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Re: [OM] Oly 4/3 vs m4/3 lens mounts and adapters

Subject: Re: [OM] Oly 4/3 vs m4/3 lens mounts and adapters
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Sat, 18 May 2013 09:06:05 -0400
Yes, reversing the 90/2.5 on the bellows is doable.  58->49mm step down 
rings are available.  Then one only needs a 49mm filter sans glass to 
make the connection to the bellows.  Whether the reversed 90mm does 
anything useful for my purposes is yet another unanswered question.

Chuck Norcutt


On 5/18/2013 7:48 AM, Chuck Norcutt wrote:
> The next question is whether the 49/55 adapter was originally supplied
> with the bellows.  Does anyone actually have one of these and does it
> look as I described that I think it must look?  Searching the eSIF
> (briefly) did not reveal such a part to me.
>
> I've got to think about how to replicate a part like that for reversing
> my 90/2.5 Viv S1 macro which a 58mm filter.  If there's a 49 to 55mm
> filter adapter that would work.  You'd need the ring from the 49mm
> filter to make a 51mm diameter attachment point for the bellows.
>
> Chuck Norcutt
>
>
> On 5/18/2013 3:03 AM, piers@xxxxxxxx wrote:
>> Splendid stuff, Chuck, it all does now make sense in a way that eSIF
>> and SIF (which I also reviewed) don't even approach. It was late, I
>> didn't follow my own advice to just try it!
>>
>> Piers
>>
>> On 18/05/2013, Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx> wrote:
>>> You're inferring stuff rather than actually measuring the bellows.  I
>>> have done my due diligence and discovered that the eSIF is perfectly
>>> correct.  The reason that a Series VI is used is that hole is supposed
>>> to take a filter... a Series VI size filter... which Wiki tells me thus:
>>> Series number       Filter size     Adapter ring
>>>     VI      41.3 mm         44 mm
>>> My handy dandy millimeter rule tells me that the thread on the back of
>>> the lens board is (whaddya know) 44mm.  I discovered that very quickly
>>> since no 49mm filter would fit there.  That threaded hole is
>>> specifically for a filter and not for reversing lenses.
>>>
>>> Once again, the bellows manual tells you nothing about that filter
>>> provision.  Your confusion about reversing lenses I think comes about
>>> from assuming that it's done the way you would on a camera body by
>>> attaching two lenses together joined by a male threaded ring with
>>> threads on each side to match the lenses to be joined.  You've assumed
>>> that the 49/55 adapter is one of those rings... but it is not.  It has a
>>> totally different function and isn't really 49mm on one end.
>>>
>>> Once you turn the front lens board around you don't need any sort of
>>> threaded adapter since the OM lens mount on the lens board is now facing
>>> the camera.  Just install the lens on the normal lens mount and it, like
>>> the lens board, is now reversed.  Where the 49/55 adapter comes in has
>>> to do with attaching the bellows itself to the lens.  The attaching ring
>>> normally attaches to a ring on the back of the lens board that is about
>>> 51mm diameter... or the outside diameter of a lens having a 49mm filter.
>>>     When you reverse a lens having a 49mm filter the bellows attaching
>>> ring fits over the lens in the same way as it does the ring on the back
>>> of the lens board.  But when you use a lens with 55mm filter the lens is
>>> too large.  It needs a step-down ring.  Now, since I have never seen one
>>> of these step-down rings I can only conclude that it has a 55mm thread
>>> on one end and a 51mm unthreaded ring on the other such that it presents
>>> the same diameter to the bellows attaching ring as the ring on the back
>>> side of the lens board.
>>>
>>> Or something like that.  If you know something else correct me.
>>>
>>> Chuck Norcutt
>>>
>>>
>>>
>>>
>>> On 5/17/2013 6:23 PM, Piers Hemy wrote:
>>>> Without looking at the Bellows manual I would opine that it would be
>>>> surprising to find that Olympus did not use the 49/55mm thread there, as
>>>> it
>>>> is intended for reversing OM lenses on the (reversed) front standard. Why
>>>> would they use a thread incompatible with all and any of their own
>>>> lenses?
