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Thread: Before I de-solder...

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    Question Before I de-solder...

    ...I just wonder what are the drawbacks of bypassing the electronics in the EX-25 extension tube?

    It is lyinging right here in front of me in pieces; 14 tiny screws, 3 O-rings, some concentric fittings and bayonet flanges plus a plastic core holding the printed circuit board with the two connectors soldered to it; and I am hesitating one last moment before doing it...

    I am most worried about if the exposure will come out incorrectly when the camera doesn't know that it is shooting with an extension tube.
    (The fact that it won't be registered in the EXIF data is not a problem for me.)

    Anyone here with any experience of an EX-25 that has gotten lobotomy?

    Cheers, Jens

    PS.
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

  2. #2
    Doug Palmer Guest

    Default Re: Before I de-solder...

    I seem to remember someone doing this and reporting the process on DPReview. I think they had pictures on myfourthirds. I don't remember any side effects other than the loss of EXIF.

    Regards
    Doug

  3. #3
    Doug Palmer Guest

    Default Re: Before I de-solder...

    Here is a link to the thread http://forums.dpreview.com/forums/re...ssage=21636044; the poster in question was R2elk.

    Regards
    Doug

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    Default Re: Before I de-solder...

    I was speculating in this area in the 50mm thread, but can better follow up here. I know the start of this is old hat to you, but I'll just include it for thoroughness.

    Typical lenses focus closer by moving either a group of elements (in those that drop focal length) or the whole works, or a combination of both further from the sensor. Macro lenses often also include a second "floating" group that moves with respect the others in order to counter aberrations that crop up as the focal point grows close.

    In a typical macro, this group only becomes engaged as the lens nears the end of its travel by means of a cam or suchlike. But because fourthirds is a pure electronic protocol, it's possible for a lens to know that it has been connected to an extension tube and use an independent servo to engage the close range corrections even when it's own focus travel is not fully utilised.

    If any fourthirds lenses actually implement this optimisation then there is a drawback to hiding the extension tube from them. If none do, then there are no drawbacks I'm aware of from an optical/mechanical standpoint. In the later case, however, with a lens that includes a floating group, you should only operate the lens at the extreme end of its focus travel. For this advice to be practical, an EX-7 and an EX-14 would be nice to have.

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    Default Re: Before I de-solder...

    Hi Jens,

    I waited until after my EX-25 was out of warranty before I lobotomized it. You have obviously taken yours farther apart than I did since I only removed the mount side. I therefore believe that I only had one Oring to deal with.

    When I am using the Ex-25s with a macro lens, I tend to only use manual focus but did try the Sigma 105mm macro just to see how the AF would work. In the vast majority of cases I already have the lens set for maximum magnification and achieve focus by moving the camera closer or farther away.

    I have not found any negatives in the use of the altered EX-25. As far as the camera is concerned, it doesn't exist and all other attachments work normally.

    A side thought is that I never use the camera's macro mode. My understanding of that mode is that it does limit the lens travel to the close focus end when focusing with the 35mm or 50mm macro. The last firmware update for the E-300 did mention improved exposure in its macro mode. So maybe you are on to something in your other post.

    All that I can really say is that I am extremely happy being able to use the EC-14 and EX-25 together and still maintain full control of the attached lens. It is also really nice to be able to use two EX-25s together (only one needs to be altered) with the Sigma 105mm macro. I haven't tried that set up with the 35mm or 50mm macro. I am guessing that no focus would be possible with the 35mm macro as at maximum magnification with just one EX-25 attached leaves only about 12.5mm (0.5") working distance from the front of the lens to the subject.
    Comments and critiques welcome.
    Bob K.

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    Default Re: Before I de-solder...

    Thanks for that input acme,

    I hadn't thought of the floating lens group possibility. However, I wonder if Olympus could have fit two motors in those small macro lenses? For their price, I'd suspect a machanical coupling - but with mechanics becoming more and more expensive in relation to electronics you never know...

    Thanks for the input!

    Jens.
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

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    Default Re: Before I de-solder...

    Hi Bob,

    thanks for the very encouraging response.
    My intention is to fuse an EX-25 with a bellows and the question is if I should keep the electronics or remove it.

