Simon Shasha Posted January 15, 2017 Share Posted January 15, 2017 Hi guys, I have my GH5 on pre-order. I will also be ordering a Metabones Speed Booster Ultra 0.71x to use on the GH5 with my Sigma 18-35mm F1.8. However, given that this turns the GH5's crop-factor into x1.4, I started to worry that this will cause vignetting with the Sigma 18-35mm F1.8. Having conducted my own tests with the Sigma 18-35mm F1.8 in the past on a full-frame sensor (http://www.eoshd.com/comments/topic/8444-sigma-18-35mm-f18-on-ff-sensor/?do=findComment&comment=92144), I feel as though the Sigma 18-35mm F1.8 is actually designed, and can work with, sensors larger than APS-C. This is something I also noticed with my Sigma 30mm EX F1.4 - which worked perfectly back when I used to use it on the 1D Mark IV (an APS-H sensor). What I wish to request from GH4 owners, that both own the Speed Booster Ultra 0.71x and Sigma 18-35mm F1.8, is that if they could please test the GH4, with this combination, in 1080P mode (which does not suffer from a 2.4 crop-factor like 4K) and verify that there is no vignetting... Whats more, given the results I found when using the Sigma 18-35mm with my A7S, I am starting to wonder if the Sigma 18-35mm F1.8 will work fine with the Metabones Speed Booster XL 0.64x - which turns the crop-factor into APS-H (x1.3)... Axel 1 Quote Link to comment Share on other sites More sharing options...
John_Harrison Posted January 17, 2017 Share Posted January 17, 2017 I've used the 18-35 on a FS700 with a Speed Booster, and I found that it was useable with light vignetting at 20mm and completely fine by 24mm. Corner resolution might suffer, but I think you should be ok even with a 1.3x crop. Simon Shasha 1 Quote Link to comment Share on other sites More sharing options...
Simon Shasha Posted January 20, 2017 Author Share Posted January 20, 2017 Anyone? Quote Link to comment Share on other sites More sharing options...
funkyou86 Posted January 20, 2017 Share Posted January 20, 2017 I am using the my GH4 with the Sigma 18-35 and the Mitakon Lens Turbo, which is very similar to the SB. With its 0.72x there is no vignetting in 1080p mode. Also, never heard of that any of the 0,71x speedboosters ever vignetted. The 0,64x XL version does vignette in 1080p mode. Quote Link to comment Share on other sites More sharing options...
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