Trouble grasping numbers and resolution with higher mag

Just bought that first macro lens? Post here to get helpful feedback and answers to any questions you might have.

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Koorosh
Posts: 215
Joined: Fri Jun 20, 2014 3:39 pm
Location: London

Post by Koorosh »

Actually, I can give you a link to one of my images on Flickr. That wasp I would say is about 1.5mm maybe, and I imaged it for a man of high standards. Not to say that the image is excellent or anything, but that the body was not obscured and the wings are flat and clear (albeit entirely articificial in appearance for my liking). I took six separate stacks in all to get the lighting right for a few awkward parts, and there wasn't a great deal I could do about the separated pronotal collar. Critical point drying is one of the best methods for preventing collapse of tiny wasps but the results aren't 100 percent (this one is from a museum specimen, mounted on top of a micropin with wings removed and placed on a separate slide). The micropin would best be painted matt black based on issues fast with burnout.
On the point of wasps, what type of wasp are you having trouble with? I can't image many of the wasps I want to because they collapse with drying, but I have been told about alcohol xylene amyl acetate producing excellent results. If you search for AXA method of drying in Google you should be able to find a paper on it if you aren't already familiar with it.
For the stuff I've posted, I have them all on card points. Again, I really wish I had grey or black points because it would make controlling light a lot easier. I only point wasps that I know don't really collapse because they have quite a sclerotised exoskeleton. I have calibrations for my scales at various magnifications so I'll add some if I get more time. I've never used them but think they would definitely help.
What glue are you using and are you diluting it? I would only ever recommend secotine fish glue for wasps because it doesn't leave a residue and is easy to dilute/ get off if remounting. For tiny wasps I do use points as well, which will inevitably be quite large in comparison to the wasp and probably a photoshop job to get rid of. An absolutely tiny wasp my be worth actually gluing to the tip of the point instead of bending the end down. I haven't tried anything less than about 1.5mm yet I think, but I'm not sure. Usually that's because they will collapse, but Diapriids and Platygastrids would be fine, being made of solid rock :)
My other suggestion is also that- I found catching wasps and killing them with a very light fuming of ethyl acetate, or a quick freeze, appeared to make them collapse much less than out of ethanol. Ethyl killed also makes them a lot more flexible. If body parts are unwilling to stay in position, I leave them for a little while to stiffen slightly and have another go. Sometimes that ends badly :)

Koorosh
Posts: 215
Joined: Fri Jun 20, 2014 3:39 pm
Location: London

Post by Koorosh »

And thank you for the compliments, glad you like the images!

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