You need a camera with a macro setting. I assume you are using that. Try using a neutral gray background so the case isn't made too dark. Manual exposure is an alternative there to let you get the case brightness and focus correct.
Try backing up a little and using a tripod together with the optical telephoto setting and macro functions simultaneously. That will increase depth of field a little so focus is less critical. If you can manually force it to use a higher f stop number, that will also increase depth of field, but will cause exposure to lengthen to compensate, so, again, the tripod may be needed. You can set it on the tripod then set the timer to trigger the shutter so your hands are off to reduce the shakes.
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