Some diatoms and a question

Images made through a microscope. All subject types.

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Pau
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Re: Some diatoms and a question

Post by Pau »

This doesn't sound good
First: forgiving for a moment the camera, is the microscope parfocal (or almost parfocal) when changing objectives? If not, you first need to parfocalize it:
- if the eyepieces are regulable put both them to "0" or to you diopter graduation if you need eyeglasses and you do not use them at the microscope*. Put a flat slide with a small high contrast detail and focus it with the 10X objective, then change to the lower and higher magnifications: if well set you still would need a bit of refocusing with the fine focus knob but not much.

When you had got the microscope parfocal, set the camera with the Nikon adapter (and without the NEX adapter, of course) and with a 10X objective move the camera adapter up and down until the focus plane is about the same than with the eyepieces


* With some old style binocular and trinocular heads the focus point changes when you change the inter-ocular distance. In this case parfocalization is more complex. Detailed images of you microscope can help.
Pau

Biollantefan54
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Re: Some diatoms and a question

Post by Biollantefan54 »

I will try to get some pictures as soon as I can but now that you mention it, I don’t think it is exactly parfocal. I don’t remember on the lower objectives but I know when I got from 20x to 40x, I have to turn the fine focus knob toward me a bit. I’m not sure how close that means it is but maybe I do need to try to adjust it. I’ll check that out and get back to you. Thank you for the advice.

LouiseScot
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Re: Some diatoms and a question

Post by LouiseScot »

Hi

Are you using the D750 in liveview mode and tethered to a PC/laptop? That's how I use my Canon and avoid camera/mirror vibration which otherwise spoils images. Also, you should be able to adjust your trinocular port / sensor distance to get parfocality with the oculars.

Louise

Biollantefan54
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Re: Some diatoms and a question

Post by Biollantefan54 »

LouiseScot wrote:
Wed Aug 10, 2022 11:45 am
Hi

Are you using the D750 in liveview mode and tethered to a PC/laptop? That's how I use my Canon and avoid camera/mirror vibration which otherwise spoils images. Also, you should be able to adjust your trinocular port / sensor distance to get parfocality with the oculars.

Louise
Sorry I haven’t responded in a bit, been very busy with my telescope lol, a whole different world to this! But I was able to snap some photos of the objectives, I don’t see anything I can adjust. I also don’t see anyway to adjust the trinocular port either. I do use my d7500 in live view mode but I don’t have it connected to my laptop. I was using an exposure delay to try to cut out any vibration.
39401B32-9C38-4297-80B0-B149AC56058F.jpeg
2089DDA0-5A74-4589-B66F-755420B8A451.jpeg

LouiseScot
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Re: Some diatoms and a question

Post by LouiseScot »

Hi
I would try with the camera tethered. That ensures the mirror is locked up and a larger screen makes it easier to check how well the camera sensor is focused at the time of exposure. If you have a clear, sharp image on your PC/laptop screen then you should expect that to be the same in the saved image. If the image is still blurred then that must be due to vibration. I'm not familiar with Nikons and their live view settings so I can only recommend double checking them. You want to keep the exposure times short. Make sure EFCS is ON https://photographylife.com/what-is-ele ... ikon-dslrs
It's been a while since I used my old Canon on a microscope but I got best results in manual mode, tethered, live view, efcs enabled, no time delay.
Hope that helps
Louise

LouiseScot
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Re: Some diatoms and a question

Post by LouiseScot »

LouiseScot wrote:
Mon Aug 15, 2022 1:43 am
Hi
I would try with the camera tethered. That ensures the mirror is locked up and a larger screen makes it easier to check how well the camera sensor is focused at the time of exposure. If you have a clear, sharp image on your PC/laptop screen then you should expect that to be the same in the saved image. If the image is still blurred then that must be due to vibration. I'm not familiar with Nikons and their live view settings so I can only recommend double checking them. You want to keep the exposure times short. Make sure EFCS is ON https://photographylife.com/what-is-ele ... ikon-dslrs
It's been a while since I used my old Canon on a microscope but I got best results in manual mode, tethered, live view, efcs enabled, no time delay.
Hope that helps
Louise
ps Apologies - I just read that the d750 doesn't appear to have a efcs. I'm not sure what the consequences of that might be. If the problem persists you might try short as possible exposures with very bright illumination, or even rig up a flash.

Biollantefan54
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Re: Some diatoms and a question

Post by Biollantefan54 »

My camera does have EFSC, I think you are getting mixed up with the D750 and the D7500 haha. I’m not sure if I wrote a typo somewhere but I’m using the D7500. I’ll try connecting it to a laptop, but I can tell on my live view screen that the image is sharper than the resulting photo so it is definitely vibration induced. However it’s definitely not parfocal with the eyepiece either.

LouiseScot
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Re: Some diatoms and a question

Post by LouiseScot »

Biollantefan54 wrote:
Mon Aug 15, 2022 3:56 am
My camera does have EFSC, I think you are getting mixed up with the D750 and the D7500 haha. I’m not sure if I wrote a typo somewhere but I’m using the D7500. I’ll try connecting it to a laptop, but I can tell on my live view screen that the image is sharper than the resulting photo so it is definitely vibration induced. However it’s definitely not parfocal with the eyepiece either.
Oh ok - that's good! Still, you maybe need to check all the relevant settings e.g 'On Nikon D7500, D500, D810 and D5 cameras, you must use Mirror Up mode (with or without Live View)' I don't know if there are other settings that come into play. I presume you are taking short exposures < 1/60 ? The shorter the better, obviously.
Good luck!

Louise

Pau
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Re: Some diatoms and a question

Post by Pau »

LouiseScot wrote:
Tue Aug 16, 2022 3:26 pm
... I presume you are taking short exposures < 1/60 ? The shorter the better, obviously.
Not so obvious, in general this is true for hand held photography but if the subject is motion less (like a typical prepared slide) and you haven't environmental vibrations often long exposures can minimize camera induced vibration effects because most part of the image is taken when the vibration has been damped. Vibration is a complex phenomenon, it depends of multiple factors like the camera, the microscope stand, the coupling between them and of course the camera settings. Usually the worst scenario for camera induced vibrations is between 1/15s and 1/60s

A classic trick is to get at least 1s or 2s of exposure time (of course in a darkened room) or even better to start the long camera exposure without light for example covering the light source with a black cardboard and remove it to start the actual exposure. This doesn't seem very practical but will allow good comparisons with the image taken at more normal speeds in order to isolate the blur causes.
The opposite approach is the use of electronic flash fired at low power because it provides actual exposure times much shorter than what the typical camera maximum speed can do.
(More info condensed at https://www.photomacrography.net/forum/ ... 63#p161563 )
Pau

Pau
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Re: Some diatoms and a question

Post by Pau »

Biollantefan54 wrote:
Mon Aug 15, 2022 3:56 am
... However it’s definitely not parfocal with the eyepiece either.
Did you try the approaches I suggested?

Clear pictures of your microscope, in particular of the phototube, camera coupling and eyepiece tubes would be useful to provide more specific advice. An easy test is to put one eyepiece at the photoport to try if it is parfocal with the other one and to try the camera with its adapter in place of one of the visual eyepieces

I wont say anything more without such infos
Pau

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