Spider

Images taken in a controlled environment or with a posed subject. All subject types.

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PaulFurman
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Spider

Post by PaulFurman »

Found dead in an outdoor sink, my guess is male orb weaver Araneus trifolium, I've seen a a female nearby.
Does anyone understand the structures below the crab claws?

Image Image
Oly 20mm f/2 fairly small bellows extension (5x?)

f/5.6, 2 sec, 67 steps of 20 microns each - f/2, 1/2 sec, 46 steps of 10 microns each
Last edited by PaulFurman on Mon Dec 21, 2009 9:14 am, edited 1 time in total.

rjlittlefield
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Post by rjlittlefield »

I think the "crab claws" are expanded lobes on non-terminal segments of the pedipalps. The big ball-shaped things below them will be the terminal segments. On the inner face, those will have elaborate structures used in sperm transfer. See HERE for a closer view of a very different species. Scroll down for stereo (here), which will help a lot to understand the structure.

--Rik

PaulFurman
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Post by PaulFurman »

Oh, excellent, now it all makes sense.

I'll see if I can get another peek from underneath. I've got this guy mounted on thin copper wire on a thumbtack with enough wire that I might be able to bend it back. Or maybe peeking in from straight above.

PaulFurman
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Post by PaulFurman »

Two more shots from above, looking down into his love-mitt. The second is from the same viewpoint at around 10x on the oly 20mm f/2.
Image Image

LordV
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Post by LordV »

Lovely series of captures :)
Brian v.
www.flickr.com/photos/lordv
canon20D,350D,40D,5Dmk2, sigma 105mm EX, Tamron 90mm, canon MPE-65

ChrisR
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Post by ChrisR »

The one on the left last looks like a deep stack. It would look good as a 3D pair??{-o<
I'm curious sbout the shadow repeats of the dust bugs in the one on the right. They seem to be all over but show clearly
here

The BAT
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Post by The BAT »

ChrisR wrote:The one on the left last looks like a deep stack. It would look good as a 3D pair??{-o<
I'm curious sbout the shadow repeats of the dust bugs in the one on the right. They seem to be all over but show clearly
here
:shock: Sheez, there's no hiding anything from you blokes, is there? :o

PaulFurman
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Post by PaulFurman »

I can't do stereo pairs without goggles of some sort. I did save these as projects so could try the rocking thing in Zerene.

Pic #3 (zoomed out) is 78 frames, the others are at least 47 deep.

These were on the Oly 20mm f/2, not that Canon 35mm (corrected in my text above now).

Regarding dust trails, I messed up & did the closeup #4 at f/5.6 and max bellows so diffraction softened it & the dust went berzerk :-(
I think that was more like 13x so effective f/78

I just re-shot at about 7x f/2 = f/16 and 121 frames at 50 microns, zoomed out to include the eyes (but clipped the fancy elbows).
(corrected from 5 microns)

Pic #1 above is also at f/5.6 but a much shorter bellows draw.

Pic #2 is at f/2.

Pic #3 is 85mm f/5.6 at maybe 1.5x

Image
Last edited by PaulFurman on Tue Jan 05, 2010 9:45 am, edited 1 time in total.

rjlittlefield
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Post by rjlittlefield »

At original size, these all have a granular appearance that looks like aggressive sharpening of PMax output. I guess that would also explain the dust spots turning into little doughnuts.

What sort of sharpening are you doing with these?

--Rik

ChrisR
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Post by ChrisR »

But does that explain the second/shadow/dimmer repeated dust trail?
double "original" size, left half of clip above.

Didn't NU have some of these?

rjlittlefield
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Post by rjlittlefield »

ChrisR wrote:But does that explain the second/shadow/dimmer repeated dust trail?
Oh, I see the concern now.

Those are just two dust spots, each producing its own trail. Two dust spots close together will always produce trails that have the same shape and size. In this case, the lower-right spot happens to be not quite as intense as the upper-left one, so it gives the impression of being a "shadow".

NU's were particularly interesting (HERE) because the "trails" formed dense triangles that I did not recognize as trails and thought were some other artifact.

--Rik

PaulFurman
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Post by PaulFurman »

Yep, aggressive sharpening but at a very small 1/2 pixel radius. This approach makes background noise, jpeg artifacts & jaggies look bad but increases visible detail for prints IMO without halos. I guess it is too much for on-screen. I'm almost tempted to anti-alias with a very small blur first.

Here's a full crop of the same scene at 14.4x (stretching the lens), effective aperture f/31 with the left side sharpened, the right straight out of zerene:

-click-link is to the full un-cropped, sharpened original
[edit, this is now a 200% view]
Image
Last edited by PaulFurman on Mon Dec 21, 2009 4:33 pm, edited 2 times in total.

rjlittlefield
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Post by rjlittlefield »

Paul, the best parameters for sharpening depend on how much the image was blurred by the optics.

Strong sharpening with 1/2 pixel width is appropriate for printing images that were shot with very sharp optics.

But in this extreme macro regime, diffraction blurring means that the optics are not very sharp. The 1/2-pixel level contains very little besides noise. Aggressive sharpening at that level makes the noise more obvious but does not restore the finest real detail, which is at a coarser level.

I suggest to experiment with significantly wider filters, say in the range of 1.5 or 2 pixels, probably with a smaller coefficient. While you're doing this, beware the pixel level noise. It's not uncommon for that stuff to look like real detail even though it isn't. Comparing with featureless OOF background can give some insight about this.

--Rik

PaulFurman
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Post by PaulFurman »

I replaced the crop with a 200% view side by side to make it clearer.

Sometimes it makes things worse but this area seems to get improved detail.

I have used the sharpen tool as a way of measuring sharpness; if you reduce the radius to 0.3mm in photoshop, and crank up the amount, a soft shot will not show any change other than noise. Then slide the radius till it's having an effect. But these macros don't seem to play by those rules. There's always diffraction circle edges to be sharpened :-) Or just blob edges, since I'm probably beyond the resolving power of this lens.

ChrisR
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Post by ChrisR »

"Threshold" at 1 will help hold pixel noise in Unsharp Mask, and
"Smart Sharpen" can work better.
AndrewC and others use specialist products, which may be better.

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