What the thread found

• The Preston DM4 motor lacks sufficient torque for reliable focus pulling on camera lenses
• The Preston DM4 motor moves slowly to reach focus marks, making it unsuitable as a primary focus motor
• The Preston DM4 motor performs adequately as an iris control motor due to its light weight

Depends on

• Limited testing data provided in the discussion
• No specific lens types or modern lens models tested are mentioned
• The assessment appears to be based on subjective testing rather than formal specifications

Parts

Follow Focus

Same gear or parts

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