A diatom?

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xys
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A diatom?

Post by xys »

Another picture. I couldn't identify the object from the web nor from a little booklet I have (Needham & Needham). I would appreciate any comments about image quality (focus, resolution, over- or under-sharpening, noise, color, etc.) that anyone might provide. 10x objective, 5x projection lens, E-P1 camera. I am also uncertain as to the best plane to focus on in objects that have thickness.

Many thanks for looking and commenting.

Rashid

Image

Mitch640
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Post by Mitch640 »

Well, it is for sure a diatom, but I can't ID it. There are people here who probably know it's first name though. :)

Image quality seems OK for brightfield. I always try and focus on the little bumps and dots in the shell, or, the gold stuff inside if there are organelles showing. I did find out that the gold stuff is a kind of chlorophyl though, like the green, it makes sugars from sunlight.

xys
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Post by xys »

Mitch, thank you. The closest I came to identifying it was cyclotella but since the drawings in Needham & Needham are black-and-white line drawings, I wasn't sure at all. These critters are all totally new to me (I need to read up a little-- so much to learn!) Thanks for the info on the "gold chlorophyll". Thanks also for the tip on focusing, and for your comment on image quality.

Rashid

Mitch640
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Post by Mitch640 »

I don't have one, but prepared slides of certain diatoms are sold just to check the resolution of microscopes and lenses. The holes in the shell are of a known diameter and the test is, to see if your lens can even see them, then how well. :)

I'm just a hobbyist with a microscope. I can't afford the books for learning the names of all these microbes, but it's enough for me, just to find them and get good pics of them. I usually use Google to find an ID if I know where to start.

xys
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Joined: Thu Apr 21, 2011 11:42 am

Post by xys »

Mitch,

Many thanks for your reply. Yes, I have bought a beautifully prepared test slide with 8 different diatoms from K.D. Kemp (that is what I used for my initial post).

I've been trying to improve my system as well as my technique (I got a a Labophot on ebay for a very good price; this should go well with the projection lens that I had bought earlier). The Labophot is much easier and more pleasant to use (the lighting system, the nice xy-stage, except for the condenser-- unlike the Olympus, the top element does not flip out). So I hope I'll be able to post some better pictures when I have the new setup ready.

By the way, your "purple coffee beans:) " are beautiful.

Rashid

Mitch640
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Post by Mitch640 »

Rashid, thanks for looking at the coffee beans. :)

The Labophot is a good scope. You should be able to find more optional equipment for it. I bought the Fluophot, and while it is a great scope, there are few parts for sale for it. Like a phase contrast condenser. You should be able to find one for the Labophot though.

Focus on getting the best objectives you can afford though. Good images start there. :)

xys
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Post by xys »

Mitch, the Labophot came with 4 E Plan objectives (10x, 20x, 40x, and oil immersion). Of course one problem, as is often the case, is the expense. This is a "retirement hobby" for me, and better objectives tend to be expensive :)

Mitch640
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Post by Mitch640 »

Yes, me too. Fixed incomes are the pits. LOL

Nikon E lenses are lowball though, for educational use, by students who will steal them to sell for a few bucks. Here is a link to a company that sells Nkon achromats, brand new, for a decent price.

http://www.edmundoptics.com/onlinecatal ... uctID=2943

rjlittlefield
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Post by rjlittlefield »

Um, if you already have Nikon E Plan's, then don't jump on those new Nikon finite conjugate achromats from Edmund. As far as we can tell, they're very similar and possibly identical to the older plain old E's, probably inferior to E Plans.

--Rik

xys
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Post by xys »

Mitch: Thank you. I think you misread what I wrote-- the objectives I have are the E PLAN achromats, not the E achromats. I find Nikon's type designations for objectives to be very confusing. Then there is CFI60 vs. CF 160! The Nikon CF document that one of the posts (I think by Charles) links to was very helpful to me, which lists achromats in the order CF/CF N Plan Achromat, E Plan Achromat, Achromat, E Achromat, but I couldn't tell from the description whether the E Plan Achromat or the Achromat were the better choice. But since the objectives came as part of the microscope, I didn't, so far, have to grapple with this choice (but I will when I get a 4x).


Rik: Thank you for the clarification. I will need to get a 4x objective as I find the 10x to be not low enough for scanning and for some large critters, particularly that the field of view of the camera will be reduced by the use of the 2.5 projection lens on my 4/3 sensor.. Which should I try to get, an "E Plan Achromat" or an "Achromat", given that the "E Achromats" are the least desirable? Many thanks.

Rashid

Mitch640
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Post by Mitch640 »

Ah, yeah, I have one of those old E 40's. Didn't know there was a difference. It's terrible. Everything comes out with a green tinge. :)

xys
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Apology

Post by xys »

I apologize to Charles and to Rik: it turns out the link that I used for the Nikon CF system was indeed provided by Rik.

Rashid

rjlittlefield
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Re: Apology

Post by rjlittlefield »

xys wrote:I apologize to Charles and to Rik: it turns out the link that I used for the Nikon CF system was indeed provided by Rik.
No apologies needed -- the link I provide to a CF brochure was originally provided by Charles and goes to his site!
Which should I try to get, an "E Plan Achromat" or an "Achromat", given that the "E Achromats" are the least desirable?
This is a hard question. I own a 4X "E" and I am not particularly happy with it due to softness and color fringes away from center. (Being an "achromat" is not proof against color fringes. The term just means that two particular colors are matched, not that all of them are.) I have no experience with E Plan or with other 4X objectives. The 4X Nikon finite conjugate objective sold by Edmund has been used by another member (scitch), who also is not very happy with it. For purposes of scanning it would be fine, but for photography the flaws are evident.

4X seems to be a difficult range. For a long time I have had a saved search posted at eBay for "Nikon 4x objective". Almost all of what comes back are either E's or infinites. There is currently a finite 4X CF plan phase contrast posted for Buy It Now (item 280630193833). The NA is relatively high (0.13), which should imply good resolution and higher corrections, but I have not seen test results and do not know anything more about that model. Certainly the phase ring will introduce some "doughnut" artifacts in OOF areas, though this would probably not be an issue if you are stacking. (See http://www.photomacrography.net/forum/v ... php?t=6647, "Nikon CF N 10/0.30 Plan Achromat. Phase vs BF version" by Charles Krebs.)

I believe that member NikonUser has explored quite a range of high quality objectives in this range, but I don't have links handy.

I don't know an ideal solution for you, sorry!

--Rik

xys
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Joined: Thu Apr 21, 2011 11:42 am

Post by xys »

Rik,

Many thanks for the very helpful reply. There is currently a 4x E Plan for 160mm tube length on Ebay that I might bid for unless something else pops up as an affordable "buy it now" in the coming couple of days, otherwise I'll have to be content with the Edmund offering (and use a green filter where color is unimportant). The 4x with a phase ring that you mention is a bit steep for me at present.

Thanks again,

Rashid

lauriek
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Post by lauriek »

I'm not convinced there is anything better than the Olympus 38mm/f2.8 macro bellows lens in this range. It's more expensive than most of these objectives (except some of the APOs) but does have aperture control and is superb optically. (Unfortunately you'll be lucky to get one for less than about $600 these days)

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