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#1 Hugh Peck

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Posted 22 October 2019 - 11:14 AM

I'm guessing it's just me. The problem is maintaining focus. Apparently the er is about a hundredth of a mm. Is this normal? Also, some things I see I can only get parts of in focus and much of it almost disappears,  even though when out of focus I can see a lot more of whatever it is. I'm only going up to 400x. This is an under $200 AmScope 2500x thing so the quality probably isn't the greatest. Assuming it's a microscope equivalent of the department store telescope. Again, I know next to nothing about microscopes.



#2 db2005

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Posted 22 October 2019 - 12:31 PM

Yes, microscopes have an extremely shallow depth of focus; and it gets worse with increasing magnification. You can increase contrast and depth of focus by reducing the aperture of the field diagraphm, at the cost of some spatial resolution. Also, basic, inexpensive microscope objectives are only sharply focused in the central 60-ish percent of the field. To maintain a completely flat, focused field of view you need to shell out for "Plan" objectives; Semi-Plan objectives are also available at a lower price.

 

Enjoy your microscope. I used a 30 $ toy-store microscope for many years and it gave me many hours of enjoyment. Your 200$ microscope is several leagues better than my first microscope.


Edited by db2005, 22 October 2019 - 12:31 PM.


#3 Hugh Peck

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Posted 22 October 2019 - 01:00 PM

Thank you. I kind of figured that was the case. I'll probably spring for some better objectives in the future. Just not the $800+ ones!  shocked.gif  More like the $50 ones. And maybe some better eps. Apparently, like most hobbies, it's easy to get into but upgrading can be pricey. grin.gif 



#4 Hugh Peck

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Posted 22 October 2019 - 02:28 PM

Can anyone give me an idea of what these mean in the real world? Since I'm not likely to be using any in a metallurgical sense I'm sure I can scratch that off. Probably fluorescence as well. Am presuming an iris will help with dof and possibly contrast and sharpness.

 

Brightfield (44)
Darkfield (42)
Fluorescence (5)
Metallurgical (7)
 

With Iris (3)
Without Iris (45)
 

Achromatic (9)
Fluor (5)
Plan (54)
Infinity (22)



#5 Hugh Peck

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Posted 22 October 2019 - 05:53 PM

Also, would better quality eps help? 



#6 PatrickVt

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Posted 29 October 2019 - 09:12 AM

I just recently educated myself on most of the terms related to microscopy and microscope parts.  I found that just running a basic search for each of the items you listed works fine to get a good explanation.  ie, "What is a Plan objective?"  

 

You mentioned having "er" of only a hundredth of a mm...  I assume you are referring to eye relief.  That is all about the eyepieces.  If it was DOF (depth of field/focus) you were referring to, then what has been said above is correct.  Just like in photography, DOF gets smaller with more magnification.  And, depth of field is very shallow in microscopy.  Same with shooting macro photography...  to get the depth of field necessary to see an entire specimen, front to back, you need to layer many images captured at a different depth in the focus field then use software to stack them.  Visually, your only option is to rock the focuser back and forth to see each layer of your specimen.  

 

Objectives can be improved by purchasing PLAN objectives.  PLAN objectives provide a flatter field across the frame.  Just make sure you purchase objectives with the same focal length has your originals...  ie...  160/0.17.    The 160 is for 160mm focal length...  distance from objective to eyepiece.  The 0.17 is for the thickness of the glass slide.  160/0.17 is the most common size.  If this is printed on the side of your objectives, this is the size you need.  

 

Objectives do have different threads too.  DIN is the standard...  and the 160/0.17 ones will be DIN (I'm almost certain).  

 

Objectives come in 4x, 10x, 20x, 40x, 60x and 100x (plus a few odd ones too).  100x objectives are used with oil...  I believe that 60x objectives come in both varieties, dry and oil.  Also, the longer 60x and 100x objectives are usually spring loaded to keep you from breaking the slide as you focus.  Spring loaded objectives are usually marked as (S).  My microscope came with a 4x, 10x, 40x and 100x.  However, I'm finding I prefer to use 4x, 10x, 20x and 40x objectives for most viewing.  

 

Eyepieces are where you can get more ER if that is really what you need.  Because I wear eyeglasses, I require two things in my eyepieces...  that "high eyepoint" which is called eye relief in astronomy...  and a larger eye lens which is marked as F.N. for Field Number.  This measurement is the diameter of the top eye lens.  Naturally, I require the same in my astronomy eyepieces.  So, if your eye relief is so small that you have your eye pressed up against the eyepiece, you should upgrade your eyepiece(s).  Oh yeah...  just like in astronomy, there are multiple sizes/diameters of eyepieces.  Better/larger microscopes have 30mm eyepieces and most beginner microscopes (like mine) have 23.2mm eyepieces.  Obviously, if your microscope takes 23.2mm eyepieces, don't purchase a 30mm eyepiece.  In my search for decent 23.2mm eyepieces, I came across a lot more 30mm eyepieces which I can't use.  

