Zak Forsman Posted June 11, 2016 Share Posted June 11, 2016 I own two Metabones BMPCC EF mount Speed Boosters. Today I was trying them out with an anamorphic rig (Kowa B&H) using an EF mount Voigtländer 40mm f/2 as a taking lens. Seen here... Sadly, I saw soft, smeared edges at the far reaches of the frame. Before deciding that this particular setup just wasn't going to work, I tried the second Speed Booster and noticed a big improvement. So I immediately did a quick test of identical frames, seen below. These are grabs from the very top of the frame. This shows the worse of the two, on top. And the better booster on the bottom. I've verified that the smeary edges on the top are not motion blur from wind or anything like that. The second one, while sharper, is not quite as sharp as the center of the frame. but it's much closer, so i wonder if it's improvable. Both of these Speed Boosters have been adjusted to lock in infinity focus by loosening and rotating the rear optic. and they both keep my Sigma 18-35mm parfocal. But now i'm wondering if there is something else I can do, or a specific adjustment to be made that will eliminate the smeared edges for this particular setup. Anyone had success tinkering with their Speed Booster optics to get rid of soft edges? Quote Link to comment Share on other sites More sharing options...
Zak Forsman Posted June 11, 2016 Author Share Posted June 11, 2016 zach, i love you, but please... i'm hoping for some insight from people who have first-hand experience with optics. don't derail my thread before it's even had a chance to begin. in that spirit, this post does not require a reply. Quote Link to comment Share on other sites More sharing options...
Nikkor Posted June 11, 2016 Share Posted June 11, 2016 1 hour ago, Zak Forsman said: zach, i love you, but please... i'm hoping for some insight from people who have first-hand experience with optics. don't derail my thread before it's even had a chance to begin. in that spirit, this post does not require a reply. I don't have first hand experience but I would check every corner and compare. One might be better in one corner and the other way around. Maybe the optics don't sit correctly in the helicoid? Quote Link to comment Share on other sites More sharing options...
Zak Forsman Posted June 11, 2016 Author Share Posted June 11, 2016 yeah, it's definitely improved across the board -- top, bottom, left, right. and center frame is equally sharp on both. the difference is only at the edges. if I can find the time, I'll start experimenting with how the rear optical cell is seated, but was hoping someone else out there might have already done the same. Quote Link to comment Share on other sites More sharing options...
bunk Posted June 11, 2016 Share Posted June 11, 2016 What exactly do you mean by 'rear optic'? I have two Lens Turbo's and both were adapted ...but I did so by adjusting the lens unit, not a by adjusting the rear optic within the unit. First thing that come to mind is the little screw on the side. It should only fastened so slightly. Enough to not get stuck within the mount and loose enough to not push the unit out of it's center position ...and mess up yor corners(?) Quote Link to comment Share on other sites More sharing options...
gsenroc Posted June 11, 2016 Share Posted June 11, 2016 Zak, I've noticed that the SB lens module is actually sitting loosely in the thread, and it will shift to one side when locked with the screw. It's only a little shift, but it may cause some issues depending on the copy. Zak Forsman 1 Quote Link to comment Share on other sites More sharing options...
Zak Forsman Posted June 12, 2016 Author Share Posted June 12, 2016 Thanks for the input everyone. Truly appreciated. I believe gsenroc was right. This morning I went to work on the worse of the two speed boosters, adjusting the rear optical element for infinity focus again, but also holding it in place with my thumb so that tightening the holding screw wouldn't lift it up. that basically did the trick. at f/1.4 I can still see the slightest variation at the edges, but at f/1.8 it's sharp across the board. Zach Goodwin 1 Quote Link to comment Share on other sites More sharing options...
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