GH4 Speed Booster and "Onion" Bokeh

S

Simon Shasha

Well-known member
Hey guys,


I was watching Dave Dugdale's GH4 review, and I noticed some strange "onion-like" bokeh - if you fast-forward to 14:15 you can see it:


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


Is this common among Speed Boosters?


Does the x0.58 BMPCC specific Speed Booster suffer from this too when the lens is wide-open?


Would love to know what experiences you guys have had with Speed Boosters and bokeh rendition :)
 
Those onion rings in the bokeh aren't a result of the Speedbooster. They're quite common in many low cost lenses. It's a result of the molding process to create aspheric lenses. The Panasonic Rep in this video explains it at 1:23:00

http://youtu.be/Z6mKJyhtCO0

I've been using the Metabones Speedbooster Nikon-to-MFT adapter for a Sigma 18-35mm and Tokina 11-16mm and I've never noticed the effect. It's only noticeable in unique situations (like those found in Dugdale's video tests).
 
It's not the "onion ring" effect that the Panasonic rep is going on about, it's the "onion shape" of the bokeh itself. Fast-forward to 14:15. And it cant be the lens - he's using the Sigma 35mm F1.4. One of the best lenses on the market.
 
Sigma never made the best lenses on the market, and likely never will. Some may be pretty good but some are downright awful. They just don't have the level of quality control we find from Canon or some of the other major quality makers.
 
Bruce Foreman said:
Sigma never made the best lenses on the market, and likely never will. Some may be pretty good but some are downright awful. They just don't have the level of quality control we find from Canon or some of the other major quality makers.
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Really? You think Art series lenses are worst than Canon or Nikon equivalent lenses? I don't own 35mm or 50mm Sigmas yet, but I did rent them and they blow Canon 35mm L and 50mm L out of the water completely! and yes, I have used, to be more correct used to own Canons 35mm and 50mm (will be getting Sigmas some time in the future).

Sigma doesn't make the best lenses on the market (probably will never make), but their Art series lenses are not just equal, but better in some/many ways than Canon or other major brand equivalent.

My non fanboy 2cents with opinion based on personal tests and taste.

Sorry, for the off topic.
 
egproductions said:
I agree. Bruce, check out the Art Series Lenses...sigma has been crushing it lately at a fraction of the cost.
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And how. Lately, my Leica Summilux-R 35 (a lens of which Leica and I are extremely proud) has been staying home in deference to the 18-35. A ZOOM, for God's sake! There's a downside in the amount of plastic used in Sigma lenses, I still might not fully trust their durability, but functionally they've really improved their game.

As to the onions, it's also known as "cats eye bokeh" to some. Lots of lenses display it, usually very fast and very wide examples... in many cases, very very very good and expensive lenses. If you open the lens fully and look at it from all the angles the light may be entering, it's easy to see why this can occur. Lenses such as the f0.95 Voigtlanders, Canon 85L, Nikon 70-200, the ~$10K Leica Noctilux-M 50, and many others can display it... some folks find it desirable, others not so much. The SpeedBooster may make this more apparent as it's refracting the light even more, increasing speed and decreasing focal length.

Here's an article that explains it to lengths I can't:
http://toothwalker.org/optics/vignetting.html#fig3
 
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I agree with everyone else above. I use my sigma 18-35mm all the time and the fact that it can focus so close just amazes me, since in some situations there is no need for macro lens. Although I still wish to get their 35mm and 50mm, those are gorgeous as well.
 
Bruce Foreman said:
Sigma never made the best lenses on the market, and likely never will. Some may be pretty good but some are downright awful. They just don't have the level of quality control we find from Canon or some of the other major quality makers.
Click to expand...

As a guy with a shelf full of Canon glass and portfolios full of work in film and photography with them, this just isn't so any more Bruce.
The Sigma 18-35mm is a superior lens, in every way, to any Canon L zoom I've used and rivals my best L primes.
It's built better than the 24-105 f/4 for instance and simply kills it w/ beautiful wide and responsive manual focus ring (the 24-105 has pretty blah manual focus)

But the IQ, especially paired with the Metabones speed booster, is simply stunning - the fastest sharpest zoom you've ever shot I promise.
The new 50mm Art is built and operates the same and again, there isn't a Canon prime that betters it.

Gotta call foul on this one Bruce - you'd be crazy to pay the premium of Canon L glass with the over all quality of the new Sigma line and again, the 18-35mm is the standard of zoom lenses at this point.
And holy crap - it only cost me $850.
 
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