How to minimize the oscillations/mechanical vibrations ?

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Adalbert
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How to minimize the oscillations/mechanical vibrations ?

Post by Adalbert »

Hello everybody,
How can I minimize the vibrations caused by the mirror or shutter?
What kind of the setup it better: vertical or horizontal?
Thank you in advance.
Best regards,
Adi

Charles Krebs
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Post by Charles Krebs »

I don't think either vertical or horizontal is inherently better in this regard, it all depends how it is constructed.

Probably the biggest thing you can do in this regard is your camera selection. Electronic first shutter curtains can be found now on several brands, not just Canon. There is even some availability (very few however) of full electronic shutters (both front and rear curtains).

One thing that does not get mentioned is the great desirability, when recording an image stack, for very low vibration even after the exposure. This is more obvious with higher magnification microscope images, and particularly "wet mounts". With good EFSC there will be no vibration effects in each individual frame. However, in some DSLRs the mirror will cycle before the next exposure in conjunction with the shutter "re-cocking". In some instances, this mirror motion can cause a slight "jiggling" of the subject on the slide, making stacking more difficult or even impossible. Naturally this is not an issue with a mirrorless camera. Certain Canon models use a separate motors for the shutter and mirror mechanisms, and those can be set so that the mirror does not cycle between shots.

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Adalbert
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Post by Adalbert »

Hello Charles,

Many thanks for your useful hints!

I have already constructed one vertical setup (based on Biolam from LOMO) and one horizontal setup (self-made based on a lineal-table with a micrometre screw).
Fortunately I have the CANON EOS 6D. What do you think about it?
It has an electronic first shutter in the live-view mode (called silent-mode).
But when I’m recording an image stack then I set the shutter speed to the two seconds and flash with low level on the second curtain.

Actually I only wanted to buy an APS-C camera with a smaller sensor, because of the finite microscope lenses, which I’m using in the focal-mode (without ocular, without relay optics).
For the afocal - mode I have an adapter with the relay-lens 60mm, so I can use full-frame.
Unfortunately the sensor of the full-frame camera is too big for the finite microscope lenses used in the focal-mode, I heard :-(
“Certain Canon models use a separate motors for the shutter and mirror mechanisms, and those can be set so that the mirror does not cycle between shots”
Do you know which models support this feature?

Thank you in advance.

Best regards,
Adi

Charles Krebs
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Post by Charles Krebs »

I should have mentioned earlier that electronic flash and EFSC generally cannot be used together. (One exception I am aware of it the "Nikon 1" series cameras that have a 1" sensor...12.8mm x 9.6mm... and a fully electronic shutter. There may be others).

Canon, unfortunately, does not have a 100% "PMG.NET acceptable" rating for all EFSC models. While I have a few bodies, I have no hands on experience with all their models, so I can only report on the experience of others. The 60D was one that apparently exhibited some vibration even with EFSC. The 6D "reports" were mixed... some felt it was fine, others felt they experienced some vibration problems. (Albeit in extreme circumstances... high magnification "wet mount", microscope mounted camera).
Quote:

“Certain Canon models use a separate motors for the shutter and mirror mechanisms, and those can be set so that the mirror does not cycle between shots”
Unfortunately the sensor of the full-frame camera is too big for the finite microscope lenses
True in many cases. A few have reported OK results wit certain Nikon M Plans. In any event, if you are very critical about good performance right out to the corners of the frame, there are really not that many microscope objectives (finite or infinity) that can "cover" a 43mm diagonal sensor (full-frame, 24mm x 36mm).

Do you know which models support this feature?
All models above the "Digital Rebels" ("Kiss" xxxD)

Unfortunately the sensor of the full-frame camera is too big for the finite microscope lenses
True in most, but not all cases. With finite objectives a few have reported OK results with certain Nikon M Plans. In any event, if you are very critical about good performance right out to the corners of the frame, there are really not that many microscope objectives (finite or infinity) that can "cover" a 43mm diagonal sensor (full-frame, 24mm x 36mm).

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Adalbert
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Post by Adalbert »

Hello Charles,

Many thanks for the info!
“electronic flash and EFSC generally cannot be used together”
what a pity :-(

I had a curious problem with the remote control of the flashes. As you already know I usually use the second curtain sync.
But I wanted to block the mirror too. Unfortunately it was not possible.
I was not able to control the flashes on the second curtain sync remotely and simultaneously block the mirror.
So, I had to change the Yongnuo 662C on my EOS 6D to the 662-TX, which overwrites the signals from the camera :-)


OK, if you had a choice between 5DS and 5DSR which one would choose?
Which model is better for the macrophotography (with the blocked pass filter or with it) ?
So, I also would be able to switch to the APS-C mode in easy way.
“a few have reported OK results with certain Nikon M Plans”
My other idea was to connect the tele-lens with the infinity NIKON CFI.
I have already asked for that in another thread but in general not for the full-frame especially.
http://www.photomacrography.net/forum/v ... highlight=
Would it be a solution of the problem with the full-frame too?

Thank you in advance.
BR, Adi

fotoopa
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Post by fotoopa »

I made a wooden frame:

Image
Mini Doka under construction. by Frans, on Flickr

My wife has made a black covering:

Image
Partially open darkroom system PC034991 by Frans, on Flickr


Thus, the environment is completely dark:

Image
Fully enclosed darkroom system PC034966 by Frans, on Flickr

I use the mirror-up function on the D7100 camera, wait 1.2 sec, I open the camera shutter, and wait another 420 ms to drive the LED flash for about 2 to 4 msec. Result, no EFSC function needed, no vibrations and sharp images.

Frans.

