[optimal] Re: Zeiss FF450 Plus flash/expopsure question
- From: Michael Turano <turano@xxxxxxxxx>
- To: "optimal@xxxxxxxxxxxxx" <optimal@xxxxxxxxxxxxx>
- Date: Tue, 21 May 2013 18:31:44 -0400
That being said you could put your own ND filter in the filter holder down on
the camera body itself and see if it works (I think it would nock down the
exposure for sure). Just make sure you secure it you don't want it falling into
the machine.
I do agree that the manufacturer of the digital system should be able to tune
the sensitivity or add a filter at the sensor level. A flash level of 1
shouldn't blow out a test eye.
FYI I also work for Zeiss.
Mike
Michael R. Turano, Jr., CRA, OCT-C
Imaging Specialist
C 917.826.9506
F 917.591.1841
turano@xxxxxxxxx
Sent from my iPhone
On May 21, 2013, at 5:12 PM, kevinlangton@xxxxxxxxx wrote:
> Group
>
> There is no ND slider for the FF-450 on the lower port. Fernando did you
> contact Merge / OIS to have the gain lowered on the digital sensor? The flash
> output should be able to give you an well exposed image if the sensor is
> properly set. Most digital imaging manufactures calibrate the sensor on sight
> to "marry" it to the retinal camera.
>
> Regards
>
> Kevin
>
> FYI I do work for Zeiss.
> Sent from my Verizon Wireless BlackBerry
> From: Noelle Pensec <npensec@xxxxxxxxx>
> Sender: optimal-bounce@xxxxxxxxxxxxx
> Date: Tue, 21 May 2013 17:05:36 -0400
> To: <optimal@xxxxxxxxxxxxx>
> ReplyTo: optimal@xxxxxxxxxxxxx
> Subject: [optimal] Re: Zeiss FF450 Plus flash/expopsure question
>
> 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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