500mm vs 600mm?

WilbaW wrote:

1Dx4me wrote:

WilbaW wrote:

BirdShooter7 wrote:

If you are suggesting that there is no advantage of having an f/2.8 lens vs f/4 lens vs f/5.6 lens... when it comes to AF in a given lighting condition (particularly low light) then you don't have a clue what you are talking about. That seemed to be what you were suggesting in your original post.

If we are talking about a camera with only f/5.6 AF sensors, then yes, I'm stating there is no advantage to a lens with a maximum aperture wider than that (all other things being equal).

complete asinine!!!!!! it has nothing to do with the camera but rather the lens' aperture (how much light will the lens admit to pass through to the camera sensor)! if you hold a dark filter in front of a f2.8 lens, it'll still be a f2.8 lens and the camera will select the focusing spots designed for a f2.8 lens (unless you use a TC)!

How can it have nothing to do with the camera if "the camera will select the focusing spots"?

The original discussion is about f/5.6 vs f/4, so F/2.8 points are not relevant and I ruled them out explicitly to avoid the hole you're in.

that was just an example, who carers? f5.6....f4.0...now are you happy?

you are ignoring the size of aperture in your flawed argument, instead, you are emphasizing the amount of light and AF sensors.

My argument is entirely about the size of the aperture, but the "amount of light" "the lens admit to pass through to the camera sensor" is irrelevant, as BirdShooter7 agrees below.

Yes giving more light to a lens with a max aperture of f/8 will not help if AF when the sensors are only good to f/5.6.

So you agree - the f/5.6 limit is not about the level of illumination provided to the image sensor through the lens. Therefore it must be about something else about the aperture... right? I've already told you what that is but I'm happy to provide a much more explicit explanation if you're interested.

well, if your "much explicit" explanation is going to be like your argument, no thank you, save your breath!

It's "much moreexplicit". Might even include a diagram for those with challenges with imagination. But no amount of explanation will crack open a closed mind.

there is no use arguing with you, so you think what you want, buddy!!!! click!