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