Electronical Focus Aid with DF & Schneider TS

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Electronical Focus Aid with DF & Schneider TS

Postby Dirk3 » Sat Jan 11, 2014 10:24 am

Hi all,

Manual PDF:
Manual focusing using the focus mark (Focus confirmation method) With this camera, the focus mark lights in the viewfinder’s LCD when the picture is in focus. With the shutter release button half-pressed, turn the lens focusing ring to focus on the subject. When the subject is in focus, the focus mark lights in the viewfinder’s LCD.
...
- Use the focus mark when taking photos in manual focus mode or using the M645 manual lens.
- If you adjust focus using the focus mark with an M645 lens, make sure to open the aperture. You can use this function with a lens of f/5.6 aperture or higher.


I have found that when using the Schneider 120mm PC TS
focus marks in the viewfinder does not work. Not even when I use the focus switch to "manually" set. :?:
Is this intentional or just a mistake?
If the lens is not shifted/tilted, the focus mark would be very useful. j.m.t.c. :?
With all the other manual lenses, including my old adapted Hasselblad Zeiss lenses, does the Focus marks properly. :!:

Sorry, english by Google :roll:

best regards

Dirk
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Re: Electronical Focus Aid with DF & Schneider TS

Postby Dirk3 » Wed Jan 22, 2014 2:54 pm

Hi all,

Mail from Phase One Support, Germany, Translation by Google:

Hello Mr. W.,

I have since learned that the focus of support is suppressed aware of the 120mm TS. The reason is that with a shift of the focus level no reliable focus support is guaranteed.
If you still want to use the Focus Assist, then helps just a strip of scotch tape on the contacts. However, then no metadata is passed from the lens (lens type and aperture setting).


For me, this is so far not a problem as I focus the lens almost exclusively with Live View Help.

best regards
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Re: Electronical Focus Aid with DF & Schneider TS

Postby flashsplash » Wed Jan 22, 2014 7:51 pm

Hi Dirk3,

I think that this is normal, here is why.

The focus measuring technique applied in the camera will correctly indicate the focus distance, however that measuring is not done through the lens. With a normal lens , the focus , lens and CCD plane are parallel. Hence the algorithm can calculate the correct focus indication.
Image

With a TS lens the focus,lens and CCD plane are not parallel , yet the measuring technique is as above as it assumes paralel planes. The TS lens has a variable angel, hence changing the focusing distance changes the angle of the focus plane in addition to changing its distance. (P.S in the picture below the TC lens in the picture is not in the correct angle according to the line a draw, demo only)
Image

Best method with a TS is to focus on LV as stated before.

Steve
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