Diatom photo test (was: Finally my old_new Olympus BH2 is refurbished)

[deBult]

Ha,

Finally my new old Olympus BH2 BHT is cleaned, fixed and lubricated (so now the BH2 family has extended with a new member)

Thanks to Olav, Mario and Peter for spare parts (racks).

Thanks to Carl Hunsinger for wonderful instruction video's on the cleaning and lubrication.

Thanks to Bastian for the wrench.

Thanks to Gerhard for the Phase objectives.

Thanks to Anne for wonderful diatom slides.

My first stacked picture  (Olympus PL5 M4/3, NFK 2.5, 9 pictures, Picolay wit default parameters): Feed Back appreciated.

Best, Maarten

[Stephan Hiller]

Hi Marten,

very nice image. Congratulation.

What is missig on your BH-2 is this part:



Will come soon.

Regards

Stephan

[rhamvossen]

Hallo Maarten,

Which objective did you use for the image, is this made with a phase objective? I see quite some chromatic aberration, I think something ist not yet optimal. How do the unstacked images look? When optimising, I would focus on single images and I wonder if this diatom needs stacking. Vriendelijke groeten,

Rolf

[deBult]

Ha Rolf,

Thanks for feedback, appreciated.
The objective used was a phase contrast one, this may be the reason of the color artefacts.

The depth of field of a single image is insufficient to cover the diatom.

Will continue experimenting and stack without phase next weekend and show the results.

Best, Maarten

[rhamvossen]

Hallo Maarten,

The depth of field of a single image is insufficient to cover the diatom.

Is this Arachnoidiscus? The picture below is a single image of Arachnoidiscus, also from a slide from Anne. Leitz Fluotar 25/0.55, normal brightfield.  Best,

Rolf

[deBult]

Hmm thanks, work to do as I'm not able to get the same result ..... yet.

Is this a plan objective?

Maarten

[rhamvossen]

Hallo Maarten,

It's a NPL Fluotar, so a plan objective, but that's not that important. A normal achromat also works well. Which objective exactly did you use? Best,

Rolf

[anne]

Hallo zusammen,
ich freue mich über die schönen Bilder von Arachnoidiscus ornatus Ehrenberg aus einer Probe von Japan.
lg
anne

[deBult]

Hi, Your feed back is appreciated.

After seeing Rolf's picture I tried anew.

Data:
* Olympus BH2-BHT stand, NFK 2.5 projective, Adapter L, SPlan 20 na 0.46 and SPlan Apo na 0.7
* Olympus PL6 M4/3 camera, JPEG all auto settings, approx. 1/400 second

Observation 1: Still cannot get sufficient depth of field to capture the entire diatom (I tried 2 different slides)
Observation 2: Slightly better depth of field using the SPlan 20 with na 0.46 (as expected)
Observation 3: The setup is not stable enough: small shake visible in the eyepiece after each shot (not good)

Picture below is my 2nd try, Bright Field this time, 7 shots stacked with Picolay (standard settings, I'm new to P.)

Not at all satisfied: will try to eliminate the camera shake by separating the camera from the microscope stand (while maintaining proper length of the extension tube: 151.2 mm from base of adapter L to the sensor plane of the camera).

[Bob]

Hi Maarten,
it always is a question of image capture and editing too. Here I took your first image, used only the green channel and applied some unsharp masking. Since diatoms themselves have not much colour using just one colour channel makes the achromat the poor man's apo.

Cheers,
Bob

[deBult]

Ha Bob,

Thank you for the feed back.

Good thinking I will use a green filter with next phase experiment.

Best, Maarten

[rhamvossen]

Hallo Maarten,

Your second image is already much better, there is way less chromatic aberration, this image is much cleaner. Is it made with the Splan or Splanapo? The only thing that needs to be solved are the vibrations that may be the reason that the image is not completely sharp. I see that you are using a mirrorless micro 4/3 camera. My image of Arachnoidiscus was made with a Olympus PEN EP1, so an older mirrorless micro 4/3 camera. When short exposure times are used with this camera, the images get blurry because of shutter vibrations, so I always use an exposure time of 2 seconds or longer. Regarding Bob's comments, it's fine to edit and process the image or use a green filter but it is much better to troubleshoot the chromatic aberrations and get rid of them. You want the unprocessed image to be as good as possible. Could you try a longer exposure time and take a single image? Best,

Rolf

[Bob]

Hi together,
shutter viration really is an important thing with diatom images. My wife had an Olympue E-Pl1 and it had quite some shutter shock, though a lot less than the SONY NEX 5. Some newer Olympus cameras have EFSC, electronic first shutter curtain, I think it is called silent mode.

It would be interesting to see the difference between an image taken with a green filter and one taken without filter where only the green channel is used.

Bob

[deBult]

Thank you Bob, my E-PL6 does not have this electronic shutter (you need an E-PL9 for this).

The previous picture was with the SPlan Apo 20.

Will try 2 polarisers to reduce the amount of light and/or use my CH2 trino with a separate stand to decouple the camera from the scope.

Best, Maarten

[Bob]

Hi Maarten,
the shutter runs back and forth when sitting on the microscope so a direct support towards the wall behind the microscope would help a lot to dampen the shock.

Bob