Sweet Spot Fujinon XF 18-55

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Swaleimageguy

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Andrew Spreadbury
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The plan is to find the sweet spot on the above lens (and I suspect it's a couple of stops from wide open) and to use focus stacking to create landscape images Sharp all the way through the frame from top to bottom.

I've read conflicting material from different sources as to exactly where this is.

One source I read said max sharpness was at 18 mm. f5.6 at the wide end and 55 mm. and f8.0 at the other end.

Another source said that 35 mm. Between f4 and f8 the lens was at it's sharpest.

MTF charts were quoted (which I don't understand) and I'm wondering whether a knowledge of this data is essential to what I'm trying to do. The aim is to find the sharpest combination of focal length and aperture and exploit it to produce the sharpest images.
 
On paper, I'm not sure but in real life, it's acceptably sharp wide open but does improve marginally as you stop don a little. Slightly unusually, it seems sharper at 18mm and f/4 than the 18mm Fuji XF prime at the same aperture!
 
Thanks for putting this up. The results were really surprising. It has certainly encouraged me to test my own lens which I think is really the only way to evaluate sharpness.

Many thanks
 
As far as I am concerned my copy of the XF 18 55. Is fully usable at all settings.
As I am never likely to take comparative shots with another lens in the identical conditions and situations.
I will never know how it compares shot for shot.

In real life it is an excellent lens. That is as sharp and contrasty as I could possibly need and with minimal residual aberrations.
It focusses quickly and and accurately, and it's anti-shake works as well as expected.
All zoom lenses are a compromise. In this lens, Fuji have produced a standard kit zoom that is way above the average.

They also produce standard Zooms, with other focal and aperture ranges and features, and at various price points with other users in mind .
To My mind this 18-55 makes an outstanding general purpose lens.

Like all lenses, it improves slightly as you stop down, untill it reaches the point where this improvement is overtaken by diffraction.
As with most lenses this sweet spot is around one to one and a. Half stops down.

I am uninterested in knowing if one focal length setting is slightly better than another. As I will be using the lens at the appropriate Zoom
setting for the shot anyway. All of the focal lengths are fully usable.

I do not expect any zoom lens to match the highest quality of a single focus lens, as they never are. Nor a m I surprised that their quality is never consistent between one sample of the lens and another. There are always differences between samples of even the very best Zoom lenses.

However the quality standards of Fuji are very high and samples seem to range good better and best. Rather than bad , poor and just acceptable.

In the event you are not happy with your sample of any of their lenses, you can always return it.
 
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