[optimal] Re: Zeiss FF450 Plus flash/expopsure question
- From: Noelle Pensec <npensec@xxxxxxxxx>
- To: optimal@xxxxxxxxxxxxx
- Date: Tue, 21 May 2013 17:05:36 -0400
From time to time we use an ND filter in the slider slot. On our FF-450
plus, redfree images are often overexposed on the lowest flash setting for
patients with blonde retinas and reflective pathology. The filter was
purchased directly from Zeiss...
On May 21, 2013 4:59 PM, "Fernando Corrada" <fcorrada@xxxxxxxxxxx> wrote:
> Hi fellow Optimalers.
>
> Recently we purchased a new Zeiss FF-450 Plus IR camera to image with
> a Merge/OIS WS5000 system. The only issue I have encountered is that the
> flash output is quite strong for taking pictures of the DARC test eye. I am
> using the lowest flash setting on the FF450 (1) and an ISO of 1oo on the
> sensor.
> I am curious about how other people have solved this issue. ND filter on
> the WS5000 sensor or on the FF450 filter slider? Changed the sensor
> sensitivity settings in the ini files? Or.....?
>
> I did call DARC and they suggested to take the color images with the green
> filter (red free) in place but that did not work either. The colors photos
> and the red frees are way overexposed. The FA images are fine.
>
> A level 2 tech at Zeiss said that I could not use the slider filter on the
> FF450 with an ND filter. That it is only used for green filters & FA
> filters. They did not explain in detail why it is not possible. I think it
> should work but I do not have a gelatin ND filter to try it out. I imagine
> that a 0.9 (3 stops) ND filter would be fine. The other possibilty is to
> place an ND filter in front of the WS5000 sensor but I hate to expose the
> sensor to dust and whatnot. What have you creative people have done? Thank
> you in advance.
>
> Merge Healthcare/OIS is going to call me back with a solution which I
> think involves an ND filter. Will see what they suggest.
>
> Fernando B. Corrada
> Burlington, VT
>
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