 

10x eyepieces are the most useful.  Higher magnifications, just like in astronomy, are oftentimes just hollow magnification.  My microscope came with a set of 20mm eyepieces in addition to a 10x set but they were difficult for me to use.  The top eye lens was far too small for me and there was not nearly enough eye relief.  I upgraded the 20mm eyepieces to ones with more eye relief and larger eye lenses and now I find them more comfortable.  That being said, I rarely use the 20x.  When I do use the 20x eyepieces, it is usually only with the lower power objectives.  

 

I know I am a bit late to your thread and questions but hopefully this info will help.  

 

Patrick


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#7 Hugh Peck

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Posted 29 October 2019 - 11:03 AM

Thanks for the info. I've been trying to find both eyepieces and objectives. Have found a couple of sites but a lot of the eps are 30 or 30.2mm and often seem for particular scopes. The objectives on mine a 4,10, 40 and 100. The eps are 10 and 25.. Have never used the 100x objective. Currently I have a 25 ep in one side and a camera in the other. 

 

Right now only the very center is clear or reaches focus. It would be nice if at least 50% was good. The camera seems to give a better image but it has a lot smaller field of view. It's also an Amscope. The image from it is rather dark.



#8 PatrickVt

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Posted 29 October 2019 - 11:42 AM

Better glass will help with getting better views toward the edge of the frame.  The first thing to try for crisper views to the edge is a PLAN objective.  If I remember correctly, these are corrected to get a flat field over 95% of the frame.  Semi-PLAN is 80%.  And, a simple achromat is only 65% of the frame before field curvature affects the image.  I am about to purchase some PLAN objectives so it will be interesting to see how well this works for correcting the field curvature.  This field curvature is driving me crazy.  I'm looking at purchasing the Amscope PLAN Achromatic objectives and I'm hoping for a noticeable improvement.  We'll see.  These are in the price range of $20 to $69 depending upon magnification.  Even considering the low cost of these, a set of them will cost more than my microscope cost me.  Maybe I'll start by only purchasing two...  a 4x and a 10x...  and see how it goes.  If I like the improvement, then I'll fill out the rest of the set.  If I don't see much of an improvement, then I'll stick with what I have.  

 

Better eyepieces can help too but I really think that at the low end (sub $100), you are only really changing the physical characteristics like Field Number and eye point both of which are very important to me.  I suspect that the higher end eyepieces are the ones that provide crisper views.  

 

I've been using a camera with an APS-C sized sensor so I'm seeing more field curvature in my images than I see through the eyepiece.  I find that kind of frustrating.  My Celestron 5mp microscope imager provides crisper images that my good cameras and I suspect it is due to the smaller sensor.  

 

Keep us posted on what you upgrade and how it turns out.

 

Patrick



#9 Hugh Peck

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Posted 29 October 2019 - 12:18 PM

Maybe I'll start by only purchasing two...  a 4x and a 10x...  and see how it goes.  If I like the improvement, then I'll fill out the rest of the set.  If I don't see much of an improvement, then I'll stick with what I have.  

 

 

I think that's what I'll do, too. They're too pricey to just buy a whole set. Don't think mine give 65%. Seems less. But, hey, it's a student scope. Still, for a first one it's okay. 


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#10 Hugh Peck

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Posted 31 October 2019 - 07:44 PM

Ordered  4x and 10x Plan objectives. They're not premium ones but combined they cost over  50% the cost of the microscope. Also going to upgrade the eyepieces. 


Edited by Hugh Peck, 31 October 2019 - 07:46 PM.


#11 PatrickVt

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Posted 31 October 2019 - 09:22 PM

My Amscope 10X PLAN Objective arrived this afternoon. 

 

The first thing I noticed was that it is heavier than my kit objectives.  Since we're talking about lenses, heavier in this case is probably an indication of extra glass or glass instead of plastic lenses.  So, I felt good about it even before viewing through it. 

 

I didn't have a lot of time to play with viewing things and imaging things (it's Halloween and the grandkids were here) but, after a quick look, I could visually see sharpness to the edge of the frame now.  With the kit objective (10x), the outer 25% or so was horrendously out of focus.  So, there is a definite improvement for a minimal cost. 

 

I think this PLAN objective cost me $33.  I have a 4x PLAN objective coming as well and that cost only $20 or so.  Little by little, I'll replace the rest of my objectives with PLAN objectives.  I hope to purchase 20x, 40x, 60x...  and, maybe, a 100x.  I rarely use the 100x so I'm not sure about that one.  I guess I'll probably purchase it so I have it for when I need it.  

