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First Jumping Spider of the year

 
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acerola



Joined: 13 Dec 2006
Posts: 251
Location: Hungary

PostPosted: Wed Apr 02, 2008 1:23 am    Post subject: First Jumping Spider of the year Reply with quote

I photographed all day Monday. I spent an hour with this spider. This picture is one of the best from the batch.


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Péter
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Ken Ramos



Joined: 27 Jul 2006
Posts: 7076
Location: lat=35.4005&lon=-81.9841

PostPosted: Wed Apr 02, 2008 2:42 am    Post subject: Reply with quote

I wonder what makes the hair stand up on their heads? Maybe it is the thought of being photographed. Think Laughing Anwyway a very good shot there Péter, nice background too. Very Happy
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beetleman



Joined: 04 Aug 2006
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PostPosted: Sun Apr 06, 2008 12:08 pm    Post subject: Reply with quote

The colors just make the picture more exciting. A wonderful picture.
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Harold Gough



Joined: 09 Mar 2008
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Location: Reading, Berkshire, England

PostPosted: Sun Apr 06, 2008 11:37 pm    Post subject: Reply with quote

Superb, although my personal style would be to get more DOF by closing down by at least one stop to get the palps sharp.

Harold
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acerola



Joined: 13 Dec 2006
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Location: Hungary

PostPosted: Mon Apr 07, 2008 1:42 am    Post subject: Reply with quote

Thanks Harold. I have to notice thought, that this is an extreme magnification 2x or 3x. And the aperture is around F20. I never use F32 because of the diffraction.
All I can do to play with the plane of focus.
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Péter
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Harold Gough



Joined: 09 Mar 2008
Posts: 5787
Location: Reading, Berkshire, England

PostPosted: Mon Apr 07, 2008 3:10 am    Post subject: Reply with quote

Péter,

I would differ with you as to the magnification being "extreme", reserving that designation for x 10 or more. However, I would agree with your reservations about diffraction. In fact it would be rare for me to use an aperture as small as f16 set on the lens.

For lower magnifications I would increase magnification by using a teleconverter (possibly two) next to the camera body. According to Alfred Blaker you gain the depth of field, when using teleconverters, equivalent to the effective smaller aperture but "somewhat" lose it due to the effects of magnification, an overall gain.

Again, according to Blaker, if you place a teleconverter behind a prime lens and an extension tubes behind the teleconverter, you will get the magnification of the teleconverter plus that as if the tubes had been between the lens and the teleconverter, but maintaining the working distance of the prime lens. (I had missed this and not tried it). This works only in close-up or macro work.

Harold
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acerola



Joined: 13 Dec 2006
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Location: Hungary

PostPosted: Mon Apr 07, 2008 9:27 am    Post subject: Reply with quote

I think this magnification is extreme enough for a live moving subject in the field. Smile
This setup is a Canon 100mm macro lens and a 55mm F1.4 M42 lens reversed as a closeup lens. I must use a fairly high F value for usable DOF. If I use teleconverter or extension tube then I can use smaller F value on the lens, but the effective aperture value will be higher. But I'm not at home in the theory like some other member in this forum. I will definitely try the teleconverter again as I manage to produce a little more light now.

This system has a very bright picture in the viewfinder. If I add the converter or the extension, the DOF will be increased with the same lens settings. But the effective aperture will change along with the brightness of the viewfinder and the working distance.
If I speak only from the DOF it must be the same to set a higher F number as to adding the extra elements before the macro lens.

With shorter focal length on the other hand you can achieve a less blurred background and in this case foreground for the same magnification. So the palps can be seen somewhat less blurred but it is true to the background too, resulting a less homogeneous background.

I read in John Shaw's book the setup you mentioned, I think I need to reread that again. All I remember is "there is no free lunch" you have to compromise.

Its a subject which worth the discussion.
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rjlittlefield
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Joined: 01 Aug 2006
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PostPosted: Mon Apr 07, 2008 10:09 am    Post subject: Reply with quote

Harold,

It is easy to get lost in the details of trading off DOF, resolution, and magnification by playing around with various lens arrangements. But as acerola writes, "There is no free lunch."

The bottom line is simple: everything depends on the final magnification and the angular diameter of the entrance pupil as seen by the subject. This is because the entrance pupil determines what light is captured to create the image. Ignoring second-order effects like aberration, all lens systems that capture the same light will create the same image, both for DOF and for diffraction blur.

It makes no difference to the DOF/resolution/magnification tradeoff whether you use a single lens on a long extension, or stacked lenses (short in front of long), or an ordinary lens plus a teleconverter, or any other combination of lenses somebody can think up.

The tradeoff is not even affected by what size of film or sensor you use, or how many stages of focusing are involved (macro lens vs compound microscope).

The major source of confusion about this issue is a failure to be clear about what is being held constant. I haven't read Blaker's presentation, so I can't comment on it specifically.

The forums have accumulated quite a lot of writing on this subject, but it is scattered across various threads that are themselves often confusing due to the interplay between various posters. I suggest starting with this posting: http://www.photomacrography.net/forum/viewtopic.php?t=4108&start=6, the links that it gives, and the follow-up postings, especially this one near the end of the thread, the part that begins
Quote:
The key insight behind "outside the box" and "equivalent images" analysis is that frequently it's better to concentrate on the light that forms the image, as opposed to the device that forms the image.

--Rik

PS. You can go to the start of the topic by removing the "&start=6" from the end of the URL.

Edit: to clarify the references.
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Harold Gough



Joined: 09 Mar 2008
Posts: 5787
Location: Reading, Berkshire, England

PostPosted: Mon Apr 07, 2008 11:55 pm    Post subject: Reply with quote

Rik,

Thanks. My understanding (all photography, not just macro) is that the situation is as you say. I dropped in the Blaker comment as I knew it would stimulate discussion. His use of the word "somewhat" is significant. It is one of those "it means what I want it to mean" words, or, perhaps, "it means what you decide it means".

Blaker, a very eminent specialist in photography, was, at one time, Head of the University of California Scientific Photography Laboratory. Of course, that does not mean he is not bound by the laws of optics.

Nothing to do with DOF; another interesting observation: he found that getting x6 magnification by stacking a 2x converter and a 3x converter behind a x1 setup gave a 7 stops loss of light, compared with getting the same magnification with extension tubes, where the loss was "a little under six stops".

In both cases I have quoted Blaker's Field Photography book.

See my 7 April posting:

http://www.photomacrography.net/forum/viewtopic.php?t=424&start=15


Thanks for the link to the thread. I have to say that the term "entrance pupil" might be correct but I relate more to rays of light being +/- parallel to the axis of the lens (telecentric) and thus giving great depth of field, a matter of geometry.

I saw something about old, large format cameras and blurred images at wide apertures. Those lenses were made, and optimised, to be used only at small apertures for landscape work and were of poor quality for use with their wider apertures which were, presumably, for focusing and composition.

As a film user, I have a minimal understanding of digital technology. However, it seems important, in some contexts, to differentiate sensors from pixels, as in "digital sensors are essentially photon counters". While that is true, they also, via filters, have to differentiate between wavelengths or we would have monochrome.

Harold
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