| View previous topic :: View next topic |
| Author |
Message |
ChrisR
Joined: 14 Mar 2009
Posts: 3035
Location: Near London, UK
|
 Posted: Tue Feb 14, 2012 2:50 am Post subject: |
 |
|
Harold:
No confusion at all my end!
In response to
| Quote: | | Of course, the question of supporting the mountless lens then arose. |
I suggested a means of using a flange which you can screw on. You can suport the lens from the front, as Charlie did. A Cokin adapter gives you a cheap large flat flange you can do lots of things with.
Unless your Tamron lens doesn't have a filter thread involved at the front..? I have some lenses like that.
Charlie that's interesting. Perhaps there's particular scope in still-life compositions.
I say that because the coins ( not being familiar) and the screws don't immediately shout "close" , but the razor blade does, quite strongly. Coins and screws are a bit like leaves  !
Not much wrong with the lens, is there 
I wonder if the shorter lenses will allow any more magnification before the subect is inside the front element.
You're at what, around a 45mm fov here?
I'll get some blu-tak out for a few single images.. Later, just off to buy more junk... |
|
| Back to top |
|
 |
Harold Gough
Joined: 09 Mar 2008
Posts: 5711
Location: Reading, Berkshire, England
|
| Posted: Tue Feb 14, 2012 2:59 am Post subject: |
|
|
Thanks, Chris,
I was confused (so easily done  ) but with some reason here. My 17mm does not have a front filter thread, the only way of attaching threaded lenses being on the dedicated, flower-type, hood, which takes 82mm filters.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
|
| Back to top |
|
|
ChrisR
Joined: 14 Mar 2009
Posts: 3035
Location: Near London, UK
|
| Posted: Tue Feb 14, 2012 3:47 am Post subject: |
|
|
| Cokin P series goes to 82mm - might give you something to glue to, they look too big to have a flange to put screws though. Only £1 or so though! |
|
| Back to top |
|
|
Harold Gough
Joined: 09 Mar 2008
Posts: 5711
Location: Reading, Berkshire, England
|
| Posted: Tue Feb 14, 2012 4:11 am Post subject: |
|
|
| ChrisR wrote: | | Cokin P series goes to 82mm - might give you something to glue to, they look too big to have a flange to put screws though. Only £1 or so though! |
I'll keep it in mind but that would probably mean trashing the (very rare, expensive) hood by removing the "petals".
I have Hi-Tech 100mm system (think 'Lee') filter holders with adapters for various filter sizes and already sacrificed a hood from my 24-48mm Tamron so as to attached it via the 77mm ring. It took many months to find a spare hood for that project. (One factor there, not a concern on 4/3, is potential vignetting on full frame 35mm).
Flare is a major issue with these ultra-wides in non-macro use, especially so with the 17mm, such that I have to keep intact hoods available.
Anyway, I think the 17mm, with its OM adapter attached, will work, starting from direct on the OM to m4/3 adapter and switching to the bellows for closer frames.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
|
| Back to top |
|
|
ChrisR
Joined: 14 Mar 2009
Posts: 3035
Location: Near London, UK
|
| Posted: Tue Feb 14, 2012 11:28 am Post subject: |
|
|
A different point ( there are already too many in this thread...) is that if(?) we're after a bug-eyed view of the world, then we need a lens with the entrance pupil near the front of the lens. Wider and wider angle retrofocus designs are likely to have it deep within, I think. Fisheye lenses can have it really deep.
So we want a high macro ratio AND wide angle of view, retrofocus lens.
I can't predict where that'll be. |
|
| Back to top |
|
|
Charles Krebs
Joined: 01 Aug 2006
Posts: 4066
Location: Issaquah, WA USA
|
| Posted: Tue Feb 14, 2012 11:35 am Post subject: |
|
|
Harold,
I certainly don't want to discourage your experimentation, but I would not irreversibly hack your 17mm lens. At least not until you are convinced it will give you a perspective that is worth it to you.
At least for me, the wide-angle perspective is a key characteristic that makes all this fun to play around with. A 28mm of a 24x36mm sensor is about where this begins to show itself (again, for my tastes). A 24mm or 21mm would be even better. A 17mm on 4/3 is not all that wide. Also, keep in mind the diagram Chris drew earlier (near top of page 4). You definitely lose some "width" on the far background as the stacking software does its job, which makes the lens less "wide" than it would be with a single distant shot. (It is quite amazing how well the software deals with this situation).
