Photography of biological specimens

[dumbdora]

Hello,

I am biologist, however high-minded that may sound (and rather dull ) on the onset of my photgraphic actions. I have no prior experience in photography, but now i must take some serious photos. My objects are skull skeletons. The fact is that my analysis exerts some serious standardizations of taking photos of specimens. I am in doubt not so much of the type of camera that i should use, but of the construction of some kind of holder. With the help of that thing i could orient every skull precisely in various planes. Specimens are numerous and standardizing photographic environment is essential to analyzing them later. Should i use some wood construct, metal, or even plexiglass is beyond me. It should be lightweight because thees are field photos. Also it should contain mechanism for accommodating skulls of various sizes, and orient them in regard to some marker.

Any ideas?

[David]

Hi Dumbdora - I'm not sure about the specifics of what you ask, but I would have thought that there must be scientific texts on this type of photography. Probably even basic forensic texts would give some information about standards and protocols for such shots. Perhaps there are others on the forum that have more expert advice.

Cheers

David


PS Welcome to the forum.

[dumbdora]

thanks David,

belive me i searched and i searched through scientific community and forensic texts also but always they hide their methodology or, in most cases there is none. They rely on experience solely so measurement mistake is unpredictable. I am thinking on some kind of grip, like the ones used to hold lighting...i guess

[Dave Humphries]

Hi dumbdora,

Firstly, please tell us a real first name (err, Dora?), so I don't have to call you dumb everytime! Ta.

OK, I'm an ex-engineer and I like a challenge, but I need to know more.

1) Am I correct to assume we are talking purely human skulls? for now I shall assume so.
2) I would think there must be an 'industry standard' way to view a skull square-on to a camera, this obviously needs to work regardless of the ethnic origin of the donor, which maybe an issue - I would imagine that differences might result in a change in perspective, and hence the relative size of features between forehead and chin.
3) Assuming also that the photos will be computer analysed or modelled, I would think the holding/mounting mechanics wants to be either;
a) as simple and obvious as possible so that the computer recognises and discards it, or
b) effectively invisible (e.g. your plexi-glass idea)
4) Are they still "evidence" or 'sacred' and hence not able to be damaged in anyway? (unlike those donated for research)
5) What quantity of skulls do you envisage? A rig for 10 could be more basic than one for 100, 1000 or more
6) How much time do you have for each shot, or put another way, how many per day to process?
7) Is this field or lab work?
8) Does the budget allow some computer controlled robotics to position the skulls semi-automatically for consistency?
9) Are you working alone on this, or what facilities can you call upon?

This is an unusual request for help and one can only guess at how or why you need to do this
Not that I am qualified beyond being interested in the challenge, maybe a PM would be a better place to progress this. However, I'm sure there are better sources of information than me!

If you could also do me a favour by popping over to the introductions thread and telling us a bit about yourself, where you are, etc.

Regards,

[Raycer]

[COLOR=#cfcfcf]Hi Dora, (my girls love Dora)
[COLOR=#cfcfcf]
[COLOR=#cfcfcf]This sounds like a project that's calling my name.
[COLOR=#cfcfcf]I’m just thinking out loud here.
[COLOR=#cfcfcf]
[COLOR=#cfcfcf]The frame:
[COLOR=#cfcfcf]I am thinking an aluminium framed cube with covered with dark cloth to keep ambient light out. I am assuming you want to have consistent lighting.
[COLOR=#cfcfcf]
[COLOR=#cfcfcf]The table top:
[COLOR=#cfcfcf]Plywood with a 'lazy Suzan' like turn table for the skull. It would have to have grid to show angle and placement.
[COLOR=#cfcfcf]
[COLOR=#cfcfcf]Lights:
[COLOR=#cfcfcf]At least 2 flashes with 45° at 45° set up. possibly with softbox.
[COLOR=#cfcfcf]
[COLOR=#cfcfcf]Camera holder
[COLOR=#cfcfcf]A macro rail?

Additonal table for a laptop?

