Search found 435 matches

by Chas
Sat Jan 06, 2024 9:10 pm
Forum: Microscopes and optics
Topic: Diy phase contrast on BHS
Replies: 3
Views: 5044

Re: Diy phase contrast on BHS

I dont know if this would work for your particular microscope but see here: https://microscopyofnature.com/low-budget-condenser-darkfield-phase-contrast-and-circular-oblique-illumination Or perhaps this?: http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artjan01/...
by Chas
Sat Jan 06, 2024 11:18 am
Forum: Pictures and Videos
Topic: Advices to improve my pictures
Replies: 11
Views: 8102

Re: Advices to improve my pictures

Actually, Sacrodactyl is correct :-)
by Chas
Fri Jan 05, 2024 10:00 pm
Forum: Specimens, samples and slides
Topic: How to best photograph parasitoid wasp collection for ID
Replies: 6
Views: 6960

Re: How to best photograph parasitoid wasp collection for ID

A deep cell sounds like a good idea, but if you are after more control in terms of rotation, you could try putting them in a thin walled glass tube and then rotate that . Things like this were made 100 years or so ago. The only example pic I can find at the moment is this one: https://www.flintsauct...
by Chas
Wed Jan 03, 2024 12:02 pm
Forum: Home-made microscope adaptations
Topic: Dichromatic Illumination?
Replies: 61
Views: 120251

Re: Dichromatic Illumination?

'Why the flare out' .. 'why the black ring' ? My guess; the light that is entering the cone and going less than the critical angle will exit the cone and other light (heading straighter) will bounce down the inside of the cone (?) I think that the cone ought to concentrate light. Conrad Beck in 'The...
by Chas
Wed Jan 03, 2024 10:15 am
Forum: Beginner's corner
Topic: Question Regarding Darkfield Condensers
Replies: 39
Views: 117964

Re: Question Regarding Darkfield Condensers

Just pop out the BF condenser and pop in the DF condenser. No It would be nice wouldn't it be? ......Tooo nice, the manufactures might say. (and if you really want the freedom to use a standardised condenser you are going to have to purchase a special mount ). Of course they each maintained other d...
by Chas
Tue Jan 02, 2024 6:57 pm
Forum: Beginner's corner
Topic: Question Regarding Darkfield Condensers
Replies: 39
Views: 117964

Re: Question Regarding Darkfield Condensers

The inability to get the correct height for the DF oil condenser is strange, especially given the fact that I have found no such difficulty. Would I be right in thinking that when you used the darkfield condenser on the No.5 that it came pre-mounted on a push-in disc similar to the disc with the RM...
by Chas
Sun Dec 31, 2023 1:02 pm
Forum: Beginner's corner
Topic: Question Regarding Darkfield Condensers
Replies: 39
Views: 117964

Re: Question Regarding Darkfield Condensers

Maybe the first thing to do is to try out the DF condenser head? ... You could attach the DF head directly to the RMS condenser mount disc with some hot melt glue if the RMS disc is flat enough in the right area and the threading on the head is long enough to raise the darkfield condenser head to to...
by Chas
Sat Dec 30, 2023 10:02 am
Forum: Beginner's corner
Topic: Question Regarding Darkfield Condensers
Replies: 39
Views: 117964

Re: Question Regarding Darkfield Condensers

It seems that Spencer had to put a darkfield condenser onto an extension tube at some point: Spencer darkfield long.jpg I have a Leitz ' helldunkenfield' (whose head has pretty much the same thread measurements as you measure on your condenser) and fitted that into a Watson centering mount with a pu...
by Chas
Fri Dec 29, 2023 12:49 pm
Forum: Illumination Techniques
Topic: Does phase contrast make sense for its price?
Replies: 49
Views: 35103

Re: Does phase contrast make sense for its price?

I think more likely, use a 70 to .75 objective. with your dry DF condenser. Maybe even less The dry darkfield condenser made a good annular illuminator for the 1.25 oil objective. The yeast cells dont seem to be the right target for darkfield. Quite a nice set of three photographs in the middle of ...
by Chas
Fri Dec 29, 2023 11:59 am
Forum: Beginner's corner
Topic: Question Regarding Darkfield Condensers
Replies: 39
Views: 117964

Re: Question Regarding Darkfield Condensers

There seems to be a general and ongoing problem uploading images :
viewtopic.php?f=8&t=19281
by Chas
Fri Dec 29, 2023 11:26 am
Forum: About the website, the magazine and this forum
Topic: New trouble uploading images...
Replies: 19
Views: 17590

Re: New trouble uploading images...

