Drawbacks of a 2x Range Extender

[Adam Etherington]

Hi All,

 

Bit of a tech question here.

 

Does anybody know the quantifiable drawbacks of a 2x range extender on the 35mm format? I was on a 35mm job last month and needed an extreme long telephoto POV. Our longest lens was a 135mm so we employed that with a doubler. Compensated for exposure etc and the footage came back looking lovely.

 

However during the process I was chatting with my 1st AC and we were trying to work out what, other than the obvious loss in stop, is degraded by the use of a doubler. Obviously you are introducing 3rd party glass into the equation. I was wondering if any of the experienced heads on here could enlighten as to any written quantifiable loss in quality or any specific effect brought about by using one. (I'm thinking loss of resolution? Sharpness? Any shift in the area of coverage etc?)

 

Many thanks!

 

Adam

[John Sprung]

There's a little loss in resolution, usually well worth it to get the composition you want. And the exposure you already know about. You can shoot a chart if you're worried about the resolution.

 

 

 

 

-- J.S.