MICROSCOPES - what to expect

Here are summaries and links to discussions for Frequently Asked Questions.

Moderators: Chris S., Pau, rjlittlefield, ChrisR

NikonUser
Posts: 2588
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Olympus 100x SPlan Apo oil

Post by NikonUser »

BH2-BHS with 2.5x NFK photoeyepiece; flash; Nikon D90 23.6 mm wide sensor.
ZS PMax stack
Desmid chain from FW lake. (thanks to Pau for correcting my ID as Desmidium)
Top: 19 frames @ 0.7µ
Bottom: 6 frames @ 0.7µ

NB: These fine detail objects that are not absolutely flat need several frames to get everything in focus. However, this causes loss of detail in the subject's surface. The bottom image of just 6 frames shows some surface striations but with the loss of sharpness at the sides.
Image
NUM10060
Last edited by NikonUser on Fri Sep 17, 2010 4:51 pm, edited 1 time in total.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Pau
Site Admin
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Post by Pau »

Very nice images, NU, but I think it isn't a Desmidium but a diatom
Pau

NikonUser
Posts: 2588
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Post by NikonUser »

Thanks Pau.
So, these guys have silicaceous cell walls with ornamentation, grooves in these individuals = diatom
The similar image on the 1st page has cellulose cell walls with no markings = desmid
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Mitch640
Posts: 2137
Joined: Sun Aug 15, 2010 1:43 pm

Post by Mitch640 »

I wonder what happened to the white one?

gpmatthews
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Joined: Thu Aug 03, 2006 10:54 am
Location: Horsham, W. Sussex, UK
Contact:

Post by gpmatthews »

Most of the images so far have been pretty good. I thought it might be useful to illustrate some problems. The following pictures were taken using a Canon Powershot G9 mounted on a Zarf Adapter attached to a Zeiss Standard GFL microscope with a Zeiss 1.6/0.03 - 5/0.1 zoom objective.

Image
This first image shows several problems:
1. The bright splodges at the top left corner are dust or other rubbish on the camera sensor or in the camera optics.
2. The sections of large circular objects RH top and just inside LH bottom corners show the typical appearance you can expect of air bubbles in a water mount and show bright centres with dark perimeters
3. There is colour fringing due to chromatic aberration. This is particularly noticeable on the detritus above the water flea's head and on the claw of the water flea, as well as around the air bubbles.



Image
The second image is a full resolution crop of the offending claw, showing chromatic aberration


Image
This third image shows extreme chromatic aberration around the margins of the midge larva. It is worse the further from image centre you look. Particularly ghastly in the upper left and lower right corners.

You can also see some vertical striations on the left hand side of the image, which is also slightly darker. These result from using a cavity slide with a central concave depression and are "ripples" in the glass. The darker region is due to the lens-like effect of the cavity.



Chromatic aberration is one of the problems with the Zarf adapter. It varies with which objective lens is used, but appears particularly awful with this low powered Zeiss lens, which with a Zeiss eyepiece and either a suitable fixed lens camera or a DSLR gives quite acceptable results. It is the camera/adapter that is to blame, not the microscope optics.

Within camera dirt is potentially a problem with all types of camera. With a fixed lens camera such as the G9, you can't get inside it to clean. With a DSLR, at least you can clean the sensor cover, but it can be nigh on impossible to remove those very tiny specks that really only show as trails when stacking. Such small dust is too small to dislodge using the built in cleaning systems that attempt to dislodge dust by vibration. I have removed individual specks in a DSLR by using a degreased size 00 brush (washed in toluene) and a stereo microscope. A tricky procedure.
Graham

Though we lean upon the same balustrade, the colours of the mountain are different.

NikonUser
Posts: 2588
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Olympus 4x D Plan

Post by NikonUser »

on BH2-BHS with 2.5x NFK photoeyepiece.The wide coverage of the 4x objective makes the use of the 1.25 condenser unusable (gives a bright hot spot in the center). These images with the condenser removed.
Diffused flash, transmitted light.

Green Hydra, contracted and partially extended. When fully extended the specimen was too long to fit in the frame.

Living, active specimen on cavity slide; single exposures.
Image
NUM10063
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

NikonUser
Posts: 2588
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

40x Phase Contrast

Post by NikonUser »

Living Vorticella
Olympus BHS 40x PC S Plan PL (NA 0.7) + NFK 2.5x; full single frame
Image
NUM10074

Here's what they look like with a 100x S Plan Apo oil immersion, not phase contrast:
Image
NUM10075

Compare these with similar images using DIC on PMG.net (no contest)
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

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