topic Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube in EF & RF Lenses

Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

LarryS1 — Sun, 05 Apr 2020 23:14:17 GMT

I have an EOS7dii, with my 100-400mm canon lens I attached a 2.0 tc with a 12mm lens tube to a 1.4 tc. The first time, no problem, second time lens doesn't seem to focus at in manual focus. The lens & teleconvertors are all Canon gear.

Any suggestions?

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

Waddizzle — Sun, 05 Apr 2020 23:22:26 GMT

I suggest that you forget the idea of using the 2x teleconverter and the macro tube together. In fact, I suggest that you forget the idea of using either one of them with that lens. Buy a real macro lens, instead.

Why is it that you cannot focus on anything? Physics. A macro tube reduces the MFD, minimum focusing distance, by sacrificing your ability to focus the lens at infinity. But, if all you are trying to do is focus on something very small and close to the camera, what difference does it make if you cannot focus out to infinity? None, it does not make any difference.

Except, if a little is good, then more is not always better. By adding the 2x TC, you have probably magnified the 2x teleconverter's effect to the point where the MFD is probably INSIDE of the lens barrel. Remember, MFD is measured from the image sensor, not the end of the lens.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

LarryS1 — Sun, 05 Apr 2020 23:29:27 GMT

I was trying to extend my zoom lens, by adding the 2.0 & 1.4 tc, in a series to my lens. I was told that could be done by attaching the ext tube to allow both teleconvertors to connect to each other. What's strange is it worked the first time I tried it, when I went in the field to try it, the lens wouldn't focus.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

wq9nsc — Mon, 06 Apr 2020 00:14:25 GMT

The 100-400 is a slow lens with variable aperture from 4.5-5.6 and even the 1 series cannot use AF with the very high minimum aperture created by this lens with stacked converters.

Using two in combination EVEN with a very good sharp prime will result in a tremendous loss of IQ and to AF with two converters on a lens you would need a fairly fast lens on a 1 series body.

Rodger

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

kvbarkley — Mon, 06 Apr 2020 02:17:32 GMT

Doing things like this quickly leads to diminishing returns, if not negative returns. While one Canon TC is probably effective, adding anything else is probably no better than cropping.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

Peter — Mon, 06 Apr 2020 05:23:05 GMT

I tried 2xIII+12mm macro tube+1.4II+300/2.8L IS+M5. It works, even when focusing to infinity or the moon. The image quality is "OK" at short distance like 20 meters.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

LarryS1 — Mon, 06 Apr 2020 12:00:05 GMT

Peter, thanks for trying and letting me know it worked for you. I had tried it a week ago, and I was able to focus on distant objects. Then went out this last weekend for the purpose I intended on, I couldn't get any of the lenses I tried (24-70, 70-200 or my 100-400). I wish I could figure out what went wrong with the camera.

i really appreciate your efforts and response,

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

Peter — Mon, 06 Apr 2020 12:48:54 GMT

Perhaps lack of light.
Have you tried Live view?

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

ebiggs1 — Mon, 06 Apr 2020 14:25:09 GMT

Years, and years ago I tried to use a 1.4x, a 2x and a 3x tel con stacked together on a FD 300mm f4 lens. I found out quickly it was a horrible idea. I suspect you will come to the same conclusion..................soon, I hope.

IMHO, the use of any tel-con or x-tube is a bandaide fix for a problem that requires the proper lens alone.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

Peter — Mon, 06 Apr 2020 19:42:55 GMT

Some raw files to play around with. x1.4II+x2III vs x2III.
https://drive.google.com/file/d/1SwItmSZG9Wu4J1a1EYQ8_rA5SsGrGh7W/view?usp=sharing

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

RobertTheFat — Mon, 06 Apr 2020 23:35:07 GMT

@ebiggs1 wrote:
Years, and years ago I tried to use a 1.4x, a 2x and a 3x tel con stacked together on a FD 300mm f4 lens. I found out quickly it was a horrible idea. I suspect you will come to the same conclusion..................soon, I hope.

