mononoke_'s reviews

  • Sigma 30mm f/1.4 EX DC HSM

    8 out of 10 points and recommended
    Solid build, sharpness even wise open, smooth and precise manual focus ring, good autofocus, excellent value for money
    Field curvature, large coma wide open, AF can be inconsistent - extra care needed

    Bought in in spite of negative reviews that dominate the net, mainly for the lack of alternatives in fast normal primes for APS-C segment. Fastest lens I had before this purchase was f2.8 60mm. At first I couldn't get good results out of it yet somehow I was hesitant to return it back and kept on practising. AF wasn't consistent and I don't have AF adjust on my Canon 40D. After awhile I have learned few things:
    - AF is very accurate and consistent if it slews from close focus onto the target, and very inconsistent vice versa. It only takes a quick spin of the focusing ring towards the close focus just before the AF (allow to focus only once).
    - Focus pane is somewhat spherical with corners coming in closer. Therefore to get sharp focus in corners, one has to focus in the corner and recompose. With smaller apertures, one would need to focus slightly past the subject in the centre to bring in the corner into focus field.
    -Keeping the above points in mind, it is possible to get sharp (corner to corner) images even @ f2!
    -Field curvature sometimes plays an advantage - brings in foreground objects into focus in landscape photography
    -@ f1.4 sharpness is very good, but coma is visible in high contrast scenes and can look unpleasant. Overall, very usable @ f1.4
    -Excellent sharpness and contrast @f1.8 - f2.0
    -Maximum sharpness achieved at f2.8!

    Things I don't like:
    -Coma is somewhat bothersome wide open
    -OOF highlights bokeh sometimes produces 'onion' effect
    -Requires extra care when auto focusing



    All in all - It wasn't a love from a first sight, but I grew to love it. Once you learn it's character and quirks, it starts to shine. Highly recommended for persistent users on a budget.

    reviewed December 29th, 2012 (purchased for $500)

  • Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary

    9 out of 10 points and recommended
    well built, versatile, sharp at all focals/apertures, nice bokeh, spot-on focusing, price
    no full time manual focus override, field curvature @ wide angle

    Bought it for our holiday. Having previously owned an original 17-70mm, I can safely say that this one is much better in every category plus a bit brighter at the long end and the OS is a bonus. Build is surprisingly good for a price - definitely head and shoulders above the original 17-70. Focusing was spot on without needing to tweak (bar that corner case, see below). This I can tell now after pixel-peeping thousands of photos - very solid performance.
    In response to a bad press on the internets re: 'soft corners @ wide angle', my observation is that it's only partially true. Yes, some wide landscape shots have soft corners even @ f8, but some others have tack sharp corners even @ 17mm f4 (which was never the case with my old 17-70). I reckon this is due to field curvature: AF picks up sharpness at the centre and leaves corners beyond the field. Will try to adjust AF to focus a bit past near the infinity with USB dock to compensate. Have a look at few samples below - corners are very sharp mid range but a bit soft at the infinity.

    https://www.dropbox.com/sc/v1eyhrkrgvpwzb6/zX1YoyvTHc

    Will update after I get my hands on USB dock.

    My biggest gripe is a missing full-time manual focus override and a constatt f2.8 would be nice, but hey, it's already a lot of bang for your buck as it is:)
    Overall, I'm very pleased - super versatile and solid performer! A nice addition to my kit that contains a few fast primes.

    reviewed October 17th, 2013