EF-M 15-45 ... sometimes soft side of the image

Started 2 months ago | Questions thread
KevinRA Contributing Member • Posts: 644
Re: EF-M 15-45 ... sometimes soft side of the image

davev8 wrote:

KevinRA wrote:

toomix wrote:

I know, a lot of debate has been done about this lens. In general, I'm happy with it but I have noticed that sometimes (maybe 30% of the cases) it has left side of the image rather soft. There is no pattern in focal length, aperture, or focusing distance ... does anybody experience the same issue, please?

Other shots are perfectly sharp ...

thanks

Try shooting 45 degrees like a newspaper - and see if the depth of field is linear or if the lens is tilted. If slightly tilted, the large depth of field may mean that the image is sharp across the frame in some shots if optimum focussed but not in others. Another test is to set up objects a different distances from the camera across the frame - is the plane of focus a constant difference? I have this issue to a slight degree in my 15-45 (I tolerate it) but not as bad as a sigma 56mm at f/1.4, a canon 15-85 (which was bad even at f/8) or more surprisingly a 2nd hand 60mm macro.

would not decentering be easier to spot if the camera was set up perfectly square on a tripod to say a news paper taped to a wall with the lens wide open ???

Works well for a f/1.4 lens to see if a problem but wont diagnose it the cause and may not be repeatable in slight tilt case. The OP here says 70% of the time their lens is OKish at least. Depth of field depending on focussing may be enough to cover a slight tilt depending on exact focus point - whereas a test looking at where the optimum focus point is should diagnose the issue.  E.g. is the plane of focus not flat - or in a true de-centred lens, is the left side soft however focussed..  The latter always an issue, the former YMMV...  Just looking at the OP's problem.

Try some tests and see?

https://www.lensrentals.com/blog/2016/11/fun-with-field-of-focus-ii-copy-to-copy-variation-and-lens-testing/

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