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You are here: Home / GFX 100 / No front focusing on Fuji 35-70 GF on GFX 100S

No front focusing on Fuji 35-70 GF on GFX 100S

December 28, 2021 JimK 1 Comment

Some people have reported AF front focusing with the Fujifilm 35=70 GF lens wide open at close distances. I tested my copy on a GFX 100S at minimum focusing distance, using a low-contrast Siemens Star. I processed the images in LrC using the defaults except for the white balance and defeating sharpening.

Full frame

 

Near-100% crop

It’s an inkjet-printed target that was never meant to be used this close, which is why the radial lines are wonky. Not the sharpest image I’ve seen, and there sure is a lot flare, but it looks like it’s very close to being in focus. I’m guessing some of the early 35-70 lenses had the problem, and that Fuji has fixed it.

GFX 100, GFX 100S, GFX 50S

← Fuji 35-70 GF Siemens star visuals, corner Field curvature in the Fuji GF 35-70 →

Comments

  1. Vladimir says

    April 2, 2022 at 2:56 pm

    Hi Jim,
    Did you ever check focusing issues at the coners of GF45-100 at the coners of the frame ?
    I have something interesting on my GFX100.
    First of all testing in manual focus my lens is absolutely sharp even at extreme coners.
    In AFS mode it is the same tack sharp when focusing from longer distance or infinity to closer target distance.
    When focusing from closer distance to longer distance to target result is front focus issue at the corners. I can finish it to final point in dmf mode by manually moving focus point futher away.
    In AFC mode it is better but still not very good.
    But in the central part of the frame (about 2/3 of the frame) all is perfect both for AFS ans AFC.
    Stopping down from f4 to f5 or f5.6 results are noticably better – area of perfect focus is expanding.
    Did anybody do the same tests or reported similar issues to you ?
    Could be some issues with firmware , acually interference between AF and OSS ?
    I did that tests long time back and recently repeated them with newest firmware and result is the same.
    Any thoughts ?
    Regards,
    Vladimir

    Reply

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