Should I return/replace my lens? EF-S 55-250mm sharpness/focus

streetsnyc wrote:

Jura S wrote:

streetsnyc wrote:

Speaking of which, would the autofocus system of my camera be another issue? Because I believe that I achieved the sharpest image (using the watch as a test) by manually focusing. The difference is barely noticeable except when viewed at 100%, but it made me wonder if there's anything I can do to optimize AF accuracy? For instance, I use an AmazonBasics UV filter.

What mode of focus acquisition do you use?

I typically use One Shot autofocus, but have also experimented with AI Servo. I've read that AI Focus isn't reliable or is generally rubbish.

AI focus just switches to ai servo once movement is detected, which includes you moving the camera. That's probably why it's judged unreliable, because camera movement can trigger it.

https://www.canon.com.au/explore/glossary/ai-focus

With AI servo, it's important to note that the camera will just shoot, whether anything is in focus or not, it just tries to track movement.    with one shot, the shutter is only released when focus is achieved.

Good advice re cheap filters and hoods. I'll replace my filter with a better one. As for the hood, I'm not sure which to buy. Is there a specific form/shape I should look for? Or would a generic 58mm lens hood suffice?

buy the right hood for your lens - for each lens or group of lenses canon has an appropriately designated hood. there are also third party hoods that replicate that design that are cheaper.     generic hoods have only use in some special situations (e.g. the foldable rubber hoods, useful to press against glass, when shooting through windows etc. to reduce reflections.

For testing your lens, try without filter to get best performance.