Nikon D200 on a microscope F-mount

DoctorIt

We just got a sweet new Nikon in the lab... a nice inverted microscope! :clap

A C- to F-mount adapter is pretty easy to get, and will allow us to take some nice still pictures through the scope. There's plenty of imaging going on in here, so we're at the point where between the scope and many other projects, its time we got a dedicated DSLR for the lab. My advisor and I are both photogs, so we've been using our own until now.

But I need some help, obviously, on just an F-mount adapter, there will be no lens information coming back to the camera. According to Nikon, I think the D200 will do the trick. I don't have the adapter yet, so I can't verify it, but I'm pretty sure my D70 won't like it at all. I'm not sure it would even allow me to trip the shutter (it won't if there's no lens mounted). I do recall that my D2H would work with any F-mount, but we actually need more pixels over the pro functions of the D2H - and lower cost would be good too.

According to Nikon, the D200 will spot meter (and therefore function well enough for us) with AI-P lenses. Do AI-P lenses have any contacts? The F-mount adapter will obviously have no contacts, it will just depress the mounting pin so the camera knows there is a piece of glass covering the shutter.

ziggy53

Erik,

Before you purchase a camera, what light sources are you going to use?

If this is one of the TE2000 microscopes with a fluorescent light source, I'm not sure that the in camera exposure system will work perfectly. You may still need to look at one of the Gossen meters and attachments designed for microscope work, for instance.

http://www.bhphotovideo.com/bnh/controller/home?A=details&Q=&is=REG&O=productlist&sku=429737
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=20971&is=REG&addedTroughType=search

Some polarizing light sources can also be a problem metering properly.

Since you will be shooting digital, test exposures might be the most accurate of all methods until you log enough samples to understand how the camera reacts to the different sources.

Some sources also yield vignetting (and some combinations of optics) so you might look for software which allows some level of automated vignetting correction.

http://www.bibblelabs.com/products/bibble/lens-correction.html

Have you looked at the Nikon DS-5Mc Camera? It is specifically designed for photomicrography and can be used with the U1 controller to provide direct to PC images.

http://www.nikonusa.com/template.php?cat=5&grp=26&productNr=DS5MCU1

ziggy53

DoctorIt

I think this post was wasted on the masses, I should have just sent you a PM.

Great info, all of it. In terms of light, we have 2 sources, and yes, flourescent is one of them although the majority of the work we'd probably shoot still with would be brightfield. You nailed it: the idea is it's digital, so test exposures will be how we'd proceed. The in-tube meter is neat, thanks, would have never thought something like that existed. Our motivation for wanting a DSLR is that it could be used for multiple experiments, not just the microscope, which is why we're shying away from the Nikon DS micro-specific camera. It does indeed yield the best results, but the majority of our work, and the reason we got our own scope was for the velocimetry work we do, for which we already have a very nice Phantom hi-speed camera (amazing tool). The ability to put a C-F adapter on there and using a DSLR is just a bonus.

I'll pass on the software and meter links to the lab.

Now to the original question: I got brave and held down the mounting pin on my D70. Sure enough, in M, I could actually activate the shutter. No metering to speak of, but that's what histograms are for. We can also run Capture on the computer right next to the scope and practically process in real time. So I guess the D200 would work fine, maybe even spot-meter. The push for the D200 would be resolution. The stuff we work with is small, even in an optical microscope, so the more pixels, the better.

I'll try to take some photos of the new setup tomorrow. It was just installed today.

Seymore

Interesting thread Erik...
So, any PICs yet? I'd like to see the setup. And images you create...

DoctorIt

Seymore wrote:

So, any PICs yet? I'd like to see the setup. And images you create...

Me too. This level of scope leaves a lot to the end-user. I've been working on designing the specimen plate which attaches to our stage. The translation stage is really, really bada**. Little joystick which can be adjusted to move down to the micron level, very, very sensitive. But it comes without any real mounting plate, so I've been designing/machining one. When its done, we'll get some images out of it.

