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Subject: My 3rd test drive of digiscoping [Print This Page]

Author: jojomau Time: 15/10/2010 21:47 Subject: My 3rd test drive of digiscoping

Swar STS80 HD, 25-50x, UCA; Panasonic GH1; Leica 35mm Summicron ASPH

Oct 15 2010, Inner cove of Tiu Keung Bay, 25x, f5.6, ISO320

[ Last edited by jojomau at 15/10/2010 21:54 ]

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Author: jojomau Time: 16/10/2010 22:32

Another one, at 50x.

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Author: jojomau Time: 16/10/2010 22:37

At 25x.......

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Author: cwchan Time: 17/10/2010 20:12

Can you share with us the arrangement of your setup, including the tripod and its head, as the image here is a bit blurred that a 35mm lens should not be like that ?

Did you use cable release to activate the shutter?
Did you focus in wide open and then step down to take the photo?

[ Last edited by cwchan at 17/10/2010 20:41 ]

Author: jojomau Time: 18/10/2010 12:32

Hi CW,

Thanks for your critical comments.

Supporting the core pieces, I used a Swar Telescope rail, Velbon 530, Manfrotto 510 HDV (as suggested by a forum member), and release cable.

In retrospective, I did not have a methodological testing.  Just played around and look for an initial success at a very low benchmark.  No incremental ISO, nor f-stop. I was very busy in searching for an object through the camera LCD and manipulating the focusing ring on the scope barrel.  As an aging retiree with presbyopia, I needed to take off my glasses when I concentrated on the LCD for focusing and put them on again.  Vibration and viewer blackout were new for me too.  The results were predictable and I had no reason to be proud with them.  I am glad that you have made it straight.

Will use an AF zoom with a fixed focus eyepiece in my next test after its delivery.  Your suggested incremental approach will be used.  Will take along another pair of lo fa glasses and see it helps.

Thanks again, CW.  Till then,

jojomau

Author: cwchan Time: 18/10/2010 20:23

Hi Jojomau,
The setup is quite good and gives you a very stable support.
However, the 35mm (equivalent to 70mm in 135mm format in G1)is a bit too long focal length, in my opinion, which needs epecial attention in focus and vibration control. In the G1 system, don't miss the giant killer, its kit lens 14-45mm. It works fine with 30x eyepiece (with some vignetting),The prime lens 20mm is also good. The most important of all, they are auto focus on the 30X eyepiece.

Some suggestion on using manual prime lens in digiscoping,
(1) take away any lens lens protector , UV, Skylight... such thing.
(2) set it infinitive.
(3) set aperture at f4, f5.6.
(4) DON'T focus wide open and then take photo stepe down; use your intended aperture to focus.
(5) use the focus aid of G1 (the image enlarging spot)for critical focus.

CW

Author: jojomau Time: 19/10/2010 07:46

Hi CW,

Thanks for your advice. Will try out.

jojomau

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