Chris...
| Quote: | | I wonder if the shorter lenses will allow any more magnification before the subject is inside the front element. |
A valid concern and one that need to be checked carefully before putting the tools to a lens! 
Another point... while I used an old bellows, you really do not need a great amount of extension to do this with a wide-angle lens. As mentioned earlier a simple DIY "bag" bellows would suffice. That's why mounting the camera by its base to a movable platform is an option to consider since, if a rear bellows mount is avoided you pick up some very precious room to get to infinity focus.
_________________
http://www.krebsmicro.com |
|
| Back to top |
|
|
ChrisR
Joined: 14 Mar 2009
Posts: 3035
Location: Near London, UK
|
| Posted: Tue Feb 14, 2012 12:25 pm Post subject: |
|
|
| Quote: | | before putting the tools to a lens! |
Only screwdrivers, honest...
I've thought of about 9 ways to hold them... |
|
| Back to top |
|
|
ChrisR
Joined: 14 Mar 2009
Posts: 3035
Location: Near London, UK
|
| Posted: Tue Feb 14, 2012 5:13 pm Post subject: |
|
|
Measurements for the distance between the front of the filter thread, and the focused iris edge (f/8 ). looking from the outside end, come out as follows:
| Code: | 21mm f/3.5 17mm
24mm f/3.5 15mm
28mm f/3.5 18mm |
Not so bad then.
These are single shots of the edge of a vernier calliper, so the divisions are 1/40th of an inch (0.635 mm) Both at f/11.
One (lower) is with the 21mm out about 50mm from the camera ( 24 x 36 sensor), the other with a 20mm f/2 macro Oly simply held as close as it would go against the body.. It's not meant to be used at magnifications as low as this, but the FL is close and it was sitting there.
Sorry I left the ISO rather high.
Focus is a little way back from the edge on the 21mm pic, this is as close as I could get, almost touching the lens on the calliper so rather difficult to hand hold.
And the 21mm debarreled:
I wonder what Zerene would make of a stack which includes unstraightened frames.. I suppose Photoshop’s straightening tools might do it better?
I'll be trying a 20mm Nikkor. I might use that instead.
--
Last edited by ChrisR on Wed Feb 15, 2012 12:24 am; edited 2 times in total |
|
| Back to top |
|
|
rjlittlefield
Site Admin
Joined: 01 Aug 2006
Posts: 12557
Location: Richland, Washington State, USA
|
| Posted: Tue Feb 14, 2012 7:15 pm Post subject: |
|
|
| ChrisR wrote: | | I wonder what Zerene would make of a stack which includes unstraightened frames. |
Just tracing rays in my head, I think this will be fine. In a setup where nothing changes except the lens-to-camera distance, "refocusing" doesn't change any of the ray directions. As a result, whatever geometry distortion is introduced by the lens should be the same regardless of where the sensor plane is placed. Refocusing will certainly change the scale, by about 2X as you go between infinity and 1:1, but correcting for scale changes is just business as usual for stacking software.
The troubling case is with lenses that focus by changing the spacing of elements within the lens. In that case the ray directions can change, and for example the lens may develop more or less barrel distortion at close focus than it has at infinity focus. I've only tried that situation once (HERE) and in that case it worked OK with both Helicon and (later) Zerene, but that could have been luck.
--Rik |
|
| Back to top |
|
|
ChrisR
Joined: 14 Mar 2009
Posts: 3035
Location: Near London, UK
|
| Posted: Wed Feb 15, 2012 12:25 am Post subject: |
|
|
One obvious but ungainly way to do the focusing could be to use an M52(filter thread) - M42 helicoid, and an M42 camera adapter. The lens-heads would go inside the M52 end. Tha part of the lens which Charlie indicated as good to mount to, is about 43mm diameter. (They're all about the same). The thinnest available helicoid is 12mm, which looks to be thin enough. Focus would have to be by eg extending the helicoid 1mm, and moving the camera back 1mm. You'd need more than one helicoid and/or a full set of tubes to get out to say 50mm, but at least there would be nothing around the lens, in the way.