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Adalbert
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Post by Adalbert »

Hello Frans,

Your wooden frame is great! I only have a low-cost wooden slat :-(

Have you separated the metal-construction for the camera and for the subject in order to avoid the transfer of the mechanical vibrations?
“I use the mirror-up function on the D7100 camera, wait 1.2 sec, I open the camera shutter, and wait another 420 ms to drive the LED flash for about 2 to 4 msec. “
This is similar to my method. I set 2 seconds for the shutter and synchronize the flashes on the second curtain. So, my wooden construction has 2 seconds in order to be vibration-free.

BR, Adi

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Post by Chris S. »

Adalbert wrote:Hello Frans,

Your wooden frame is great! I only have a low-cost wooden slat :-(

Have you separated the metal-construction for the camera and for the subject in order to avoid the transfer of the mechanical vibrations?
Adi, Frans makes amazingly wonderful things doesn't he? We're fortunate that he documents them and participates in this forum.

Frans will have a definite answer to your question, but I suspect that both the metal camera and subject assemblies are mounted on the wooden board beneath, for mechanical coupling.

One of the most important things that studio macro photographers can do is mechanically couple camera and subject. This way, if one of these vibrates, the other is likely to vibrate in concert with it. Movement per se isn't a problem--it's relative movement between camera and subject. Remember that on a you're a passenger on an airliner, you are moving very fast, but the other passengers do not appear to be moving. You're mechanically coupled to them by the airliner. Various members here create their coupling base from different materials--steel (my preference), wood, granite, aluminum breadboards, etc. So far as I know, they all work

--Chris

fotoopa
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Post by fotoopa »

Adalbert wrote:Have you separated the metal-construction for the camera and for the subject in order to avoid the transfer of the mechanical vibrations?
Yes, camera, linear stage, backlighting, foreground illumination and object holder stand together fixed on a single thick wood block 500x650x40 mm. This block is loose on my desktop. The wooden frame is made around but is not attached to it. No vibrations are transferred so.

Camera recording time ( shutter open time) is 0.5 sec. For me this is more than enough. The cycle time is 2.3 sec per picture. This is enough to send real-time images to the PC via the USB connection (ControlMyNikon v4.3). Stacking therefore is fully automatic and fast.

Next year I make a new version of the LED module. Which is 8x more powerful in the same housing and specially adapted for the Mitutoyo lenses. The exposure time would be go from 2.4 msec to 300 usec. This corresponds to a conventional flash.

Frans.

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Adalbert
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Post by Adalbert »

Hello Chris,
“Frans makes amazingly wonderful things doesn't he?”
Yes, he does !
“This way, if one of these vibrates, the other is likely to vibrate in concert with it”
Yes, on the one hand you want to couple the camera with the subject in order to synchronize their relative movements but on the other hand you want to avoid the transfer of the vibrations and resonant frequency. Frans solved this problem very clever by using different materials (wood and metal).
“from different materials--steel (my preference)”
Do you prefer a combination of the different materials or only steel?
BR, Adi

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Adalbert
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Post by Adalbert »

Hello Frans,
“Yes, camera, linear stage, backlighting, foreground illumination and object holder stand together fixed on a single thick wood block 500x650x40 mm”
But you have two metal-assemblies on the single thick wood block, which are not connected to each other by any metallic compound.
I'm doing some handicrafts now and would like to ask for an advice. Should I take a wooden or metallic block as a basis for my rig?
Thank you in advance.
BR, Adi

fotoopa
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Post by fotoopa »

Until now I have always used a wooden block. Something screw in a wooden block is easier. I had by chance found a very thick block of 40 mm. I really do not know if a metal plate would be better, but suspect that wood absorbs more. In the longer term, wood can deform. My wooden block was dry stored over a long period of time before I used it. There is no more noticeable distortion.

My linear stage weighs 14 kg. It is a stable unit and has 1 um resolution for a full step. The linear stage has a built-in rotary encoder and a reading scale per 1um. You can also turn on the index button when the stepper motor is off, the LCD display on my DIY controller box follows the read out of the correct position.

Image
MT160-250_index: 200 div each full rotation. by Frans, on Flickr

Image
MT160-250 1um lineaire stage module. by Frans, on Flickr

Frans.

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Adalbert
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Post by Adalbert »

Hello Frans,
“My linear stage weighs 14 kg”
Awesome!

As far as I can see your linear stage allows the movements for very long distances.
Do you take photos from the large subjects?

BTW,
I’m looking for a linear-stage with a fine resolution (but a small one).

BR, Adi

fotoopa
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Post by fotoopa »

Yes this linear stage has a range of 250 mm. In fact, this is not really necessary but useful. You can use different camera or lenses and work less close if needed. I was Lucky to buy this linear stage very cheap. including the stepper motor controller and connection cable. There is no slack on the carriage, the sides contain ball bearings over a great length, as well as the spindle. My readout is 6 digits such as 125.000 mm.
Something like that you do not find every day.

For the background module, I made on a DIY sliding carriage:

Image
DIY Z axis system for backlight module PB042602 by Frans, on Flickr


Thereupon is my color LED module.
Into the next photo you have a better overview The wooden block can you see too.
A little further into the background is another X-Y table with two extra rotary axes for the objects. The foreground led module state on separate rails. The Mitutoyo lens goes into the LED module. A security is in place to avoid damaging the lens if you were going too deep with the lens.

Image
Overview macro recording system R40_0344 by Frans, on Flickr

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Adalbert
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Post by Adalbert »

Hello Frans,
“Something like that you do not find every day.”
Yes, that’s true. The background module doesn’t look like a self-made.
And the whole equipment is the finest one, which I only can dream of.
BR, Adi

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