drhemlock Posted July 21, 2011 Share Posted July 21, 2011 i am a little confused on the use of barlow lenses for my stereo disecting microscope how they are used and if one of the attached will work for my system. in the first image this is what it looks like under the scope next two are some ebay barlows and the scope itself has two setting a 1x and a 3x rotating thing that i can turn for different magnifications. for a barlow to work do i place the barlow lense in front of the four little lenses shown in the first image there is no way to screw the barlow lenses into the bottom of the turret surrounding those four lenses. help please thanks in advance james "doc" underwood Link to comment Share on other sites More sharing options...
Bill Posted July 21, 2011 Share Posted July 21, 2011 (edited) As I understand it, you put the occular in/on the top of the barlow, then the barlow in/on the microscope where the occular was. So, occular, barlow, microscope. Forgot to add, the barlow lens tube should be the same diameter as the occular tube to fit the microscope. 2nd edit... see here for an example Edited July 21, 2011 by Bill KOF, Bill. Welcome to the forum, all new members www.ukfossils check it out. Link to comment Share on other sites More sharing options...
drhemlock Posted July 21, 2011 Author Share Posted July 21, 2011 As I understand it, you put the occular in/on the top of the barlow, then the barlow in/on the microscope where the occular was. So, occular, barlow, microscope. Forgot to add, the barlow lens tube should be the same diameter as the occular tube to fit the microscope. 2nd edit... see here for an example so i would need two of these puppies for my stereo scope Link to comment Share on other sites More sharing options...
Auspex Posted July 22, 2011 Share Posted July 22, 2011 so i would need two of these puppies for my stereo scope Correct, and here's the rub: they would have to be perfectly matched. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
drhemlock Posted July 22, 2011 Author Share Posted July 22, 2011 Correct, and here's the rub: they would have to be perfectly matched. they would have to be perfectly matched? not sure what you mean by this doc Link to comment Share on other sites More sharing options...
Auspex Posted July 22, 2011 Share Posted July 22, 2011 Matched in focal length, down to several decimal points. Just pulling a number out of the air, let's say the nominal focal length of the barlows is 28mm: with normal tolerances, one could be 27.943mm and the other 28.057mm; the difference of .114mm is plenty 'nuf to wreck the stereo resolution at the magnifications you're working with. You'd want to buy a matched pair, rather than just "two of the same" nominal focal lengths. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
drhemlock Posted July 22, 2011 Author Share Posted July 22, 2011 Matched in focal length, down to several decimal points. Just pulling a number out of the air, let's say the nominal focal length of the barlows is 28mm: with normal tolerances, one could be 27.943mm and the other 28.057mm; the difference of .114mm is plenty 'nuf to wreck the stereo resolution at the magnifications you're working with. You'd want to buy a matched pair, rather than just "two of the same" nominal focal lengths. okay so the ones "Bill" linked me to at the surplus shed i would have to buy two of these of the same focal length. if not how do i determine what the focal length should be and where would i find a matched pair? thanks'doc Link to comment Share on other sites More sharing options...
Auspex Posted July 22, 2011 Share Posted July 22, 2011 okay so the ones "Bill" linked me to at the surplus shed i would have to buy two of these of the same focal length. if not how do i determine what the focal length should be and where would i find a matched pair? thanks'doc I'd contact the prospective sellers and tell them you need a matched set of barlows for a stereo microscope. If their business is microscopes, they will know what you need. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
pleecan Posted July 22, 2011 Share Posted July 22, 2011 (edited) i am a little confused on the use of barlow lenses for my stereo disecting microscope how they are used and if one of the attached will work for my system. in the first image this is what it looks like under the scope next two are some ebay barlows and the scope itself has two setting a 1x and a 3x rotating thing that i can turn for different magnifications. for a barlow to work do i place the barlow lense in front of the four little lenses shown in the first image there is no way to screw the barlow lenses into the bottom of the turret surrounding those four lenses. help please thanks in advance james "doc" underwood Hi James: you thread the barlow 0.5x at the bottom of the scope... this will increase the depth of field.... some barlows allow one to attach a series of barlow... on occasions I have used three 0.5x barlows in series threaded to the bottom optic assembly of the microscope. There are some dissecting scopes that don't have a thread at the bottom of the scope.... these are in the minority... PL Edited July 22, 2011 by pleecan Link to comment Share on other sites More sharing options...
