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Harold Gough
Joined: 09 Mar 2008
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Location: Reading, Berkshire, England
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ChrisR
Joined: 14 Mar 2009
Posts: 3037
Location: Near London, UK
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 Posted: Sun Feb 12, 2012 3:22 am Post subject: |
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| Harold wrote: | | Where unmodified OM lenses could be used I wonder if one could substitute a macro lens for a conventional lens of the same focal length as the stack moved outwards (as the camera moves forwards, closing the bellows). |
Not sure what you're looking to achieve Harold. I don't see any point in not using the 80mm lens all the way.
One thing I think you may be missing is that you can't combine the full field of the infinity end with the field at the short end, because the field of view changes ( to half what it was, at 1:1, compared with infinity).
You have to throw the edges of the infinity, wide-field view, away. Or just have a sharp middle!
One way round that that would be to rotate the shooting set-up about the entrance pupil position, and re-stack. That's what Ed French (elf) does with his specially made rig. I don't know any reason why a good quality "normal" pano head (Nodal Ninja or similar) couldn't be used, with a suitable macro-rail on it allowing the lens entrance pupil to stay put and move the sensor backwards.
Because of the distances involved you'd have better-than-normal holding precision requirements. Half a millimetre which might not matter on a restaurant interior 360, would show quite a lot if the subject's 100mm away.
I'e done this with a 100mm lens on a bellows, without panning. It works OK but the results aren't encouraging. A major reason is that you need a subject which flows from near to far, if you don't want it to look like a paste-up. That makes for compositional constraints when you have a field of view equivalent to what you'd have with a 200mm lens on 35mm.
If you uses a smaller sensor cameras such as a 4/3rd to "gain" sensor-lens distance flexibility then you need even shorter lenses to get the field of view, so you're not necessarily any better off. Mirrorless cameras could have a shorter flange to sensor distance, so there may be some benefit there.
We can make a ($100) Olympus 21mm lens work on full 24 x 36 frame, so that's the target. Can you suggest a better combination?
Rik demonstrated the serendipitous benefit of the focus arrangement on some compacts where the entrance pupil doesn't shift during focus. That's by far the easiest way to get a "pretty decent" result. I bought a used Powershot A600 (or similar), £10, just to try it. (Its 6MP is scorned these days, but not when you’re looking at the print!)
My Lumix has gone all magenta so I’m looking for a “better” compact. I’ve had several funny looks in camera shops, while squinting sideways at the lens to see how it focuses. |
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Harold Gough
Joined: 09 Mar 2008
Posts: 5716
Location: Reading, Berkshire, England
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| Posted: Sun Feb 12, 2012 6:57 am Post subject: |
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Chris,
I'm really just looking at possibilities.
At the back of my mind is the work of John Brackenbury:
http://www.photomacrography.net/forum/viewtopic.php?t=4569&highlight=brackenbury (The second linkthere no longer works)
Charles featured, in his woodland stack, some flowers and a mushroom as moderate close-ups, stating some reservations as to the quality of the 28mm at close range.
My thoughts went to the Olympus 38mm macro but its range is too narrow. The other option of a high quality bellows lens, with a wider range, was the 80mm Zuiko, which does not focus at infinity. Having the 35-80mm, which won't go down to 1:1 suggested that I might have a pair of lenses which could each give high quality in their working ranges.
I was contemplating how far the Brackenbury macro-to-infinity idea might be taken with stacking (instead of his 2mm lens).
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
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ChrisR
Joined: 14 Mar 2009
Posts: 3037
Location: Near London, UK
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| Posted: Sun Feb 12, 2012 8:55 am Post subject: |
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| Quote: | | Charles featured, in his woodland stack, some flowers and a mushroom as moderate close-ups, stating some reservations as to the quality of the 28mm at close range. |
Uh Ok.
Ok, that's one potential issue, though not one anyone has shown yet. (?)Stacking images from two lenses sounds fraught with problems. Oo er. I suppose if you could get the EP close enough, and the distortions weren't a problem, and the colour balance, then OK, apart from the things I've forgotten.
I've thought of something to try, but it involves stuff I don't have. At least not much of it. Off to ebay then.
Sorry I can't tell you what it is, in case there's only one. Then I'd have to shoot you. 
