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Choosing Microscope Optics

Lesson 4 from: Beyond Macro Photography: Into the Microscopic World

Charles Krebs

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Lesson Info

4. Choosing Microscope Optics

Lesson Info

Choosing Microscope Optics

Now I'm going to get into the these optics of these microscope optics it's microscope objectives because they are really a solution for for the for the for the above five x with ten x for twenty years and obviously they have a solution that they're made to be used on microscopes okay most conventional lenses that will use the macro lenses the enlarging lenders that he reversed ah usually around two eight two eight is the largest nominal aperture many of them you have to stop down toe before too sort of get the lens chugging along at its best performance so you get kind of to eight f four lands as a result if you wanted to limit your that effective aperture we talked about twenty you really can't use these for more than about three to five x magnification because five x the effective aperture at afford five exits six times four is twenty four so it's effectively f twenty four with two eight lens within that four lines rather so the point is that you can't you can't open the lens up larg...

e enough ah to avoid diffraction with a two eight or f four lens microsort microscope optics microscope objectives have a very very large can have a very, very large like gathering ability much larger than we can accomplish with a photographic lens, but they're the this is where we get into an area where even very, very accomplished, very knowledgeable photographers with you know there's one fella I was conversing with you know you've been a long time photographer he knew you know, view cameras, everything inside and out started doing this you know, it's all its alien the nomenclature and everything is a little bit a lead so we're going to go over and I'm going to spend a little time trying to get you guys really up to speed on on what we're talking about our microscope objective now the light gathering ability on a microscope objective has not stated in an f number like we used 00:01:58.854 --> 00:02:02. to we think of a an f two eight lands and an f one 00:02:02.21 --> 00:02:04. point four lands the afghan put four lines has a much 00:02:04.75 --> 00:02:06. greater larger aperture much greater light gathering 00:02:07.44 --> 00:02:11. we don't talk enough numbers in in microscopes we 00:02:11.29 --> 00:02:14. talkabout numerical apertures is very analogous to 00:02:14.87 --> 00:02:18. the f stop the numbers are a little different but 00:02:18.09 --> 00:02:21. the the point is the larger the numerical aperture 00:02:21.66 --> 00:02:24. numerically numerically the larger than america lapped 00:02:24.93 --> 00:02:28. the greater the light gathering ability of that optic 00:02:28.87 --> 00:02:33. and the easier it isthe or the less the how the easier 00:02:33.35 --> 00:02:36. just avoid the horrible diffraction effects 00:02:37.48 --> 00:02:40. and the numerical aperture really because of the diffraction 00:02:40.48 --> 00:02:42. effects than america laughter really is the key to 00:02:42.45 --> 00:02:45. a resolution if you haven't a te next that's got a 00:02:46.26 --> 00:02:49. and I'll show you these numbers but a point to america 00:02:49.43 --> 00:02:51. laps or you have a ten exit has a point four in america 00:02:51.96 --> 00:02:54. lab mature the larger the one with point four will 00:02:54.44 --> 00:02:57. actually resolved twice as much detail as the other 00:02:57.05 --> 00:03:00. one so the miracle aperture is key to resolution 00:03:01.42 --> 00:03:03. you don't have zoom you don't have our lovely zoom 00:03:03.51 --> 00:03:06. landers they typically fixed their steps like four 00:03:06.1 --> 00:03:12. to five x ten x twenty x forty fifty x sixty x and 00:03:12.46 --> 00:03:15. they're so so there are jumps would be like you know 00:03:15.44 --> 00:03:18. going maybe like having a set of lenses being a twenty 00:03:18.21 --> 00:03:21. five fifty one hundred two hundred with nothing in 00:03:21.44 --> 00:03:24. between at the end of the world but that's just the 00:03:24.18 --> 00:03:27. way it is on obviously what they were designed to 00:03:27.14 --> 