Auspex Posted July 22, 2011 Share Posted July 22, 2011 OK, I'm confused. Is this a stereo 'scope, or a binocular 'scope? "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Bill Posted July 22, 2011 Share Posted July 22, 2011 (edited) Doc.. which do you want to increase, the magnification, or the depth of field? Edit: that last should have been Field of View, not depth of field. Edited July 23, 2011 by Bill KOF, Bill. Welcome to the forum, all new members www.ukfossils check it out. Link to comment Share on other sites More sharing options...
pleecan Posted July 22, 2011 Share Posted July 22, 2011 The picture james has posted is disecting scope with 1 x and 3X objective = 10x and 30X magnification with 10X occular. The reason why one would use a barlow would be for applications of ie fossil prep where you want a large field of view as well as depth of view... Link to comment Share on other sites More sharing options...
drhemlock Posted July 23, 2011 Author Share Posted July 23, 2011 i was looking at the scope and took out each eyepiece one is fixed the other is zoom capiable i think and they are indeed threaded for the addtion of something i would suspect perhaps a barlow or some other accessory. i have contacted the place that i bought it from and hope to hear back from them soon as to whether or not this option is available and what barlows mags they offer. it is made by AMSCOPE and here is the ebay listing for info not for a sell or anything Item Id: 200546694780 as there are some nunbers i do not understand as to what size i can get or adapt if they do not have a set availiable. as to the barlow mentiined and linked to by bill, i think it was from surplus shed. i asked some questions via email and all they said it should fit any microscope, i am somewhat sketptical i was wondering if someone has experience with this type of scope. as i will be using it for prep work, so wide field of view and depth whould be needed. i am not sure how much of either i would need i am almost sure that one would not use the scope inside the prep tank and one would look through the glass. so a what depth of field should i look for? wide field etc. please look at the specs at the aove mentioned scope and see what the specs say as to what i need to get as far as barlow lenses size wise dia etc. i looked at some crinoid's that i am practicing on and with the 1x or the 3x i can bring it to focus under the the scope say to about five inches from the fossil. i realize that i will have to make some adjustments to the base and making a boom stand perhaps i can get one second hand after looking at the prices on the bay this might happen. let me know what you guys and gals come up with please thanks in advance doc Link to comment Share on other sites More sharing options...
ashcraft Posted July 23, 2011 Share Posted July 23, 2011 My friend has his barlow lens glued into the bottom frame of the objective. It occasionally falls out, but he just re-glues it. Hotmelt, I believe. Brent Ashcraft (I am back) ashcraft, brent allen Link to comment Share on other sites More sharing options...
Auspex Posted July 23, 2011 Share Posted July 23, 2011 My friend has his barlow lens glued into the bottom frame of the objective. It occasionally falls out, but he just re-glues it. Hotmelt, I believe. Brent Ashcraft (I am back) I really enjoy direct ("crude") solutions to high-end problems! (Welcome back) "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
pleecan Posted July 24, 2011 Share Posted July 24, 2011 i was looking at the scope and took out each eyepiece one is fixed the other is zoom capiable i think and they are indeed threaded for the addtion of something i would suspect perhaps a barlow or some other accessory. i have contacted the place that i bought it from and hope to hear back from them soon as to whether or not this option is available and what barlows mags they offer. it is made by AMSCOPE and here is the ebay listing for info not for a sell or anything Item Id: 200546694780 as there are some nunbers i do not understand as to what size i can get or adapt if they do not have a set availiable. as to the barlow mentiined and linked to by bill, i think it was from surplus shed. i asked some questions via email and all they said it should fit any microscope, i am somewhat sketptical i was wondering if someone has experience with this type of scope. as i will be using it for prep work, so wide field of view and depth whould be needed. i am not sure how much of either i would need i am almost sure that one would not use the scope inside the prep tank and one would look through the glass. so a what depth of field should i look for? wide field etc. please look at the specs at the aove mentioned scope and see what the specs say as to what i need to get as far as barlow lenses size wise dia etc. i looked at some crinoid's that i am practicing on and with the 1x or the 3x i can bring it to focus under the the scope say to about five inches from the fossil. i realize that i will have to make some adjustments to the base and making a boom stand perhaps i can get one second hand after looking at the prices on the bay this might happen. let me know what you guys and gals come up with please thanks in advance doc No. The eyepiece one is fixed focus the other one is use to adjust the focal length to accomadate variability in the focus in ones eyes... it is not a zoom eyepiece. I have never seen barlows that fit eyepiece for disecting scope only telescope optics have them and I have been playing with optics for quite some time now... I am familiar with both telescope and microscope optics. For prep work I prefer variable zoom discecting scope with boom stand and 0.5x zoom attached increase field of field and field of depth ie increase working distance between your fossil and scope lens... a system like this cost around $500 as a starting point... PL Link to comment Share on other sites More sharing options...
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