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Mineral PhotographyAdvantage of heavy base on macro setup?

15th Jan 2017 15:17 UTCJyrki Autio Expert

I'm experimenting photography first time beyond 1:1. Now at 5:1 - 10:1 but would like later to try 10:1-20:1.

There are several questions I haven't found satisfactory answers when thinking how to improve my current sketchy setup. First is the base everything is built on.

I see many have built their setup on heavy slab or use heavy stand to reduce vibration.

Is this mainly for shutter caused vibration or environmental vibration?

I understand that the small energy released from the shutter (mirror locked up) cant accelerate large mass, but doubt that the same mass would do anything for vibration of environment if the whole house moves.

If the cause is camera wouldn't it be more advantageous attach some mass directly to camera?

16th Jan 2017 13:42 UTCVolker Betz 🌟 Expert

Hi Jirky,

what you ask is not easy to answer. If you want to make good resolved pictures in the 10 to 20 x range you will end up in a setup with M-Plan Apo-lenses with a tube lens and the typical 200 mm extention tube or bellows.

The first step is a setup is a vibration free !!! base. This cannot be near train lines, streets with havy truck traffic and buildings made of wooden framework, even the upper floors in a concrete construction can be a troublemaker, also nearby beaches with larger waves. And of course anybody walking around in the room or vincinity.

The best position is in the basement over a heavy concrete plate.

If you have not this ideal conditions you can use a hevy stone plate on a sand bed or shock adsorbers.

A possibility is also the noise adsorbers sold for wash machines.

The second step ist minimizing vibration in the setup itself. To my knowledge the stands used for steromicoscopes are not really statisfactory. I made my own stands from aluminium profiles as 10 years sufficent stands have been either to expensive (>5000 €) or not stable enough. Meanwhile a small company in germany (stonemaster.eu) offers several good stands and also excellent stacking devices.

The third point is the camera shutter and the mirror. I present use Canon DSLR in remote remote control. So the final focus ist made from the computer control, the mirror is alsways up and the first curtain is electronic, only the second is mechanical.

Much better would be a 25 Mpixel mirrorless with electronic shutter only, but this is still future.

At present a alternative is mirror-less cameras fram olympus or sony, with the disadvantage that independent remote software support mostly canon and nikon only.

While up to 5x the photography is not so difficult and can made with a 40 mm finitve optic ( I like my Luminar 40 mm) the step to 10 and 20 times is much more difficult due to vibration, resolution of lenses, working distance, number of frames in a stack and so on.

Regards

Volker

16th Jan 2017 17:59 UTCJyrki Autio Expert

Thank you Volker for your advice. Heavy and rigid base is obviously good and tested method.

I anticipate some problems living in worst vibration conditions. It is a wooden house built on floating foundation and 13 meters of soft clay beneath. In the middle of town.

Horizontal setup seems easier to build and more rigid. I thought about fixed and heavy camera stand and focusing by moving the target mineral. This oviously leaves less room and free directions for light.

Remote controlling camera and focusing device should be no problem.

One thing I do not fully understand is proper shutter speed for example 5:1;10:1 or 20:1 photography. Is there an ideal speed you should use by increasing light or ISO when adding magnification? In my tests I did not notice much difference in sharpness between 1/10s and 1/50s. Maybe there was not enough difference in time.

16th Jan 2017 19:11 UTCEugene & Sharon Cisneros Expert

Jyrki,

I am in somewhat the same situation as you. My setup in on the third floor of a wood frame house. My previous system could detect the wind blowing against the house! Slowly, I have improved the system by adding a heavy stand (30 lbs) mounted onto a granite slab that weighs approximately 150 lbs. This made a huge difference in stability and allowed me to work at 10X without any vibration issues. I then found that there were still issues when moving up to 20X. I was surprised to find, after much experimentation, that the source was between the specimen holder and the granite slab. By adding a heavy (5 lb) base to the specimen holder and making sure that it was solid to the granite slab, most of those vibrations were mitigated. My next step will be similar to what Volker recommended, the addition of Sorbothane dampers between the granite slab and the desk.

Best of luck in solving your vibration issues. Of course, high speed flash may be an easier solution than continuous lighting..

Regards,

Gene

17th Jan 2017 16:13 UTCJyrki Autio Expert

Thank you MRC for encouraging reply.

Flash is an option and Sorbothane looks like a product to learn more.

Maybe there is no need to worry before problems arise. I have seen the movement in 1:1 and much more in 10:1 from app live view but it has been not a real problem this far.

Couple of more questions:

Typical table under everything else is surely a poor performer?

Shaky environment needs a faster shutter speed?

Cheers

Jyrki

17th Jan 2017 18:17 UTCEugene & Sharon Cisneros Expert

Jyrki Autio Wrote:

-------------------------------------------------------

> Couple of more questions:

>

> Typical table under everything else is surely a

> poor performer?

> Shaky environment needs a faster shutter speed?

My experience is that a typical table is not the best support for a micro imaging system. As Volker pointed out, a concrete floor would be best.

The requirement for faster shutter speed depends upon the cause of the vibrations.

If you have a solid supporting setup and only shutter movement is causing vibration, then it can be beneficial to go to long shutter speeds. For example, a shutter speed of perhaps 1 or 2 seconds allows all of the shutter induced vibration to damp out early in the exposure and is not seen in the final image.

On the other hand, if vibrations are caused by poor rigidity of the supporting structure, then the only recourse is faster shutter speeds. I'm guessing that speeds faster than perhaps 1/200 of a second would be required, depending upon magnification. For that reason, flash is a good solution, but it comes with its own problems. Flash can be problematic due to lack of modeling light.

Think of it this way... If this were easy, there would be no challenge and everyone would be producing technically perfect images. So, we get to have fun solving all the problems until then.

18th Jan 2017 15:42 UTCJyrki Autio Expert

This has been helpfull. Thank you.

I have changed my original plans accordingly.

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