Extension tubes - what am I doing wrong?

[MargaretR]

Just got a set of the Kenko extension tubes (Amazon voucher prezzie!), and was making a first attempt to try them out. You wouldn't think there could be much to get wrong, but I seem to be doing it...

Have tried one and/or both on each of the 60mm macro prime (at the 'up to infinity' setting), and the 25mm prime on the EM-1. Each lens works fine in itself, but when I attach a tube, the focus won't work .... the EVF is initially blurred, and when I try to focus automatically, the focus hunts within a short range and clunks a bit, but never finds a point where anything comes into focus. On manual focus, I can turn the focus rings as much as I like, but again, nothing ever comes into focus.

There's obviously a connection through the tube, as auto-focus does hunt somewhat, so am I missing a trick somewhere? Any settings I need? How can an empty ring make life so difficult?!

[andym]

Re: Extension tubes - what am I doing wrong?

How close are you to your subject? I believe the the working focal distance gets very short with extension tubes.

Have a look at this link for working out you working distance.

http://www.cambridgeincolour.com/tutorials/macro-extension-tubes-closeup.htm

[MargaretR]

Re: Extension tubes - what am I doing wrong?

Mm, yeah ... maybe Not Close Enough, given that the focus was hunting through a very short distance, implying a narrow depth of potential focus. I had the camera on a tripod pointing at a subject on the far end of a Plamp ... probably I need to bring it a lot closer. Duh!

I'll give that go when I get a moment. Thanks Andy. I knew it must be me!

[AMc]

Re: Extension tubes - what am I doing wrong?

My guess is also you're not close enough. I recently bought a cheap set of FOTGA tubes from eBay and spent some time working out why they wouldn't focus until I realised I needed to be VERY close.


Coffee beans - FOTGA extension tube test IV
by AMcUK, on Flickr

[Graham_of_Rainham]

Re: Extension tubes - what am I doing wrong?

With the tubes on I don't use AF at all.

[peak4]

Re: Extension tubes - what am I doing wrong?

Well this may sound silly, so apologies if I'm stating the blindingly obvious.

What happens when you leave the camera just sitting there, focussed to infinity, on MF and move the subject closer to / further from the lens, and watch the screen to see when it pops into focus?

I don't have either lens, but using the 12-40mm @ 25mm , I get the following;

10mm tube set to about infinity;
focal plane to subject about 16cm
front of lens to subject about 4cm


10mm tube set to closest focus
focal plane to subject about 13.5cm
front of lens to subject about 1.5cm

16mm tube set to about infinity
focal plane to subject about 13.5cm
front of lens to subject about 1.5cm

16mm tube set to closest focus
focal plane to subject about 13cm
front of lens to subject about touching the filter housing

10mm + 16mm tube set to infinity
focal plane to subject less than 13cm
i.e. somewhere inside the lens!!

That is to use both tubes together, you need a lens of greater focal length and/or shorter physical length.
You might just manage with a 25mm prime, as it will be physically shorter than my zoom.

Where it's possible to focus, AF does work. I was using a Q code sticker so flat plane and lots of contrasty edges.

[IanB]

Re: Extension tubes - what am I doing wrong?

How close are you to your subject? I believe the the working focal distance gets very short with extension tubes.

Have a look at this link for working out you working distance.

http://www.cambridgeincolour.com/tut...es-closeup.htm

A little off topic but mentioned in the article

Close-up filters: there are two sorts of close up filters; cheap and expensive. The cheap ones; often sold in sets will give cheap results. The expensive ones (Au$100>>)are actually a proper lens in that they have two pieces of glass in each screw in filter/lens. Call an Achromatic lens they will give far better results compared to the cheap ones. I use a Canon D250 on my Lumix FZ200.

Mark makes it all look easy Just of interest; he 'recently' bought a dslr to get better pics but that dream was short lived and forgotton and the dslr sold off. Down in the article he mentions gear

Don't get caught with "macro close up filter set"; not even worth the free freight imo

Sorry Magaret; not really answering your original question

[Loup Garou]

Re: Extension tubes - what am I doing wrong?

With the tubes on I don't use AF at all.

Likewise. Apart from the Olympus 60mm f2.8 macro prime, the other lens that I use for macro is the Olympus 40-150mm f4-5.6 R. With the latter, I use both Mieke extension tubes plus the Siocore Achromatic macro converter. Even in manual focus, I seldom use the focus ring; after manoeuvring approximately close enough, it is far easier to use tiny movements of the zoom ring to fine focus. In that lens zooming is associated with extension of the lens and in a macro situation that can be actually an advantage.

[MargaretR]

Re: Extension tubes - what am I doing wrong?

Thanks all. Indeed, I needed to get a LOT closer than I first thought, but knowing that now, I can begin to get to grips with it all.

[alfbranch]

Re: Extension tubes - what am I doing wrong?

Yeah as said above the 12-40 is not suitable for use with tubes.

I suggest if you want to use AF you set back button focus and then the AF will not hunt once you have achieved focus.

With the 60mm lens and both tubes fitted and the focus set to 1:1 the subject will need to be approx 6.5 cm from the fron of the lens.

This will give you an area of approximately 10 mm across the frame.

[Guest]

Re: Extension tubes - what am I doing wrong?

I'm having similar issues with the Meike tubes. Nought wrong with the functionality of the tubes but I need to learn how to get the best out of them

[peak4]

Re: Extension tubes - what am I doing wrong?

Yeah as said above the 12-40 is not suitable for use with tubes.

Alfbranch, I wouldn't go quite as far as not suitable at all.

Certainly not suitable for true macro for sure.

As a rough guide, I've just had a quick play whilst Jane's preparing tea. Nothing of sufficiently high quality to post up, but just to give an idea.

The 12-40mm does focus quite close in its native state; I could get close enough @ 40mm FL to fill the frame with about 2 1/2 standard postage stamps.

With either, but not both tubes, again @ 40mm, I could fill the frame with a single stamp, though that is very close to the filter.

You do need to be at the long end of the lens; the stuff I posted earlier was deliberately @ 25mm, as that was the prime length i was giving the measurement estimates for.

AF worked fine, though clearly MF, a macro rail, tripod etc would give better and more repeatable results than me wobbling round in a dimly lit room.

I could imagine it might work OK for slide copying for example. I must have a go one day.

[alfbranch]

Re: Extension tubes - what am I doing wrong?

Thisis a set up I have trying out it gives up to 3X magnification about 6mm across the frame.


This is my Olympus OMD E-M5 MKII with 60mm f2.8 macro lens 3 Kooka extensions tubes 48mm in total and a Raynox DCR250 and a Nissin Di466 with homemade diffuser.


Macro rigg E M5II by Alf Branch, on Flickr


This was taken with this set up I



Orchesella cincta juvenile by Alf Branch, on Flickr

This is an uncropped shot with this set up


Dicyrtomina saundersi by Alf Branch, on Flickr

[Loup Garou]

Re: Extension tubes - what am I doing wrong?

This is my Olympus OMD E-M5 MKII with 60mm f2.8 macro lens 3 Kooka extensions tubes 48mm in total and a Raynox DCR250 and a Nissin Di466 with homemade diffuser.

With that sort of setup you'd probably spot an approaching Zika virus.