>>>> And in place of reading a secondary source (useful as the eSIF is), why
>>>> not
>>>> try it?
>>>>
>>>> So I did look at the 12/81 edition of the Auto Bellows manual, and guess
>>>> what?
>>>>
>>>> I was wrong.
>>>>
>>>> And so is the eSIF, only more wronger (!)
>>>>
>>>> It's a 49mm thread, as "The adapter ring 55-49mm is needed to reverse the
>>>> Macro 55mm F1.2 on the bellows" (p 14). Granted, they described the
>>>> 55/1.2
>>>> as a Macro lens, which it isn't, but it does have a 55mm filter thread,
>>>> from
>>>> which I conclude the bellows has only a 49mm thread.
>>>>
>>>> Piers
>>>>
>>>> -----Original Message-----
>>>> From: Chuck Norcutt [mailto:chucknorcutt@xxxxxxxxxxxxxxxx]
>>>> Sent: 17 May 2013 22:26
>>>> To: Olympus Camera Discussion
>>>> Subject: Re: [OM] Oly 4/3 vs m4/3 lens mounts and adapters
>>>>
>>>> I tried the focusing stage since Wayne said he'd gotten such an
>>>> arrangement
>>>> to work with his Pen and, if it worked, would require nothing more than
>>>> what
>>>> I already have.
>>>>
>>>> I didn't come up with your solution since I've never completely read the
>>>> bellows description in the eSIF which is, I think, the only place that
>>>> tells
>>>> you that the back of the lens board is threaded.  But it looks like you
>>>> need
>>>> to re-read it yourself :-) since the thread is for a Series VI filter and
>>>> is
>>>> not a 49/55 filter thread.  Nevertheless, your solution should work given
>>>> the right bits and pieces.
>>>>
>>>> But re-reading the eSIF to understand what you had written caused me to
>>>> think about reversing the lens which might provide a bit more room to
>>>> maneuver since it moves the thick base of the lens board to the back
>>>> side.
>>>> Maybe.  Thanks for the memory jog.
>>>>
>>>> Chuck Norcutt
>>>>
>>>>
>>>> On 5/17/2013 5:35 AM, Piers Hemy wrote:
>>>>> I may have missed something obvious, but why are you using the
>>>>> focusing stage? Remove the rear standard (camera mounting board) and
>>>>> bellows from the bellows rail, and use the 49/55mm filter threads on
>>>>> the back of the front standard (lens board) to mount the OM-D. You'll
>>>>> need a 55mm m4/3 reverse adaptor such as 271191801433 on the auction
>>>>> site, and a female-female filter adaptor such as this:
>>>>> http://www.camera-filters.com/index.php?main_page=product_info&cPath=4
>>>>> 31&pro
>>>>> ducts_id=7214
>>>>>
>>>>> You may also need a blank filter ring to get extra separation, but I'm
>>>>> sure you'll work that out!
>>>>>
>>>>> Piers
>>>>>
>>>>> -----Original Message-----
>>>>> From: Chuck Norcutt [mailto:chucknorcutt@xxxxxxxxxxxxxxxx]
>>>>> Sent: 16 May 2013 18:04
>>>>> To: Olympus Camera Discussion
>>>>> Subject: Re: [OM] Oly 4/3 vs m4/3 lens mounts and adapters
>>>>>
>>>>> I'm removing the grain of salt.  I mounted the E-M5 on the focusing
>>>>> stage, installed the OM adapter and some OM extension tubes and then
>>>>> put the OM body mount from the bellows onto the end of the tubes.
>>>>> Running the body mount into the bellows connector resulted in the E-M5
>>>>> setting in a non-level position on the focusing stage.  I think my
>>>>> guess of 3mm (maybe 2mm) vertical misalignment may be about right but
>>>>> it's not the height of the body or lens center lines.
