Hi, first of all congratulations for the project which is great. I have already printed and assembled my PUMA microscope and I am very satisfied. I have a question that I can't find the answer to myself. It is possible to attach the LED illuminator directly to the Abbe Condenser instead of using mirrow?
It is 'almost' possible by using the DI_M3_Adjustment_ring model (page 124 of the current 3D printing guide PDF) to hold the illuminator. This is normally used to hold the lamp for the epi-illumination config, however if you can print a short male thread ring to act as an adaptor you can attach the DI_M3_Adjustment_ring to the base of the condenser (where the DI_Cnd_to_UC or DI_Cnd_Mirror_holder_socket would normally go). I say 'almost' possible because I have not included such a 'short male thread ring' in the project as yet but you could fashion one using the top male threads from those latter-mentioned parts' FreeCAD models. I did actually make such an adaptor but just haven't released it in the GitHub repo because I did not see the advantage or need to stick the illuminator directly under the condenser - it will not give good illumination like that (poor NA). In a future video I will show you the PUMA High NA illuminator which has a similar compact config to what you want but uses a specially made diffuser in place of the Abbe condenser to give high NA illumination.
The PUMA project looks interesting. But... It is so lightweight. No mass to prevent vibrations ruining the image. Microscopes need a good heavy structure and base to be any use.
Hello. I agree with the need for more stability for certain uses (not 'any use' though!). I have made a stabiliser system to help with its current configuration ( see: th-cam.com/video/d8tMtWFhNY4/w-d-xo.html ). I am also working on an alternative stage for high end projects. This will be more stable and have motorised XYZ for precision experiments. Remember, one of the design goals of PUMA is the 'P' bit - portability. The present lightweight system is actually quite useable out in the field for visual observations and on a sturdy desk is has proven useful for imaging too, despite its lightweight construction. The video I linked above gives some examples of that. PUMA also has other uses and unique strong points compared to other scopes and was never intended to be a 'drop-in' replacement for a Zeiss Axioscop 3 or an Olympus BX51, etc. Thanks for taking the time to watch and make a considered comment. I appreciate that.
Hello! I think that the example images with and without the condenser lens at 17:26 might be mixed up. I think that the image with the condenser is actually on the left, whereas without the condenser is on the right. This is in the opposite sense of the labels on the slide and the description in the transcript. I might be wrong about this, however.
Hello. Thanks for watching and taking the time to comment. I just checked and I can confirm the labels are correct as shown. The one without condenser (left) shows the increased refractility and coherence artefacts associated with a smaller numerical aperture (as you would expect when not using a condenser with a high NA lens). Note, for example, the increased visibility of the clear mucin in the lumena and the coarse texture of the cellular cytoplasm. These are examples of the enhanced phase-based contrast that you see when a condenser is either absent or the IAD is reduced to significantly below the rated NA of the objective. I'll say more about these things when I publish my video on the PUMA high NA illuminator (probably later this year).
Great video!! Thank you so much!! I was just wondering if you have any comparison between Schlieren phase contrast and other commercial phase contrast microscope that use a phase ring in their objective.
That would be a good comparison to do. I need to check if any of my old Leitz/Zeiss scopes have a phase condenser (I have some phase objectives for them) - or otherwise get hold of a phase scope to do the comparison. I intend to make a dedicated video on Fourier filtration microscopy (to include phase, dark ground and other effects) so that would be a good platform to show the differences / similarities. In the mean time if I get hold of a standard phase scope I can post some pictures on my twitter account.
@@PUMAMicroscope Love what you do! I wish you the best of health and encourage you to keep creating and sharing more videos and knowledge to make this world better. - How do you create an image for the 'calculated phase image from all Schlieren masks'? - How does phase contrast work without a phase contrast objective? How could it save money by not purchasing phase contrast objectives? - It would be great if you could make another video using your phase contrast microscope to examine various samples, such as bacteria. For example, you could take a sample from yogurt.
@@leminhduc93 Thanks. Yes I will be covering such topics in future videos. However, to understand the answers viewers need to know more microscopy theory so my next few videos will cover important theory topics like convolution and Fourier transforms.
My understanding is that Schlieren can be seen as one particular type or variety of 'oblique illumination' but not all forms of oblique illumination are Schlieren. For example simply shining a light obliquely on a specimen (as I show in my video on epi-illumination here: th-cam.com/video/cAEB10K8PqI/w-d-xo.html ) is a form of oblique illumination microscopy but it is not a Schlieren method. In the olden days, many microscopes had condenser / mirror holders that could be swung from side to side to give oblique illumination from below - again providing oblique illumination in a general sense without the Fourier-pane bisection characteristic of a Schlieren method. If you would like an overview of these things do a Google Scholar search for a paper entitled: "Beyond Brightfield: “Forgotten” Microscopic Modalities" by Radek Pelc. I hope that helps.
I have published details of the lenses and the optical paths on GitHub here: github.com/TadPath/PUMA/blob/main/docs/PUMA_Kohler_Illuminator_Specs.pdf
20:45 PLEASE WATCH THIS BEFORE WATCHING THE WHOLE VIDEO ! ! !
This is the real benefit of the magical condenser in action!
Hi, first of all congratulations for the project which is great. I have already printed and assembled my PUMA microscope and I am very satisfied.
I have a question that I can't find the answer to myself.
It is possible to attach the LED illuminator directly to the Abbe Condenser instead of using mirrow?