29 December;
'The image file you tried to attach is invalid'

:-(
by Chas
Thu Dec 28, 2023 9:22 am
Forum: Illumination Techniques
Topic: Does phase contrast make sense for its price?
Replies: 49
Views: 35103

Re: Does phase contrast make sense for its price?

What about the movement of the organelles inside the yeast cells? Is that brownian movement as well or rather a result of cellular function and metabolism? Or both? Here is a timelapse video, taken in light-grey darkfield; a dry darkfield condenser under a 1.25 oil Lomo objective (it covers about 1...
by Chas
Mon Dec 25, 2023 9:26 pm
Forum: Illumination Techniques
Topic: Does phase contrast make sense for its price?
Replies: 49
Views: 35103

Re: Does phase contrast make sense for its price?

My 40x images of yeast are not any better (slightly worse in fact ) however the Cooke Troughton & Simms phase kit I used is not new (cough). The 95x 1.3 does rather better at showing interior detail. If you look at DIC images of yeast they are maybe the best you could dream for: https://www.youtube....
by Chas
Mon Dec 25, 2023 9:14 am
Forum: Beginner's corner
Topic: Question Regarding Darkfield Condensers
Replies: 39
Views: 117964

Re: Question Regarding Darkfield Condensers

Is it possible that the wedge-shaped ring is mounted the wrong way up? ....I only say this because R&J Beck condensers have the flanged face of the wedge-ring turned towards the bottom.
(I guess it helps to keep the condenser body aligned)
by Chas
Sun Dec 24, 2023 9:40 pm
Forum: Pictures and Videos
Topic: Amoeba
Replies: 0
Views: 2018

Amoeba

Something rather soothing about it;
https://streamable.com/gen0xp

(It's a timelapse).

It says that the link will expire in a couple of days.
by Chas
Fri Dec 22, 2023 7:11 pm
Forum: Beginner's corner
Topic: Best size objective for Pond life?
Replies: 36
Views: 58517

Re: Best size objective for Pond life?

A lot of interesting things live on or around duckweed (lemna) so it is easy to drop a plant or two under a coverslip ..however this sort of deep/thick mounting makes a 'dangerous' combination with an x40 objective.
So I would go for (with a triple nose piece) 4x 10x 20x .
by Chas
Thu Dec 21, 2023 7:46 pm
Forum: Pictures and Videos
Topic: Advices to improve my pictures
Replies: 11
Views: 8102

Re: Advices to improve my pictures

I've just took my two first pictures Quite a special moment :-) I think it is good to consider what you have got rather than what you havent ! ..and they are nice If there is one thing ; I notice that the large bristles on the back of the fly seem to have a slight "softness" to them .. do check tha...
by Chas
Tue Dec 19, 2023 10:51 pm
Forum: Camera systems and imaging
Topic: OM1 Objective adapter
Replies: 21
Views: 7929

Re: OM1 Objective adapter

Do you know of a good "Cone" that fits M4/3 (Olympus OM-1)? Is there a good brand I should look for that has the light baffles you spoke of? I have only one cone adapter (M42:RMS) so I cant really say too much, however looking on the internet they all appear to have the same shiny black-anodised fi...
by Chas
Sat Dec 16, 2023 11:35 pm
Forum: Pictures and Videos
Topic: First experience with Vit C crystals
Replies: 4
Views: 1639

Re: First experience with Vit C crystals

Very nice, I had my first go too a couple of months ago (not as nice as some of the growth shown in your video ).
Out of curiosity; How do you get the zooming out effect... Is it an Iphone App or was it done in something else?
by Chas
Sat Dec 16, 2023 12:13 pm
Forum: Camera systems and imaging
Topic: OM1 Objective adapter
Replies: 21
Views: 7929

Re: OM1 Objective adapter

Do consider a cone-shaped adapter* ...they are very lightweight (~100grams) and ergonomic. They can be purchased for around 25$ (some cost nearly double that, for some reason). As far as objective quality goes; most bottom end 4x 5x finite objectives work pretty reasonably. * This sort of thing: htt...
by Chas
Tue Dec 12, 2023 10:11 am
Forum: Beginner's corner
Topic: Question Regarding Darkfield Condensers
Replies: 39
Views: 117964

