Image quality at different zoom levels

[Vaaaan]

Hi, I'm a noob photographer and I'm hoping one of the knowledgeables here can help me with a question.. On a zoom lens, specifically a lower quality zoom lens, regarding the zoom positions where the min/max aperture changes, does it make any difference in image quality if you shoot at a zoom right next to one of the points where the aperture changes, as opposed to shooting near the middle of two points? For example, say you have a 18-55mm Canon kit lens and you're at about 24mm where the minimum aperture changes from f/3.5 to f/4.0, should you use f/4.0 to ensure the best image quality? Conversely if you're at about 50mm where it changes from f/36 to f/32, should you use f/32?

My reasoning for thinking this is that if you're at the very maximum (or minimum) zoom that a given lens can handle at a certain aperture, wouldn't the image quality suffer a bit because you're stretching the lens' abilities?

Thanks for any help

[RichardTaylor]

Usually lenses perform best at around 2 stops smaller than the maximum aperture.
Also performance may drop off at different focal lenghts. This is is lens dependant.

With high quality lenses the variation in quality is minimised.

Also keep in mind at very small apertures(eg >F16 and again lens dependant) diffraction may cause problems.

In practice other things like exposure & lighting and DOF that I want influence my decision of what aperture to use. I do tend to use mostly high quality lenses.

[Vaaaan]

Thank you that helps a lot. I was shooting video in low light with the widest aperture that the zoom level could handle and I noticed the sharpness wasn't quite on par with other videos I'd taken, so I will try using a higher ISO and slightly smaller aperture and see if that helps.

[OsmosisStudios]

With video, if youre zooming, some lenses will become out of focus as you zoom. That could be the issue.

Generally lenses have stronger and weaker focal lengths as well.