EX-25 cannot be used in multiples

[alfbranch]

Why do companies like Olympus do strange things like preventing more than one EX-25 together.

I can use 4 cheap auto tubes plus a MMF3 and one EX-25 no problems.
I cannot use the MMF3 and two EX-25's together and the manual states this is case.

Why do this?

[alfbranch]

Also why does it need firmware and electronic circuitry.
The firmware was updated to 1.1.


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[David M]

Originally Posted by alfbranch

Also why does it need firmware and electronic circuitry.
The firmware was updated to 1.1.

The circuitry so that the lens can communicate with the body, the firmware so they can communicate better presumably.

I seem to remember someone one coming up with a workaround in the past but IIRC it involved some rewiring.

You can't stack the EC tele-converters or even the EX-25 with one of the TCs if you want AF. I'm not sure if you can use the focus by wire when any of them are stacked.

[alfbranch]

AF I can manage without but aperture control I want.

Rewiring is an option I was considering.


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[peak4]

I can remember Jens Birch doing a job on one several years ago, where he halved one and joined the bits together with OM mounts. I got as far as buying a spare EX-25, but never got round to starting the project.
Go to his web site then Browse-Technical Stuff-Gear-Page 2/3 for a few photos of it.
Do explore the rest of his site while you're there.

It also opens the possibility of using the Olympus OM 65-116 variable extension tube if you have one from film days.

[alfbranch]

Originally Posted by peak4

I can remember Jens Birch doing a job on one several years ago, where he halved one and joined the bits together with OM mounts. I got as far as buying a spare EX-25, but never got round to starting the project.
Go to his web site then Browse-Technical Stuff-Gear-Page 2/3 for a few photos of it.
Do explore the rest of his site while you're there.

It also opens the possibility of using the Olympus OM 65-116 variable extension tube if you have one from film days.

I do not want to use OM kit as such if I did I would get a MF2-OM and 65-116 and OM 80mm

Here is the EX-25 modified

https://jensbirch.smugmug.com/Photog...ar/i-jG3cRHr/A

https://jensbirch.smugmug.com/Photog...ar/i-v5H3wbw/A

[Phill D]

Alf what are you trying to achieve by doing this?

[David M]

Originally Posted by peak4

I can remember Jens Birch doing a job on one several years ago, where he halved one and joined the bits together with OM mounts. I got as far as buying a spare EX-25, but never got round to starting the project.
Go to his web site then Browse-Technical Stuff-Gear-Page 2/3 for a few photos of it.
Do explore the rest of his site while you're there.

It also opens the possibility of using the Olympus OM 65-116 variable extension tube if you have one from film days.

Thanks Bill, I think that's what I remember.

Alf, I think the OM mounts.are a way to connect the extension tubes together. There's plenty out there with the OM system being so popular for macro work.

[peak4]

Originally Posted by David M

Thanks Bill, I think that's what I remember.

Alf, I think the OM mounts.are a way to connect the extension tubes together. There's plenty out there with the OM system being so popular for macro work.

I remember there was someone else on, what was before admin moved to Australia, the US 4/3s forum who made what he called an EX-40, which also bypassed the contacts, but I don't recall the details.

It's not just about extension tubes of course, telescopic or otherwise, it also enables bellows with a 4/3s lens.
The other thing I'd thought of at the time, was to add a shorting switch to the EX25's ribbon cable, to bypass the electronics completely so it could be used at the same time as a teleconverter.

This was one of Jens' original posts; http://forum.fourthirdsphoto.com/thr...ight=extension

[David M]

It's an interesting exercise but with a case full of OM macro equipment not something I would spend time on. IIRC it was Jens who made a shift adapter to use the Tamron 17mm on 4/3.

I was surprised how well the Tamron 17mm works on 4/3 considering I didn't do my usual trick of fitting an appropriate hood. Mainly because coming up with a 35mm hood to fit the front of the 17mm was to much effort.

[peak4]

Originally Posted by David M

It's an interesting exercise but with a case full of OM macro equipment not something I would spend time on. IIRC it was Jens who made a shift adapter to use the Tamron 17mm on 4/3.

I was surprised how well the Tamron 17mm works on 4/3 considering I didn't do my usual trick of fitting an appropriate hood. Mainly because coming up with a 35mm hood to fit the front of the 17mm was to much effort.

It was yes, using microscope slides, as I recall.
I did look into it at the time, but never did find a 17mm at an acceptable price.

[David M]

Originally Posted by peak4

It was yes, using microscope slides, as I recall.
I did look into it at the time, but never did find a 17mm at an acceptable price.

I had one from my film era but a different version than the one Jens used. Having tried and found the 17mm quite nice I found the Samyang 14mm on Amazon Canada at such a good price I couldn't resist so the Tamron went back into the backup equipment cases.

[gazza95]

I seem to remember someone simple removing the electronics and direct wiring the pins. That way you maintain the electrical functions but camera does not realise that extra extension tube was there.

This also involved adding EX25 to an EC14 converter.

Gary

[alfbranch]

Originally Posted by Phill D

Alf what are you trying to achieve by doing this?

50mm of sturdy extension to my Sigma 105 f2.8 None of the m4/3 tubes are anywhere near as well constructed.

It is surprising that Olympus limits thnings in this way considering things from the past that they made for the OM system. Modern equivelants of the 20, 38 and 80 macro lenses and auto 65-116 tubes with the flash system could offer amazing possibilities.

I understand this was made to be optimised for the 50mm f2 which IMO fell short at 1:2 as standard.

[alfbranch]

Originally Posted by gazza95

I seem to remember someone simple removing the electronics and direct wiring the pins. That way you maintain the electrical functions but camera does not realise that extra extension tube was there.

This also involved adding EX25 to an EC14 converter.

Gary

Gary that would be an idea too