    If I keep the electronics, the minimum length of final EX-25+bellows will have to be about 40-45 mm. That would not be any problem for a 100 mm or longer lens but I suspect that it might be a problem with the ZD35/3.5 macro, maybe also with the ZD50/2.0 macro.
    Therefore, It would be very valuable for me if you could just check with your ZD macro lenses if they will work with two stacked EX-25 (one lobo).

    If I take out the electronics and jump the connectors, I can make the bellows to contract to about 30-35 mm and that will certainly work with the ZD50/2.0.

    I prefer to keep the electronics as it requires less work, both mechanically and electronically but if I can't use the ZD50/2.0 then I will scrap the chips and go for the slimmer bellows.

    Cheers, Jens.
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

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    Default Re: Before I de-solder...

    Quote Originally Posted by jebir View Post
    Thanks for that input acme,

    I hadn't thought of the floating lens group possibility. However, I wonder if Olympus could have fit two motors in those small macro lenses? For their price, I'd suspect a machanical coupling - but with mechanics becoming more and more expensive in relation to electronics you never know...
    I agree it may be wishful thinking, but it's also testable. If someone with the ZD 50mm macro (best bet) wants to try, first set the lens to maximum extension without the tube and snap a photo of something with a lot of pixel level detail, with the lens wide open. An ideal subject would be a ronchi grating angled at 45 degrees so the focus crosses its centre. Next insert the EX-25 and wind the lens all the way in. Repeat the photo. If the photos are identical then something magical may have happened. If not, then the likely culprit is lack of close focus correction.

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    Default Re: Before I de-solder...

    OK Jens,

    From a quick check, both the 35mm and 50mm macros will obtain focus when connected with an unaltered plus an altered EX-25 stacked. The 35mm macro leaves approximately 6mm (1/4") working distance from the front of the lens to the subject. The 50 mm macro has about 32mm ( 1-1/4") working distance from the front of the lens to the subject. These are at maximum magnification and closest focus distance.
    Comments and critiques welcome.
    Bob K.

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    Default Re: Before I de-solder...

    Thanks a lot Bob!

    That makes the decision a no brainer. I'll keep the electronics, making an EX-25 wanabee bellows, and perform the lobotomy on an EC-14 instead.

    Cheers Jens.
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

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    Default Re: Before I de-solder...

    Jens,

    I have not heard of anyone doing the alteration on an EC-14. I have heard of someone who had problems with the EC-14 because it appeared not to be assembled correctly (loose).

    I am not brave enough to take an EC-14 apart as I would fear getting the optics out of proper alignment.
    Comments and critiques welcome.
    Bob K.

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    Default Re: Before I de-solder...

    Quote Originally Posted by jebir View Post
    Thanks a lot Bob!

    That makes the decision a no brainer. I'll keep the electronics, making an EX-25 wanabee bellows, and perform the lobotomy on an EC-14 instead.

    Cheers Jens.
    This one will have software ramifications in defeating the system's ability determine the current f ratio. Oly should release a fourthirds auto bellows as nice as their old one, but in the meantime what bellows were you thinking of modifying?

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    Default Re: Before I de-solder...

    Hi Bob,

    I just today recieved my second EC-14 intended for this operation. The first thing I did was to stack it with my other EC-14 and, as expected, the focusing didn't work. However, what was a bit alarming was that the numbers and symbols in the viewfinder was blinking in a very strange and overly intense way that I actually think is not good for the body.

    Never mind, I'll put some paper between the contacts and make some initial check photographs with them stacked this weekend and if the Image quality is good, I plan to relieve one of them from its intelligence as soon as possible.

    All teleconverters I have disassmbled have had the lenses stacked in one core unit. As long as one doesn't open that unit, it should be pretty easy to get it back together.

    I'll let you know how it goes.

    Cheers, Jens.
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

  14. #14
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    Default Re: Before I de-solder...

    Hi acme,

    I'm modifying an Olympus-Pen F Bellows 2. The reason is that it is the most compact bellows out there (20-100 mm) with 2 guide-rails. With the 1/2-sized sensor of 4/3, one just need 1/2 the extension capability in order to achieve the same FOV as with 35 mm.

