*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****

We've always seen that in our LSM 710 but the light is not from the lasers,
it is from the widefield excitation source (X-cite lamp).  We can close the
lamp's shutter to get rid of the stray light.  I've never seen it affect
the images but we close the shutter with dim specimens just to be safe.

-Esteban


On Mon, Aug 12, 2013 at 10:11 AM, Z.J. Zhang <[log in to unmask]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Hi everyone:
>
> I am having a weird problem with my Zeiss LSM 700 confocal microscope and
> hope you could shed light on it -
>
> When I tried to scan with the lasers off (turning the lasers off via the
> ZEN software), I can literally see a relatively bright light coming from
> the objective! The light looks white, which I assume is the combination of
> the blue, green and red lasers. Although the detected fluorescence signal
> is 'minimal', it still worries that 1). It might photobleach my sample; and
> 2). When I scan with one laser, the other lasers might be on as well, so I
> wouldn't know what exactly I am scanning with!
>
> I was told by Zeiss that this is "normal" because there are no mechanical
> shutters in the scan head. I have a hard time to believe it and here are my
> questions:
>
> 1). Does anyone experience the same/similar problem?
> 2). What could be the possible cause?
> 3). How am I supposed to fix it?
>
> Thank you,
>
> Zhaojie
>
> Zhaojie Zhang, Ph. D.
> Director, Jenkins Microscopy Facility
> University of Wyoming
> Laramie, WY 82071
> PHONE: 307-766-3038
> FAX: 307-766-5625
>