Search found 2550 matches

by MicroBob
Thu Mar 29, 2018 10:37 am
Forum: Microscopes and optics
Topic: BRESSER TRM-301
Replies: 8
Views: 1882

Re: BRESSER TRM-301

In Germany we have about 15 microscopy societies so most people have quite some way to get to the meetings. To our meetings in Hamburg people come from as far away as 120km. May be you find a way to combine activities so you can make better use of the travelled way. You could e.g. drop your wife and...
by MicroBob
Wed Mar 28, 2018 9:23 am
Forum: Sandbox
Topic: Beautiful - STEM OF COTTON PLANT 40X
Replies: 4
Views: 5606

Re: Beautiful - STEM OF COTTON PLANT 40X

If you are good at guessing you don't have to know much! :lol:
I think you mentioned it somewhere that you use a phone.

Stacking requires a fixed camera focus and a fixed camera. If you can acheive this with your phone you could of cause use stacking.
by MicroBob
Tue Mar 27, 2018 5:34 am
Forum: Beginner's corner
Topic: Help with microscope aquisition!
Replies: 57
Views: 9766

Re: Help with microscope aquisition!

160TL are cheaper and can be mixed (at least if they have same threads).. There have been lot of different microscope systems with 160mm tube lenght where the optical components are not compatible or don't work together well. The tube lenght is only one aspect of four when it comes to compatability...
by MicroBob
Sun Mar 25, 2018 9:41 pm
Forum: Sandbox
Topic: practicing with phone camera settings
Replies: 16
Views: 9147

Re: practicing with phone camera settings

A 10:1 objective covers 100 times the area of a 100:1 objectives. At 0,30 it roughly has 25% of the linaear resolution. Squared it has 1/16th of the 100:1 objective. 100/16 = ca. 6 So the 10:1 has 6 times the amount of image detail than the 100:1 The world is not always fair. :lol: Calculate this fo...
by MicroBob
Sun Mar 25, 2018 9:33 pm
Forum: Illumination Techniques
Topic: Dark field illumination: Questions and answers
Replies: 65
Views: 19072

Re: Dark field illumination: Questions and answers

It seems to be a 0,15W LED strip.
by MicroBob
Sun Mar 25, 2018 9:31 pm
Forum: Home-made microscope adaptations
Topic: Quick cheap & easy LED conversion for my Halogen 'scope
Replies: 72
Views: 30251

Re: Quick cheap & easy LED conversion for my Halogen 'scope

I would suggest to critical compare the image you get with the two illuminations. If the image with your bicycle lamp is bright but looks somewhat overly contrasty as if you have your condenser aperture closed too much the light beam might be wrong.
by MicroBob
Sun Mar 25, 2018 2:27 pm
Forum: Camera systems and imaging
Topic: Comparing Zeiss PMIII internal camera to a Canon AE-1 and Sony a6000
Replies: 3
Views: 2842

Re: Comparing Zeiss PMIII internal camera to a Canon AE-1 and Sony a6000

Thank you for posting this interesting comparison! This is equipment from several decades in direct comparison. I have no experience with the photomicroscope so I have no answers why the field of view is so restricted - may be a mismatch of components? It is not unexpected for me that the Canon AE1 ...
by MicroBob
Sun Mar 25, 2018 7:10 am
Forum: Sandbox
Topic: practicing with phone camera settings
Replies: 16
Views: 9147

Re: practicing with phone camera settings

From my point of view these criteria are important for the choice of a microscope camera: - EFSC - Proven concept for the adaptation to the microscope - image quality - tethering to Android or Windows if needed - remote release (IR-gadget for 1€, smartphone app, cable release (FUJI)) - handling on t...
by MicroBob
Sat Mar 24, 2018 3:32 pm
Forum: Illumination Techniques
Topic: Dark field illumination: Questions and answers
Replies: 65
Views: 19072

Re: Dark field illumination: Questions and answers

Hi Doron, nice find! Here are pictures of the Darklite product: https://www.google.de/imgres?imgurl=https%3A%2F%2Fd2ydh70d4b5xgv.cloudfront.net%2Fimages%2F8%2F5%2Fmvi-darklite-vertical-illuminated-slide-holder-w-fiber-lite-pc-750-illuminator-f9436b55aae5efa71e1ad5a1bc36dff8.jpg&imgrefurl=https%3A%2F...
by MicroBob
Fri Mar 23, 2018 8:25 pm
Forum: Introduce yourself
Topic: Greetings everyone from Rio!
Replies: 9
Views: 3208

Re: Greetings everyone from Rio!

