Question about Teleconverters

[ElCapitan]

I am renting a few lenses and a teleconverter. They are the Canon 70-200 f/2.8L USM II, Canon 100-400 f/4.5-5.6L, and the Canon 2x II.

I am trying to figure out which lens I want to get, and if the 2x II would be worth getting with the 70-200 f/2.8L USM II.

My question is that when testing out the 100-400 at 400, and then putting the 70-200 with the 2x (at 400) on the tripod on the exact same spot on the exact same tripod, the 70-200 with 2x at 400 is even more zoomed in than the 100-400 at 400.

I am trying to figure this out and just want to know why it does this. Is the 2x making it approximately 400? Is it that the lens is technically closer? Or is it a flaw with the teleconverter itself?

Thanks for any help.

[inkista]

Lenses aren't always exactly the focal lengths they're speced as. Either the 70-200's longer, the 100-400's shorter, the tc isn't exactly 2x, or you're not focused at infinity.

BTW, you do know there are newer Mark III tcs from Canon, right? They're about $500 apiece.

[ElCapitan]

Originally Posted by inkista

Lenses aren't always exactly the focal lengths they're speced as. Either the 70-200's longer, the 100-400's shorter, the tc isn't exactly 2x, or you're not focused at infinity.

BTW, you do know there are newer Mark III tcs from Canon, right? They're about $500 apiece.

Good to know. that was one of my thoughts. Also good to know about the 2x III. I have to say, It is really hard to tell which one is better at 400. They are extremely close, and have different areas that are sharper than others. I am very surprised with how well the 2x is with the 70-200.

I can't imagine how much the 2x III will improve upon this. Are the 2x III from Canon out now? Cause I cannot find anything on them from the usual sites I check.

[inkista]

Nope, I don't think they're out yet. They were just announced at Photokina, and a lot of times with lenses, it can be quite a while before announced lenses actually arrive.

[ElCapitan]

Originally Posted by inkista

Nope, I don't think they're out yet. They were just announced at Photokina, and a lot of times with lenses, it can be quite a while before announced lenses actually arrive.

Well thanks for the info. I had tried to read as many reviews on using the 70-200 f/2.8 with a 2x, but much of what I found was dealing with older versions of the 70-200 and the original 2x. These reviews made it seem like there was absolutely no reason to use the 2x with the 70-200 f/2.8, and perhaps with the older models they were right.

I still have all week to test more, but I can say so far that the Canon 70-200 f/2.8L USM II combined with the Canon 2x II is amazing. So much so, that I have an extreme difficulty telling which is better between the 100-400 at 400 and the 70-200 at 400.

I think what I am going to do is get the 70-200 f/2.8L USM II for now, and then perhaps wait for the 2x III. It will cost more than the 100-400 that is for sure, but will offer a much wider variety of options for what I can see as little to no loss of quality.

[inkista]

Sounds like a wise move. From what I've been reading the 70-200 f/2.8L IS USM II is sharper than the 100-400L.

I think I read somewhere that the Mark III tcs are a new optical design, so just as well to wait and see what folks say about 'em.

[ElCapitan]

Originally Posted by inkista

Sounds like a wise move. From what I've been reading the 70-200 f/2.8L IS USM II is sharper than the 100-400L.

I think I read somewhere that the Mark III tcs are a new optical design, so just as well to wait and see what folks say about 'em.

From what I can find online, it seems the new lenses announced at Photokina were delayed till March at the earliest, but possibly summer or next fall. An update says the new teleconverters are among them. I can wait for the teleconverters. With the instant rebate and free shipping at B&H, I think I am going to go ahead and pick up the 70-200 f/2.8L USM II.