Home · Register · Search · View Winners · Software · Hosting · Software · Join Upload & Sell

Moderated by: Fred Miranda
Username   Password

  New fredmiranda.com Mobile Site
  

FM Forums | General Gear-talk | Join Upload & Sell

  

Archive 2013 · Photography through a microscope?
  
 
binary visions
Offline
• • • •
Upload & Sell: Off
p.1 #1 · Photography through a microscope?


For grins, yesterday I brought in my tripod/ballhead/camera/macro lens to my girlfriend's microbiology lab. I was hoping to set up one of the microscopes and take some photos of the microorganisms that they have on the plates.

I'm sure there are all kinds of sophisticated attachments to mount cameras directly to the microscope or output directly to an image sensor but this was just an experiment and I figured I could get some pretty reasonable pictures with careful technique by just focusing through the eyepiece.

Well, no matter what I did, I seemingly could not get a good focus. Even the best focus was still pretty fuzzy - distinct enough that you could make everything out, and I could clearly find the point of "best" focus - but very poor acuity.

I could not resolve this. I tried adjusting focus in the microscope, the lens and even changing the diopter on the microscope. I changed the distance between the lens and the scope eyepiece... nothing.

I have taken some reasonable shots by holding a point-and-shoot in front of the eyepiece, that were far sharper than the results I was getting from my DSLR. There was no problem with vibration - I could not get sharp focus using live view, and the final shots (~1" exposure times) exactly mirrored the fuzziness I saw in live view, no additional vibration appeared present.

Thoughts?



Mar 25, 2013 at 09:02 PM
mpmendenhall
Offline
• • • •
Upload & Sell: Off
p.1 #2 · Photography through a microscope?


One problem might be using too much of the microscope's exit pupil.

Microscope eyepieces for visual use are sometimes optimized to work with the human eye's pupil forming an aperture that only passes a smaller portion of the light exiting the eyepiece, which has an exit pupil larger than your eyeball's pupil so you can easily view without super-critically aligning your head in exactly the right position.

As your eyeball moves to different portions of the exit pupil, the image is focused at slightly different distances and with different distortions --- but, because you only see a small portion at a time, you see a nice sharp image. A point-and-shoot with a tiny sensor and lens entrance pupil sees the same. However, your DSLR has a great big lens entrance pupil, which captures more or all of the light from the 'scope's exit pupil at once --- overlaying simultaneous views of the image with different focal distances and distortions into a blurry mess.

To avoid this, you need to stop down as much as possible (and maybe use a wider lens) to get your DSLR's entrance pupil down to the size of your eye's or point-and-shoot's. It might be the case that you should just keep using the point-and-shoot that already gets decent results (solidly tripod mounted), since you may not be able to do much better with a fancy DSLR unless you also use a proper camera adapter.



Mar 25, 2013 at 10:00 PM
binary visions
Offline
• • • •
Upload & Sell: Off
p.1 #3 · Photography through a microscope?


Ah. I suspected the size of the exit pupil was the cause but couldn't really articulate/determine why exactly I could get the image projected to the viewfinder but not focus it.

I was using a 90mm macro lens. I did try stopping way down and got absolutely no better results at f/11 than wide open. I guess I could have tried stopping down even more, it didn't occur to me that actually narrowing the entrance pupil might help.

I have lenses all the way to 10mm so a wider lens would be easy, I guess I can bring an arsenal one weekend and experiment. I know I could just use the point-and-shoot, but the quality out of that was pretty mediocre as well, it was just sharp enough that I knew shooting through the eyepiece was feasible.

This was by far the best of the day, which wasn't completely terrible but not nearly as sharp as I was hoping. Thanks for your suggestions.




  NIKON D7100    90mm    f/8.0    1s    100 ISO    +1.0 EV  




Mar 25, 2013 at 10:45 PM
jcolwell
Online
• • • • • •
Upload & Sell: On
p.1 #4 · Photography through a microscope?


My daughter is getting great results on her microscope with no lens on the camera. She's using an old Pentax Microscope Adapter II (with M42 to EOS adapter) that I had hanging around, and shooting either down the eyepiece tube (after removing the eyepiece), or straight down the 'photo tube' that's on one of her mic's. She has the camera (5DII) on USB tether to a computer, where she uses LiveView Remote shooting in EOS Utility to view the image on screen and adjust focus on the mic. The microscope adapter isn't actually a good fit on the mic's she has, but it keeps the camera in place on top of the vertical 'photo tube'. It also works fine shooting down one of the two the eyepiece tubes, but she has to handhold it. It would be pretty easy to rig a magic arm and/or macro focus rail to hold the camera steady for shooting down an eyepiece tube. The cardboard core from a roll of toilet paper would probably do just as good a job, if you could find a TP > EOS adapter.

P.S. don't tell anybody that it's a N*k*n microscope.






















Mar 26, 2013 at 12:13 AM
 

Search in Used Dept. 



binary visions
Offline
• • • •
Upload & Sell: Off
p.1 #5 · Photography through a microscope?


Huh, thanks for the idea.

Does she get good magnification after removing the eyepiece? I mean, the eyepiece provides 10x magnification on the 100x objective lens, so you aren't going to get nearly the magnification. Perhaps the high pixel density over the image area makes up for that?

I suppose she must have to clean her sensor regularly, leaving it all open like that!

I didn't have a macro rail, but some very careful positioning of the tripod/ball head seemed to suffice yesterday, since it could stay put once I got it in place.



Mar 26, 2013 at 12:32 AM
jcolwell
Online
• • • • • •
Upload & Sell: On
p.1 #6 · Photography through a microscope?


binary visions wrote:
Does she get good magnification after removing the eyepiece? I mean, the eyepiece provides 10x magnification on the 100x objective lens, so you aren't going to get nearly the magnification. Perhaps the high pixel density over the image area makes up for that?


I just asked her, and she said it seemed about the same. She's used some of these photos in a recent presentation at her university, so they must be OK. She's going to send me a sample or two tomorrow. I'll post it/them here.

binary visions wrote:
I suppose she must have to clean her sensor regularly, leaving it all open like that!


Well... it's my 5DII. She normally uses one of my old 5D camera. I let her use the 5DII for this, because it has LiveView. I guess that explains why it needed so much cleaning last time I got ready for a shoot (light goes on above Jim's head).



Mar 26, 2013 at 12:58 AM
jcolwell
Online
• • • • • •
Upload & Sell: On
p.1 #7 · Photography through a microscope?


Here's a sample. Cranberry pollen at about 800x.







Mar 26, 2013 at 08:57 AM
Two23
Offline
• • • •
Upload & Sell: Off
p.1 #8 · Photography through a microscope?


I used to do this in my college science classes. The term is "micrographs." Best done with an adapter from a place like Carolina Biological Supply. A point & shoot camera can be adapted fairly easily with some of their kits.


Kent in SD



Mar 31, 2013 at 01:53 AM





FM Forums | General Gear-talk | Join Upload & Sell

    
 

You are not logged in. Login or Register

Username   Password    Retrive password