Hi Marcelo, welcome to the forum! With old microscopes it all depends on condition and what one needs. The instruments from the 1920 or 30s have their drawbacks when it comes to comfort and micro photography. A while ago I had the opportunity to look through a Seibert microscope of this time with go...
by MicroBob
Fri Mar 23, 2018 5:10 pm
Forum: Sandbox
Topic: Beautiful - STEM OF COTTON PLANT 40X
Replies: 4
Views: 5606

Re: Beautiful - STEM OF COTTON PLANT 40X

Thank you for showing this image! Did you slice, stain and cover it yourself? The image is perfectl sharp at the border, but somewhat unsharp in the middle. This is probably caused by your objectives not beeing planar types". You might improve this by stacking severals shots. I think you are using a...
by MicroBob
Sun Mar 18, 2018 7:11 pm
Forum: Illumination Techniques
Topic: A DIY LED ring for darkfield
Replies: 78
Views: 34187

Re: A DIY LED ring for darkfield

Hi Doron, as always a very interesting and innovative post from you! I'm happy to see that your experiment was a success. There is always a point when a practical test is more useful than trying to get the problem evaluated in a theoretical way. I like your idea with the central cylinder. I can imag...
by MicroBob
Sun Mar 18, 2018 10:40 am
Forum: Beginner's corner
Topic: Oil immersion tolerances
Replies: 27
Views: 4204

Re: Oil immersion tolerances

In the current state it is not very usable because it changes forus on its own. The optical parts are in the inner barrel. Asprint surrounds this inner barrel or is behind it and then there is somthing like a screwed in ring that hols it together against the sprint pressure. You might have a look if...
by MicroBob
Sun Mar 18, 2018 6:40 am
Forum: Pictures and Videos
Topic: IPHONE SCREEN - 100X
Replies: 16
Views: 2708

Re: IPHONE SCREEN - 100X

The given eyepiece magnification means that you see the image 10x enlarged compared to viewing it with the naked eye from a distance of 250mm. This is recorded by the camera. When you look at the photo from the right distance, this magnification is maintained.
by MicroBob
Sat Mar 17, 2018 8:18 pm
Forum: Beginner's corner
Topic: Oil immersion tolerances
Replies: 27
Views: 4204

Re: Oil immersion tolerances

My problem with "nearly touches" is allways that the drop of oil connects long before it really becomes critical. With a spring loaded objective no problem ...
by MicroBob
Sat Mar 17, 2018 8:12 pm
Forum: Pictures and Videos
Topic: IPHONE SCREEN - 100X
Replies: 16
Views: 2708

Re: IPHONE SCREEN - 100X

I see an image width of about 21 pixels and this means that at 326 dpi this is 1,6mm

Here is a formula for the calculation of the FOV:
https://www.microscopyu.com/microscopy- ... ld-of-view

With a field number of 16 and an objective of 10:1 this would fit. Looks perfectly normal to me.
by MicroBob
Sat Mar 17, 2018 6:36 pm
Forum: Beginner's corner
Topic: Looking for first microscope
Replies: 86
Views: 13707

Re: Looking for first microscope

Is it possible there could be something wrong with my condenser? I viewed a drop of water and then took off the condenser. The view didn't look any different to me as far as resolution or contrast. I'm not sure that I have a swing out front lens. Here's a picture of the top of my condenser. I saw t...
by MicroBob
Sat Mar 17, 2018 6:20 pm
Forum: Beginner's corner
Topic: Oil immersion tolerances
Replies: 27
Views: 4204

Re: Oil immersion tolerances

There are oil immersion objectives for cover slip use an one for use without coverslip. It is difficult to keep them apart as the immersion oil has the same refractive index as glass and teh cover slip doesn't matter as long as there is enough room for it. I habe a Leitz NPL Fluotar 50:1 n.a.1,0 tha...
by MicroBob
Sat Mar 17, 2018 8:48 am
Forum: Collecting microscopes and slides
Topic: Another side by side comparison
Replies: 12
Views: 3531

Re: Another side by side comparison

Thank you for showing these beautiful instruments! I live in Germany where nearly no american microscopes were sold, so they are especially exotic for me. I like old well made things a lot but restrain myself from collecting them. (Most people would call my extensive, old and sometimes exotic work e...
by MicroBob
Sat Mar 17, 2018 6:57 am
Forum: Pictures and Videos
Topic: IPHONE SCREEN - 100X
Replies: 16
Views: 2708

Re: IPHONE SCREEN - 100X

Good idea for a microscope object!
Compared to biological objects it is not so easy to find small man-made structures to look at under the microscope.

