GH4 Speedbooster Sigma 17-50 or Tamron 17-50?

[trw_mavrik]

Hi Guys

Looking to buy an EF Speedbooster and was wondering which of these 2 lenses to but, either the Sigma 17-50 or the Tamron17-50? Does the Sigma vignette and would Iget IS with either?

I currently have a Mitakon lens turbo 2 and Tamron 17-50 Nikon mount. Love this lens with normal adapter but find it vignettes on my AF100 when using the lens turbo.

Regards

T

p.s anyone now how to disable the stupid autosave when making posts as I make loads of spelling mistakes and slows typing?

 

[nyvz]

Well I wouldn't expect an apsc lens to work on a 1.4x focal reducer on an af100 since the imaging area is almost 19mm wide and apsc is usually designed for about 25mm wide, so a focal reduction of more than 1.3x is likely to vignette unless you get lucky. The gh4, however uses an imaging area only about 16mm wide in video, so any apsc lens should work with focal reduction as high as 1.5x.

As for lenses I tend to prefer sigma but don't have specific experience with those lenses. I highly recommend testing them at a camera store first. One factor might be which way you prefer the focusing ring to turn. If you're used to Nikon 'backwards' focusing you might prefer Tamron.