Extreme image:- The Tip of a Needle

[sjastro]

Amazing how much detail is on the tip of a needle.

This a combination of microscope and telescope techniques.
In order to obtain sufficient image scale I used eyepiece projection using one of the eyepieces from a stereo microscope and a tele-extender from my old C11 scope.

Due to the extreme focal length the shutter was triggered remotely to avoid camera vibration.

Five separate images were taken at different focus and stacked using Zerene Stacker.
Each exposure was for 5 seconds @ 200 ISO using a Pentax k-r.

Regards

Steven

[Larryp]

Amazing image, Steven!

[multiweb]

That's very cool Steven. What's the diameter of the pin shaft?

[sjastro]

Thanks Laurie and Marc.

The pin shaft diameter is 0.5mm

Regards

Steven

[stardust steve]

really sharp image :D
seriously, well done, looks great.
Love how the point, even being so small, still reflects light:thumbsup:

[multiweb]

Quick question Steven: the very tip seems to be darker as if (heat) tempered or of different composition?

[jjjnettie]

:) Love it. Well worth all the effort you put into the capture.

[sjastro]

Thanks Jeanette and Steve.



Marc I'd say the blue colour is due to the tempering process.
Since the entire needle is tempered the question is why the needle isn't blue overall? Perhaps since there is less metal at the tip it has reached the required temperature to turn blue.:shrug:

I'm sure any metallurgists out there can provide an explanation.

Regards

Steven

[multiweb]

Yes that'd make sense.

[Omaroo]

Excellent image Steven - unique

[Octane]

That looks awesome. Like a bullet coming at you.

Great shallow depth of field.

H

[gregbradley]

Very unique image.

Greg.

[sjastro]

Thanks Chris, H and Greg for the feedback.

The lack of depth of focus is the main problem with imaging through a microscope. One needs to stack images taken at different points of focus in order to achieve a reasonable depth of focus.

Regards

Steven

[space oddity]

I also think this looks like a bullet or torpedo. I wonder how this would have gone with stopping down and holding a small flash nearby. With the inverse square law, a flash held very close and fired while the shutter is open gives the potential for very stopped down apertures and thus depth of field. Even a cheapie GN 10 flash held a modest 10cm from the subject gives f/1,000 shooting conditions. In practice, you could get in to 1 cm for f/100,000 shooting, enough to compensate for the light loss from this extreme macro.Quick maths here -50x shooting = 2500 x LESS light, so the f/100,000 is equivalent to f/40 .Loose a stop or two for lack of reflections from wall etc gets down to more or less f/22 on the camera lens for iso 100 shooting.
With such a monster rig here with a lot of extension, the scheimflug principle could be used with tilting the lens to increase depth of field. Focusing this rig would be the hard part.

[sjastro]

An interesting idea but unfortunately it won't work with respect to microscope optics. Microscope optics are considerably more complicated than camera lenses or telescopes and have a much smaller depth of field.
The f/ratio of a microscope is related to the numerical aperture of the microscope objective not the aperture or opening of the objective. Placing a stop on the aperture won't increase the f/ratio as the numerical aperture doesn't change. The numerical aperture is determined by the refractive index of the medium in which the lenses operate and the maximum cone of light that can enter the objective. In fact the depth of field decreases with increasing magnification. The high magnifying objectives of 100X incidentally have apertures or openings not much larger than a pinhole.

Regards

Steven

[Davros]

WHat about a Z stacker microscope?

[sjastro]

Z stacking has been used for this image.
It is a combination of 5 images at different focus.

The software used is Zerene Stacker.

Regards

Steven