A Belated New Year Dragon (Dytiscus leg) Pic. added

Cactusdave · Post by **Cactusdave** » Mon Jan 30, 2012 2:48 pm

A bit late for the Chinese New Year, but when I saw this under polarisation with a 1/4 wave plate it just looked so much like one of those dancing dragons that I couldn't resist posting it.

Actually of course this is the modified forelimb of the Great Diving Beetle, Dytiscus, a favourite subject for Victorian slide mounters and a favourite of photomicrographers. I see for example images of this subject featured in the winning list of both the Nikon, Olympus and Wellcome Images competions in recent years. The fore tarsi, of male Dytiscus marginalis, have an expanded plate with 2 large suction cups and dozens of additional smaller cups. These are used by the male to clasp the back of the female during mating in water. These suction cups are capable of holding onto objects that weigh over 4 times more than a female beetle.

This particular picture was taken on a Nikon Diaphot with front mounted (2.5X magnification factor) Canon 40D, Nikon LWD 0.55 phase/DIC condenser and Zeiss Planapo 4X 0.15 objective. Illumination was by polarisation with a 1/4 wave plate inserted. The image is stitched from 29 individual images with Microsoft ICE.

This is what the same subject looks like without the 1/4 wave plate in the light path. A stitch of 30 images.

To complete the set I took a series of images with the X4 Zeiss objective and the X40 DIC prism. This mismatch gives a fairly weak, but useful DIC effect, and some work was needed in Photoshop to even up the background. This is a stitch of 33 images.

Edit: Link to a Photosynth large version (124 Megapixels) for the last image. http://photosynth.net/view.aspx?cid=376 ... 638a2524a6

RogelioMoreno · Post by **RogelioMoreno** » Mon Jan 30, 2012 2:58 pm

Wow, very beautiful!

Rogelio

Cactusdave · Post by **Cactusdave** » Mon Jan 30, 2012 3:25 pm

Thanks Rogelio.

curt0909 · Post by **curt0909** » Tue Jan 31, 2012 2:03 am

These could be award winning photos. Nice work

Cactusdave · Post by **Cactusdave** » Tue Jan 31, 2012 2:19 am

That's very kind of you Curt, thanks. Take a look at Spike Walker's image though. You can see why that got a lot of acclaim. http://www.mnn.com/earth-matters/wilder ... s-biosc-15 I think I have a way to go to match that.

arturoag75 · Post by **arturoag75** » Tue Jan 31, 2012 2:21 am

Really artistic shot..well done!

Arturo

Cactusdave · Post by **Cactusdave** » Tue Jan 31, 2012 3:06 am

Thanks very much Arturo.

Mitch640 · Post by **Mitch640** » Tue Jan 31, 2012 5:56 am

Beautiful work Dave. I am partial to the last one, because it seems to show more real detail than the others, and it looks much sharper. All your images are just awesome.

Cactusdave · Post by **Cactusdave** » Tue Jan 31, 2012 2:06 pm

Thanks Mitch. It took three attempts to get that last composite. The first two gave just too much variation in illumination across the subject to be able to compensate sensibly in Photoshop. Little tweaks in the DIC settings make a huge difference, especially when working with mismatched components.

curt0909 · Post by **curt0909** » Tue Jan 31, 2012 2:47 pm

Cactusdave wrote:That's very kind of you Curt, thanks. Take a look at Spike Walker's image though. You can see why that got a lot of acclaim. http://www.mnn.com/earth-matters/wilder ... s-biosc-15 I think I have a way to go to match that.

I've seen that photo before. It reminds me of an impressionist oil painting. If Monet painted beetle legs it would look similar to that. Your image is good in its own right, different lighting technique. And if its not as aesthetically pleasing which is subjective anyway, it is more detailed.

curt0909 · Post by **curt0909** » Tue Jan 31, 2012 2:48 pm

Mitch640 wrote:Beautiful work Curt. I am partial to the last one, because it seems to show more real detail than the others, and it looks much sharper. All your images are just awesome.

I'm confused is CactusDave's real name Curt also?

Cactusdave · Post by **Cactusdave** » Tue Jan 31, 2012 3:05 pm

Thanks Curt. No Cactusdave is actually a David who is also interested in Cacti. I think Mitch had a momentary confusion between us as we both recently posted images he kindly commented on.

David

Mitch640 · Post by **Mitch640** » Tue Jan 31, 2012 3:10 pm

OOpps, I meant Dave.

harisA · Post by **harisA** » Thu Feb 02, 2012 2:14 am

Magnificent award winning images David. I like most the third one.As far as i understand zeiss 4x/0,15 is of finite type and is mounted on a nikon microscope.Do you project directly to canon sensor or there is some kind of correcting optics (photo eyepiece )between sensor and objective?

Thank you in advance

Haris.A

Cactusdave · Post by **Cactusdave** » Thu Feb 02, 2012 8:17 am

Firstly thanks very much for your compliments Haris. A.

You raise a good point about the use of objectives not matched to the rest of the microscope optics. The Nikon Diaphot inverted microscope I use is a 160mm tube length design and, as I understand is designed for finite CF objectives, ideally for its original purpose, long working distance designs. The microscope is equipped with two photoports, one at the side designed to take a large format camera back or a video camera and one at the front designed to take an SLR film back. This front port uses an in-microscope X2.5 lens to form the image at the camera sensor plane. My understanding is that this lens does not make any correction of residual chromatic aberration from the objective and the expectation is the use of CF objectives. I mount a Canon DSLR at the front port, using a chipped Nikon F to Canon EOS adapter. I have several Nikon CF objectives that I use on this microscope, a X2, X4, X10 DIC, and X40 DIC. I also have several other non-CF and non-Nikon objectives that I use on this microscope that I have found work reasonably well. Lenses I use from time to time include a Nikon M plan X20 DIC designed for 210mm tube length, Zeiss X4 0.14 planapo, Zeiss X6.3 0.20 Neofluar, Zeiss x25 0.65 planapo and LOMO X30 0.90 water immersion. There is no doubt that these lenses give chromatic aberration issues with the Nikon setup, but with these relatively low magnification objectives the issues are able to be compensated for more or less adequately in post processing. I use these lenses because of their high resolution, because they fill in magnification gaps in my CF lens collection, and experience has shown they work, to a greater or lesser extent, and often with considerable problems of uneven field illumination, with my Nikon DIC condenser's X10 and X40 prisms, a very useful attribute.