Shattuckite - first post to this forum

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

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JW
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Shattuckite - first post to this forum

Post by JW »

Been doing photomicrography for a while, always striving for improvements. After reviewing many posts here, finally decided to stop lurking and get posting.

Equipment is a Nikon CF Plan 10x EPI stuck onto the end of about 20 cm of extension tubes (no tube lens) on a Canon 10D (yes, that old!) with dual off-camera flash. Manual exposure at 1/200 shutter. I tried using a 75/300 zoom lens as a tube lens, but vibration was not acceptable, need to work on better stablization, so decided to try without tube lens

Subject - shattuckite from the Eagle Eye mine, La Paz Co., Arizona
subject was a bit soft in that there were no areas of good contrast, and was sitting in a deep vug as well.

ZS Pmax, 43 images - some chromic aberation is apparent, but this may be a prism-type scattering from some of the crystallites rather then arising from the lens

Full size image has about a 1.5 mm field of view

Comments and suggestions welcome
thanks, Jeff

after stacking and a bit of PS to adjust histogram
Image

100% crop of above
Image

rjlittlefield
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Post by rjlittlefield »

Jeff, welcome aboard! :D

This looks promising.

Assuming that objective is an infinite, then it will definitely give a sharper image with a tube lens.

I'm curious about the vibration problem. If you're using consumer-type flash units at low power, then their flashes will be quite short, something around 1/10,000 second at 1/8 power or less. In this range, vibration is normally not much of a problem. However, if you have some continuous lighting mixed in, then it might contribute enough during a 1/200 exposure that you'll see the vibration. Can you say some words about your vibration problem, and maybe post out an image so we can see what you're talking about?

--Rik

JW
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Post by JW »

Rik

Thanks for the comments - I am thinking of going back to my old vertical setup whioch should minimize some of the vibration. I'll get to this once I recover from a head cold, right now can't even focus to walk across the room!

Jeff

phreakocious
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Post by phreakocious »

Cool pics, Jeff! There's a nice chunk of shattuckite sitting here waiting for similar attention... =)

JW
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Post by JW »

Here is the same subject with a Canon 75/300 (IS off) zoom as a tube lens, set to 200mm and f/8. I used Charles Kreb' suggestion to set exposure time to 1 sec, with second curtain sync on the flash, to allow vibrations to dampen prior to exposure. Although not clearly apparent, there is an improvement in the image quality - the two sets of images being taken on different days, with different flash and specimen orientations.

Field of view = 1.5 mm. Crystals are shattuckite, smooth blue is chrysocolla, minute yellow may be mimetite, and clear crystal at top looks like calcite, but this mineral is not reported from the locality.
Image
It's not what you look at that matters, it's what you see - Henry David Thoreau

JW
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Joined: Wed Feb 23, 2011 7:38 am
Location: New Haven, CT, USA

Post by JW »

It's not what you look at that matters, it's what you see - Henry David Thoreau

conkar
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Post by conkar »

Hi JW!

I looked at your setup and one thing that consider me was the silvery surface of the IKEA candle stick. To hit a flash on that surface might add unwanted reflections and flare to the lense. I think that it would be a good idea to cover that silvery surface with some neutral none reflective material.

I have found out that a white cheap coffee filter turns out to be great if you like a good white background. A black background is harder to get nice if your subject is close to the surface when the flash hit it. It tends to be grey. IMO it's best to get the subject away from the black surface if you like to get a nice black background, or spend some time in PP.

In the end of the day it's all about trial and error..... :roll:

Best regards,

Conny

JW
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Post by JW »

Conny

thanks for your comments - yes, I do cover the IKEA candle stick holders with a flat black cloth to prevent flare and stray reflections. Since my field of view with this set-up, with the 10x Nikon objective lens, is only 2 mm, I am not concerned with backgrounds, as the 2 mm field does not go beyond the specimen that is being imaged.

For larger items, with subject matter larger than 1 cm or so, I don't use the candlestick holders, but rather place the items on a sheet of glass - placing the glass about 6" above the enlarger baseboard gives me an out-of-focus neutral grey background from the baseboard, or as needed, I place white, black, or colored backgrounds and even adjust lighting to get a gradiated background.

Jeff
It's not what you look at that matters, it's what you see - Henry David Thoreau

conkar
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Post by conkar »

JW wrote:Conny

thanks for your comments - yes, I do cover the IKEA candle stick holders with a flat black cloth to prevent flare and stray reflections.Jeff
Ok, thats sounds good, I just thought it looked kinda dangerous to hit a flash at that surface when I saw your setup.

BTW,

I been recommended a book about lightning by a friend of mine that works as a professional photographer.

It's called:
Lights: Science & Magic: An Introduction to Photographic Lighting
ISBN: 9780240808192

She said thats's the books of books if you like to know more about lightning.

Regards,

Conny

JW
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Joined: Wed Feb 23, 2011 7:38 am
Location: New Haven, CT, USA

Post by JW »

Thank you Conny

Another good, more specialized reference, is Jeff Scovil's "Photographing Minerals, Fossils, and Lapidary Materials"

I have used 1000 Watts of tungsten lighting, LED and halogen fiber optic, ambient daylight, and electronic flash depending on lens choice, subject, and studio or field location. Since working with the Nikon 10x objective I've had to rethink my lighting a bit. I am quite pleased with my latest effort, uvarovite

Jeff
It's not what you look at that matters, it's what you see - Henry David Thoreau

JW
Posts: 249
Joined: Wed Feb 23, 2011 7:38 am
Location: New Haven, CT, USA

Post by JW »

I revisited this specimen recently with significant improvements to the setup. The Nikon 10x objective is now correctly attached to the end of a tube lens, in this case a 75/300 IS Canon zoom, I used second-curtain synch on the flash with a 3 second exposure time, to allow for vibrations to settle after mirror up - exposure without flash is practically nil. Also more carefully in stacking, manually, in about 15 micron steps, and better use of diffusion to control the light.

Result is still soft, but may be due to both the nature of the crystals and the limitations of my equipment.

Thanks to all who commented here and in other posts.

94 images stacked with ZS Pmax, corrected with Dmap, sharpened with PS
Image

here is a 100 % crop from the middle, showing how the crystals diffuse the light
Image
It's not what you look at that matters, it's what you see - Henry David Thoreau

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