Tele converter question

[LightBright]

I know a 2 x teleconverter reduces maximum aperture by two stops. But how about if I couple two 1.4x teleconverters will they reduce the same amount of light as a 2x?

Thank you

[DonSchap]

Yeah, pretty much, with some serious image quality distortion. I'd rethink that idea real quick, LOL. :mad2: :idea:

[LightBright]

Ha it seemed like a good idea at first, had no idea it would cause image distortion! Ill go with the 2x tele instead. Thanks Don

[DonSchap]

Stacking glass normally creates a defective image with each layer. The ideal is to have the pure lens at the length desired. Adding a T/C normally is just an emergency choice, because it darkens the lens, interferes with autofocus and reduces the IQ.

1.4x will cost you 1 f/stop of light
2x will cost you 2 f/stops
3x will cost you 3 f/stops

I recommend avoiding having to use these. It may be a cheap fix, but it cheapens your photography, too. Now, there are some really good T/Cs out there ... and they are usually used in conjunction with high-end prime (fixed focal length) and zoom lenses. They often will not work on other lenses, due to the way they are constructed (see compatibility list -> e.g., the SAL20TC is compatible with SAL135F28 and G Series SAL70200G, SAL70400G, SAL300F28G only) and cost in excess of $400.

Anyway, enjoy!

[DennisT]

Everything Don says is true - too true - BUT I nevertheless use the Sigma 2x EX DG coupled to Sigma 50-500 f4-6.3 on my A900 on occassions when the subject is just so far that the only other option is to forgo the shot. You need a solid tripod and plenty of light - so is it worth it?? DEFINITELY.