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17 hours ago, M.Chapman said:


This looks softer to me than diffraction alone could cause. The Canon EFS 18-55 Mk3 is also a pretty good kit lens. 

A 13sec exposure in bright sunlight at F25..... There are several other things that might be going on.


The EXIF data shows that long exposure noise removal is OFF which is good, but it also shows that focussing was done manually, presumably becuase there's not enough light for AF through the ND filter. Not ideal for manual focus either...


Could there also have been camera or IS movement during the exposure? The EXIF data doesn't show if lens IS was ON or OFF.

IS should be off when doing long exposures.


A high level of ND filtering has been used. Is the ND filter poor quality and internal reflections/scattering are causing some loss of sharpness and flare around high contrast edges? NB. Even if that is the cause, F25 is too small an aperture to give images that are sharp enough for Alamy, due to diffraction. 



Amazing detail and information thank you, the Filter is brand new it is a Gobe which I am told is a middle of the range, I auto focused the lens without the filter on then put the lens on, then turned off the AF so it didnt try and focus with the lens on, there is no IS on this lens.


Would I have been better off with about F11 and shorten the time on the lens, I was concerned not having enough open lens time to blur the water enough, I have hear of people using the ND1000 and having the lens open for 4mins.


Again thanks for everyone's help with this.


Normally the pics with this lens are crystal clear, I may have to check the Filter to see if it has any issues.


Many thanks

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There are some lines around the straight parts of the bridge. They could just be compression artefacts, but more likely they're double images caused by the filter. Try a with/without test on a subject with straight lines and high contrast edges.

And check that focus, if those metadata are correct you've focussed too close and you've run out of depth of field.

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I would forget about complex explanations here like diffraction.Having looked at the pics I think there are two main issues - flare and camera shake


The reason why the images are softer on one side than the other is simply flare. The light is coming from above and to the right which is causing awful flare at the right side on both images. It is causing that softness and low contrast that comes from shooting into a strong light source.


The image that was shot at 1/85 s is "reasonably sharp" on the left side. I use inverted commas because it is still not great but the technique seems ok.


The image that was shot at 12s is unsharp everywhere so is presumably camera shake - even softer at the right due to flare.


As has been said, don't shoot at f22. Lens quality typically rapidly deteriorates at apertures smaller than f11, particularly the edges and diffraction also comes into play. If you are going to shoot into strong light like that, then a better lens is advisable - a cheap second hand Canon prime lens would be far better than a kit zoom.

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3 hours ago, FotoFinishMe said:

 I auto focused the lens without the filter on then put the lens on, then turned off the AF so it didnt try and focus with the lens on....


That maybe a significant factor. If the lens is anything like the Canon 18-55 MkII lens I had, it was optically pretty good, but mechanically very, very lightweight plastic construction and hence flimsy. There's no way I could have screwed a filter on without significantly disturbing the focus.



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