Olympus-OM
[Top] [All Lists]

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 07:48:51 -0400
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
>>>>>>>>> --
>>>>>>>>>
>>>>>>> __________________________________________________________
>>>>>>>>> _______
>>>>>>>>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
>>>>>>>>> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
>>>>>>>>> Themed Olympus Photo Exhibition: http://www.tope.nl/
>>>>>>>>
>>>>>>> --
>>>>>>> __________________________________________________________
>>>>>>> _______
>>>>>>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
>>>>>>> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
>>>>>>> Themed Olympus Photo Exhibition: http://www.tope.nl/
>>>>>>
>>>> --
>>>> _________________________________________________________________
>>>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
>>>> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
>>>> Themed Olympus Photo Exhibition: http://www.tope.nl/
>>>>
>>> --
>>> _________________________________________________________________
>>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
>>> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
>>> Themed Olympus Photo Exhibition: http://www.tope.nl/
>>>
>> --
>> _________________________________________________________________
>> Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
>> Archives: http://lists.thomasclausen.net/mailman/private/olympus/
>> Themed Olympus Photo Exhibition: http://www.tope.nl/
>>
>>
-- 
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz