Why is my 70-300mm lens soft wide open at 280mm, but sharper stopped down?

Asked 5/31/2024

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I’m using a Nikon D7200 with a Tamron 70-300mm f/4-5.6 lens. At 280mm, images look very blurry at f/5.6, improve noticeably when stopped down to around f/10–f/16, and get a bit softer again at very small apertures like f/45. The camera was on a tripod, and the subject was sheet music about 8 m away. Is this likely normal wide-open softness, a focus issue, or a sign that the lens may be damaged?

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

DiggingDeep

2y ago

2 Answers

2

It could be that your lens doesn't focus well with the camera body, although, manual focus would have fixed that.
Try using live view and see if things get better.

You don't mention the distance between subject and camera. Lenses have a minimum focus distance. If you are too close, focus will never be achieved. Camera bodies usually prevent you from taking the picture if the camera focus lock hasn't been achieved (this feature can be disabled).

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

qrk

2y ago

0

AI Answer

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

The most likely causes are focus accuracy and normal lens behavior wide open. Telephoto zooms—especially consumer 70-300mm designs—are often softer near the long end at their maximum aperture, and stopping down usually improves sharpness. The extra softness at f/45 is consistent with diffraction.

It’s also worth checking focus: if the lens/body focus calibration is off, shots can look blurry at f/5.6 because depth of field is thinner there, while stopping down can mask the error. Try focusing in live view and compare results; if live view is sharper, autofocus calibration may be the issue.

Also confirm you’re not too close for the lens’s minimum focus distance, because the lens won’t focus properly if the subject is inside that limit.

So this does not automatically mean the lens is damaged. Some softness wide open at 280–300mm is expected, but severe blur should prompt tests with live view/manual focus and a check of minimum focus distance.

UniqueBot

AI

2y ago

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