FS7: Metabones Ultra - early concerns

B

bengiles

Well-known member
Here are some screen grabs of a Canon 24-105/f4 L Lens, shot on XAVCI 1080P:

Metabones Ultra

Metabones Ultra CU crop of frame

Commlite adapter (no intermediate glass)



MB Ultra.jpg
MB Ultra CU.jpg
Commlite.jpg

They were taken a few minutes apart, while running some initial FS7 camera tests this afternoon. I was shocked when I first saw the pronounced colour artifacts on the black railings in right of frame, thinking they might be some kind of sensor artifacts. A quick lens adapter swap to check the optics suggests it's rather nasty CA.


Would be gratetful for any thoughts. Seems my giddiness at getting an extra stop and wider FOV may have been premature...

Ben.
 
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It's not color artifacts but CAs.
The Speedboosters are CA machines.

They make CAs (chromatic aberrations) much more pronounced especially on the outer part of the frame.

The 24-105 is not very good in that area and it flares very easy on the Speedbooster to.
I have the Canon EF-S 17-55/2,8 IS on a non Speedbooster Smart adapter and it's much better here.
 
While I have a 'dumb' EF Mount focal reducer (Camdiox is the only one I found which fits the FS7 after going through a few) for when it is necessary, I must say I've always been a bit wary of them being on the camera 100% of the time and permanently being part of the optical path. No matter how high quality the elements involved are, introducing further glass into the optical chain is going to degrade the image, no matter how slightly. It might be in a desired way like with a black pro mist filter or a crazy lensbaby type deal, or in an undesired way with CA and fringing or low contrast or other optical artefacts. And if that glass is made to bend and reshape the optical path like with a focal reducer, then the results will be even more degraded.

If your work is all web based then it probably isn't too much of an issue. They are a great tool but for me they're not an 'always on' tool.
 
I remember shooting small chip cameras with the big ground glass adapters. Under ideal circumstances, with everything aligned properly, using a Letus Ultimate with a Sony EX1 made incredibly sharp and clean images. But it also added multiple points of potential failure, and things could get misaligned in a number of ways, resulting in decreased performance that frequently wasn't detected until post.

Likewise, these adapters introduce additional points of potential failure or misalignment. They're great tools, but anytime you modify the optical path, you risk image degradation. Sometimes it's worth the price, sometimes it isn't. Optics is all about tradeoffs, and you never get something for nothing.
 
Yeah. That ^^

Nice to have in the bag for when you absolutely positively must go wider/brighter. Aside from that I prefer as few bits of glass in the optical path as possible.
 
The sun is out in one shot and not the other. Maybe you need to retest this. It might be the lens, not the adapter. Certainly, I haven't spotted anything like this with my speedbooster.
 
No surprise at all . These are great tools for extra low DOF , for lowlight and for an extra wide shot but the corners are dangerous so be careful where you use it .
 
I have to say that I used this combination (Canon 24-105 + Speedbooster) for weeks on my FS100
when shooting doco. It never let me down... Fantastic allround combo as long as your not shooting backlight...

I didn't have this crazy aberrations and fringing.

Now, on the FS7 with its 4k capabilities, we're in a different situation. That's why I switched to the EF-S 17-55.
This is my goto lens now (+ Canon 80-200/2,8L).
 
Liam Hall said:
The sun is out in one shot and not the other. Maybe you need to retest this. It might be the lens, not the adapter. Certainly, I haven't spotted anything like this with my speedbooster.
Click to expand...

Good point, Liam, and I did think after posting that maybe it wasn't an entirely fair comparison. However, the CA on the trees behind that have more equal light is also tangibly worse.

One for another trial over next few days.

I wanted to gauge opinions to see if others have already reached conclusions on this - interesting to read Erik saying he's getting on OK with the 24-105/SB.

I think I'm suffering that first phase of new camera numptiness - I've got a foreign shoot coming up in a week's time and I'm trying to get comfortable with this new camera/lens system, while dashing around sorting dull admin stuff.

Thanks for all the contributions.

Ben.
 
I had two days to test after picking up my camera in October. Metabones didn't work with half my lenses, batteries didn't work at all, camera didn't fit in my carry-on...

