16 MM Camera Lens Out Of Calibration? (#2)

16 MM Camera Lens Out Of Calibration? (#2)

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This is the second in a series of posts.  The prior post can be found here: Student Asks, Was The Lens Out Of Calibration? (#1) https://ypw.wrq.mybluehost.me/website_12972da0/?p=1032

On 11/18/10 9:57 PM, “A. B.”  wrote:

All this information is very useful and I have been told since emailing you many of the same things.  All these things are definitely key in my future filming.  I was told by another about the ground glass being specifically important as well.  Although I new about the ground glass, for my previous shoot I set the diopter based on opening up the f-stop and setting the focus to infinite and then adjusting diopter so that the buildings a couple hundred feet away were as sharp as possible, focusing on the lines and edges of the building.  I’m not sure if the grain was as focused as possible because I hadn’t learned that information yet and didn’t think to check.  Although my future focusing will definitely involve the grain on the ground glass, is the method I used incorrect?  I have to send all my rolls in at once due to budget constraints so theres no way to see if I should reshoot or not. Budgeting also is an issue for reshooting with this new knowledge.  Everything was focused to my eye and then rechecked by my DP.  Should I be worried or am I being overly concerned?  I have never shot on 16 and want my first project to be a success in my academic journey into 16. Again thank you for the detailed response and it is very appreciated.

Best,
A. B.

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Dear A. B.,

I just found your reply in my junk e-mail folder.  Entourage, my main e-mail software, can be a pain at times.  Most sorry I did not spot this e-mail earlier.

Your method of placing the lens to infinity and opening up the iris all the way impresses me that you seem to understand the principal of an open iris will diminish the the area of acceptable focus.  Your next procedure of using infinity lens focus as a “trick” to make sure the lens is in calibration, is correct but might be premature.  (By the way, opening up the iris all the way has ruined many a student project.  Make darn sure you reset the iris to proper setting before filming.)  The process you followed worries me a bit.  The eye focus adjustment (diopter) must be properly set so the grain you see in the viewfinder achieves best focus before you do anything with the camera.  I tell students to shoot a blank wall or even a sheet of paper so they and YOU are forced to concentrate on the viewfinder screen grain.

AFTER you can guarantee that the ground glass is in proper focus, THEN shoot objects at infinity with the lens and shoot building edges and power lines to see if the lens is in proper calibration.

What you can do if you find a perfect lenses:  You can do the Siemens star chart tests for closer than infinity to make sure that the lens is accurate all along its markings.  If you know for sure that the lens is dead on perfect for focus at every mark on the focus ring, you can then run a “TAPE” (tape measure) out from the camera to the subject and then rotate the lens focus ring to the corresponding mark.    Every professional camera has a film plane marking.  It looks like a circle with a line through it and the line is ALWAYS vertical.  I personally would viewfinder focus the shot and then tape it to check that my eye had found the correct lens focus plane.  The reason for this is my eyes are getting a bit old and that ground glass just does not do it for me every time.  In other words you can viewfinder the camera for correct focus.  You can actually tape the camera for correct focus (only if the lens is perfect for the camera you are using). Best of all, use both methods and you should NEVER get back out of focus film.

Tip: Proper focus requires LINES.  I defy you to find proper focus shooting a black curtain with no wrinkles.   I love shooting women with all that eye make up that approaches a Siemens start chart.  LOL.  Always look for lines at the plane (from the camera) that you want to look the best.

Tip: When shooting a person, focus on the eyes!   If the camera person can not determine accurate focus, for any reason, put a Siemens star chart at the SAME distance as the object you intend to shoot to make the setting of perfect focus more easy.

Tip: Just as I told you to make sure that you reset your iris to the proper setting before pushing film, ALSO make sure that the camera person sets viewfinder focus for his or her eye before they start the camera.  You would not believe the number of student films that were shot slightly out of focus because the director viewed the scene, adjusted the viewfinder and then the camera operator took over and did NOT reset the viewfinder focus.

