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Sharp, nice bokeh -- great lens!

Started Dec 27, 2019 | User reviews thread
MayaTlab0 Senior Member • Posts: 2,985
Re: Sharp, nice bokeh -- great lens!

J A C S wrote:

MayaTlab0 wrote:

J A C S wrote:

medon78 wrote:

J A C S wrote:

Here is a curve derived from one of you RAW files:

It goes to -2.1 or -2.2 in the extreme corners.

OK! Thank you very much. So... no -3EV or more as the Optical Limits guys sampled. Then there must be either something wrong with my uncalibrated ceiling ;)... hmmm.

I do not think that you can make the vignetting weaker by doing a bad test, this is very hard. On the other hand, a poor test can easily make it look stronger, if the light is more directional than one would think. Taking a shot of a wall pained with a glossy paint is an example. This is especially tricky with wide lenses.

Are there methodologies that can eliminate focusing distance

One usually tests with focusing distance infinity.

One thing I like with Photographylife's tests is that they do it at two focusing distances.

I'm not sure that all lens testing websites are quite rigorous enough to bother with that or many other variables though.

I mean, this is Les Numériques's latest chart concerning the Nikon 58 0.95 :

According to them, the vignetting actually increases past f2 when closing the lens down... ???

or colour profiles as a variable when expressing vignetting in EV ?

I measure RAW files.

Gotcha.

Most websites however (except DXO, I guess) measure JPEGs, and the tone curve would affect what they report.

That could be where some of the differences are seen, no ? Tone curves can dramatically affect pictures.

DXO might be evaluating raw files, but sometimes they still managed to produce some strange results :

A lot has been said about the way they aggregate their data into meaningless scores, but sometimes the data itself - or at least the way it's presented - looks a bit weird.

Honestly these days, as far as vignetting is concerned, I find its expression in EV at infinity, provided it's actually properly done (and I don't trust a lot of websites in that regard), quite insufficient to actually describe how a lens is affected by vignetting.

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