It is 'almost' possible by using the DI_M3_Adjustment_ring model (page 124 of the current 3D printing guide PDF) to hold the illuminator. This is normally used to hold the lamp for the epi-illumination config, however if you can print a short male thread ring to act as an adaptor you can attach the DI_M3_Adjustment_ring to the base of the condenser (where the DI_Cnd_to_UC or DI_Cnd_Mirror_holder_socket would normally go).
I say 'almost' possible because I have not included such a 'short male thread ring' in the project as yet but you could fashion one using the top male threads from those latter-mentioned parts' FreeCAD models. I did actually make such an adaptor but just haven't released it in the GitHub repo because I did not see the advantage or need to stick the illuminator directly under the condenser - it will not give good illumination like that (poor NA). In a future video I will show you the PUMA High NA illuminator which has a similar compact config to what you want but uses a specially made diffuser in place of the Abbe condenser to give high NA illumination.
The PUMA project looks interesting. But... It is so lightweight. No mass to prevent vibrations ruining the image. Microscopes need a good heavy structure and base to be any use.
Hello. I agree with the need for more stability for certain uses (not 'any use' though!). I have made a stabiliser system to help with its current configuration ( see: th-cam.com/video/d8tMtWFhNY4/w-d-xo.html ). I am also working on an alternative stage for high end projects. This will be more stable and have motorised XYZ for precision experiments. Remember, one of the design goals of PUMA is the 'P' bit - portability. The present lightweight system is actually quite useable out in the field for visual observations and on a sturdy desk is has proven useful for imaging too, despite its lightweight construction. The video I linked above gives some examples of that.
PUMA also has other uses and unique strong points compared to other scopes and was never intended to be a 'drop-in' replacement for a Zeiss Axioscop 3 or an Olympus BX51, etc.
Thanks for taking the time to watch and make a considered comment. I appreciate that.
Great video again!
Thank you. Soon I will be uploading the definitive guide to building a complete Foundation scope from scratch - stay tuned.
Nice work
Thanks
Hello! I think that the example images with and without the condenser lens at 17:26 might be mixed up. I think that the image with the condenser is actually on the left, whereas without the condenser is on the right. This is in the opposite sense of the labels on the slide and the description in the transcript.
I might be wrong about this, however.
Hello. Thanks for watching and taking the time to comment. I just checked and I can confirm the labels are correct as shown. The one without condenser (left) shows the increased refractility and coherence artefacts associated with a smaller numerical aperture (as you would expect when not using a condenser with a high NA lens). Note, for example, the increased visibility of the clear mucin in the lumena and the coarse texture of the cellular cytoplasm. These are examples of the enhanced phase-based contrast that you see when a condenser is either absent or the IAD is reduced to significantly below the rated NA of the objective. I'll say more about these things when I publish my video on the PUMA high NA illuminator (probably later this year).
@@PUMAMicroscope ah I see. Thanks for the explanation! Probably I am mistaking the diffraction artifacts for higher resolution.
Great video!! Thank you so much!!
I was just wondering if you have any comparison between Schlieren phase contrast and other commercial phase contrast microscope that use a phase ring in their objective.
That would be a good comparison to do. I need to check if any of my old Leitz/Zeiss scopes have a phase condenser (I have some phase objectives for them) - or otherwise get hold of a phase scope to do the comparison. I intend to make a dedicated video on Fourier filtration microscopy (to include phase, dark ground and other effects) so that would be a good platform to show the differences / similarities. In the mean time if I get hold of a standard phase scope I can post some pictures on my twitter account.
@@PUMAMicroscope Great! Thank you so much for this! I can't wait to see.
How does our cheek skin cells look like under phase contrast module of PUMA?
I show this in a series of tweet images here: twitter.com/Paul_Tadrous/status/1565387314586701826?s=20&t=FjuUJGnTtWmiWkJ3Cox83w
@@PUMAMicroscope Love what you do! I wish you the best of health and encourage you to keep creating and sharing more videos and knowledge to make this world better.
- How do you create an image for the 'calculated phase image from all Schlieren masks'?
- How does phase contrast work without a phase contrast objective? How could it save money by not purchasing phase contrast objectives?
- It would be great if you could make another video using your phase contrast microscope to examine various samples, such as bacteria. For example, you could take a sample from yogurt.
@@leminhduc93 Thanks. Yes I will be covering such topics in future videos. However, to understand the answers viewers need to know more microscopy theory so my next few videos will cover important theory topics like convolution and Fourier transforms.
@@PUMAMicroscope Thank you very much for your response! I will wait for the video and watch it.
Hello. Can you provide links for where the lens condensers can be purchased?
There are some links to these (and other) parts in the Bill of Materials on the GitHub page: github.com/TadPath/PUMA
Is this "Schlieren phase contrast" the same as the technique called oblique illumination? If not, how do they differ?
My understanding is that Schlieren can be seen as one particular type or variety of 'oblique illumination' but not all forms of oblique illumination are Schlieren. For example simply shining a light obliquely on a specimen (as I show in my video on epi-illumination here: th-cam.com/video/cAEB10K8PqI/w-d-xo.html ) is a form of oblique illumination microscopy but it is not a Schlieren method. In the olden days, many microscopes had condenser / mirror holders that could be swung from side to side to give oblique illumination from below - again providing oblique illumination in a general sense without the Fourier-pane bisection characteristic of a Schlieren method. If you would like an overview of these things do a Google Scholar search for a paper entitled: "Beyond Brightfield: “Forgotten” Microscopic Modalities" by Radek Pelc. I hope that helps.
@@PUMAMicroscope Thank you, I'll look into it.