can one use extenders together

Choderboy wrote in post #17648404
Absolutely, beyond doubt, no question, 100%.

So extension is not extension is not extension in this case.

Google Romy Ocon or Liquidstone (same person). See his results shooting the moon, among other things, with up to 3 Canon TCs, or search POTN for x_tan who has posted examples. etc etc etc

Well... I'm scratching my head how then.

5D3 + 1.4x III + 12mm extension tube + 2x III + 70-200 IS II will focus to maybe ~25-30m out (as a rough guess). Something around 40m is a no go - you "run out" of focus range.

Flipping the TCs over, so 5D3 + 2x III + 12mm extension tube + 1.4x III + 70-200 IS II gives worse results (maybe only ~10m max).

I'm struggling to see how a different lens wouldn't be affected by the tube (it's just the physics of lenses). A longer lens should I believe be affected less, but for a moon shot? It might work but it doesn't make sense to me.

EDIT: Ah. Got it (http://www.dpreview.co​m/forums/post/25302892). Some lenses can of course focus past infinity, I believe to stop them bumping up against infinity with the AF motor, and also to allow for the infinity point to change as the lens expands and shrinks with temperature varations. With a long enough lens (affected less by a short tube) and a large enough margin "past" infinity (I guess more likely on a large telephoto lens) it appears it's just possible to retain infinity focus with a 12mm tube. I.e. infinity focus is affected by the tube (so I'm right ) but as the lens can usually focus past infinity I'm wrong .

As a surf photographer I tried out of curiousity and it's a hit and miss due to manual focus. IQ really takes a hit.

patrickf117 wrote in post #17649358
As a surf photographer I tried out of curiousity and it's a hit and miss due to manual focus. IQ really takes a hit.

Hosted photo: posted by shutterpat in
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forum: Canon Lenses

Hosted photo: posted by shutterpat in
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forum: Canon Lenses

I believe the version III TCs are a bit better for AF, but you can't stack them directly unfortunately.

thanks all.

patrickf117 - that is a helluva unwiedly lens!!
But i got my answer and for that I thank all of you for participating!

JWdlft wrote in post #17648406
My answer was correct, as in it answered the question:

Apologies, agree, as an answer to the question you are correct.

DoughnutPhoto wrote in post #17648612
That looks really interesting!

Can you tell us a bit more? What lens did you use?
And, what was the rest of your setup? How did you steady the lens?

Owl shot:
Lens was 100-400 II. Lens was not really steadied. I have an Arca Swiss Z1 Monoball head and Manfrotto 055 tripod.
The 055 is reasonable, the Z1 is usually solid. With that load, shooting at around 45 degree angle, I tightened the Z1 with the lens aimed below the owl's head and it sagged to where the owl's head was centred in the frame. Then there was the freeplay of 3 extra connections, ie 2 converters and 1 extension tube. Even with a lens with IS recommended to be off when on a tripod, leaving IS on would be the sensible choice.

The butcher bird was much simpler. Same lens but a concrete table in a park and several beanbags provided some actual steadiness.

sploo wrote in post #17648707
Well... I'm scratching my head how then.

5D3 + 1.4x III + 12mm extension tube + 2x III + 70-200 IS II will focus to maybe ~25-30m out (as a rough guess). Something around 40m is a no go - you "run out" of focus range.

Flipping the TCs over, so 5D3 + 2x III + 12mm extension tube + 1.4x III + 70-200 IS II gives worse results (maybe only ~10m max).

I'm struggling to see how a different lens wouldn't be affected by the tube (it's just the physics of lenses). A longer lens should I believe be affected less, but for a moon shot? It might work but it doesn't make sense to me.

EDIT: Ah. Got it (http://www.dpreview.co​m/forums/post/25302892). Some lenses can of course focus past infinity, I believe to stop them bumping up against infinity with the AF motor, and also to allow for the infinity point to change as the lens expands and shrinks with temperature varations. With a long enough lens (affected less by a short tube) and a large enough margin "past" infinity (I guess more likely on a large telephoto lens) it appears it's just possible to retain infinity focus with a 12mm tube. I.e. infinity focus is affected by the tube (so I'm right ) but as the lens can usually focus past infinity I'm wrong .

I think the moon can be considered infinity for photography and the 12mm tube allows focusing on the moon. I have not attempted planets further away than the moon so can't say if I would be able to determine where the limit is, but that's probably true for the bare lens.

Choderboy wrote in post #17651159
Owl shot:
Lens was 100-400 II. Lens was not really steadied. I have an Arca Swiss Z1 Monoball head and Manfrotto 055 tripod.
The 055 is reasonable, the Z1 is usually solid. With that load, shooting at around 45 degree angle, I tightened the Z1 with the lens aimed below the owl's head and it sagged to where the owl's head was centred in the frame.

I'm glad I'm not the only one that suffers that problem (tripod head sagging). I did experiment with a few good heads (including the Z1) but find there's always something that moves a bit - even just a bit of flex of a Wimberely plate on the body. Using a tripod ring on a lens with a long Wimberley plate (so the camera + lens is fairly balanced on the head) seems to help a bit.

Choderboy wrote in post #17651163
I think the moon can be considered infinity for photography and the 12mm tube allows focusing on the moon. I have not attempted planets further away than the moon so can't say if I would be able to determine where the limit is, but that's probably true for the bare lens.

Absolutely: moon == infinity from my point of view. As DOF increases with distance I suspect that at some focus distance (e.g. hyperfocal) you'll get everything including infinity, so the lens and extender combination probably doesn't technically even need to hit infinity.

It did get me wondering if a 6mm tube would be short enough for the two version III TCs (and long enough so they would mate) with the 70-200. I'd like one for some experimental stuff for a 14mm prime too, but I don't think they're commercially available.

sploo wrote in post #17651170
I'm glad I'm not the only one that suffers that problem (tripod head sagging). I did experiment with a few good heads (including the Z1) but find there's always something that moves a bit - even just a bit of flex of a Wimberely plate on the body. Using a tripod ring on a lens with a long Wimberley plate (so the camera + lens is fairly balanced on the head) seems to help a bit.

Absolutely: moon == infinity from my point of view. As DOF increases with distance I suspect that at some focus distance (e.g. hyperfocal) you'll get everything including infinity, so the lens and extender combination probably doesn't technically even need to hit infinity.

It did get me wondering if a 6mm tube would be short enough for the two version III TCs (and long enough so they would mate) with the 70-200. I'd like one for some experimental stuff for a 14mm prime too, but I don't think they're commercially available.

I could be wrong, but maybe it was ZoneV (POTN member) who made a 6mm tube.

Choderboy wrote in post #17652185
I could be wrong, but maybe it was ZoneV (POTN member) who made a 6mm tube.

Yea, that rings a bell. Never got round to trying it myself.