I'll try to take a photo of the setup today.

(We've also been a bit pre-occupied with a conference we have next week, but once we come back, the scope will take full priority.)

mmroden

Hi DoctorIt,

I worked with microscopes for 10 years (the last seven as a programmer for 3i, http://www.intellligent-imaging.com), so I know a bit about them.

You should not rely on the metering in the camera at all in order to take the picture, especially if you are trying to capture scientific data. You're already going to use histograms and Capture, which is good; that's how modern microscopy packages work.

It really matters what you are trying to take pictures of. Bayer sensors and foveon sensors aren't really very useful in any kind of fluorescence microscopy, because color information for that kind of imaging is processed optically through separate filters for each color. That is, you'll get filters from Chroma or Omega, and then each color will be determined independently. This way, it's possible to capture 5 or 6 colors, rather than the standard rgb. Also, you will know that each pixel is receiving the exact same amount of filtering, because the filter is over the whole imaging device, rather than on a per-pixel basis. It will also allow you to do interesting things like ratio captures, which use specific concentration-sensitive dyes in order to determine the concentration of an ion (say, the FURA dyes, which can indicate the concentration of calcium ions using two different wavelengths of emitted fluorescence). If you're taking images of histology samples or the like, I would be wary of a bayer sensor, because of inter-pixel interpolation used to get the final results. You will need your colors to register perfectly, and I always ended up pixel peeping the data in order to make sure it's useful.

Finally, it'd be worth it to get a dedicated camera and dedicated software. With the stage you describe, it's possible to take montage images (or panoramas, as they're called in photography terms) by moving the stage around. You can use photoshop, if you want, but photoshop does not respect original pixel values at all, and you will need original pixel values in order for your data to be at all useful or your results replicatable. Some packages (not least the one I worked on for a while) can also do stereology, or principled random sampling that will allow you to get accurate statistics of cell growth patterns and other phenomena that can occur on a microscope coverslip but are generally too large to be imaged and examined. In order to unlock the goodness of your equipment, you'll need other equipment. They combine like Voltron.

I could keep going, but there's only so much brain dump I can do.

DoctorIt

I'm doing this to most of the above.

However, what you don't know is that we usually don't give a darn about color. We're a fluid dynamics lab, so we're mostly concerned with capturing where and how fast our little particles are going. Hence, we really don't need another $8000 microscope specific camera. At least not at this point.

Microfluidics is pretty advanced with it comes to the optics, not so much the filtering. I'm sure you've heard of uPIV and TIRF? Just some examples of what we'll be doing. The D200 (or any SLR) would be more for publication type images rather than true data-aquisition. Pretty pictures get you on the cover of Nature or Science. They don't necessarily have to be full of good data.


Thanks for the cool responses so far!

mmroden

I'm going to guess, if you're doing TIRF, you've got one of those 1.65 NA lenses where you have a TIRF target about the size of a barn door.

TIRF definitely is fluorescent, and you will definitely want to have a very color-neutral camera. I did lots of work with TIRF analysis (I could say with who, but I think that would be considered bragging, and since he's a biologist and not a fluid dynamics guy, I'm not sure it would matter anyway), and there is a lot of stuff that's a single pixel big, where a pixel has a pitch of 6.7 microns. Since the d70 and d200 are in that neighborhood (perhaps smaller), and since the d70 has a framerate of only 3 fps and is bayer, well, it might not be the best for your application. I'm thinking of light loss when the particle moves over pixels that don't collect the wavelength the particles'll be emitting.

If it works for you, more power to you. I do know of a fluid dynamics lab that uses a canon camera for their images, and they couldn't be happier, mainly because being happier would require a lot more funding than they have.

DoctorIt

mmroden wrote:

...mainly because being happier would require a lot more funding than they have.

ain't that the truth