00:03:30. be used on a microscope but it's got a zillion different 00:03:30.31 --> 00:03:33. optics that's designed to be used on microscopes which 00:03:33.21 --> 00:03:37. ones are usable for what we want to do and out this 00:03:37.54 --> 00:03:38. is just 00:03:39.77 --> 00:03:43. just to show you for example a ten x microscope objective 00:03:43.32 --> 00:03:47. ten x is a this is the ten x here the tenants on the 00:03:47.03 --> 00:03:51. front of this one there okay that's these air effectively 00:03:51.25 --> 00:03:53. if if we want to think in photographic terms these 00:03:53.6 --> 00:03:56. are effectively twenty millimeter f one point eight 00:03:56.35 --> 00:04:01. lenses okay design designed to be used who's at at 00:04:01.41 --> 00:04:04. at ten x okay so at ten next effective apertures about 00:04:04.72 --> 00:04:08. f eighteen if I took my large grayson large england 00:04:08.15 --> 00:04:09. you know one of the best maid 00:04:10.69 --> 00:04:14. but it's a two eight if I shoot it to eight ten x. 00:04:14.87 --> 00:04:17. My effective after is thirty one. If I have to stop 00:04:17.48 --> 00:04:20. it down to stop my effective after becomes forty four, 00:04:20.39 --> 00:04:23. so you can see I'm way, way beyond my sort of benchmark 00:04:23.46 --> 00:04:24. of twenty two 00:04:25.99 --> 00:04:27. when they got to get to ten x there's. No way I can 00:04:27.94 --> 00:04:30. get the resolution. I want without a microscope projected 00:04:30.59 --> 00:04:32. twenty exits, even it's, even a stronger case for 00:04:32.66 --> 00:04:33. the microscope objective. 00:04:35.33 --> 00:04:38. Twenty its objectives, like a ten millimeter. Ah, 00:04:39.99 --> 00:04:40. ah, 00:04:42.0 --> 00:04:43. they got down there. Ten millimeter, one point two 00:04:43.72 --> 00:04:46. let's. Well, there aren't. There aren't very many 00:04:46.32 --> 00:04:47. good one point two lenses. 00:04:49.89 --> 00:04:51. There aren't any that I know of that could be used 00:04:51.86 --> 00:04:54. for macro work so the effect of apertura twenty exes 00:04:54.7 --> 00:04:57. twenty four and look how horrible now the conventional 00:04:57.78 --> 00:05:02. lands would be at an f to a to b f fifty nine and 00:05:02.01 --> 00:05:04. f forward b f eighty for me that's a joke that you're 00:05:04.58 --> 00:05:06. talking about apertures that ansel adams probably 00:05:06.47 --> 00:05:08. wouldn't have even to use and there's eight by ten 00:05:08.24 --> 00:05:11. because the diffraction I'm joking there a little 00:05:11.11 --> 00:05:12. bit not that much 00:05:13.69 --> 00:05:14. okay two 00:05:16.59 --> 00:05:19. types of objective exist out there in the world when 00:05:19.21 --> 00:05:22. you when you foret out there in the world t get out 00:05:22.27 --> 00:05:26. this one is a finite type and one is an infinity type 00:05:26.79 --> 00:05:30. and the difference you can see in these tool streets 00:05:30.22 --> 00:05:32. on top of the finite you can think of a finite type 00:05:32.55 --> 00:05:35. this is a finite type looks like a microscope dejected 00:05:35.48 --> 00:05:38. but you can think of it as just a lens it's just a 00:05:38.68 --> 00:05:40. lens if you can put it on the bellows you could put 00:05:40.51 --> 00:05:43. it on extension tube's and ah 00:05:44.59 --> 00:05:47. you need nothing in between the lens and the camera 00:05:47.05 --> 00:05:47. sensor 00:05:48.57 --> 00:05:52. infinity type is pretty much all they make these days 00:05:52.15 --> 00:05:54. all the manufacturers make these days and there are 00:05:54.61 --> 00:05:57. reasons for it but they need an additional optic they 00:05:57.33 --> 00:06:01. need what's called a two blends okay to blend in between 00:06:01.56 --> 00:06:02. the objective 00:06:03.5 --> 00:06:06. and the camera sensor ah 00:06:10.42 --> 00:06:12. just kind of keep that in mind with infinity you need 00:06:12.62 --> 00:06:16. additional lens in between with the finite type it's 00:06:16.04 --> 00:06:17. just like putting a lens on a bellows 00:06:19.91 --> 00:06:23. like camera lenses you have higher quality and lower 00:06:23.04 --> 00:06:26. quality objectives you have the plan apples at plant 00:06:26.7 --> 00:06:30. up a chromatic which are very very high quality nearly 00:06:30.83 --> 00:06:34. very expensive you have fairly