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Old Sep 21, 2006, 3:06 AM   #1
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We've been using some Canon PS A95's for microscopy work for about a year, and its time to buy some more cameras. Unfortunately the A95's have had... issues from the beginning, and we'd like to improve on those this time around.

By issues I mean focus limitations. The live image capture software doesn't give us a high enough quality image to accurately focus the microscope, and the LCD on the camera is even worse. It appears that no camera manufacturer builds a higher-quality (throughput) live image via USB, so to improve the situation I want some more zoom to get closer to our chromosomes.

What we need from a digital camera are the following:

5 or 6x optical zoom. 10x is too much as the barrel length inhibits the image we can get at very close range (get a tunnelling effect and lose the edges of the image). Currently working with 3x and that is too low. Estimate 5x should be optimal, but 6x gives us head room (and are more common).

Lens mount attachment. The camera MUST be able to take some kind of lens mount, as we need to attach it to a microscope. We can have the final mount custom made, but the camera must have a lens mount that we can actually attach it to!

Control and image capture via PC & software. As we need to be able to focus the microscope using what the camera sees and immediately import the photo into custom software for editing and storage, we need live image capture software.

A camera that'd be almost perfect if it had software capture is the Canon PowerShot A700, except Canon have for some reason decided to stop supporting computer control for most of their cameras and only offer it for the A620 now. Nice work Canon

So if anyone can offer suggestions as to what cameras might actually fit our criteria that would be very appreciated. Been looking at review sites etc but its quite a lot to go through when nothing (that I have seen) allows you to just input criteria and get a list of cameras that meet it.

So does anyone know of anything that might be what we're looking for?

Thanks!

SA
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Old Sep 24, 2006, 9:52 PM   #2
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So does no one know of anything that might be what we're looking for? Or does nothing like this exist?
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Old Sep 24, 2006, 10:08 PM   #3
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As a general rule, we ask that "what camera should I buy" questions be limited to this forum.

But, given the unique nature of your needs, you may want to ask the same thing in our Digiscoping Forum, since the camera to eyepiece interface requirements are most likely going to be similar.

I have very little experience with microscopy, other than messing around with a couple of cameras about 5 years back, and settling on using a Nikon Coolpix for what I was doing. From what I could tell from the small amount of time I messed with it, eliminating vignetting (that tunnel effect you're talking about) would be very tough to do at longer focal lengths with most lens designs.

At the time, it seemed to me that using a higher magnification eyepiece was a better way to go. But, I know very little about trying to use a camera and microscope together.

So, feel free to ask this question in our Digiscoping Forum, and perhaps you can get some ideas from there that may help out.

As for the image resolution you're seeing with remote capture software, there is another way to approach that part if you don't mind a separate display. You could use the video out with most cameras and see the same thing as you get on the camera's LCD. So, you may want to give that a try and see if it's any better compared to what you're getting over the USB connection. That's a popular technique for macro shooters so that they can get a better feel for focus and depth of field compared to the camera's LCD or viewfinder.

You may also want to see if a third party alternative performs any better than Canon's solution. You can download a working demo (except that it won't let you save images).

http://www.breezesys.com/PSRemote/index.htm

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Old Sep 25, 2006, 10:49 AM   #4
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Hi Jim,

Thanks very much for your reply. Yes, vignetting is a problem that you have to be aware of. From my experiences the two things I've found are 1) at least 3x optical zoom (in digicam language) is a mandatory requirement, and even that is a little on the low side. However, 2) going to a super-zoom causes vignetting because the distance between the foremost lens and either the secondary lens or the image sensor built into the camera is too great when you're looking into a microscope. So you need to keep this distance within the lense aparatus of the camera as short as possible AND get as much optical zoom as possible. Hence my search for 5 or 6x zoom.

I've seen some reasonable results with DSLRs, as you can fit better lenses on them in-line with the microscope, however the solution is somewhat cumbersome as the only way you can focus the 'scope is by looking into the camera viewfinder, and typically with a 100x lens and looking at tiny things like chromosomes, getting really accurate focus is nearly impossible... and focus is the name of the game!

I've heard that some of the high-end cameras from Olympus for flourescent microscopy are meant to be very good, but we're not about to throw around five figures just to take a look! Unfortunately we don't have the limitless budgets of grant funded labs in the US...

All this would be much simpler if the vertical barrel on the microscopes had the same focal length as the binocular eyepieces, however this is rarely the case (certainly not with our equipment).

As for getting a better live image, yes we've tried the software from Chris Breeze and inPhoto Capture, and while they are both good suites (far superior to the Canon bloatware), neither of them increases the size or quality of the live image, as that is a limitation of the camera itself.

We have even tried using the video lead from the camera to both a TV and an image capture card in the PC, however the results were horrible. The problem is resolution - if we can't see a crisp image, its impossible to adjust the focus accurately. And a TV image, even with a PAL signal, just doesn't cut it unfortunately.

So thanks for your suggestions, I'll try the digiscoping forum and see if I get any results over there.

Cheers,

SA
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Old Sep 25, 2006, 11:37 AM   #5
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Good luck with it.

I've actually got a very interesting camera to microscope adapter set in my office somewhere. We don't want to talk about the stacks of boxes, etc, I'd need to go through to find it though. :-)

It's a rather dated device in a nice wooden box, and it came with a number of inserts designed for different eyepiece and lens diameters. It's probably an antique for sure. But, it's perfectly functional. I found it on Ebay when looking for a solution at the time.

I experimented with it quite a while back before deciding on a simpler solution for what I was trying to accomplish at the time (using a Nikon Coolpoix 950 that seemed to work much better from a vignetting perspective compared to models with larger lenses).

If I can find this adapter set, I'll take a photo of it for you. It was designed to be very flexbile in the types of camera lenses and microscope eyepieces you could interface with it.

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Old Sep 28, 2006, 8:37 PM   #6
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That does sound interesting! Currently we have a machine shop custom make our mounts. Works out about a third of the price of the official Olympus mounts for their cameras (which wouldn't fit our's anyway). But then anything to do with science and / or medicine is rediculously overpriced...

Thanks again for your help Jim :-)
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Old Sep 28, 2006, 9:00 PM   #7
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No luck yet. To see my office looks like a tornado hit is probaby an understatement. It may take me a while to locate it.

Perhaps this will give me an excuse to clean up. I can't even get to some of the boxes (I've got desks and drawers in pieces on one side of the office with stacks of boxes behind it). My wife makes me shut the door when company comes over it's so bad. :-)

I'm sure it's in here somewhere. I remember seeing it when I put together a new desk a while back and was boxing up some stuff I didn't use anymore.


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