>>>>>
>>>>> I had assumed that the OM body was lower and would align properly.
>>>>> Nope, the two camera's lens centers appear to be at the same height so
>>>>> an
>>>>> OM-1 on the focusing stage doesn't align either.  The problem of
>>>>> vertical misalignment is caused by the height of the focusing stage.
>>>>>
>>>>> Chuck Norcutt
>>>>>
>>>>>
>>>>> On 5/15/2013 11:15 AM, Chuck Norcutt wrote:
>>>>>> A quick and very rough measurement looks like the vertical centerline
>>>>>> of the E-M5 is about 3mm higher than an OM body.  But take that with
>>>>>> a grain of salt.  Also, like the E-P1 the tripod thread is off center
>>>>>> from the lens center by about 9mm.  That, however, could likely be
>>>>>> solved by drilling and tapping a new hole in the focusing stage.
>>>>>> I'll take a better measurement later since this has some promise.
>>>>>>
>>>>>> Chuck Norcutt
>>>>>>
>>>>>>
>>>>>> On 5/15/2013 8:17 AM, Wayne Harridge wrote:
>>>>>>> G'day Chuck,
>>>>>>>
>>>>>>> Something like this should work:
>>>>>>>
>>>>>>> http://www.structuregraphs.com/RandomStuff/15-May-2013/index.html#20
>>>>>>> 1
>>>>>>> 30515-A
>>>>>>> .jpg
>>>>>>>
>>>>>>> OM focussing rail with slide copier attached E-P1 with om -> m4/3
>>>>>>> adapter and 50/3.5 @1:2
>>>>>>>
>>>>>>> The only problem with this is that the E-P1 tripod thread is not
>>>>>>> below the optical axis of the lens.  Vertical alignment is ok.  What
>>>>>>> is the situation with the E-M5 ?
>>>>>>>
>>>>>>> To get good contrast you'd probably need to cover the gap between
>>>>>>> the lens and slide copier with a dark cloth.
>>>>>>>
>>>>>>> ...Wayne
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> Thanks, Wayne.  That answers my question; the 4/3 mount is not
>>>>>>>> physically compatible with the m4/3 mount.  But I'm afraid OM tubes
>>>>>>>> won't solve my problem.  My problem is that the OM->m4/3 adapter is
>>>>>>>> already too long for what I'm trying to do with the bellows and
>>>>>>>> slide copier.  I can't connect
>>>>>>> with
>>>>>>>> the slide copier using tubes alone and adding tubes to the bellows
>>>>>>>> would make the problem worse.
>>>>>>>>
>>>>>>>> Steve Barbour sent me links to the 4/3->m4/3 adapter (thanks,
>>>>>>>> Steve) but that won't help me either.  I would still have to
>>>>>>>> connect that up to an OM adapter which gets me right back to the
>>>>>>>> length problem I'm trying to overcome.
>>>>>>>>
>>>>>>>> What I need is an OM->m4/3 adapter with a 15-20mm section sawed out
>>>>>>>> of the middle.  The 80/4 is probably the right solution but I don't
>>>>>>>> have one
>>>>>>> of
>>>>>>>> those. :-)  I'll have to think about this some more.  What I need
>>>>>>>> is
>>>>>>> something
>>>>>>>> like an m4/3 lens flange glued directly to the back of an OM body
>>>>> flange.
>>>>>>>> Basically an m4/3->OM adapter without the tube between the two
>>>>>>>> mounts.
>>>>>>>>
>>>>>>>> Chuck Norcutt
>>>>>>>>
>>>>>>>>
>>>>>>>> On 5/14/2013 11:28 PM, Wayne Harridge wrote:
>>>>>>>>> I tried to mount one of my OM->4/3 adapters on my E-P1 - too big.