[dumbdora]

Thank you for all the interest...i didn`t even imagine that this could be interesting. First i need to answer some of David`s questions...Unfortunately skulls that i deal with are mostly deer and chamois goat type (i will upload a picture). All specimens come from variety of natural settings, and measurements and photos must be taken on sight in natural setting, or, at best, in nearby (very hospitable ) villages (because local hunters have some nice specimens). So equipment that i carry should be as lightweight as possible. And it should be easy to separate from skull itself in post-processing of digital photo. It just needs to be in contrast so that i can erase it later easily. Also number of specimens is fairly large, about 200 i guess, and maybe 20-30 per day photos, and measurements. Budget is fairly low so unfortunately no robotics can be planned. And i am afraid that this "monster construct" will be mine, and mine alone to create, though i will have some help in the field.
Second i want to thank Raycer for the interest, and i must say that i didn`t even know about "macro rail" camera holder for which i think will be good for positioning. Other things i cannot even envision but i deem they must be somehow turned to lightweight for reasons stated above. You will see the photo of things that i talk about, and i hope it will be of some help.

As for DumbDora, i really dont know why i got addicted to that nickname...sometimes it is a form of social critic, and sometimes (mostly ) it is a critic of me... http://www.comicstripfan.com/newspaper/d/dumbdora.htm

[dumbdora]

these are the images i should deal with. This is the skull of roe-deer Capreolus capreolus. They are about 20 cm (the most) in length.

[Steaphany]

Dora,

What form of post data collection information extraction will you be doing with these photographs ?

If you need to calculate measurements in three dimensions, an obvious requirement from my point of view, you may need to shoot perspective or stereo pairs of images, similar to what is done to create the Red-Cyan Anaglyph images. Additionally, you may want to consider processing perspective pairs into Red-Cyan Anaglyphs for presentation purposes which would allow people reviewing your research to perceive the three dimensional nature of your source images, especially since skeletal structures are three dimensional.

A reference source for information of how to proceed that comes straight to my mind is to talk with the image processing and analysis teams at NASA who work with the data collected from the Mars rovers. The cameras on the Mars rovers record scenes and objects in two dimensions, yet, for accurate analysis and presentation, the images are processed to permit the data extraction necessary. Much of the photography is done as perspective or stereo image pairs specifically to extract the three dimensional nature of the scene.

Mars Exploration Rover Mission Project Team

Potential contacts:
Adnan Ansar
Shane Brennan
Yang_Cheng

Please do not hesitate contacting NASA staff, NASA has a long track record of technology transfer and applying their research efforts to sciences well outside aerospace and space exploration.

You can use a macro rail rotated 90 degrees to translate a camera a set distance left and right allowing for stereo image pair photography. For later analysis, knowing the precise distance that the camera was translated is critical to computing the three dimensional features. I also recommend that you use a prime lens instead of a zoom. Knowing the exact focal length is also important for stereo pair processing.

For a camera suggestion, take a look at the Sigma SD14, presently low cost since it's successor, the SD15, is about to come out. The SD14 provides wonderful clarity since it does not use a Bayer masked imager and it does not utilize an anti-aliasing, soft focus, filter common to all cameras based on Bayer imagers. Lens wise, I recommend the Sigma Primes with Macro focusing with the EX designation - their higher quality lenses.

BTW, this is interesting, I'm a techi, and a perfect application for photography.

[dumbdora]

thanks Steaphany,

i have contacted dr.Chang and am waiting for the reply. I hope he will be interested in this subject.

The analysis i intend to conduct later focuses primarily on geometric morphometrics techniques such as superimposition methods,grid thin-plate splines, and analysis of outlines. So it is mainly 2D analysis but it would be a waste not to be able conduct 3D coordinate analysis later (in my career ). I doubt i would get a second chance at taking those photos and it is best to take all the information i can get.

and a noob question...what is prime lens?

[Steaphany]

A Prime lens is one which has a fixed focal length which generally provides better performance than a Zoom which needs to balance a larger range of optics parameters to achieve the variable Zoom functionality.

[Colin Southern]

A Prime lens ... generally provides better performance than a Zoom which needs to balance a larger range of optics parameters to achieve the variable Zoom functionality.

At least that's the theory anyway.

A lot of people seem to read into this something along the lines of "prime = best image quality" and "zoom = not so good image quality" whereas - especially with L-Series Canon primes and zooms - the image quality from both types is superb ...

... with the only difference in reality often being that the primes may require a little less post-processing to get essentially the same result.

In my opinion, primes are more useful for their increased speed where there isn't a zoom to do the job (eg EF85/1.2L), but for general use the zooms win out by having more than adequate image quality, but the versatility of the varying focal lengths.