Stem Cross Section Photograph

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Bill D
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Stem Cross Section Photograph

Post by Bill D »

Using advice I learned from Charles K., I shot this image of a Limewood stem stained cross section. I tried different, smaller apertures on my diaphram. I am getting alot better contrast than before. Closing down the aperture also allows me to increase the exposure time. This I hoped would give the vibrations from the mirror and shutter time to dampen. The photograph is still soft. Next I will apply the use of mirror lock-up. I did not want to change to many things at once, I wouldn't know which change was effecting what!

Image
Bill

Ken Ramos
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Post by Ken Ramos »

You know Bill in this image, it looks more than just soft, it does look like some sort of vibration. You know what may solve all this is the use of a photo copy stand, a heavy one, like what Charlie uses to hold that camera a little more steady over the microscope eyepiece. The vibration may not only be due to mirror slap but from the instability of the tripod as well when both the mirror comes up and when the shutter fires. Just a thought. :-k

Bill D
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Joined: Mon Nov 27, 2006 4:51 pm
Location: Raleigh, NC
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Post by Bill D »

As always, your advice is appreciated. Thanks. At this point in my first attemps at capturing an image through my microscope, I probably have a whole lot of issues to address! But, vibration from the mirror, shutter, tripod or all three, are at the top of my list to conquer first. I need to think about a camera bracket? The eyepiece tube adapters don't really work? What about a telescope "Tee" adapter? I am also worried I am not getting the film plane parallel to the stage.
Bill

Charles Krebs
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Post by Charles Krebs »

Bill... First you need to be sure the illumination is set up and aligned properly. And as I mentioned earlier the degree to which the condenser diaphram is closed is rather critical.

On page 4 of this pdf there is a good diagram of what you should see when you look down the eyepiece tube with the eyepiece removed. This 60-80% "open"is the amount you should be using when taking pictures.

http://www.cci.ca.gov/Reference/PDF/koehlr.pdf

If you can adjust the power to the bulb in your microscope, turn it up to about "full power" for the photo. This should get the color up to about 3200 degree Kelvin which will should color balance pretty well with the tungsten color balance setting on your camera. Sometimes there is a temptation to adjust the power down so that you can get the 1-2 second exposure with stationary subjects, but this will really make the light very "red" to the camera, and it will likely not give accurate color, even if set to AWB.

If you use your mirror "lock-up" and a decent tripod you should be OK as far as vibration goes.

Bill D
Posts: 118
Joined: Mon Nov 27, 2006 4:51 pm
Location: Raleigh, NC
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Post by Bill D »

Charles- You are right on the money once again! That is exactly what I did. I turned the diaphram down to a small opening so I could drag my shutter. I did very little post processing the the image above. It still has the red/pink hue in the whites, where my AWB missed the color balance, because I had it so dim. Thank you for the PDF. And, Thank You for sharing your knowledge!
Bill

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