Old microchips are interesting, but it is difficult to remove the housing.
by MicroBob
Fri Mar 16, 2018 7:56 pm
Forum: Collecting microscopes and slides
Topic: Another side by side comparison
Replies: 12
Views: 3531

Re: Another side by side comparison

@Apochronaut: These bi-/monocular tubes are really an interesting piece of history. How common it is that people need a while to accustom themselves to new designs. In our microscopy group there always was a lack of binocular microscopes until recently. Now we have enough binocular microscopes but t...
by MicroBob
Fri Mar 16, 2018 7:51 pm
Forum: Collecting microscopes and slides
Topic: B&l research stand
Replies: 6
Views: 2200

Re: B&l research stand

These large fields of view are impressive for most people today - how impressed must they have been in the 1930s!
From the year of manufacture this microscope would be a contemporary of a Zeiss Standard GFL. It's interesting to see how different designs can be used to fulfil the same requirements.
by MicroBob
Thu Mar 15, 2018 8:20 pm
Forum: Collecting microscopes and slides
Topic: B&l research stand
Replies: 6
Views: 2200

Re: B&l research stand

Beautiful microscope! I looks like a very nice oldtimer for regular use.
I can't really see where it swivels - in the binocular head?

Are these eyepieces original? The entrance lenses have a very big diameter.

Bob
by MicroBob
Wed Mar 14, 2018 9:32 pm
Forum: Specimens, samples and slides
Topic: My First Diatom Hunt
Replies: 18
Views: 4881

Re: My First Diatom Hunt

Some camera apps allow to adjust the exposure.
Pantyhose probably will work, but it retains a lot of sample material an you might mix samples together.
Thes stainless stell meshs are really great, they are stiff, easy to mount to plastic surfaces and easy to clean.
by MicroBob
Wed Mar 14, 2018 7:56 pm
Forum: Specimens, samples and slides
Topic: My First Diatom Hunt
Replies: 18
Views: 4881

Re: My First Diatom Hunt

Maybe you have to tell your camera to expose longer, e.g. +2 stops. One always has a mixture of water and sample and a fine sieve is useful to get the right concentration of objects on the slide. I use this material to make sieves: https://www.ebay.de/itm/Edelstahlsieb-Edelstahlgewebe-200mm-x100mm-2...
by MicroBob
Wed Mar 14, 2018 12:28 am
Forum: Specimens, samples and slides
Topic: My First Diatom Hunt
Replies: 18
Views: 4881

Re: My First Diatom Hunt

Hi Charles, I really like these videos but I always was puzzled about who made them and why. There are translations in many many languages, but few videos on other topics in this channel. Did they expect to earn money over youtube and it didn't work? With drain cleaner it is important to look at the...
by MicroBob
Tue Mar 13, 2018 8:44 pm
Forum: Specimens, samples and slides
Topic: My First Diatom Hunt
Replies: 18
Views: 4881

Re: My First Diatom Hunt

I'm sure you have a mounting medium availabe: Use air! Cleaned diatoms in air are very good to see. If you store your diatoms uncleaned it would be a good idea to store them in alcohol to avoid bad smells. For me it is best to view diatoms live or cleaned. Old stored uncleaned stuff is not that attr...
by MicroBob
Mon Mar 12, 2018 5:26 pm
Forum: Microscopes and optics
Topic: Asking for help - fixing/alignment of a Zeiss condenser rack
Replies: 4
Views: 1563

Re: Asking for help - fixing/alignment of a Zeiss condenser rack

Hi Doron, here are three pics of a Zeiss- Winkel - GFL I have as a basket case in the cupboard. It will be similar but not identical to your microscope. I think the dampening is just a case of clean guides with the proper grease. You would need grease with medium dampening properties. I think it was...
by MicroBob
Sat Mar 10, 2018 12:03 pm
Forum: Miscellaneous
Topic: Site driving me nuts
Replies: 3
Views: 1956

Re: Site driving me nuts

Hi David,
I usually open a couple of topics in new tabs, then read them, close the tabs and have my original tab with the list still unchanged.


Bob
by MicroBob
Wed Mar 07, 2018 8:46 pm
Forum: Illumination Techniques
Topic: Dark field illumination: Questions and answers
Replies: 65
Views: 19072

Re: Dark field illumination: Questions and answers

Yes, the Leitz objective is without iris. The test with the n.a. 1,25 shows that the light cone of this condensor must be something like 1,25 to 1,4, so very sharp cut off between light and dark. When we look at your nice n.a. 0,75 objective I would say that you need 0,85 as a minimum for the lower ...