Quite so.

IMHO, the use of any tel-con or x-tube is a bandaide fix for a problem that requires the proper lens alone.

I don't althgether afree. My 70-200mm f/2.8 tolerates the 1.4x III quite well, I think.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

LarryS1 — Tue, 07 Apr 2020 03:31:19 GMT

I tried it again, it worked. I believe your comment about light had something to do with it.

Quality wasn't as good as I'm sure a 500mm or 600 mm with a 2x tc, but detail wasn't as bad as I expected.

Thanks again Peter, I appreciate your input.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

ebiggs1 — Tue, 07 Apr 2020 12:08:15 GMT

"Quality wasn't as good ..."

It all has to do with what you call "quality". That elusive word has different meanings to everybody.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

ebiggs1 — Tue, 07 Apr 2020 12:14:26 GMT

"Quite so.

IMHO, the use of any tel-con or x-tube is a bandaide fix for a problem that requires the proper lens alone.

I don't althgether afree. My 70-200mm f/2.8 tolerates the 1.4x III quite well, I think."

Perhaps acceptable, I freely admit. One of the very few lens combos I agree do work well with the 1.4x tel-con is the ef 70-200mm f2.8L.

Two things, though, the ef 70-200mm f2.8L has a lot of IQ it can afford to loose. Second did you take the same shot with, say, the ef 300mm f4L prime lens to compare? No, I didn't think so!

A tel-con may be the answer but it is never the best answer, IMHO, of course, as always.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

RobertTheFat — Tue, 07 Apr 2020 12:34:44 GMT

@ebiggs1 wrote:
"Quite so.
IMHO, the use of any tel-con or x-tube is a bandaide fix for a problem that requires the proper lens alone.
I don't althgether afree. My 70-200mm f/2.8 tolerates the 1.4x III quite well, I think."

Perhaps acceptable, I freely admit. One of the very few lens combos I agree do work well with the 1.4x tel-con is the ef 70-200mm f2.8L.
Two things, though, the ef 70-200mm f2.8L has a lot of IQ it can afford to loose. Second did you take the same shot with, say, the ef 300mm f4L prime lens to compare? No, I didn't think so!

A tel-con may be the answer but it is never the best answer, IMHO, of course, as always.

Well, you knew the answer to that question, Ernie, because you know that I agree with your oft-stated opinion that modern zooms have relegated the prime lens to niche product status.

Our household contains, IIRC, two prime lenses: my wife's EF-S 60mm macro (which she likes a lot) and a Sigma 30mm f/1.4 that I bought as a low-light lens for my XTi thirteen years ago and have almost never used.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

ebiggs1 — Tue, 07 Apr 2020 12:46:11 GMT

"... modern zooms have relegated the prime lens to niche product status."

Absolutely! There are very good zooms out there now. However, there are great zooms out there, too. Canon's 70-200mm f2.8L series has proven that over and over.

I have the 1.4x tel-con. I have used it perhaps a dozen times. Maybe because I have two wonderful alternatives. One being the excellent, in its own right, ef 300mm f4L IS.

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

ebiggs1 — Tue, 07 Apr 2020 12:53:57 GMT

"Some raw files to play around with. x1.4II+x2III vs x2III."

Your files are too large. Nobody is going to d/l such large files. Not me anyway!

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

Peter — Tue, 07 Apr 2020 13:45:15 GMT

@ebiggs1 wrote:
"Some raw files to play around with. x1.4II+x2III vs x2III."

Your files are too large. Nobody is going to d/l such large files. Not me anyway!

You still pay for each MB you use or don't have 406 MB of free space?

Re: Stacking 2.0 & 1.4 Teleconvertor with 12mm ext tube

ebiggs1 — Tue, 07 Apr 2020 14:30:01 GMT

Yeah they are too big to glance at. A simple jpg would suffice for your claims.