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Author Topic: Focussing with a digital view camera  (Read 2982 times)
Ralf
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« on: March 10, 2006, 08:03:31 AM »
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I've been using view cameras with digital backs for field use since early 2004. I started with a Sinar p3 and Sinarback 54H and a tethered notebook and switched to an Arca f-metric and a P25 a year ago.

A very critical point is focussing, in particular when using wide angle lenses. Focussing is even more difficult in the dark and when using a center filter (recommended for wide angle lenses). The image on the view finder is very small and the smallest movements of the focussing knobs make the difference between sharp and not sharp. Forget about tilt and swing to compensate small depth of field. Let me predict that you'll predominantly only get somewhat sharp images without using better focussing tools, in particular when stopping down to no more than f8. Scheimpflug with digital backs works in some degree in the studio with the help of a live image on a tethered laptop but not outside and unplugged.

I had never succeeded in reliable focussing until I had my "epiphany" when I used the Hasselblad Reflex Viewfinder RMfX for the first time :-)

Ralf
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michael
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« Reply #1 on: March 10, 2006, 12:22:22 PM »
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I've been testing this hypothesis by shooting tethered with a 100% window open so that I can see my focus accurately within a few seconds.

I must say that I have no problem achieving accurate focus using the Schnedier 4X loup on a compendium bellow, 90% of the time. I also defocus and the refocus for a second frame, just to be sure, and thus am getting 100% in-focus frames.

Michael
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Jack Flesher
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« Reply #2 on: March 10, 2006, 05:15:33 PM »
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Michael, that is a great hit ratio for view-cam focus!  I was worried it was going to be more difficult for you to get accurate focus un-tethered with the smaller back and correspondingly shorter lenses than you anticipated...  Sounds like I was wrong    

,
« Last Edit: March 10, 2006, 05:17:46 PM by Jack Flesher » Logged

michael
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« Reply #3 on: March 10, 2006, 05:19:43 PM »
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Well, that's when I can checked my focus in a tethered setting.

Working in the rain in California next week, in low light levels, non-tethered, may be another story.

Michael
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Jack Flesher
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« Reply #4 on: March 10, 2006, 07:50:11 PM »
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Micheal:  FWIW it SNOWED along the central coast in California today!  This happens about once every five years or so, but this storm is supposed to carry into next week -- You could be in for some very unusual image opportunities of the Redwoods  

Best,
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michael
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« Reply #5 on: March 10, 2006, 09:04:10 PM »
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I saw.

We could also be in for some extreemly shitty weather.  

Michael
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Jack Flesher
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« Reply #6 on: March 10, 2006, 11:17:24 PM »
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I was attempting some optimism for your benefit...  Unfortunately your assessment is more likely given the area you'll be in.  

You might want to postpone your trip by a week if possible.  If that's not possible, generally speaking the weather improves as you head South along the coast.  Then again there are a few options further inland as possible plan B's...

Jack
« Last Edit: March 10, 2006, 11:18:08 PM by Jack Flesher » Logged

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