Anyone tried the Tokina 12-24mm with extension rings?

I'm going to show my lack of understanding of lenses here I suspect, but I'm thinking of getting a Tokina 12-24mm wide angle lens primarily but not solely for trying out wide angle macro shots using extension rings. I normally shoot between F8-F16 and wonder a) whether it is possible to get close to 1:1 with extension rings - ie is it usable and b) whether I would get significant vignetting trying it at the apertures I normally use.
The prime reason for trying this is on the assumption I will potentially get much greater DOF than my standard 105mm EX lens- true or not?
I should add- I use the Jessops extension rings which do seem to work with EF-S type lenses
Brian V.

I think the 12-24 is somewhat short for the use of extention rings. You'ld need a very short one.
The effect of an extention ring is dependent on the Focal Length of the lens used.
When a friend of mine was visiting, we tried once to mount a 10-22 EFs lens to my 1D2 via a 21mm extention tube. An object (small chain here) would be in focus at a FL of 22mm, focussed to infinity on the lens, like this:

René Damkot wrote:
I think the 12-24 is somewhat short for the use of extention rings. You'ld need a very short one.
The effect of an extention ring is dependent on the Focal Length of the lens used.
When a friend of mine was visiting, we tried once to mount a 10-22 EFs lens to my 1D2 via a 21mm extention tube. An object (small chain here) would be in focus at a FL of 22mm, focussed to infinity on the lens, like this:

At any shorter FL the object needed to be *inside the lens*. A bit impractical

Thanks for the quick reply- think you have saved me some money .
Just did some tests with the kit lens, lowest zoom I could sensibly use was 22mm with a 13mm ring so I think the 12-24 would be a bit of a waste.
see https://photography-on-the.net/forum/showthre​ad.php?t=118971

Thanks again
Brian V.

Not. The DoF you get depends on magnification and nothing else. Shooting 1:1 with a wide angle + tubes or your 105mm and the results would be the same (apart from the different field of view). The only way to get more DoF is something you're already doing - focus stacking.

Thanks pxl8
One question about this though- it seems to me that with a wide angle lens at close focus the magnification drops off faster with distance than a normal macro lens, so could this mean that the background whilst not in focus would be less OOF than it would be with the corresponding macro lens if that makes sense.
To illustrate what I mean these two pics are at approx the same magnification at the near focus point (about .7:1) and both taken at F22
the wide angle one seems to have much more detail that is only just OOF. There is of course a difference in the angle of the shot in an attempt to get approx the same amount of ruler in.

Buy it anyway - no bugs around now so you can try your hand at landscapes and interiors. I've just bough the 400f5.6L for sport/wildlife to keep me amused until the bugs hatch in April. Sold a Concept 2 rowing machine on e bay to pay for it - good trade as I was too lazy to use it away from a gym and will get more excercise tracking Parakeets. Last lens I 'need' would be a WA and Tokina seems the way to go unless the Canon 10-20's EFS mounting doesn't put you off. Now what else can I flog on e bay?