35mm Nikon lens suddenly soft?

This is true, but don't you think i'd be getting soft sides without the speedbooster if it were a cam issue? The last image i posted just shows that different parts of the same image are in focus at different lens distance markings.
 
PaPa said:
This is true, but don't you think i'd be getting soft sides without the speedbooster if it were a cam issue? The last image i posted just shows that different parts of the same image are in focus at different lens distance markings.
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I am wondering if this is a lens optical compatibility issue with the Nikon 35mm f/2.0 and your BMPCC SpeedBooster ?

It's possible that the optical design of both of these lenses just doesn't work well together. ( i.e. try a Nikon 85mm or longer lens and see if you get the same results )
 
PaPa said:
This is true, but don't you think i'd be getting soft sides without the speedbooster if it were a cam issue? The last image i posted just shows that different parts of the same image are in focus at different lens distance markings.
Click to expand...

Try the lens on a still camera.
 
Shooter said:
Try the lens on a still camera.
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I had done this earlier on my 7D and my GH2 to rule that one out. The lens is sharp. I'm wondering if maybe you're right Dingo, i just can't really get my head around the idea that they can't be compatible. I guess my brain just can't understand the physics. Just seems so bizarre, but all my nikon primes seem to suffer from the issue, just my 35mm exhibits it so much more than the others.
 
It could be lens compabillity with the Speed Booster or just that the glass element of the SB has to be adjust because the distance to the lens isn't right. You received a small screw driver with the SB right? So you can change the position of the glass element. The wider the lens, the more precise the distances have to be.

If the alignment is slightly wrong, you end up with softer edges or sometimes even with a half or complete soft image.
Does the lens reach infinity focus, with the SB attached, on the exact mark on your lens? That's usually a pretty good indictation to see if the alignment is off.
 
PaPa said:
I'm wondering if maybe you're right Dingo, i just can't really get my head around the idea that they can't be compatible. I guess my brain just can't understand the physics. Just seems so bizarre, but all my nikon primes seem to suffer from the issue, just my 35mm exhibits it so much more than the others.
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When I saw your results it made me think of lens field curvature, which was a big problem when you were trying to copy flat art-work with a non-macro lens because you could never get the whole image sharp from the center to the edges, the sides would always have a different focus point than the center.
 
Stab said:
It could be lens compabillity with the Speed Booster or just that the glass element of the SB has to be adjust because the distance to the lens isn't right. You received a small screw driver with the SB right? So you can change the position of the glass element. The wider the lens, the more precise the distances have to be.

If the alignment is slightly wrong, you end up with softer edges or sometimes even with a half or complete soft image.
Does the lens reach infinity focus, with the SB attached, on the exact mark on your lens? That's usually a pretty good indictation to see if the alignment is off.
Click to expand...

Yeah, i adjusted my infinity to be bang on. Didn't seem to make any effect on the focal plane issue that's happening.
 
update*

Metabones has requested that I return my unit for a swap. Hopefully within the next 2 weeks i'll have another one to try out and see if the problem persists. Will report back with findings.
 
*** Update ***

The guys at Metabones sent me a new unit. I received it this morning and ran some tests. I threw on my vintage nikons as well as some newer lenses including my Tokina 11-16mm. The unit still gives me sides that are on a different focal plane to the rest of the image (field curvature). I can literally activate the "focus" button on the bmpcc and watch the green lines spread from the middle, to the sides of the image as I rack focus. I simply don't understand what the Speedbooster is doing to cause this. The only way to stop this, as someone pointed out, was to stop down my lens. However, I believed that this was done to "Sharpen" my image as gaining 1 2/3rds of a stop was softening my image. Stopping down to "eliminate" this issue simply created a very, very, very deep depth of field so that the sides, being on a different focal distance, would appear in focus.... Even if only stopping down to F 4, which equates to something like F1.8 or so, still gave me a very sharp image in the center.

So, I guess I just want to express my frustration. I feel like the conversations I had back and forth with metabones lead me absolutely no where. I wonder why it is, even after sending them images and explaining the situation, they did not look into the issue I described and simply sent me a new unit, expecting for the issue to vanish. I feel like I've done everything I can to solve the issue, but believe firmly now that perhaps this metabones speedbooster does not work for everyone. I always expected a better image, but these results leave much to be desired. Now the debate is if the shallower depth of field is worth the expense of horrible field curvature.

Thank you all for following the subject. Wishing you all much better luck with your units.
 
No I have not been able to do that. It is something I should try, but I can't believe that anything is going on optically with my camera as without the speedbooster, the image performs as expected with any lens attached - flawlessly.
 
PaPa, I strongly suspect the problem has to do with the Nikon wide-angle lens design not being compatible with your BMPCC Speed Booster. I am guessing that if you put a Nikon 85mm or longer lens this problem would be minimized or disappear completely.

With my GH4, I think of the Speed Booster only being usable for m4/3 "normal" to telephoto focal lengths, and will use native m4/3 glass for anything wider than "normal". ( still I'm very happy with the results I'm getting with the GH4 with the Speed Booster )
 
Hey Dingo, Unfortunately the problem exists on all of my lenses, even my 105mm and 135mm. The 35mm just shows it the worst. But it's there on all of the lenses. It looks like other's are finally speaking up in other forums. So i'm not alone, which is great and bad at the same time :(
 
PaPa said:
Unfortunately the problem exists on all of my lenses, even my 105mm and 135mm. The 35mm just shows it the worst. But it's there on all of the lenses.
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I'm surprised that Metabones would release a product like this, as this looks like a huge problem if you can't achieve proper focus across the frame.

I haven't tested for it, but I don't think I've ever seen this issue with the standard GH4 Metabones Speed Booster.
 
I've been in contact back and forth with metabones to try and figure out how to resolve this issue, be it on the current model or future models. But oddly, the more specific my observations became, the less I heard back from them. I'm really hoping to speak with one of the techies to have a chat about what's going on and how they can fix this for their next revisions but they don't seem to want to play ball.
 
The designer of the unit, Brian Caldwell, has contacted me an assures me that the issue i'm experiencing is due to faulty lens optics on both units and is not indicative of what the speedbooster is supposed to do. He's looking into fixing my situation and I'll report back with the findings.
 
I just did some very rough testing and have noticed the same thing with all of my Nikon AIS lenses, albeit slight, it is deffinitely there. Things on the edges exist on a different focal plane than the centre. I will try and do some more tests when I get back in town.
 
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