budget lo lo and linda's 00:06:34.2 --> 00:06:37. that are acrobats and they're cheap and some of them 00:06:37.24 --> 00:06:40. are quite good some of them are horrible you have 00:06:40.36 --> 00:06:43. biological and you have industrial objectives the's 00:06:43.63 --> 00:06:45. air industrial objectives these these are designed 00:06:46.22 --> 00:06:49. to be used with no cover glass so I can use directly 00:06:49.93 --> 00:06:53. looking at a subject the biological objectives typically 00:06:53.56 --> 00:06:56. are designed to be used with a glass slide with a 00:06:56.01 --> 00:06:58. cover glass effect that the optics have designed very 00:06:58.56 --> 00:07:01. often tohave a very specific thickness cover glass 00:07:01.41 --> 00:07:01. on it 00:07:03.51 --> 00:07:05. working distance is one of the key things for a table 00:07:05.93 --> 00:07:07. we don't worry too much about working distance on 00:07:07.6 --> 00:07:10. a microscope but on our table top set up we definitely 00:07:10.97 --> 00:07:11. definitely do 00:07:14.21 --> 00:07:16. so that's one of the key characteristics were going 00:07:16.45 --> 00:07:19. going to be looking looking for in a microscope objective 00:07:19.65 --> 00:07:23. is the working distance and it's not always marked 00:07:23.73 --> 00:07:27. but we need to find out because that's the problem 00:07:27.0 --> 00:07:28. a lot of people have it they'll buy they'll buy an 00:07:28.87 --> 00:07:32. objective that has a working just just far too for 00:07:32.51 --> 00:07:35. table top set up they don't have enough room toe like 00:07:35.85 --> 00:07:39. the subject. You're right on top of on a microscope. 00:07:39.67 --> 00:07:41. It doesn't matter that much, because the light's, 00:07:41.0 --> 00:07:43. usually coming from underneath their you have special 00:07:43.3 --> 00:07:45. lighting mechanisms toe light from the top blood on 00:07:45.89 --> 00:07:48. a tabletop set up. Yes, he definitely wants 00:07:50.06 --> 00:07:54. some good working distance. Now, uh, 00:07:56.22 --> 00:07:57. image circle. 00:07:58.21 --> 00:08:00. You know, for example, they make lenses for the you 00:08:00.97 --> 00:08:03. see cameras that can't be used on a full frame camera. 00:08:03.83 --> 00:08:05. It's kind of same thing that the image, the image 00:08:05.44 --> 00:08:07. they create isn't big enough for four camera camera 00:08:08.48 --> 00:08:10. microscope objectives were designed to create a fairly 00:08:10.9 --> 00:08:12. fairly small image circle. 00:08:14.28 --> 00:08:17. Many of them, many of the new ones, are sort of overachievers 00:08:17.06 --> 00:08:21. in that. Yeah, yeah, the design, maybe max on a microscope 00:08:21.1 --> 00:08:21. to cover 00:08:22.98 --> 00:08:26. twenty eight millimeter diameter, you know, thirty 00:08:26.26 --> 00:08:28. five millimeter sensors, which is just about right, 00:08:28.48 --> 00:08:30. is just about the size of a nap. See diagonal that's. 00:08:30.8 --> 00:08:33. Why I like absolute. You'll get some, though, that 00:08:33.49 --> 00:08:36. I'm quite good on thirty five millimeter. The 00:08:39.02 --> 00:08:40. even though first right millimeter diagonals. Forty 00:08:40.94 --> 00:08:43. three millimeters. You can still use them. But I gravitate 00:08:43.78 --> 00:08:46. to its absolute because of the limited image circle 00:08:46.83 --> 00:08:50. size. And the last thing I want to talk about till 00:08:50.92 --> 00:08:53. we actually look it's from here is if you look at 00:08:53.96 --> 00:08:55. used older microscope objectives. 00:08:58.65 --> 00:09:02. Until I don't feel not you know not that long ago 00:09:02.11 --> 00:09:05. in my microscope terms the designers made 00:09:06.48 --> 00:09:10. obviously they rejected for microscopes and it was 00:09:10.14 --> 00:09:12. hard to make all the color correction in this in the 00:09:12.83 --> 00:09:15. these little lenses so they said oh it's ok everybody 00:09:15.5 --> 00:09:18. uses the microscope is going to use eyepieces so we're 00:09:18.17 --> 00:09:20. goingto finish the color correction offer the eyepieces 00:09:20.57 --> 00:09:23. so you needed special color corrective eye pieces 00:09:23.55 --> 00:09:26. that matched the objectives well that's fine on the 00:09:26.04 --> 00:09:27. microscope is fine when you're looking but when