 

Anyway, the relatively low cost of these Amscope PLAN objectives do provide a positive difference compared to my kit objectives that came with my Celestron CB2000C. 

 

I hope you find the same with your new objectives.

 

Patrick


Edited by PatrickVt, 31 October 2019 - 09:25 PM.


#12 Hugh Peck

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Posted 31 October 2019 - 10:09 PM

I got mine from Boli Optics. Know nothing about them, either. The 4x was $50 and the 10x $60. Supposed to be here Thursday. Will probably replace the 40x and get a 60x instead of another 100x. I really want to exchange the eps as well. A really good 10x and 20x. 1200x will be more than enough for my needs. It's just a hobby. Still, I need bigger improvements because my scope is cheaper. grin.gif Think I need a better camera, too.



#13 PatrickVt

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Posted 31 October 2019 - 11:25 PM

The ones I ordered are about as inexpensive as you can get for a PLAN objective.  I've been into photography for decades so I'm definitely aware of the cost of good glass so I'm actually a bit surprised that I can easily see a difference between my kit objective and the new PLAN objective that just arrived today.  I also know that if I ever peered through a microscope with objectives that cost in the thousands of dollars each, I could probably never go back to what I have now!  This happened with my telescopes...  I finally purchased an APO refractor and I can't go back to achromat refractors!

 

I've been playing around with different cameras to use with my microscope and I've been trying to talk myself out of looking for a new one.  My microscope camera is the 5mp Celestron one.  The clarity is just fine but I don't like that it gives views like using a 30x eyepiece.  This is because of the tiny sensor.  I'm toying with the idea of purchasing a 0.5x adapter lens to stick in front of the camera so that it brings it down to equivalent to a 15x eyepiece but I'm afraid that this cheap adapter probably will introduce new problems like blurring at the corners so I'm reluctant to try going that route.  Adding more glass in the form of 0.5x is probably not a wise idea if I am picky about image quality.   I'm finding it difficult to find info on this online though so I'm only basing my thoughts on my experiences in photography and astronomy.

 

So, then I pulled out my Sony a6000 and took a few test shots with that.  The bigger sensor makes a difference when it comes to magnification.  I can actually see the whole frame that I see through the eyepiece.  Actually, I see the entire tube with vignetting.  I think I'm getting some blurring in the corners though due to the large flat sensor.  If I use some digital zoom, I can eliminate the vignetting and that blurring but at the cost of added magnification.  That puts me near the problematic magnification I am getting with my Celestron Imager. 

 

I then tried an old Panasonic G3 that I have lying around.  That camera body has a 4/3" sensor so it's a bit smaller than the APS-C sized sensor in my Sony a6000.  I think I'm still preferring the images out of my Sony though.  

 

None of that camera testing, however, was with this new PLAN objective though.  That may improve the corners a bit or even enough.  We'll see. 

 

The things I like about the little Celestron Microscope Imager is the small, lightweight size at a low cost as well as a nice big live view on my tablet or desktop computer.  This makes focusing so much easier.  I could, however, tether my Sony a6000 to my tablet or desktop and have the same but I'd need to jump through more hoops in setup for that to work.  

 

Anyway...  I like some things about the Celestron Microscope Imager...  simplicity, lightweight, small, easy to focus because I can see it on my computer.  That 30x magnification, though, really bothers me... a lot.  If I'm imaging only a tiny portion of the frame, it is no problem but, if I want to image more than a quadrant of the frame, then I'll need to stitch together images when using this Celestron imager.  

 

I think I might play around more with my Sony a6000 tomorrow and see what I can get out of that with this new PLAN objective.  Plus, maybe I'll set up tethering for it to make live view focusing easier.  We'll see how it goes.

 

Patrick



#14 Hugh Peck

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Posted 01 November 2019 - 09:11 AM

If I had a trinocular I'd try to hook up my T6s to it. Wouldn't want all that weight hanging off the end of a cheap microscope. May I should try the adapter thing. I seen them of the site but didn't read about them so didn't know what they were for. Glad you pointed that out. The camera definitely needs a bigger sensor. Or interchangeable ones.

 

I had an APO once, a WO FLT98. Very nice. But then I remembered why I sold my Meade 390. That "up-down, up-down" stuff is way too much like actual exercise. grin.gif  I liked the 390 at f/11. Except for the physical therapy part.

 

I didn't want to spend a bunch but I did want a couple steps up from what it came with. A sub $200 microscope is only a step or two up from a toy. I mean it is a "2500x" job. Just like the "675x" department store scope. If I can get it to perform well at half that I'll be happy.

 

This is a snap from a video and it's about as good a focus I could get.

 

Protozoa.jpg

 

 



#15 Hugh Peck

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Posted 01 November 2019 - 10:36 AM

Forgot I have an SL1, which is a 13oz camera. It uses the AC cord as the T6 so all I need is the adapter. Have ordered "B&L" 10x High Eyepoint eps. They made by Meiji, I believe.



