Teleconverter

[mb66energy]

every extra bit of glass will reduce iq

O.k. so I will put my eye glasses down ... asüdü aüfbis fiasbfsl lxc ... no, with eye glasses IQ is better and I see what I am typing!

LOL. Ok, now put on two pair of glasses. Is that better than one?

I always dreamed to get rid of the CAs by an achromatic correction - post processing doesn't remove them completely despite of a massive parallel processing system

 

[LetTheRightLensIn]

I'm considering getting a 2.0 teleconverter for my 70-200 2.8. Other than going to 5.6 does it also reduce the iq? Thanks I'm still learning here.

Yes, but it is usually worth it all the same if you need more reach. The 2x can get a bit dicey on some lenses where even if you do grab a trace more detail the other downsides might not be worth it.

2x on a 70-200 is pushing it past where I'd want to unless you are talking the 2.8 IS II. If you are not talking that version then I'd stick to the 1.4x TC. The 2x TC works better on the big white primes.

They do slow AF and make it a bit less precise.

 

[Mt Spokane Photography]

I was out this afternoon playing with my new 70-200 f/2.8 MK II to see how well it worked with TC's for hand held photos in low light. Its a very dark day, so the ISO on the images is high. Before I started using the 2X TC, a thunder storm hit and ISO's went up to 10,000 so I'll try again tomorrow. Each TC I add reduces the IQ, but the new 70-200 takes TC's very well, so it is quite usable with a 2X TC, but far from pixel sharp.

The first is at 200mm + 1.4X

This one has the 2X + 1.4X. AF is slow, but works.