Using a 2x converter

[MrB]

This might have been asked before but, if so, I can't find it. I'll pose the question as an example, and I would be grateful for a knowledgeable photographer's reply, not just guesses!

A depth of field calculator (like the one in the CiC tutorials) can be used to work out the DoF of a lens. I think I have read that a 2x converter not only doubles the focal length but also loses 2 stops of light. So, when using a 50mm lens set at f/2 with a 2x converter, do I input 100mm and f/4 into the DoF calculator?

Thank you in advance for your helpful replies.

Philip

[Shadowman]

This might have been asked before but, if so, I can't find it. I'll pose the question as an example, and I would be grateful for a knowledgeable photographer's reply, not just guesses!

A depth of field calculator (like the one in the CiC tutorials) can be used to work out the DoF of a lens. I think I have read that a 2x converter not only doubles the focal length but also loses 2 stops of light. So, when using a 50mm lens set at f/2 with a 2x converter, do I input 100mm and f/4 into the DoF calculator?

Thank you in advance for your helpful replies.

Philip

Yes.

[chauncey]

Assuming that you're referring to a FF sensor.

[Manfred M]

Assuming that you're referring to a FF sensor.

Sensor size makes no difference to a teleconverter; 2x is 2x on full-frame or crop. The effective focal length will be different on a crop, so in Philip's example; a 2x on a 50mm lens will yield 100mm. The fact that a 100mm lens has a different FoV on the two different sensor sizes remains a fact.