Another tip: If you go to college in a large city, you just might have a good film equipment rental house that you can use.  Check their prices for equipment rental.  If you think the college cameras are a problem, consider renting out a camera.  Now here is the trick.  Get other students to do their projects the same WEEKEND as you do yours.  This ONLY works if the rental house closes Saturday and Sunday.  Often times the rental house will consider equipment rental ONE DAY if you take the stuff out Friday and bring it back Monday.  If you find a rental house that does offer this, fine tune it a bit by asking how early Friday can you pick up the equipment and how late you can return it Monday.  You then split the costs with the other student groups.  If YOU pay for the rental and check out the equipment, I suggest that YOU attend every shoot, guard and protect that equipment, and return it back to the rental house because you are financially responsible for loss or damage.  Consider paying for insurance to further protect yourself.  That insurance is typically offered by the rental house.

You asked, “Should I be worried or am I being overly concerned?  You told me you shot the footage; it is done.  Get over it.  If it comes back out of focus, you will have more deeply and painfully learned some pretty basic and very important technical processes that need to be understood when using a film camera.

By the way, what college do you go to?

Extra credit question 1: why should you NOT set your lens ring to infinity to get the greatest (most) area in the scene in acceptable focus?
Extra credit question 2: where should the focus ring be set if NOT at infinity?

I hope this helps.
Regards,
Score Card

Student Asks, Was The Lens Out Of Calibration? (#1)

Student Asks, Was The Lens Out Of Calibration? (#1)

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This is the first in a series of e-mail posts. The next post can be found here: 16 MM Camera Lens Out Of Calibration? (#2) https://ypw.wrq.mybluehost.me/website_12972da0/?p=1035

On 11/16/10 7:43 PM, “A. B.” wrote:

Hi I am a new filmmaker still in school and I recently read your blog from 3
years ago here https://ypw.wrq.mybluehost.me/website_12972da0/?p=196
My question is what if you have done all these steps and the feet marked with
measuring tape are not matching up.  For instance my subject is 5 1/2 ft away
but image is sharp at a setting of 3 ft?  Is the camera out of calibration is
it possible for it to be this way?  Not sure what seems to be the problem, my
professor told me to just trust my eye not the measuring tape.  But I feel
like the camera focus distance should coincide with the actual distance.
These cameras are 16mm Ariflex’s from the late 70’s.

Thanks for the help
A. B.

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On Nov 17, 2010, at 11:24 PM, Score Card wrote:

Mr. A. B.,

Let me put some ideas out for you to consider.

Ideally when you rent a camera from a rental house, you should expect the camera to be in near perfect running order.  Schools can slip from that due to a number of factors.  I am somewhat impressed that you found that this can be a problem.  Your concern and the measurements we are discussing should also be used when renting from a rental house.  Rental houses always have a setup area for the customers to set up and test the equipment before it goes out.

When you shoot an object close to the camera I have noticed that the lens makings are not all that accurate on some lenses.   There are a lot of reasons for this but they all come from being used by a lot of students, not being properly maintained, and not always being matched with the correct camera.

Please be aware that lenses MUST be collimated for each camera.   A really bad idea is use a lens intended for one type of camera in another camera.  If you do this, the lens markings might (will) be off.

Keep this in mind.   The lens forms an image on to the film.  The camera intercepts the lens image on its way to the film and throws it into the camera person’s eye using some trick:

Bolex = beam splitter is used but robs a portion of the light for viewing.
Arri = rotating mirror intercepts the light briefly to throw it to the viewfinder.

The eye then looks at the light image on its way to the film either as an aerial image formed in space (Bolex) or on a clear lens or on a ground glass (Arri).

When I troubleshoot any problem, I almost always look at what can go wrong but in order of most probable cause.  Of the three components listed above, the lens being out of calibration and the camera person not setting their eye piece focus properly are tops on my list.  In other words, the two devices that people touch and can screw up are truly the most prone to failure.  Those two problem devices are typically at either end of the camera.