    I'm now 1/3 way through the conversion (one 4/3 flange attached) and now just need to find a clever way to take care of the extra cable when the bellows is contracted before I can finish it.

    Cheers, Jens
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

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    Default Re: Before I de-solder...

    Hi Acme,

    I am pretty sure that it will have more than software ramifications. Because the camera will not be getting the correct aperture readings, I believe that the exposure will be off.
    Comments and critiques welcome.
    Bob K.

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    Default Re: Before I de-solder...

    Quote Originally Posted by R2elk View Post
    Hi Acme,

    I am pretty sure that it will have more than software ramifications. Because the camera will not be getting the correct aperture readings, I believe that the exposure will be off.
    Yep, something along those lines is what concerned me. Results depend on how much the camera trusts what it's told electrically versus what it sees optically.

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    Default Re: Before I de-solder...

    I presume you guys are talking about the bellows. A lobo-TC would just require a +1 EV exposure compensation.

    Cheers, Jens.
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

  18. #18
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    Default An elegant solution...

    I just recieved a message from OlyFlyer who has been working on a 4/3 bellows as well.

    Here is the link to his latest project: a 4/3 --> OM + OM --> 4/3 extension tube with electronic bypass. It allows the use of any macro stuff that you have ever had for the OM-system to be used with a 4/3 camera. Check it out here.

    His solution is more elegant and more flexible than the approach I took for my bellows so, I'm now starting from scratch and making something similar to his double extension tube.

    Cheers, Jens
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

  19. #19
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    Default Re: An elegant solution...

    Quote Originally Posted by jebir View Post
    Here is the link to his latest project: a 4/3 --> OM + OM --> 4/3 extension tube with electronic bypass. It allows the use of any macro stuff that you have ever had for the OM-system to be used with a 4/3 camera. Check it out here.
    I've considered doing this, but the gains seemed fairly meagre. None of the present fourthirds lenses are designed for use on bellows, and no electrical interconnect is required of lenses that are.

    It would be useful for keeping control of a reversed fourthirds lens though, and if any perform well in this orientation it could be worthwhile.

  20. #20
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    Default Re: An elegant solution...

    Quote Originally Posted by acme View Post
    None of the present fourthirds lenses are designed for use on bellows...
    They are most likely not but there are four existing 4/3 compatible macro lenses and they are most likely designed to compensate for the field curvature at close focus. We just don't know to what degree and if it is enough for more extension than the EX-25 in the case of ZD.

    Besides, if no-one tries nobody will know.

    Cheers, Jens.
    Motto: Wildlife won't come to me unless I go to it.
    --------------------------------------------------------
    My Wildlife Photos: jensbirch.smugmug.com

    E-5, E-3, E-510, IR-E-1 ,E-P2
    ZD: 7-14, 14-54, 50, 50-200 SWD, 90-250/2.8, 300/2.8, EC-14, EC-20
    Peleng 8mm fisheye, shift Tamron SP 17/3.5, Tokina AT-X 300/2.8
    FL-50R, FL-40, FL-20, HLD-2, HLD-4, cleaved ZD EX-25 w. electric bypass, 250D, 500D, KatzEye Plus OptiBrite
    Feisol CT-3472LV and CM-1471

  21. #21
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    Default Re: An elegant solution...

    Quote Originally Posted by jebir View Post
    They are most likely not but there are four existing 4/3 compatible macro lenses and they are most likely designed to compensate for the field curvature at close focus.
    Those macros with close focus correction maximise that correction at the end of their native focal range. Yet higher magnifications benefit from yet more correction, or a different lens design. The auto-bellows plus adapter tubes will add a minimum of 70mm of extension, which is quite a bit even for an extremely long macro like the sigma 150.

    Field curvature would be the least objectionable aberration to accentuate, unless microdot reproduction was the objective!

    Quote Originally Posted by jebir View Post
    We just don't know to what degree and if it is enough for more extension than the EX-25 in the case of ZD.

    Besides, if no-one tries nobody will know.

    Cheers, Jens.
    I can't disagree, and I'm grateful people are willing to take the time and money to undertake experiments like this despite some skeptics being dubious!

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