[Neuroscience] Re: Automatic focus control for microscope?

tomte via neur-sci%40net.bio.net (by tehgabriel from web.de)
Wed May 9 03:12:01 EST 2007


Thanks for your reply.

> I think you may be mistaken about what is needed.  There is no reason
> for a microscope to go out of focus unless there is some really weird
> temperature change that is causing expansion and contraction.  High
> quality microscopes are very stable and don't change position so once
> you put an item into focus it stays in focus.

Well my microscope does. And as far as i know, there are many
colleagues complaining about small drifts in their optics during
fluorescence imaging.
I guess that's why some companies came up with these autofocus systems
using image processing software. But these are not suitable for
fluorescence imaging since they require a continuous image. But i need
to avoid this in order to protect my preparation from bleaching.

> Do you have particular trouble focusing or keeping focus?  Describe
> your problem and perhaps we can help you solve it.

I am using an Olympus  IX-71 with a 40x objective for fluorescence
imaging on cultures of hippocampal neurons.
During a specific experiment i want to sample 10 pictures with a time
interval of 4 min between each. But sometimes (~50 %) i can observe
over the timecourse ot the experiment that the images loose focus
(interstingly, i never see this with DIC).

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