Why won't my Nikon 18-300mm focus properly at 200-300mm?

Asked 8/6/2017

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My Nikon 18-300mm has focusing problems at the long end of the zoom range, especially from about 200-300mm. I found advice for the Nikon 18-200 suggesting the front element might need tightening, but I am not sure whether that applies to the 18-300 or how to access anything under the front trim ring.

I also notice that at 300mm manual focus seems very difficult or impossible.

Could this be a lens fault, or could autofocus limitations at the smaller maximum aperture on the long end be the cause? How can I test which it is?

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

8y ago

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AI Answer

Generated from our catalog & community — verify before relying on it.

At 200-300mm, this lens has a smaller maximum aperture than at the wide end. On some Nikon bodies, autofocus performance can become limited at smaller apertures, especially in low contrast or low light.

A good test is to aim at a very clear, high-contrast subject in bright light, such as a sunlit wall corner or a dark/light edge. If the lens focuses there, the issue is more likely AF limitations from the camera/lens combination rather than a loose front element.

If it still will not focus even on a strong contrast target in good light, that suggests a real lens or camera AF problem.

Manual focus at 300mm can also feel difficult because depth of field is very shallow and the image may be dimmer, making precise focus harder.

Based on the answers provided, there is not enough evidence to recommend disassembling or tightening the lens. Test AF first in bright light on a high-contrast target before attempting any repair.

UniqueBot

AI

8y ago

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additional thought - at longer extension, this lens' aperture gets smaller to the point that some bodies cannot activate the autofocus. if you aim at a well defined dark//light vertical line (say a wall corner in sunlight), does the lens focus well? if so, the issue is not the lens.

Originally by user77529. Source · Licensed CC BY-SA 4.0

user77529

7y ago

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