You are correct that if you shoot a Siemens star chart and then taped the distance from camera film marking (line though a circle) to chart, the best focus should read on the lens pretty close to the tape reading.  If it does not, you should check the following:

For all the following tests, make sure you have the lens iris set to wide open.  This diminishes the depth of field.  This will make all lens measurements very accurate.
Look closely at the lens you are having problem with.  Are any rings loose?  Does the lens move side to side in any way?  Rotate the focus ring on the lens you are concerned about to both extremes, that being, infinity and then the closest focus marking on the lens.  Of particular interest for me is to see if the focus for infinity lines up EXACTLY.  If the infinity marking does not line up with the marking for the exact focus line on the rotating barrel, the focus ring has slipped and would then make the lens markings for focus be incorrect.   Resetting that ring is very easy and I had to do that many times.
Typically the camera has a viewfinder to see the image “through the taking lens”.  You must appreciate that you MUST focus your eye to the plane where the image is formed for your eye.  On the Arri S camera, they added a ground glass so the lens image stops and is rendered on a ground glass like a small theatre screen.  The camera operator then views this image from the opposite side of the ground glass.  Problem is that the camera operator, being you, must focus your eye so that the grain (NOT TO THE IMAGE).   That ground glass should look as sharp  as you can make it.  In other words you want to shoot a blank surface with the camera so you concentrate on that ground glass and rotate the diopter lens adjustment until that ground glass looks as grainy as possible.  It is best to rock the diopter lens adjustment back and forth until the ground glass “pops with definition”.  If you did not do that correct, this would easily create a lens focus error.  Another tip:  Some cameras come with a turret of three lenses.   If your viewfinder is not set for proper diopter, all the lenses on the camera should show focus ring errors.  Or you can screw on other lenses and see if they all have the same error.  If they do, I would suspect a diopter or lens viewfinder error.
If you have a Bolex camera you do not have a ground glass.  This method am going to tell you will also work for Arri.  Set the taking lens to infinity.  Next, focus on power lines or a building edge far far away.   Next, set your viewfinder dipoter so those power lines and/or building edge look as sharp as you can make them.  If this does NOT work properly; you do not get good results, the camera optics are suspect.  Now, take a Siemens Star Chart and set it to some close in distance. I look at my lens and look for a good convenient marking and tape that distance out from the camera and place the chart.  You set the diopter for infinity so do NOT change it!!!  Shooting the Siemens Star Chart, rock the camera lens focus back and forth until the center of that chart looks as best as it can get.  Bad is fuzzy.  Good is sharp pie shaped wedges.  (Note: Arri ground glass focus cameras will never look terrific).  If your tape distance to chart does not match pretty close to the lens markings, I would suspect the camera might be out of calibration.
A very telling test is to shoot some film with the camera.  I would shoot the Siemens Star Chart at different distances and put up a large label under the chart that can easily be read as to the distance from camera.  If you find a consistent error, jot it down and use that figure to compensate future shoots or send the lens in for repair if it is way off.
If you have access to an autocollimator that device is used by professionals to confirm lens focus to the FILM plane.  These devices are time consuming and tricky to use but the ultimate tool.

You have to get your hands on a Siemens Star Chart.  Use your computer and Google it.  Find a FREE one.  Print it out.

Next read up about the chart: http://en.wikipedia.org/wiki/Siemens_star <http://en.wikipedia.org/wiki/Siemens_star>

Print out one of the charts and glue it to a stiff board.   Tip: you can use dry mount tissue and a clothes iron will work on cardboard and smooth wood.

The Siemens Star chart is intuitive and thus simple to use.  Just focus your camera lens until the chart snaps into focus at the center.  An out of focus image rapidly appears bad when the center of the chart goes blurry.  Some smart camera operators sometimes use this chart to find or confirm correct focal distance for difficult camera shots.

I hope this helps.
Score Card

(Parts of this blog post revised Dec 7, 2017)

November 2010 Election Result Reflections

November 2010 Election Result Reflections

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Let me examine some factors that might be behind some of the November 2010 election results.  When I say “behind” I actually mean a bit more behind and less apparent.

A very big concern voiced from many corners was the huge government spending which resulted in the Republican party making significant gains.  The American public was close to being incensed in seeing it’s government spending huge amounts of the peoples money on huge projects some of which at times appeared to smell like rotting pork.

