f stop loss with a 1.7 teleconverter?

[OregonT3i]

Hi all. Just a quick question regarding a 1.7x teleconverter. If I were to buy a Nikon 1.7x teleconverter and use it in conjunction with a 70-200 2.8 vrII, what would the maximum aperture become?

 

[TheLost]

The f/2.8 becomes a f/4.8 with the 1.7... (you lose 1 1/2 stop).

 

[2WheelPhoto]

loss is "too much"!

 

[OregonT3i]

Great. Thanks for the replies. That's what I was looking for.

 

[Helen B]

You simply multiply the f-number by the teleconverter's multiplication factor.

The f-number is the focal length divided by the diameter of the entrance pupil (the 'aperture'). If you add a teleconverter behind the lens you change the focal length, but not the diameter of the entrance pupil, therefore the f-number changes in the same proportion as the focal length. If you use a teleconverter in front of the lens you can increase both the focal length and the entrance pupil diameter, but those TCs are usually optically inferior to the ones that go behind the lens.

 

[Mike_E]

loss is "too much"!

Not for everyone.

510mm @ f4.8 cropped is absolutely worth it to me. (200*1.5*1.7= 510)

 

[EIngerson]

loss is "too much"!

Not for everyone.

510mm @ f4.8 cropped is absolutely worth it to me. (200*1.5*1.7= 510)

Absolutely.

 

[leeroix]

ive used this setup before and wasn't happy with the results. i would have preferred to rent a lens with more firepower...

 

[2WheelPhoto]

loss is "too much"!

loss is "too much"!

Not for everyone.

510mm @ f4.8 cropped is absolutely worth it to me. (200*1.5*1.7= 510)

You're right, I shouldn't have thrown a blanket statement out there like that and apologize. Its "too much for me" is more accurate. I shoot a lot of dark venues at distance where its available light only and it wouldn't work for me.