#16 PatrickVt

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Posted 01 November 2019 - 11:09 AM

If that is the best focus you can get then there is obviously a problem of some sort but since there are no eyepieces in the mix when you are imaging, then we know it isn't the eyepieces causing what we are seeing in the image and video.  It is probably the objectives causing some problems.

 

Another thing I'm going to throw out there...  we know that the depth of field is a narrow sliver so I wonder if your sample is too deep.  For instance, if you use a depression slide, that water is going to be far deeper than on a normal flat slide with a cover glass.  If those tiny micro-organisms are swimming through deeper water, then you would have problems getting them into that sliver of your in-focus depth of field.  If you are using a cover glass on a flat slide, then the only other thing causing blurry views would be the objective(s).  

 

It will be interesting to see how much of a difference the new objective makes for you.

 

Patrick



#17 Microscopy

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Posted 01 November 2019 - 11:15 AM

(...) Will probably replace the 40x and get a 60x instead of another 100x. (...)

I didn't follow this discussion, but I would like to warn against the use of a 60x dry objective.

These are very sensitive towards coverslip thickness. Even minor deviations of the coverglass thickness they are designed for (usually 0.17mm, which is, it should definitely be noted, the thickness of the coverslip + the thickness of the specimen + the thickness of the layer of whatever mountant used in between) will result in marked spherical aberration, resulting in poor, unsharp images. 

 

60x and 63x dry objectives are highly specialised systems, only of value in those circumstances where slide prep and the resulting slides can be carefully controlled, for example in the examination of semi-thin plastic sections of histological and histopathological samples, which are usually sectioned at about 0.25 micrometers thickness.

 

Replacing a 40x dry with a 60x dry would really be a bad idea (you didn't sead that). The fact that a 40x/0.65-0.70 is considered to be the highest magnification/resolution availlable in dry systems didn't fell out of the sky: an aperture of about 0.65-0.70 is about the highest usable dry system, while spherical aberration still being within limits.


Edited by Microscopy, 01 November 2019 - 11:31 AM.

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#18 PatrickVt

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Posted 01 November 2019 - 11:41 AM

Thanks for the info, Microscopy.  

 

Maybe I'll just stick with my initial phase 1 plan for new objectives then...  a 4x, 10x, 20x and 40x...  and then leave it at that.  That is good news on my bank account too!

 

Thanks again.

 

Patrick



#19 Hugh Peck

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Posted 01 November 2019 - 12:15 PM

I didn't follow this discussion, but I would like to warn against the use of a 60x dry objective.

These are very sensitive towards coverslip thickness. Even minor deviations of the coverglass thickness they are designed for (usually 0.17mm, which is, it should definitely be noted, the thickness of the coverslip + the thickness of the specimen + the thickness of the layer of whatever mountant used in between) will result in marked spherical aberration, resulting in poor, unsharp images. 

 

60x and 63x dry objectives are highly specialised systems, only of value in those circumstances where slide prep and the resulting slides can be carefully controlled, for example in the examination of semi-thin plastic sections of histological and histopathological samples, which are usually sectioned at about 0.25 micrometers thickness.

 

Replacing a 40x dry with a 60x dry would really be a bad idea (you didn't sead that). The fact that a 40x/0.65-0.70 is considered to be the highest magnification/resolution availlable in dry systems didn't fell out of the sky: an aperture of about 0.65-0.70 is about the highest usable dry system, while spherical aberration still being within limits.

Thanks for the knowledge. It's all new to me. Mine came with a 100x oil immersion, but I've never used it. It's just that 2500x on a cheap one is like the bazillion power telescope. I got some cover slips that are 0.12-0.16mm. I suppose a 100x oil Plan and good 15x eps would be a better way to go.  



#20 Hugh Peck

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Posted 04 November 2019 - 08:21 PM

The new 10x eps arrived today. B&L HE. The difference is amazing. Much brighter and clearer and easier to use.  


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#21 Hugh Peck

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Posted 05 November 2019 - 02:03 PM

The 4x and 10x objectives arrived today. The 10x is great. The 4x will not reach focus. Have contacted the seller about an exchange.



#22 PatrickVt

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Posted 05 November 2019 - 09:19 PM

That's great about the eyepieces providing a big improvement.  

 

What did the seller say about the 4x objective you purchased?  Did they send the wrong one or were the specs wrong for your microscope?  

 

I look forward to seeing new and improved images and video!

 

Patrick



#23 Hugh Peck

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Posted 05 November 2019 - 09:40 PM

It doesn't work with that microscope. Guessing it's the distance between ep and objective that the problem. They said they would see if they had one that would work for the model I have. 


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