35mm Nikon lens suddenly soft?

PaPa

PaPa

Major Contributor
Hey gang,

I just received some new filters with for my BMPCC and tested them out at a dog park. When I got home, I noticed that every shot had very sharp centers but incredibly soft edges. Not even soft really, but out of focus. My 35mm lens has been a staple in my lens kit and I've never seen this problem. the lens hasn't been dropped, and looks undamaged, but I'm wondering what could have caused this. I will definitely call to get it repaired, but before that, I wanted to get the pro's opinions on the matter. What do you think is going on with my lens? Notice the "Soft" areas, look more out of focus then just soft (bokeh not smear)

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Which Nikon lens ?

I own a Nikon 35mm f/2.0 AI-S, that I've been pretty happy with.

With all of my Nikon AI-S lenses ( except for the Macro lenses ) they are a little soft at the edges when shooting wide open, but clean up considerably when closed down 1-2 stops. ( 50mm f/1.4 is the worst of the bunch )
 
Hey dingo,

I have the same one. Honestly, even at wide open edges would never look ilke that. There is a problem with it somewhere and I just don't know what it is. The problem is exacerbated when i open up, but even closed it's still there.
 
PaPa said:
I have the same one. Honestly, even at wide open edges would never look like that. There is a problem with it somewhere and I just don't know what it is. The problem is exacerbated when i open up, but even closed it's still there.
Click to expand...

Do you have another camera you can use to test the 35mm ?
 
Yeah, I threw it on my GH2, but because the lens is more cropped and getting the sweeter spot in the image, it's hard to really compare. But i just did another test with the 35mm, speedbooster off then on, and although the speedbooster brings into frame the less sharp portions of the glass, even the building has less sharpness across the middle (with speedbooster) than without the speedbooster. I just don't know what's up :(


*** I INCORRECTLY LABELLED THEM ****

WITHOUT SPEEDBOOSTER

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WITH SPEEDBOOSTER
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I popped the 35mm lens on to my 7D, and did another comparison. I'm convinced that it's the speedbooster and not the lens. Would love for anyone else with similar experiences to chime in here. Thanks!


Notice the buildings in the background on the left hand side are much sharper on the 7D than the BMPCC.



7D

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BMPCC SB


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Well, if its the legit speed booster... there shouldn't be this issue.
I bought a "copy", Fotodioxpro. Black with an Anodized red aperture ring.
Anyhow, they had a deal going where you get an "Vizelex Light Cannon" free with it. Turns out, that "art" lens was actually their first try at making a speed booster. It failed horribly, it was soft and caused lens to bloom that wouldn't normally bloom... so they relabled it as "Soft Focus Adapter" Ha!

The newer RED adaptor I tried on a job. It was caused my Nikon 50 f1.4 huge problems at an evening dinner party, everything was soft when I was wide open.
Needless to say, this "red" version also was a failure... so i returned both of them.

To get to the point, I think your speed booster is faulty and causing your lens to bloom or softening your edges.
If you could try another speed booster to compare... at least you test if its a bad speedbooster.

Oddly, enough... I accidentally ordered a super cheap Chinese no name one off Amazon, and the damn thing works perfectly! Thats actually how I figured out the Fotodiox one was bad.
 
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I've contacted metabones. Hopefully I hear back sooner than later. I'm going to run a few more tests today to make 100% certain that it is indeed the adapter.
 
PaPa said:
I've contacted metabones. Hopefully I hear back sooner than later. I'm going to run a few more tests today to make 100% certain that it is indeed the adapter.
Click to expand...

Try a couple of different lenses that you know are sharp, to see if it truly is the Metabones adapter.
 
Yeah. I tried them all without the speed booster and they were sharp. Today in going to try various lenses on a brick wall and then take pictures with those same lenses in the 7D as final proof.
 
To me it seems the speed booster optical block is off axis in relation to the focal plane. Might want to check all of the screws to make sure the mounts are tight- also check the optical block in the speed booster to see if its loose or has lateral "play".
 
Thank you hunter. I will have to inform myself as to what those things are and how to make the adjustments.
 
Just been searching around and found this guys video. Seems like everything away from the center is as soft as what I'm getting, even with different lenses. BMPCC + Speedbooster users, is this normal???

https://www.youtube.com/watch?v=wNFJyJD7A8U

But then I see videos like the following and wonder, what's going on here? Are some Speedboosters sharper than others, or are some not properly calibrated?

https://www.youtube.com/watch?v=56JUGYbTZUE
 
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Alright, here we go. Final test.

It looks like this are alright with the speedbooster, and simply put, it must come down to the combination of certain lenses and how they react with the speed booster, even though the lenses themselves are tack sharp, edge to edge, when used on a aps-c sensor.

Here are my tests. Everything was focused in the center of the frame, then i simply panned right and left, and then placed those sections of the image appropriately with their correct side. I'm really hoping that those who have the bmpcc + SB + Nikon AI primes can chime in here for their experiences and expertise. May start a new thread directed at those users since this might get lost in the shuffle.

Some lenses suffered more than others, which is very odd considering they are the same lens series and make. Much more to learn about optics, but now the question is, how to create a better image...

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Not sure what you have concluded here ...but it appears to me that what ever "shot" the centre row of images is consistently sharp(er) in every case.
 
Sent the unit in to Metabones for repair, receievd it back today. Problem not fixed.

Is this my lens? I can only get the entire image sharp if I shoot at F11. Otherwise, I have to choose, either the center is sharp, OR the edges.

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