Flys eyes

Charles Krebs · Post by **Charles Krebs** » Thu Sep 13, 2007 10:46 pm

I've been trying to see how much magnification I am comfortable with when making stacked images on a tabletop with camera bellows and such. The precision and stability of a compound microscope (don't have a good stereo) is wonderful, but it can sometimes be troublesome getting the subject at the proper angle, and setting up the lighting and background can get tricky.

So this fly happened along just as I was going to try a 20X shot. The "overall" shot lets you know what you are looking at in the two images below it.

Adrian · Post by **Adrian** » Thu Sep 13, 2007 10:56 pm

nice photographs, my eyes feel abit funny from the patterns of the eyes, i wonder what those little black dots are, they wouldnt be pupils would they?

Charles Krebs · Post by **Charles Krebs** » Thu Sep 13, 2007 11:33 pm

The black dots are the reflection of the front of the lens where it pokes through the small diffuser I'm using.

Adrian · Post by **Adrian** » Fri Sep 14, 2007 12:13 am

ahhh i see like in that spider eyes photo avatar your using haha..

Thanks.

Bruce Williams · Post by **Bruce Williams** » Fri Sep 14, 2007 2:17 am

Excellent work as always.

The 20X looks very clean and detailed with no obvious distortion...how much further do you think you can push the magnification with your current tabletop setup?

Bruce

Charles Krebs · Post by **Charles Krebs** » Fri Sep 14, 2007 4:07 am

Bruce... I think 20-25X is about as far as I will go regularly. The optics are not especially the problem, it's the "physical", mechanical part. Vibration issues grow exponentially. If a car drives by outside I see things jitter. I even turn off the stereo. (otherwise, when BB plays the blues my subjects bounce around in rhythm with the sub-woofer!) I've got a few more tricks to try, but after 20X the stability and precision of my Olympus BHS is awfully appealing.

puzzledpaul · Post by **puzzledpaul** » Fri Sep 14, 2007 6:16 am

Can only copy Bruce's comments - excellent as usual.

As regards vibration issues, I was wondering if something like a false plinth / top placed on the table top and mechanically isolated from it might help?

If I ever tried this sort of thing, I'd have problems with false / non concrete floors in most convenient parts of the house and considered whether a slab of marble, approx 30 in square, 1in thick (which I already have) supported by 3litre wine box bladders, semi-inflated, would be worth trying?

pp

beetleman · Post by **beetleman** » Fri Sep 14, 2007 1:09 pm

I know when I worked in optics, in the QC room, they had a table that was on four rubber inner tubes and one that was leveled by automatic air cylinders on all four corners. The table was made of steel and weighted 600 lbs. ALso, I know with the larger telescopes from Meade and celestron, they sell these little donut things called vibration surpression pads to put under the legs of the EQ (sorry Equatorial mounts) mounts.
http://www.celestron.com/c2/product.php?ProdID=380

beetleman · Post by **beetleman** » Fri Sep 14, 2007 1:15 pm

oops, forgot to comment on the pictures.............WOW

Adrian · Post by **Adrian** » Fri Sep 14, 2007 2:36 pm

oh god, those sub-woofers are a nightmare, they shoulve never been created!

Charles Krebs · Post by **Charles Krebs** » Fri Sep 14, 2007 5:02 pm

These Sorbothane hemispheres are something I'll try:
http://www.edmundoptics.com/onlinecatal ... uctID=1618

I have moved the camera and subject stands on to a 3" thick laminated wood platform that rests on the counter-top. (Before I did that, if I leaned even lightly on the counter-top, the slight "flex" of the surface would change focus about 3 DOF distances!) A heavy slab of something like marble would be even better... and Doug, that 600lb steel table sounds like just the type of "overkill" (for my situation) that is fun to contemplate.

.... hmmm ... maybe it's time for a trip to Boeing surplus....

jmlphoto · Post by **jmlphoto** » Fri Sep 14, 2007 9:14 pm

more awesome pics. i like the last one best, it would make a cool poster.

puzzledpaul · Post by **puzzledpaul** » Sun Sep 16, 2007 9:06 am

<< that 600lb steel table sounds like just the type of "overkill" (for my situation) that is fun to contemplate. >>

Make one wonder about how a 10cu foot (or greater) container (with decent, smooth, flat) top would perform - when filled with water and (also) mounted on isolating pads ...

Then empty (and move) same when swmbo complains

pp

DaveW · Post by **DaveW** » Sun Sep 16, 2007 11:06 am

The DIY anti-vibration table I heard of was an inflated car inner tube with a 2" thick 3ft x 2ft concrete paving slab placed on it. I would think one slab would weigh about 160 pounds, so you could put two on top of each other if you wanted and use two inner tubes to support their length if needed.

Failing that you could always put "In the still of the night" on the stereo!

DaveW

Charles Krebs · Post by **Charles Krebs** » Sun Sep 16, 2007 3:23 pm

Fortunately there is little traffic by my house, and I can keep the stereo off. But since I have a separate "subject" stand and "camera" stand it really becomes important to avoid any "flex" in whatever base they rest upon. And I've been amazed at how little force is needed on most surfaces to cause a deflection that becomes very noticeable through the camera.