GH3 Is my Speed Booster to blame for this? Or the lens?

S

Stab

Well-known member
I recently bought a Sigma 18-35mm and use it with my Speed Booster. Yesterday I noticed in a picture that the left side of the frame is a bit softer than the rest at 35mm.
I decided to make a test shot today, and I'm afraid that something is wrong. The question is, is it the Speed Booster or the lens?
And could it be 'fixed' with a small adjustment of the Speed Boosters glass element? Or is this a sign of a faulty lens?

Here is the picture I shot at 35mm, around f4.


P1060698.jpg

And here is a 100% crop of the top left side.

100%linksboven.jpg

And the top right side:

100%rechtsboven.jpg


Clearly a difference... The top left crop is much too soft. Ok I know that the crop from the right side is more towards the middle of the frame, but it shouldn't matter much as the wall on the far right is equally as sharp as this crop.

Any suggestions?
 
The lens must sit parallel to the chip.

Every link in the chain may cause error.

Id put money on the booster.

BUt first check everything is clean.. (ie the interfaces between body, booster, lens)

S
 
morgan_moore said:
The lens must sit parallel to the chip.

Every link in the chain may cause error.

Id put money on the booster.

BUt first check everything is clean.. (ie the interfaces between body, booster, lens)

S
Click to expand...

Thanks. Just did that already. Cleaned everything, problem still persists.

I also put money on the Speed Booster. But is it a faulty Speed Booster? Or should I just adjust the inner glass element to make the alignment better? I wouldn't know exactly how, but I'm sure a repair shop can do it for me.
 
Could this have something to do with it?
I don't know what these pins are for exactly, but the outer left one seems a bit bended downwards. Is this normal?

IMG_20140603_134119_016.jpgIMG_20140603_134102_126.jpg
 
Stab said:
Could this have something to do with it?
I don't know what these pins are for exactly, but the outer left one seems a bit bended downwards. Is this normal?
Click to expand...

Looks damaged to me. But since I don't have that lens, speed booster, et al... can't really say... but that doesn't look right...
 
Bern Caughey said:
Do as David suggested & test.

Consider testing the lens on an APC camera without an adapter too.
Click to expand...

Yes, do it. You need to isolate the problem.

It seems people need to learn to troubleshoot things, so here's a basic rule: Always eliminate as many variables as possible in whatever you're testing.
 
yslee said:
Yes, do it. You need to isolate the problem.

It seems people need to learn to troubleshoot things, so here's a basic rule: Always eliminate as many variables as possible in whatever you're testing.
Click to expand...

I always do. But in this case, I wouldn't know what it would mean if the problem would be solved at 20mm at F2.8.

I just know that at 35mm, at even the sharpest aperture setting, the lens gets softer on the left end side. The problem is also there at 18mm, but less apparent.
I don't know what it indicates if it would be different at other settings. But I'm sure it is not the DOF, or normal corner softness.
Hence, there is a problem with either the lens or the Speed Booster.

Unfortunately, I do not have an APS-C (Nikon) body here to rule out the lens. Also, I'm pretty sure it has to be the Speed Booster because I had similar problems with another lens + adapter before. It turned out to be the adapter.

What I'm wondering now is, will adjusting the glass element of the Speed Booster be a possible fix to this problem? It's not an easy task and I don't have the tools. Or is it more worthwile to go back to the shop and swap the Sigma?

Just want to know the opinion of you guys, since most here have tons of experience regarding lenses, adapters and camera's.
 
Stab said:
What I'm wondering now is, will adjusting the glass element of the Speed Booster be a possible fix to this problem? It's not an easy task and I don't have the tools. Or is it more worthwile to go back to the shop and swap the Sigma?
Click to expand...
If you're certain it's the Speedbooster, go get it exchanged if you can, otherwise have it fixed by Metabones. Some lenses have elements held in place by screws which can perform micro adjustments, but not all of them. If you have no experience in re-aligning a lens it's best to let someone else do it.
 
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