I see there are 12 - 17mm, 17 - 31mm, 25 - 52mm, and 35 - 90mm,
in M52 to M42 and M42 to M42. |
|
| Back to top |
|
|
Harold Gough
Joined: 09 Mar 2008
Posts: 5711
Location: Reading, Berkshire, England
|
| Posted: Wed Feb 15, 2012 12:39 am Post subject: |
|
|
| Charles Krebs wrote: |
Harold,
I certainly don't want to discourage your experimentation, but I would not irreversibly hack your 17mm lens. At least not until you are convinced it will give you a perspective that is worth it to you. |
Charles,
Thanks, but I have no intention of causing any harm to any of my lenses. I do have duplicates of my Tamron Adaptall-2 lenses up to 90mm but not for abuse, unless I find a very good reason.
| Charles Krebs wrote: | | At least for me, the wide-angle perspective is a key characteristic that makes all this fun to play around with. A 28mm of a 24x36mm sensor is about where this begins to show itself (again, for my tastes). A 24mm or 21mm would be even better. A 17mm on 4/3 is not all that wide. Also, keep in mind the diagram Chris drew earlier (near top of page 4). You definitely lose some "width" on the far background as the stacking software does its job, which makes the lens less "wide" than it would be with a single distant shot. (It is quite amazing how well the software deals with this situation). |
Yes. I would get only the perspective of a 35mm lens on full frame. This, again limits the value of too much effort (cost?). I don't know what is the potential is of my Lumix m4/3 7-14mm for this kind of project. This might give better resolution than e.g the Samyang 7.5mm.
[EDIT: The Lumix m4/3 7-14mm diaphragm operates entirely electrically. This prevents use of old film bellows and I have yet to find any for 4/3 or m4/3.]
In general photography I tend to use ultra-wideangle lenses more than many photographers would. However, on full frame 35mm, the desirable width brings with rather more vertical than is uiseful. This is why I increasingly use my X-Pan, with the horizontal coverage up to that of a 15mm lens.
The EP-2 gives me format options, with which I was very much preoccupied during the first few weeks of use, but I shoot in RAW and the whole file is saved anyway so I crop in PS.
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
|
| Back to top |
|
|
bvalente
Joined: 18 Jan 2010
Posts: 69
Location: Los Angeles, CA
|
| Posted: Fri Mar 30, 2012 8:04 pm Post subject: |
|
|
Hi all,
so after I don't know how many years, I think I've finally hit on my desired rig.
here's a sample shot
Stack processing is just a quickie with zerene
the rig is an NEX-7 camera with a Nikon lens mount adapter, 20mm f3.5 nikkor lens, and a bunch of really right stuff gear. The key was waiting for a high quality mirrorless camera. I had the lens mount machined in half so I could move the camera body without the lens moving. Really Right stuff and their macro plate did the rest.
What's really great about this setup is the image above is 15%, it gives a very high resolution full file, which can be viewed here:
http://bvalente.smugmug.com/Nature/infinitycam/22193298_ttXDzR#!i=1772338520&k=ZnN6ggL
image of rig here (it's a little hard to tell all the parts because it's on it's side to shoot portrait)
the camera body sits on a macro rail, the lens (adapter and lens) is attached via the lens adapter's foot to the front rail. So the camera moves behind the lens, while the lens stays in one place.
Thanks to everyone for help thinking this through and for charles coming up with the original inspiration.
Cheers
Brian
_________________
Cheers
Brian
Brian Valente
bvalente.smugmug.com |
|
| Back to top |
|
|
Harold Gough
Joined: 09 Mar 2008
Posts: 5711
Location: Reading, Berkshire, England
|
| Posted: Fri Mar 30, 2012 10:39 pm Post subject: |
|
|
| bvalente wrote: |
so after I don't know how many years, I think I've finally hit on my desired rig. |
Excellent. Just what I wanted to do, originally with film.
| bvalente wrote: | | image of rig here (it's a little hard to tell all the parts because it's on it's side to shoot portrait) |
Why not reload it, using the rotate feature of the upload?
Harold
_________________
Happiness is having the right adapter.
My manual flash setup for high magnification:
http://www.photomacrography.net/forum/viewtopic.php?p=117843#117843 |
|
| Back to top |
|
|
Craig Gerard
Joined: 01 May 2010
Posts: 2593
Location: Australia
|
| Posted: Fri Mar 30, 2012 11:06 pm Post subject: |
|
|
| Quote: | | I had the lens mount machined in half so I could move the camera body without the lens moving. |
More details...please 
Craig
_________________
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!" |
|
| Back to top |
|
|
ChrisR
Joined: 14 Mar 2009
Posts: 3035
Location: Near London, UK
|
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