>>>>>>>>> I'm not surprised actually as I reckon Oly would have copped it
>>>>>>>>> from a whole lot of customers who mounted a 4/3 lens on an m4/3
>>>>>>>>> body and
>>>>>>>> found it didn't focus.
>>>>>>>>>
>>>>>>>>> Perhaps pick up some cheap OM tubes, they seem to be plentiful on
>>>>>>>>> that auction site.
>>>>>>>>>
>>>>>>>>> ...Wayne
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Can someone who has both systems verify whether or not a 4/3 lens
>>>>>>>>>> fits on
>>>>>>>>> a
>>>>>>>>>> m4/3 camera?  I know it won't focus properly and maybe not even
>>>>>>>>>> operate electrically.  My only real concern is whether a 4/3 lens
>>>>>>>>>> (or OM to 4/3
>>>>>>>>>> adapter) physically fits into an m4/3 body.
>>>>>>>>>>
>>>>>>>>>> The reason I ask is that I was trying to use my OM bellows and
>>>>>>>>>> slide
>>>>>>>>> copier
>>>>>>>>>> today to see if I could copy slides onto my E-M5.  To do that I
>>>>>>>>>> need a magnification of approx 0.5X.  If I had a Zuiko 80/4 short
>>>>>>>>>> mount macro
>>>>>>>>> lens for
>>>>>>>>>> the bellows I'd be OK.  But my only two macro lenses are my
>>>>>>>>>> 90/2.5 Viv S1 and my 50/3.5 Zuiko.
>>>>>>>>>>
>>>>>>>>>> I don't think I can get the 90/2.5 to work at all since at 0.5X I
>>>>>>>>>> think
>>>>>>>>> the image
>>>>>>>>>> of a slide is somewhere beyond the length of the bellows rail.
>>>>>>>>>>          The 50/3.5 macro is only designed to do about 0.68X on the
>>>>> bellows.
>>>>>>>>>> The bellows itself prevents it from getting to 0.5X.  The
>>>>>>>>>> limitation is
>>>>>>>>> imposed
>>>>>>>>>> by the minimum separation of the lens board and camera mounting
>>>>>>>> board.
>>>>>>>>>> According to my possibly dodgy calculations the image plane needs
>>>>>>>>>> to be brought forward about 14mm.  If you were using an OM or 4/3
>>>>>>>>>> body that wouldn't be possible.  However, I note that the 4/3 to
>>>>>>>>>> OM adapter is about 20mm shorter than the m4/3 adapter.  If I had
>>>>>>>>>> a 4/3 adapter on the m4/3 body I think that would give me the
>>>>>>>>>> extra range I need to bring the image plane in and get the 50/3.5
>>>>>>>>>> to do 0.5X or
>>>>>>> slightly
>>>>>>>> smaller.
>>>>>>>>>>
>>>>>>>>>> So, can someone answer the physical compatibility question
>>>>>>>>>> between the two mounts, ie, will a 4/3 lens fit onto a m4/3 mount
>>>>>>>>>> even though it might not actually work electrically and certainly
>>>>>>>>>> can't focus even if it
>>>>>>>>> physically fits?
>>>>>>>>>>
>>>>>>>>>> Assuming it does, anyone got a spare OM to 4/3 mount you'd like
>>>>>>>>>> to move on?  Maybe an old one with no AF confirmation chip?  I
>>>>>>>>>> won't be needing anything like that.
>>>>>>>>>>
>>>>>>>>>> Chuck Norcutt
>>>>>>>>>> --
>>>>>>>>>>
>>>>>>>> __________________________________________________________
>>>>>>>>>> _______
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>>>>>>>>>
>>>>>>>> --
>>>>>>>> __________________________________________________________
>>>>>>>> _______
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>>>>>>>
>>>>> --
>>>>> _________________________________________________________________
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>>>>>
>>>> --
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>>>>
>>> --
>>> _________________________________________________________________
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>>>
>>>
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