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Thread: A7R autofucus Primes

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    A7R autofucus Primes

    Looking for advice for autofocus primes for a sony A7R. after reading about the G master 24-70 Iv'e decided for stick with primes. looking for sharp autofocus primes. I will order the Batis 25mm. Now looking for advice for sharp autofocus 35mm and 50mm lenses.

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    Re: A7R autofucus Primes

    The Sony Sonnar FE 55MM F1.8. It's expensive but a fabulous lens with very little sample variation.
    Others will suggest a 35 - I don't use this focal length - went to a Batis 25 instead

    Good luck
    David

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    Re: A7R autofucus Primes

    Avoid the FE 50/1.8 at any cost.

    The price on the 55/1.8 has stabilized and if you look around, you will get it for a decent price.
    Sale Items (http://www.getdpi.com/forum/gear-fs-...8806-sale.html)
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    Re: A7R autofucus Primes

    I agree and have the Batis 25/2, FE 55/1.8, and FE 35/2.8.
    If you get a good copy of the FE 35/2.8 then it's certainly a pleasure to use.
    With best regards, K-H.

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    Re: A7R autofucus Primes

    Thanks, those are exactly what I've been looking at
    what's the best way to test the 35mm for sharpness?, any simple quick method?

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    Re: A7R autofucus Primes

    Quote Originally Posted by felix5616 View Post
    Thanks, those are exactly what I've been looking at
    what's the best way to test the 35mm for sharpness?, any simple quick method?
    I am not an expert so this is just my way of doing it.

    The first thing to know is what is sharp for others may not be sharp enough for you, so your own standard is what you need to meet.

    Second, unless you know already how all your other lenses behave, it is probably best to compare a new lens with something you already have that is sharp by your standards, preferably in a similar FL and aperture.

    A simple and quick way is to point it at a brick wall, preferably with writing/graffiti/objects/doors/windows in it. You can use a tripod with remote release etc if you want to be fussy, but for a quick test, simply hand hold at speed over 1/250 and use AF. Make sure there is something with texture in the center and at the corners.

    For infinity testing, point it at a building or cluster of buildings and a horizon in the distance (usually anything over a 100ft away should do it). Make sure you tilt the camera 45 degrees so that there is something at the corners instead of blue sky.

    Take test shots at all apertures at 1 stop interval (I usually shoot at the widest, f2.8, f4, f5.6, f8 and stop there).

    Use the Compare tool in LR to view images side by side at full resolution.

    I use a big 24X36 USAF resolution target - http://www.edmundoptics.com/test-tar...r-chart/83001/ - to do my tests, but this is a quick and simple method.
    Too much to list, let's just say I have a bad case of GAS.........

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    Re: A7R autofucus Primes

    +1 for the 55mm fe f1.8
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    Re: A7R autofucus Primes

    Pradeep's method should work perfectly. What you'd mainly looking for is one side or corner that's not as sharp as the other. Most problems with this lens that I've read about concern decentering rather than sharpness overall.

    If you have to try it out in a store, just put it on the counter in front of the display of film boxes (if they still sell those!), align, and shoot as Pradeep said. Easy to tell if the corner labels are equally easy to read.

    Kirk

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