Re: Question Regarding Darkfield Condensers

As Alexander says .. the oil ones do not cover much of the field when using, say, an x4 objective with a 6x eyepiece. You might be better off trying Rolf Vossen's method/modification of an Abbe condenser, for general use : https://microscopyofnature.com/low-budget-condenser-darkfield-phase-contrast-...
by Chas
Sun Dec 03, 2023 10:16 pm
Forum: Illumination Techniques
Topic: Darkfield diagnostic test slide
Replies: 26
Views: 70068

Re: Darkfield diagnostic test slide

And the Watson RMS mount Holoscopic condenser:
Watson Holoscopic condenser.jpg
Watson Holoscopic condenser.jpg (137.55 KiB) Viewed 69059 times
by Chas
Sun Dec 03, 2023 8:41 pm
Forum: Illumination Techniques
Topic: Darkfield diagnostic test slide
Replies: 26
Views: 70068

Re: Darkfield diagnostic test slide

Here are the Cooke Troughton & Simms condensers, RMS threaded are on the bottom row:
Cooke Troughton & Simms BF Condensers.jpg
Cooke Troughton & Simms BF Condensers.jpg (51.34 KiB) Viewed 69073 times
April 1946 prices:
M1382: £1 14s
M1383: £4 14s
M1386: £7 6s
M1391: £8 12s
by Chas
Sun Dec 03, 2023 7:33 pm
Forum: Illumination Techniques
Topic: Darkfield diagnostic test slide
Replies: 26
Views: 70068

Re: Darkfield diagnostic test slide

Where are the BF condensers , though? I only ever see DF condensers. I am a bit puzzled you dont have them too...... most English microscope manufactures seemed to offer them. Maybe they just grew bigger? : The Watson Holoscopic condenser (a 6 element thing) that was initially available only in an ...
by Chas
Sat Dec 02, 2023 8:33 am
Forum: Illumination Techniques
Topic: Darkfield diagnostic test slide
Replies: 26
Views: 70068

Re: Darkfield diagnostic test slide

Phill Brown; Isn't it simpler to imagine that a bit of Cedarwood oil has leaked in through the top (??)
by Chas
Wed Nov 29, 2023 7:41 pm
Forum: Illumination Techniques
Topic: Darkfield diagnostic test slide
Replies: 26
Views: 70068

Re: Darkfield diagnostic test slide

I am always re-inventing the wheel, every day, in every way :-( Indeed, I have just come across Simon Gage's '"Modern Dark-field Microscopy" .. it's all in there (nearly) ..a good read..even a nice sounding way to size darkfield patch stops : https://archive.org/details/jstor-3221838/page/n1/mode/2u...
by Chas
Wed Nov 29, 2023 6:47 pm
Forum: Beginner's corner
Topic: Dark field using Amscope 720
Replies: 4
Views: 2042

Re: Dark field using Amscope 720

I dont know if the optical part of your condenser unscrews from the top of it's mounting tube, but if it does (and I am guessing that it should do) then a small pea-sized blob that strange aimed-at-children silicone putty can be squashed onto the back lens of the condenser: Black silicone putty blob...
by Chas
Tue Nov 28, 2023 9:14 pm
Forum: Illumination Techniques
Topic: Darkfield diagnostic test slide
Replies: 26
Views: 70068

Re: Darkfield diagnostic test slide

The Watson zonal DF oil condenser has a small refractive indent in the centre of the top lens. It can be seen in the 4x image as a ring around the central square of illumination. It's oil filled,not user serviceable. Realistically the na is still limited to .95. Considering it's 1950's RMS it's sti...
by Chas
Mon Nov 27, 2023 7:53 pm
Forum: Illumination Techniques
Topic: Darkfield diagnostic test slide
Replies: 26
Views: 70068

Re: Darkfield diagnostic test slide

Yes, the long modern sort. I tried it with an older 3.75mm 0.95 Beck too ...both the the same.
I have just scuttled off and got my micrometer; the slide thickness is ~1.1mm.
by Chas
Mon Nov 27, 2023 3:13 pm
Forum: Illumination Techniques
Topic: Darkfield diagnostic test slide
Replies: 26
Views: 70068

Re: Darkfield diagnostic test slide

Superglue is not a good mount! ..but it was deadly quick ; the refractive index seems quite different where it starts to set... the slides show a curious ripple effect. The 'screen' does help if things arent going as they should ..I had a slightly twisted mount with a CTS , one DF patched abbe conde...