Top 10 Questions for Motion Picture Camera Lens Technician Interview

1. Describe the process of collimating a motion picture camera lens.

Collimating a motion picture camera lens involves aligning the optical elements within the lens to ensure that they are all in the correct position relative to each other. This is necessary to achieve optimal image quality.

• Mount the lens on a collimator, which is a specialized optical instrument used for aligning lenses.
• Adjust the collimator’s optical elements to bring the lens into focus.
• Use the collimator’s built-in reticles or targets to align the lens elements.
• Make fine adjustments to the lens elements until the image is perfectly centered and focused.
• Once the lens is collimated, it can be used to capture high-quality images.

2. What are the different types of motion picture camera lenses, and what are their advantages and disadvantages?

Prime Lenses

• Fixed focal length
• Advantages: Faster apertures, sharper images, smaller size, lighter weight
• Disadvantages: Less versatility, more lenses required to cover a range of focal lengths

Zoom Lenses

• Variable focal length
• Advantages: Versatility, can cover a wide range of focal lengths with a single lens
• Disadvantages: Slower apertures, heavier, more complex design, more expensive

Anamorphic Lenses

• Produce a wider aspect ratio
• Advantages: Wider field of view, more cinematic look
• Disadvantages: More expensive, require specialized equipment

3. How do you troubleshoot a motion picture camera lens that is not focusing properly?

• Check the lens mount to make sure it is clean and free of debris.
• Inspect the lens elements for any damage or scratches.
• Adjust the focus ring on the lens to see if it is loose or damaged.
• Check the camera’s autofocus system to make sure it is working properly.
• If the problem persists, the lens may need to be sent to a qualified technician for repair.

4. What are the safety precautions that must be taken when working with motion picture camera lenses?

• Always wear appropriate safety gear, such as safety glasses and gloves.
• Never look directly into the lens, as the bright light can damage your eyes.
• Be careful not to drop or damage the lens, as they are delicate and expensive.
• Store the lens in a clean, dry place when not in use.
• Have the lens inspected and serviced regularly by a qualified technician.

5. What is the difference between a T-stop and an F-stop?

• T-stops measure the actual amount of light that passes through a lens.
• F-stops are calculated based on the lens’s focal length and aperture diameter.
• T-stops are more accurate than F-stops, especially for lenses with large apertures.

6. How do you calculate the depth of field for a given lens and aperture setting?

• Use the following formula: Depth of Field = (Distance to Subject * Aperture)^2 / (Aperture * Circle of Confusion)
• Distance to Subject is the distance between the camera and the subject.
• Aperture is the lens’s f-stop or t-stop.
• Circle of Confusion is the smallest circle of blur that can be perceived by the human eye at a given viewing distance.
• For motion picture cameras, the circle of confusion is typically 0.02mm – 0.03mm.

7. What is the purpose of a matte box?

• A matte box is used to block out unwanted light from entering the lens.
• This can help to prevent lens flare and other unwanted artifacts from appearing in the image.
• Matte boxes can also be used to hold filters and other accessories.

8. How do you clean a motion picture camera lens?

• Use a clean, soft cloth to wipe away any dust or debris.
• If the lens is dirty, use a lens cleaner and a soft cloth to clean it.
• Never use alcohol or other harsh chemicals to clean a lens, as this could damage the lens coating.
• Once the lens is clean, store it in a clean, dry place.

9. What are the different types of lens mounts, and which type is most commonly used on motion picture cameras?

• There are several different types of lens mounts, including PL, EF, and F.
• The PL mount is the most commonly used on motion picture cameras.
• The PL mount has a bayonet-style lock that securely attaches the lens to the camera.

10. What is the difference between a wide angle lens and a telephoto lens?

• Wide angle lenses have a wide field of view, which allows them to capture more of the scene.
• Telephoto lenses have a narrow field of view, which allows them to magnify distant objects.
• Wide angle lenses are often used for shooting landscapes and interiors, while telephoto lenses are often used for shooting portraits and wildlife.

Motion Picture Camera Lens Technicians play a crucial role in ensuring the quality and accuracy of images captured in the film and television industry.

1. Lens Maintenance and Calibration

A primary responsibility involves maintaining and calibrating motion picture camera lenses by conducting thorough inspections, cleaning, and adjusting them to ensure optimal performance.

2. Optical Alignment and Troubleshooting

They align and adjust camera lenses to the camera body, ensuring proper focus, exposure, and image quality. They also troubleshoot and resolve optical issues, such as distortion, chromatic aberration, or vignetting.

3. Lens Customization and Adaptation

Technicians may customize or adapt lenses to meet specific filming requirements, such as using special filters, attachments, or adapters to achieve unique visual effects.

4. Inventory Management and Documentation

They maintain an inventory of camera lenses and accessories, ensuring proper storage and tracking. They also document lens maintenance and calibration records for future reference and quality control.

Preparing thoroughly for an interview for a Motion Picture Camera Lens Technician position is crucial to showcase your skills and qualifications. Here are some interview tips that can help you ace the interview:

1. Research the Role and Company

Before the interview, thoroughly research the job description and the company’s history and portfolio. Understanding the specific requirements of the role and the company’s culture will help you tailor your answers accordingly.

2. Showcase Your Technical Skills and Experience

Emphasize your technical expertise in lens maintenance, calibration, and troubleshooting. Highlight your experience in handling various types of motion picture camera lenses and your ability to work with precision and accuracy.

3. Demonstrate Your Problem-Solving Abilities

Interviewers are keen on assessing your problem-solving abilities in this field. Share examples of how you have successfully diagnosed and resolved optical issues with camera lenses in previous roles.

4. Prepare for Common Interview Questions

Anticipate common interview questions such as “Why are you interested in this role?” and “Describe your experience with lens customization.” Practice answering these questions concisely and confidently.

5. Bring a Portfolio if Relevant

Consider bringing a portfolio showcasing your work or relevant projects if it is appropriate and feasible. This can provide tangible evidence of your skills and help you stand out.

6. Be Enthusiastic and Professional

Convey your passion for working with motion picture camera lenses and the industry. Demonstrate your attention to detail, dedication to quality, and eagerness to contribute to the team’s success.