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Jonathan Ashton
07-24-2014, 09:12 AM
Tripod Canon 1DX Canon 180mm macro ISO 1250 fill in flash -1.6 1/30 sec f16.
The moth is on a dead log and the background is an old brick wall. I intend to borrow a focusing rail and do some stacking.
I did some "false" staking by focusing through different parts of moths and stacking them in CS6 and much to my surprise they did not come out too badly. The resultant image will not of course be as good as when using fixed focus and a focusing rack. There is a good reason for this ..... do you know what it is?

Jonathan Ashton
07-24-2014, 09:18 AM
You are probably wondering why it is called Swallow tailed, this is why:

John Robinson
07-24-2014, 01:39 PM
Jon
Supposed to be somerhing to do with magnfication shifts etc but you may find the rail system not that easy.Needs to be a good one. Didnt work on the cheap one I had. Nice shots.
JohnR

Ron Conlon
07-25-2014, 10:19 AM
Stackfest!
There is a discussion here of why and when to use the focussing ring versus using a rail <http://zerenesystems.com/cms/stacker/docs/troubleshooting/ringversusrail>. According to that discussion, should you choose not to follow the link, the focus ring is likely preferred for subjects this large and larger over the rail.
Not that I have a lot of experience myself in stacking, but many online sources consistently recommend just a few stops down from wide open for aperture.
I soon gave up on stacking in Photoshop in frustration, once I got hooked on stacking. If it is an occasional thing and you don't feel the need to retouch it works fine some times, other times balking for no apparent reason.

nick clayton
07-26-2014, 09:03 AM
I love the second image of this beautiful looking moth Jonathan, the exposure is spot on and shows the detail well.

Diane Miller
07-27-2014, 11:20 PM
The view of the moth from the top looks like parchment -- lovely!!

Look forward to the answer to the question you posed, and will look into Stackfest. I would have thought both a rail and focus ring had the same issue of changing the magnification, but stacking algorithms seem to deal with that very well.

Jonathan Ashton
07-29-2014, 09:44 AM
The point is that when there is a fixed distance between the camera back and the subject there is a fixed magnification for a given lens. If the focal point as is moved by virtue of moving the camera then the magnification will remain constant because the focal distance has remained constant. So using this method you would end up stacking images all of the same magnification.

If you focus and shoot and then refocus further in the subject and repeatedly so until you go through the other end of the subject then the distance between the camera back and the subject would vary so you would end up stacking images of differing (yet possibly similar) magnifications.
Different programmes have varying abilities to make the stacked images compatible.