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I teach photography and one of my students images, all shot at 55mm (18-55mm canon kit lens) have a blurred vignette. Any advice? I have attached the images and the metadata enter image description here

enter image description here

enter image description here

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    \$\begingroup\$ Have you asked the student whether this is intentional? Have you examined the camera, lens, and any attachments? Are these raw or jpg? What "advice" are you seeking? Do you want to replicate this effect, fix it, prevent it, or something else? \$\endgroup\$
    – xiota
    Mar 11, 2022 at 6:08
  • \$\begingroup\$ Looks a bit like a zoom blur. How is the student holding the camera? If s.he hold the lens by the zoom ring it could move a bit. \$\endgroup\$
    – xenoid
    Mar 11, 2022 at 9:01

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Generally, zoom lenses are softer at the edges and corners. If the lens has not been cleaned for a long time, fungus builds up within the lenses and they accentuate this softness or blurriness. On the other hand, chromatic aberrations are common with the 18-55mm kit-lens and they also cause a significant amount of blurriness in a captured photo.

Have you asked your student whether he has used any filter over the lens? For example- a UV filter or macro filter? They may also be the culprits here. A low-quality UV filter produces a lot of blurring due to chromatic aberrations around the corners of a photo.

I would also advise to use a different metering mode.

Hope this helps!

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    \$\begingroup\$ This is the rather recent version of the 18-55mm. I used its predecessor (non-STM version) and it was way better than this, and here it isn't even used wide open... so it it is a problem with the lens it is a broken lens. \$\endgroup\$
    – xenoid
    Mar 11, 2022 at 17:06
  • \$\begingroup\$ @xenoid The copy of the non-IS EF-S 18-55mm f/3.5-5.6 II I got with a Rebel XTi/400D back in 2008 was horrible. There was a soft spot to the left of center that was always blurry, even when things both closer and further were sharp, and when things in the center and closer to the left edge were sharp. The quality control variance between different copies of those early non-IS 18-55mm lenses were notorious. \$\endgroup\$
    – Michael C
    Mar 15, 2022 at 7:28
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    \$\begingroup\$ @MichaelC Yes, but here we are talking about the modern STM variant according to the EXIF. \$\endgroup\$
    – xenoid
    Mar 15, 2022 at 7:39
  • \$\begingroup\$ Which was not introduced until April 2017, almost three years after the original time/date that the images were taken, also according to the EXIF \$\endgroup\$
    – Michael C
    Mar 15, 2022 at 7:46
  • \$\begingroup\$ Also, at 55mm, f/5.6 is wide open for any of the EF-S 18-55mm lenses. \$\endgroup\$
    – Michael C
    Mar 15, 2022 at 7:51
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There's something very strange going on here.

The original date/time of the image file is from October of 2014.

The lens listed is the EF-S 18-55mm f/4-5.6 IS STM.

That particular lens was not even introduced by Canon until April of 2017.

My guess is that someone (or some application) has mistakenly applied a lens correction profile for the 2017 f/4-5.6 STM version to an image taken with a different 18-55mm Canon lens, perhaps the (2013) EF-S 18-55mm f/3.5-5.6 IS STM or the (2007) EF-S 18-55mm f/3.5-5.6 IS offered as a kit lens with the 60D when it was introduced in 2010? All of the pre-STM lenses have 11 elements in 9 groups. The EF-S 18-55mm f/3.5-5.6 IS STM has 13 elements in 11 groups, while the EF-S 18-55mm f/4-5.6 IS STM has 12 elements in 10 groups. So that is three different optical formulae.

Or it could be that the lens is defective/damaged in some way.

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    \$\begingroup\$ Incorrect lens data is less likely than an incorrect date set on the camera. I doubt OP is reviewing student photos from nearly a decade ago, or that students are submitting photos taken that long ago. Many people simply have the wrong date or time set on their cameras. \$\endgroup\$
    – xiota
    Mar 15, 2022 at 21:51
  • \$\begingroup\$ Manually applying the wrong lens profile is also a possibility, especially if someone isn't aware there are more than one variety of Canon EF-S 18-55mm STM lenses with totally different optical formulae. \$\endgroup\$
    – Michael C
    Mar 16, 2022 at 20:53

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