A view can be raised that the American public failed in their responsibility to get this issue correct.  One might even state that quite a number of voters were just ignorant of some basic economic facts.

When a country’s business economic engine stalls, any remaining component of the total economic equation that is capable of being powerful enough and managed well enough to pull the boat forward should be used.  In most high school and college classes it is taught that government spending is a major engine component that sits in reserve to throttle up to help move the economy forward during hard times.

Obama used government spending to help the United States to recover out of a deep recession.  This program, as it becomes more clear with time, appears to have worked but  only for very large businesses and only part of the economic pie but more on that later.

A number of problems face the president by doing what most economists told him he must do which was to inject massive spending into the economy in attempt to raise the boat.

One of the principal talking points of the Republican Party is to lower government spending.  (their track record fails to match their pronouncements).  President Obama was forced to spend heavily and came under fire from Republicans because that action failed their talking point.

The American public was and is still not educated enough to understand some simple economic principals.  The president and congress was forced by reason and intellect to  spend vast amounts of government money to stimulate the economy.  Behind the politicians were professional economists advising the government officials to increase government spending.   Who’s money is being spent?  It is the tax payers and they viewed this action as excessive.

President Obama might have made some arguable mistakes.  He failed to become a school teacher for the nation and educate the American people about some simple economic principals.  He could have taken some wind out of the Republican talking point that we need to cut spending at absolutely the wrong time.

Congress and the president might have failed to comprehend the importance to get people back to work.  By this I mean our government swung it’s efforts toward large projects and utterly failed to balance small business growth.  Government officials might claim they can not easily core down to small job growth.  I don’t think they even tried but rather pandered to large corporations which is, in reality, their campaign finance constituents.  The administration concocted a much too simple solution and utterly failed to realize the size of the economic pie that they had to deal with.

The Obama administration also lost an opportunity to try a really gutsy tactic and that is to let the large banks fail.  Actually, not fail but to down size them so they would fall out of the category “too big to fail”.  The banks to a large extent got us into this mess and have not suffered any hurt.  The small guy gets the shaft by loosing his job and maybe his home and then, at the same time, sees his government taking care of large banks and is understandably angry.

The administration lowered interest rates to the large banks thinking that this would allow banks to loan money to small businesses and help propel a recovery.  The large banks instead used the low interest rates to further their profits but in ways that did not include small businesses and helping the economy for the individual tax payer.    The  large banks, lacking any real civic duty, purchased long term treasury notes, made acquisitions, hoarded cash, and pursued other self serving endeavors.  They seem to worship profits over what is best for this nation.  The banks are insulated from retribution from the electorate because few Americans understand economics well enough to be able to point a finger.

The banks to a large extent got us into this mess and have not suffered any hurt which seems to be pretty much understood by most Americans.  The small guy gets the shaft, sees his government looking after large financial institutions, auto manufacturing, government housing lenders  and is angry at most of the government actions which left him and her out of any recovery while the very people who caused this fiasco get rewarded.  It is not lost on the electorate that they are paying for the recovery of businesses that caused the economic problems and those businesses can better weather the storm than individuals who lost their job and home.

Another error that government made was seeing a macro problem, using macro actions and utterly missed the point that individuals were not served in the process.  You would think that politicians would understand that the people who vote them into office and keep them in office just might matter a whole lot when elections take place.  Banks, auto manufacturing, and other stimulus recipients are not allowed to vote.  So why did Obama pander to the large businesses and fail the small?

Obama should have found a mechanism for offering low interest rates to smaller banks and stipulate that bank loans be made to small business.  In a recession of this magnitude, one must think of large and small solutions.

Obama missed another opportunity.  He should have gathered all the governors together and tasked each to administer their separate recovery and step back from the process unless a state needed further help.  Different approaches would have been tried, one would expect, and we would learn a lot more about how to recover from future recessions.  We would have a huge test bed running and gain a lot of vital information out of a state run stimulus.  Politically, the White House would have administered a solution closer to the affected people and businesses  which would seem to make more sense than wide sweeping solutions generated from Washington.  The White House could distanced itself from the effort and achieved some measure of deniability when any program failed its target and blame the governor that failed his or her state.

