

 

I think I've found that the most effective solution is to use a piece of gaffer's tape (as per the last image). It's hard for me to find the right paint for the aluminum and dull it down properly, the gaffer's does a great job. The finish on it shows no fare at all.

 

My one concern now is its reliability. I want to use some glue as a safety measure to keep the gaffers' tape strip in place. Also, the chip in the shutter should somehow be filled up. I'd like to hear your suggestions, what kind of glue should I use? I'm hoping it won't melt and and goop or leave residue on the mirrored shutter with time.

 

Thanks again for all of your helpful suggestions and time,

 

- George.

[John Sprung]

What you're looking for is a glue that sticks to glass, which not many glues do on a permanent basis. The gaffer's tape adhesive will dry out in a few months or years, and then it'll fall off. Try an auto parts place and get the special glue that's used to stick rear view mirrors to the inside of windshields. Clean all the old paint off the glass with denatured alcohol or acetone -- probably also available from the auto parts place -- and a Q-tip. You want your new glue sticking to the glass, not to paint that might let go from the glass. Lightly roughening the glass surface with fine emery paper will make more surface area for the glue to grab.

 

I had another idea for testing the edge. If you can get ahold of one of those laser pointers that people use in PowerPoint presentations, or a laser level -- even a cheap one from Home Depot would work -- you can take the lens off and see what a single ray does going straight thru to the white paper in the gate. Just take great care not to ever get it directly into your eye. Come to think of it, I remember having a laser pointer. I think I even remember which box it's in. We're both in the LA area, let me know if you want me to try to find it for you.

 

 

 

-- J.S.

[GeorgeSelinsky]

What you're looking for is a glue that sticks to glass, which not many glues do on a permanent basis. 

<{POST_SNAPBACK}>

 

Hi John,

 

I'm actually on the other coast here in NY, your offer is very appreciated all the same!

 

The material on the side of the shutter to which I must glue the gaffers onto looks and feels more like metal than glass, but I gather that's because of the paint on it. I will try to get that glue and experiment, thanks!

 

- George.