All turned out fine, I'm sure your's will to.
 
Had a similar experience. Received the camera and not enough batteries 1 day before I had a shoot planned and I didn't have time to test anything. All went great :)
 
Erik Wittbusch said:
It's not color artifacts but CAs.
The Speedboosters are CA machines.

They make CAs (chromatic aberrations) much more pronounced especially on the outer part of the frame.

The 24-105 is not very good in that area and it flares very easy on the Speedbooster to.
I have the Canon EF-S 17-55/2,8 IS on a non Speedbooster Smart adapter and it's much better here.
Click to expand...

The problem here is mostly to do with the lens that is attached to the Speed Booster. What the Speed Booster does is to bring the outer parts of the image into view, but these are the very parts that are most prone to lateral color. The 24-105 Canon is well known to have plenty of lateral color in the outer part of its image circle, especially near the wide end of the zoom range.
 
I completely agree with brianc1959. The 24-105 is pretty sloppy on the edges of fullframe. I've gotten plenty of still shots from my 5DmkIII with it that had 4-5 pixels of magenta/green fringing on the edge, even at f/5.6.

Overall, my experience with speedboosters has been awesome, but garbage in=garbage out in terms of optics.
 
As I said. The 24-105 is not the best option for critical production.

But I have used it for 100 hrs of footage on my FS100 with the Speedbooster and the footage was always fine.
Because of its tendency to flare, I built the following (extremem lightweight) setup: :grin:

2014-06-24_14-43-51_115.jpg


Lately, I experienced a really bad behaviour of this lens during some night shootings. It totally ruined my footage because
the flares were all over the place. When I put it on my standard Smart Adapter instead of the Speedbooster, it was better though.

Nevertheless, I replaced it with the EF-S17-55/2,8 and have much better experiences in critical light situations.

YMMV
 
Speedbooster is on it's way back to the dealer. I bought it really just to use with a 24-105.

I'm going to try the Sony 18-105. Arrives tomorrow.

Ben.
 
18-105 is focus by wire - awkward for manual focus.

The distortion is so heavy that it needs electronic compensation. On the FS7 only available up to HD/50p and thus not really usable in UHD...

Good luck!
 
Its worse than that on the 18-105. In Cine EI, if you have the distortion adjustment on Auto (which means ON) you get all or nothing on the LUT menus.
Thus if you want a LUT, you have to record it. I sent to back.
I'm keeping the 18-105 mainly for the iS as the range., but plan to have another lens as a back-up for low light and where I need more critical image .
Maybe Nikon 28-70 , Tamron 24-70 , Canon 17-55 or something similar.
 
I've been going back and forth all weekend - for every benefit, there seems to be an equal and opposite gotcha. My head hurts and I'm disappearing up my own backside.

Here's my thinking at the mo: for my needs, I want a WYSIWYG equivalent of Canon's WDR setting - usable for offline viewings without clients saying, "but why does it look like...?", but with some scope for tweaking in the grade. Also, I'm going to have around 1500 cuts on this film when it's done and I can't afford to get bogged down having to add clip-level colour correction throughout the timeline.

The main reason I've moved from Canon to the FS7 is ergonomics - if I can get the image nearer to what I had before, that would be fab.

So I'm hoping the 18-105 distortion correction gotcha won't affect me with a custom configuration - but, as I'm learning with this camera, there are no free lunches (yet...) Also, I'm shooting exclusively 1080P on this project, so not too concerned at the mo with 4K performance of this lens. But don't get me wrong, I'm not expecting a bed of roses, just trying to find a good-enough alternative to the 24-105 and Speedbooster.

Will update when I've had a play.

Ben.
 
I've been having good success for corporate and run and gun with the EF mount-modded Contax Zeiss 28-85 f3.3-4 with the Camdiox 'dumb' focal reducer
 
My understanding is that it's rarely the speedbooster that's adding the CA, but rather the lens itself having more CA at the edges of frame.

Also I agree that comparison is not useful since the issue in the first frame appears to be a combination of lens CA and the black pixels highlight edge issue both of which are worst in high frequency, high contrast detail at the edges of frame, and the first frame has specular highlights on the bars illustrating the issue where the second does not have any such highlights or contrast in that area.
 
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