Obama’s administration and congress lives with and is in bed with large business and this pretty much punished the Democratic party.  I am speaking her of the communication and interaction aspect of this problem.  The current economic suffering is seen across the whole economy.  When people loose jobs to such a wide range of occupations, the government, seems incapable of reaching down to the state and community level to provide aid recovery.  Big government seems only capable to  communicating and helping big business.  It is so convenient and less messy to call in a few business leaders and work out solutions for their coverage area.  The trickle down theory, help large businesses to aid recovery can, at times give good results but also utterly fails to help most of the population.  Our economy depends on trickle up, consumer spending,  not trickle down and this is such an inconvenient truth for politicians to follow.

Governments need to develop better core down mechanisms to help small businesses recover, maintain, and grow in recessions.  We need job growth at local level as well as large business.  We need BOTH!  Federal and state governments need to expand their tools to include logistic support to the front lines small businesses.  State and Federal government need to understand what is needed not only by large businesses but also small businesses.

Obama is a very smart man and many of his macro solutions seem to be working but his solutions were not well thought out at the micro level and for this rather important aspect his party has taken a hit.  For this mistake, he has proven to be lacking.

A slight admonishment might be directed to the electorate.  It is too bad the American voting public could not look past their own pain, contain their anger, researched the facts more deeply and not be taken in with the distortions and lies that the Republican party has capitalized on.  For this possible mistake, the electorate just might have swung the trajectory of our future to repeat itself again.

Three LED Tally

Three LED Tally

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American tally systems typically rely on the single RED light over monitors to indicate that what that monitor represents is hot or on air.  In Europe, they adopted having three tally lights:

  • Red = Currently on air
  • Yellow = ISO.  This warns the Technical Director that this source is currently feeding a separate record deck.
  • Green = Preset by Technical Director that this source will be a part of the next take or effect.

It is quite possible to see a single monitor that has both Red and Yellow tally lights lit.  This means that the live feed (Red tally) is using this source and is also feeding an Isolated deck (Yellow tally).

I personally think the following is a possible option:

  • Red = Currently on air.
  • Yellow = Preset
  • Green = Preview
NRA Increasing Role In Politics

NRA Increasing Role In Politics

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Question from LO McC: “What are your thoughts on the NRA’s increasing role in politics – saw the story in the New York Times“.

Score Card Answer: My view is we need special interest groups and it naturally follows that they try to persuade issues. They speak for their membership who do not have time to individually pursue the issues. What I do not like is fierce tribalism, that being, our tribe is more important than this country. The special interest groups, quite naturally, follow this method at times and I measure this by rhetoric that states there is no other correct view. When anyone closes the door to compromise, will not hear and take into consideration the opposite view, I suspect the fierce tribal method is winning over what might be best for us all, this country. We need to listen to one another, consider the arguments, find some middle ground and possibly compromise. The historical pattern for how we got where we are today is through progress which means progressive ideas. Problem is, so many people were raised with old ideas and will not change. It just might be one of the unintended purposes of death to ensure progress moves forward. The NRA gun issue is a toggle switch. You are either for or against people carrying guns. Those toggle issues take a long time to change; will not happen in our life time. The best we can hope for is if the world become a safer place, countries form economic alliances much like Europe, societies solve the crime issues and this results in the NRA becoming slowly irrelevant because we no longer think of external threats and need a gun.

Southern California Edison might not be all that concerned in saving energy.

Southern California Edison might not be all that concerned in saving energy.

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(Or allegedly stupid about some energy factors).

Our pool pump went out the end of 2009.  I did quite a lot of research and found out the following:

  • Two speed or variable speed pumps are required in California to save energy.  These motors are way more expensive than single speed motors.
  • Every pool supply vendor failed to inform me of that California requirement and would be most willing to sell me a single speed motor.  I was extremely surprised that the pool supply stores and wholesale outlets were not helping to enforce the requirement but allegedly flaunting it.
  • A dual speed and variable speed motor requires a costly controller/timer (The one we purchased, the Intermatic P1353ME costs about $200).
  • Our city required a permit for installing a new pool pump.  Our cost was $98. The city was enforcing the dual or multi speed motor requirement.
  • Southern California Edison gives a $200 rebate on approved pumps but watch out, there are significant exclusions which is the main point of this posting.