Last edited by ChrisR on Sun Feb 12, 2012 10:29 am; edited 1 time in total |
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Harold Gough
Joined: 09 Mar 2008
Posts: 5716
Location: Reading, Berkshire, England
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| Posted: Sun Feb 12, 2012 10:20 am Post subject: |
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| Harold Gough wrote: |
I just compared the depth of the OM to micro 4/3 adaptor and the minimum extension of my Olympus OM autobellows. The front standard is detachable/reversable. Detaching that leaves the minimum length of the bellows very close to that for infinity focus of an unmodified OM lens.
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I did a quick test today. I removed the front stand and the rear mount. I then held my OM 28mm f2.8, focused at infinity, in the front end of the detached bellows and the rear stand opening against the EP-2. I found that the minimum spacing seemed very slightly excessive for infinity focus. [Edit] That could be simply overcome by shooting the infinity frame with the lens on the OM top m4/3 adapter.
I had no aperture control so the lens was at f2.8 whereas a small aperture might have included infinity in focus. Also, there was thin mist, making distant tree detail unclear anyway. As this was held together by hand there was also a fumble factor, although I took several shots.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843
Last edited by Harold Gough on Sun Feb 12, 2012 12:45 pm; edited 1 time in total |
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Charles Krebs
Joined: 01 Aug 2006
Posts: 4067
Location: Issaquah, WA USA
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| Posted: Sun Feb 12, 2012 11:18 am Post subject: |
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Harold, | Quote: | | Charles featured, in his woodland stack, some flowers and a mushroom as moderate close-ups, stating some reservations as to the quality of the 28mm at close range. |
Hmmm.. I'll need to re-read all my posts on this. With the 28/3.5 Oly lens, I believe it was mentioned on several occasions how surprised and pleased I was with its "extended" performance on a 24 x 36mm sensor. But I also strongly recommended checking a wide-angle lens carefully before using it like this since there are many that do very poorly when extended to get very close focus.
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Harold Gough
Joined: 09 Mar 2008
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Location: Reading, Berkshire, England
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| Posted: Sun Feb 12, 2012 12:12 pm Post subject: |
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| Charles Krebs wrote: | Harold, | Quote: | | Charles featured, in his woodland stack, some flowers and a mushroom as moderate close-ups, stating some reservations as to the quality of the 28mm at close range. |
Hmmm.. I'll need to re-read all my posts on this. With the 28/3.5 Oly lens, I believe it was mentioned on several occasions how surprised and pleased I was with its "extended" performance on a 24 x 36mm sensor. . |
My error. It was a warning about checking the performance of other lenses, in a paragraph which started with praise of the Olympus.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
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Harold Gough
Joined: 09 Mar 2008
Posts: 5716
Location: Reading, Berkshire, England
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| Posted: Mon Feb 13, 2012 1:58 am Post subject: |
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| Harold Gough wrote: | | Harold Gough wrote: |
I just compared the depth of the OM to micro 4/3 adaptor and the minimum extension of my Olympus OM autobellows. The front standard is detachable/reversable. Detaching that leaves the minimum length of the bellows very close to that for infinity focus of an unmodified OM lens.
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I did a quick test today. I removed the front stand and the rear mount. I then held my OM 28mm f2.8, focused at infinity, in the front end of the detached bellows and the rear stand opening against the EP-2. I found that the minimum spacing seemed very slightly excessive for infinity focus. [Edit] That could be simply overcome by shooting the infinity frame with the lens on the OM top m4/3 adapter.
I had no aperture control so the lens was at f2.8 whereas a small aperture might have included infinity in focus. Also, there was thin mist, making distant tree detail unclear anyway. As this was held together by hand there was also a fumble factor, although I took several shots.
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I repeated this today, in better lighting, and the extension still seems slightly too long for infinity focus. (The Tamrom 17mm gave a similar result, even at f8).
As my 17mm is an Adaptall-2 model, I removed the OM adapter and tried again. This gave infinity focus and beyond. The removal of the adapter shortened the lens by about 4mm*, indicating that the bellows without the rear stand gave a minimum lens to sensor distance about 1mm too long for infinity focus.
