Is it normal for a Nikon AF-S 50mm f/1.8G focus ring to turn past infinity and minimum focus distance?
Asked 1/10/2016
3 views
2 answers
0
I’m using a Nikon AF-S Nikkor 50mm f/1.8G on D3100 and D3300 bodies. The focus scale reaches infinity on one end and 0.45m on the other, and the internal movement seems to stop there, but the focus ring itself keeps turning without hitting a hard stop. Is this normal behavior for this lens, or does it suggest a defect?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
10y ago
2 Answers
9
Lenses such as the AF-S Nikkor 50mm 1:1.8 G use a type of motor to move the focus elements known as a Silent Wave Motor (SWM). The technology was first developed by Canon, who refers to it as an UltraSonic Motor (USM). It has since been adopted by many lensmakers and is known by such monikers as Supersonic Wave Drive (SWD) - Olympus, Supersonic Drive Motor (SDM) - Pentax, Supersonic Motor (SSM) - Pentax, Hyper-Sonic Motor (HSM) - Sigma, and Ultrasonic Silent Drive (USD) - Tamron.
The design uses rings vibrating at very high frequencies to produce the torque needed to move the lens' focus elements. Because these rings are not directly geared to each other, when the focus ring on an SWM lens is turned it allows them to slip in relation to each other without risk of damage to the focus motor. It is quite normal with this type of lens to be able to continue to move the focus ring indefinitely even after the focus elements in the lens have reached the end of their travel.
Originally by user15871. Source · Licensed CC BY-SA 4.0
user15871
10y ago
0
Generated from our catalog & community — verify before relying on it.
Yes — this is normal for the AF-S 50mm f/1.8G and similar autofocus lenses with Nikon’s Silent Wave Motor (SWM). These lenses use an internal focusing system that allows the manual focus ring to keep turning even after the optical focus mechanism has reached its limit. The ring can effectively “slip” without damaging the motor.
It’s also normal for a lens to focus slightly past infinity. Manufacturers do this so small tolerances or temperature changes don’t prevent true infinity focus, and so autofocus can reliably acquire distant subjects.
So if the focus scale stops moving at 0.45m and infinity, and the lens still focuses normally, this behavior is expected — not a defect.
Recommended products
UniqueBot
AI10y ago
Your Answer
Related Questions
Why can many lenses focus past the infinity mark?
Why do some lenses focus past infinity, and how can I set infinity focus in the dark?
Why do my Nikon D3300 lenses stop autofocus above 50mm?
Can a Nikon D3300 control aperture on an AF 50mm f/1.8D lens with an aperture ring?
Will the Nikon AF-S 50mm f/1.8G autofocus on a Nikon D3100?