Here is the rough cost of replacing the pool pump with a single speed, $200 to $300 (rough material cost).

Here is the rough cost of replacing the pool pump with a dual speed, $1,000 or more if a variable speed motor is purchased. ($1000 for our electrical and plumbing materials, dual speed motor, special timer and permit cost).  I also had to pull a second neutral wire to meet code requirements and pull out two mechanical timers (one for the pool sweep).

Just by chance, I called the manufacturer of the pool motor we intended to buy because no one could tell me with any certainty the correct size pool motor.  The technical support person asked me how large was the plumbing going to the pump.  I said 3/4 inch.  He told me that you can only push so much water through that soda straw and by his calculations, all we needed was a 3/4 horse power motor of the design I had selected.  I had contacted quite a few pool supply vendors and they all were trying to sell me a 1 horse power or higher motor.  The motor that broke was a 1 and 3/4 horse power.  We had been wasting vast amounts of energy with that old brass pool motor.  The new pool motors are way more efficient as they can push more water even at lower horse power.

Now here is my point.  The politicians and utilities want you to conserve energy.  What you need to take into consideration is the often times huge front end expense involved making the change over to energy efficient systems.  I am also a bit suspicious that conserving energy is all about certain businesses making buckets of money and your only benefit might only be a decline in your bank balance.  You can see the cost difference shown above between a direct same motor replacement, single speed  vs the new required multi speed motors of about double and when you add the special timer and city permit, the cost starts to really go up.  Now you would think that the government and utilities might help the little guy a bit to soften the huge front end cost of making an energy saving conversion.  Southern California Edison did just that by offering  $200 rebate on pool motors.  The problem is they allegedly seem to have a short list of pool motors, which I can not explain, and get this, they required that you buy a 1 horse power motor or more to qualify for the rebate.  Does that make sense?

Now let me see.  I just dropped my original horse power motor from 1.75 to less than half of that and I purchased the required dual speed motor which is way more energy efficient and expensive.  I did my civic duty and pulled a permit for the work and it was approved.  But, I get no benefit from SCE for making the energy conversion and providing the rather large energy savings.   SCE should require a matching of pool motor performance flow to the pool plumbing pipe size.  They don’t seem to get the point that vendors are pushing pool motors that are over sized, allegedly due to ignorance or wanting to make more profit.

Now looking back, I figure I could have purchased a 3/4 hp single speed motor, kept my original pool timer and saved even more money by not pulling a permit or reworking my electrical and plumbing.  The cost savings would be about $800.  By putting in a new more efficient motor with lower horse power, I still would be way more energy efficient than before my old motor died.   Southern California Edison, allegedly, just does not get it and neither did I when this all started but you are now the wiser for my mistake.

——————

April 15, 2010 I used the Southern California Edison web site portal to send the following message:

“Our pool motor quit.  I purchased a Pentair Whisperflow 3/4 HP two speed motor, model WSDS-3 012530 on 11/17/2009.  It was delivered a few days later.  It took weeks to install as I did the plumbing and electrical work myself.  The motor, being two speed, required me to purchase and install a special controller, Intermatic P1353ME, to run the high / low  speed motor and the pool sweep motor.  Our total cost approached a thousand dollars.  The city inspector signed permit February 8, 2010.  I have looked at your web site and I do not see the pool motor, we purchased, listed.  My research showed the motor I purchased as being the best, most recommended by installers and very efficient.  Is there any way I can qualify for the $200 rebate?”

My computer screen showed this image after I sent the message:

———————

The Contact Us computer image said they would send me a respose within 2 days.  It also stated that if the subject requires specialized knowledge, it might take longer.  Look at your calendar and calculate how many days it has taken from April 15, 2010.   We received NO ANSWER!

Note: This blog post went up July 4th.  We believe we waited long enough for Southern California Edison to respond before we shared this issue with the general public.  It is not our purpose to embarrass but to improve our society.