Of course, the question of supporting the mountless lens then arose. The flanges of the lens and bellows front stand are almost identical in size, such that a good metal to metal adhesive might do the job. Prior to attachment, the aperture lever can be permanently depressed by a suitable insertion, converting the lens to manual aperture control. As mentioned elsewhere, my preference would be to take infinity shots with the mount in place and using the OM to m4/3 adapter instead of the bellows.
* This factor just might be useful in some other application unknown to me.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
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ChrisR
Joined: 14 Mar 2009
Posts: 3037
Location: Near London, UK
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| Posted: Mon Feb 13, 2012 4:44 am Post subject: |
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| Quote: | | a good metal to metal adhesive might do the job. |
An option is a Cokin style A or B adapter - screws in and provides a flange. |
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Harold Gough
Joined: 09 Mar 2008
Posts: 5716
Location: Reading, Berkshire, England
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| Posted: Mon Feb 13, 2012 5:21 am Post subject: |
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| ChrisR wrote: | | Quote: | | a good metal to metal adhesive might do the job. |
An option is a Cokin style A or B adapter - screws in and provides a flange. |
Chris,
I'm having trouble visualising that, although it sounds familiar from somewhere*. Won't that involve a introducing a thinkness which pushes the lens further away from the sensor, thus (partially?) negating what was gained by removing the adapter?
* [EDIT] This was a DIY shift lens mount in another forum.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
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Charles Krebs
Joined: 01 Aug 2006
Posts: 4067
Location: Issaquah, WA USA
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| Posted: Mon Feb 13, 2012 12:49 pm Post subject: |
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I thought I would add these images to show how nicely the Oly 28/3.5 does when extended in this manner. These are 100% pixel sections taken from the original full size stack (as indicated by the red boxes).
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ChrisR
Joined: 14 Mar 2009
Posts: 3037
Location: Near London, UK
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| Posted: Mon Feb 13, 2012 1:37 pm Post subject: |
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| Harold wrote: | | Won't that involve a introducing a thinkness which pushes the lens further away from the sensor |
Wrong end - Cokin adapters go into the filter thread
| Charles wrote: | | show how nicely the Oly 28/3.5 |
Very nicely, but how close is that?
I would guess that toadstool isn't a foot across, but I don't know...
Musing - some of the impact of therse pics comes from realising the scale of things. Problem with much veg is its fractal nature, there's always a bigger/smaller version. Something recognisable like an acorn would be good. |
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Charles Krebs
Joined: 01 Aug 2006
Posts: 4067
Location: Issaquah, WA USA
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| Posted: Mon Feb 13, 2012 6:58 pm Post subject: |
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Chris,
Here's a shot of some "debris" gathered on my desk. However the coins at the bottom are at a lower magnification than some of the vegetation in the rainforest shots. (The US dime is just under 18mm in diameter).
Here's a copy of the full size stacked image:
http://www.krebsmicro.com/forumpix/messydesk_full.jpg
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Harold Gough
Joined: 09 Mar 2008
Posts: 5716
Location: Reading, Berkshire, England
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| Posted: Tue Feb 14, 2012 12:09 am Post subject: |
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| ChrisR wrote: | | Harold wrote: | | Won't that involve a introducing a thinkness which pushes the lens further away from the sensor |
Wrong end - Cokin adapters go into the filter thread |
I must have caused some confusion, as there is no filter thread to be involved. The flanges I refered to are that at the camera end of the adapterless lens and on the front (incorporating a female OM bayonet) of the front stand of the bellows.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843
Last edited by Harold Gough on Tue Feb 14, 2012 1:39 am; edited 1 time in total |
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Harold Gough
Joined: 09 Mar 2008
Posts: 5716
Location: Reading, Berkshire, England
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| Posted: Tue Feb 14, 2012 12:14 am Post subject: |
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| Charles Krebs wrote: | | I thought I would add these images to show how nicely the Oly 28/3.5 does when extended in this manner. These are 100% pixel sections taken from the original full size stack (as indicated by the red boxes). |
Wow! OK, they look like club mosses, but stunning detail.
Having very recently obtained a multicoated, later version, of the Zuiko 24mm f2.8, a lens with a particularly good reputation, I must do something about seeing what it will do. It may be that the m4/3 sensor is a limiting factor. We are just emerging from the longest freeze in many years, so nothing will happen in a hurry.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
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