Help using a reversing ring

[HDPete]

Hi guys,

I've acquired a reversing ring for my 5D MkII and my Sigma 150mm macro ring but I'm having a heck of a job getting anything to work.

I can't seem to adjust focus and don't really understand how to set the aperture or how to go about getting super extreme macro with this combination.

Should it work, or am I expecting too much with this combination?

Any pointers gratefully received.
Pete

[silversnapper1]

If your Sigma 150mm is a macro lens, I cannot see why you would want a reversing ring as you would not gain anything and would lose all of the auto functions of the lens communicating with the camera.

[HDPete]

It is the macro 150mm. It's superb.

I had seen these close up images of a fly's eyes and thought that I'd pick up an extension ring to see if I could replicate it.

I guess I got it wrong.

[silversnapper1]

Hi Pete,

Ah, an extension tube. That will give you extra reach but again, you may lose all of your auto functions dependent on which one you have bought.

The main problem with extension tubes is that you will also require extra light as they will take away a couple of stops of light. You will also have to manual focus.

[jinky]

Yes an extension tube is the way to go or if you have a 50mm lens you could get a ring with the filter size on the end for your 150macro and the other end to match your 50mm filter size. reverse mount the 50mm on the end of the 150, set the 50mm to infinity and wide open and then manual focus with the 150 and you will get some real close up shots. I have done it with my 105 macro and 5omm with some good results for the sake of a £3 ring off ebay

[Cathus]

you shouldn't lose any f-stops with extension rings as they don't contain any glass, they are completely hollow & just move the lens further from the camera allowing it focus closer to give the effect of getting a bigger image.

they can be used very successfully on macro lenses. I also use them on my 600mm sometimes in the garden when I want to focus on birds closer than 5m

Depending on the type you have you may lose autofocus & the electrical connections between the camera & lens meaning you'll need to use manual settings. However, more expensive extension tubes have the electrical connections so you don't lose any functions.

A reversing ring is an adapter which allows you to turn your lens back to front & connect it to the camera which turns it into a type of macro lens, but you would lose all your functions. I understand that in order to change the aperture you need to do some trickery involving putting the lens on normally, selecting your aperture, holding the depth of field preview button in & removing the lens which keeps it stuck on that aperture, then fitting the lens back to front.
Otherwise after you've set the aperture the lens just opens up & will be stuck on your widest aperture when you refit it back to front.

[hssutton]

Originally Posted by Cathus

you shouldn't lose any f-stops with extension rings as they don't contain any glass, they are completely hollow & just move the lens further from the camera allowing it focus closer to give the effect of getting a bigger image.

I think you got that a little wrong Cathus, you can lose up to 2-3 stops if you use a full set of three tubes.

I'm guessing the the OP has ex-tubes without the electrical connections, not a reversing ring hence the difficulty. However focus should not be a problem.

A couple of samples using the Canon 100mm macro + full set of tubes.

[Cathus]

sorry, I put that rather clumsily, what I meant was that you don't lose any f-stops in the same way you do when you fit a converter, i.e when you put a 1.4 converter on an f2.8 lens becomes an f4 & with a 2x converter it will become a f5.6

With extension tubes your f2.8 lens remains an f2.8 lens. There is a drop in light though as the light has further to travel. (so you don't lose f-stops, but you do lose light) sorry for the confusion.