Help judging performance of my FE55z, FE35f2.8z horizon/infinity

Started Jul 5, 2016 | Questions thread
(unknown member) Contributing Member • Posts: 854
Re: Help judging performance of my FE55z, FE35f2.8z horizon/infinity

l_d_allan wrote:

holin wrote:

As for the testing method, I'd test with a brick wall, carefully aligned,

Agree (and there are also more than a few other considerations to be aware of besides alignment).

A real issue with distant targets is "atmospherics" ... haze/pollution/humidity, wind, etc.

Objects at "near infinity equivalent" like 1000x to 10,000x focal length are often not all that flat, which can throw off evaluation.

And issue with distant and close targets is that you should ideally test both as lenses have different behaviour at different focusing distances.

or try to find slightly flatter infinity subject - so that almost everything is far away in the photo. Now you only have very thin corner to corner line of detail (buildings) from which to judge sharpness. Trees won't do, especially when it's windy.

I think with enough experience doing valid "good copy vs bad copy" testing with real attention to detail, testing a newly purchased lens can eventually get to be pretty quick and simple.

Agree, if the aim is to see if it has any fault  that would affect real life situations. However, if the purpose is find the absolute best holy grail copy of that lens that's as good as the most stellar review (or random forum comment) found online then it gets more time consuming. So far, without testing chart setup, I've tried find some standard subjects that I go and shoot.

However, my impression from reading way too many q/c related posts on DPR is that there is a LOT of invalid testing being done.

And then ... as much or more flawed evaluation of the test captures.

Am I the only one who has found there is a definite learning curve involved?

No, definitely a learning curve there, starting from understanding what's normal and what can be expected from different FLs to learning to see sharpness / contrast in different natural or man made textures and understanding how different aberrations affect perceived sharpness. Like the OP, I had problems "seeing it" in a normal brick wall (bricks not as usable as the mortar between) whereas for instance osv's example of the aerated concrete wall is much easier to judge.

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