you're 00:09:27.9 --> 00:09:30. when you're slapping it on the front of a camera it's 00:09:30.53 --> 00:09:33. going right to the camera sensor you no longer have 00:09:33.06 --> 00:09:35. that eyepiece in there to make the color correct is 00:09:35.44 --> 00:09:38. that air needed so this is another very common mistake 00:09:38.11 --> 00:09:42. people buying use objectives is that they get one 00:09:42.68 --> 00:09:44. and they got all kinds of weird chromatic aberration 00:09:44.91 --> 00:09:47. and they're going what the heck's going on here and 00:09:47.33 --> 00:09:50. I say well yeah that's that's one you needed corrective 00:09:50.01 --> 00:09:51. eye pieces that that's not a good choice 00:09:53.78 --> 00:09:59. for for putting on a camera a cz we have here so 00:10:00.58 --> 00:10:00. sing 00:10:02.47 --> 00:10:04. you know some injectors that I use I use regularly 00:10:06.3 --> 00:10:11. the two on the left are infinity type objectors the 00:10:11.65 --> 00:10:13. one of the middle of the finite the one of the rights 00:10:13.88 --> 00:10:17. of finite on the olympus there is also an affinity 00:10:18.2 --> 00:10:20. and what we did look look look at the numbers here 00:10:20.05 --> 00:10:22. a little bit they'll always the markings are important, 00:10:22.77 --> 00:10:24. but they're not necessarily consistent. There will 00:10:24.85 --> 00:10:27. always give you the magnification. So you know we'll 00:10:27.38 --> 00:10:30. have a twenty x on the left. We have a twenty on the 00:10:30.27 --> 00:10:34. right is well notice so that's that's, the important 00:10:34.2 --> 00:10:37. thing. That's. The important numbers you wanted the 00:10:37.69 --> 00:10:40. magnification, the numerical aptitude in numerical 00:10:40.48 --> 00:10:43. aptitude. Zero point four, zero and zero point four 00:10:44.04 --> 00:10:46. on both of these. They're both the same in that respect. 00:10:46.34 --> 00:10:48. However, the difference here is noticed on the one 00:10:48.61 --> 00:10:51. on the left. There's. That infinity symbol. You see, 00:10:51.17 --> 00:10:53. there is a clear enough there and in fact will go 00:10:53.9 --> 00:10:56. the next light. You see them? Okay. There's, the infinity 00:10:56.84 --> 00:10:59. symbol. That means this is an infiniti objective. 00:10:59.16 --> 00:11:01. This means it needs that to blitz. It needs another 00:11:01.58 --> 00:11:05. optic before the images. The sensor, dawn on the righteous 00:11:05.26 --> 00:11:08. has one sixty and that's that's, the that's, the amount 00:11:08.67 --> 00:11:11. of extension you need from the objective t of sensors. 00:11:11.89 --> 00:11:14. So it's it's just like a camera land, you could put 00:11:14.14 --> 00:11:17. it on a bellows. You put it on extension tube's, but 00:11:20.75 --> 00:11:23. you don't need. You don't need that to billings in 00:11:23.52 --> 00:11:23. there.

Class Materials

Bonus Materials with Purchase

Beyond Macro Photography: Into the Microscopic World Slides

Ratings and Reviews

a Creativelive Student

Like the other reviewers I enjoyed this class but would like a very in-depth part 2. He just mention lighting, a ping pong ball and a white dome. I'd like to learn how those are used. Where do you get the dome, what material is it, etc. I'd also like to learn about his specimens. While he mentions what they are, how do you use the water from your bird bath? Does it go on a slide? Please do a part 2. Thanks!

Sara Zancotti

Super interesting but too short. I would love to have a longer course with Charles! Thank you Charles, you made me remember my childhood. I had a simple little microscope that my father gave me back in the 90s - sweet memories!


I found this course very interesting. I, like other reviewers, would have enjoyed a longer presentation with more hands on instruction. I'd like something that goes from A-Z, everything from acquiring your subjects (Are they purchased, caught, frozen, pinned, etc) to the photographing of the subject (lighting, etc.), to the end result. The focus stacking was the most hands on portion while other sections were just informative. I really enjoyed the class and Mr. Krebs knows his stuff but I would pay to have another more in depth and hands-on kind of class with Mr. Krebs,

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