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-   -   Readjusting focus on folder from lens or film plane? (http://www.rangefinderforum.com/forums/showthread.php?t=68643)

scottyb70 01-13-2009 08:23

Readjusting focus on folder from lens or film plane?
 
Do you measure from the front of the lens or at the film plane when you are trying to adjust the front focus lens? With the rangefinder is it to the front or back.? I am adjusting my agfa isolette.

chippy 01-13-2009 08:43

do you mean where do you set the calibration scale? if so then from the film plane-always. but it will work no matter where you set it so long as the rangefinder is set exactly the same.

set it from the film plane ;) use the ground glass (or alternative methods) to set the distance on the lens...and then calibrate the rangefinder to the same spot

FallisPhoto 01-13-2009 12:18

Quote:

Originally Posted by scottyb70 (Post 971818)
Do you measure from the front of the lens or at the film plane when you are trying to adjust the front focus lens? With the rangefinder is it to the front or back.? I am adjusting my agfa isolette.

The accepted standard is to measure from the film plane. If this is an Isolette V, an Isolette I or an Isolette II that we're talking about, then this is very important -- particularly if you need to measure distances (for example if you are shooting head-and-shoulders portraits with the aperture wide open then you will need to use a tape measure to get the focus just right). However, if you have an Isolette III or a Super Isolette, then (as Chippy says) it isn't important -- just make sure the rangefinder and lens agree.

Q-Zone 01-19-2009 20:21

No need to measure. I just refurbished my Isolette and reset the infinity after cleaning out the lense.

Option 1:
- Open up the camera and lock the front standard into position.
- Screw the front cell of the lense all the way in.
- tape wax paper, frosted glass, frosted plastic, scotch tape at the film plane to serve as a ground glass.
- focus on something very far away by slowly unscrewing the front cell out
- when in focus, thats infinity.
- you can rotate the outer marked ring to the infinity mark and lock it down with the 3 retaining screws
- if your camera has a rangefinder, calibrate the rangefinder to the new infinity

Option 2: (I think its easier for these rangefinder type cameras)
- use the lense coliminating method to set infinity by using another camera
- I used my Hassy with an 80mm set at infinity
- You'll position the 2 cameras facing each other about an inch apart
- set up your rangefinder camera per the first 3 steps above
- tape a bunch of black hair on your ground glass surface or mark it with a thin marker (at the film plane surface)
- shine a strong light through the ground glass towards the lense.
- Sight through the Hassey viewfinder and rotate the lense on the rangefinder until your hair or penlines are in focus
- Infinity found - now lock in the position per above.

Hope that helps, Bharat

ZeissFan 01-20-2009 05:29

The most-accurate method is to use an SLR (preferably one with a waist-level finder) and a telephoto lens (at least 135mm) and two tripods. A cable release will come in handy, as well.

I had been using an open window for a light source, but I've changed that to a fluorescent light panel, which is more even.

Here is my method, which is similar to what others do.

Q-Zone 01-20-2009 12:24

That's the method I prefer aswell - Thanks for the link ZeissFan, the pictures are a lot clearer than my explanation above.

I used my Hasselblad with the waist level finder and the magnifier - worked perfect for infinity targeting.

Now is there a similar easy way to confirm if the intermediate distances (eg. 3', 5', 10' etc...) are also spot on? I tried the same approach by setting the focus on my Hassy at 10' and seeing if the rangefinder targeted at that, but it was just a blur in the viewfinder.

chippy 01-20-2009 13:41

Quote:

Originally Posted by Q-Zone (Post 976588)
That's the method I prefer aswell - Thanks for the link ZeissFan, the pictures are a lot clearer than my explanation above.

I used my Hasselblad with the waist level finder and the magnifier - worked perfect for infinity targeting.

Now is there a similar easy way to confirm if the intermediate distances (eg. 3', 5', 10' etc...) are also spot on? I tried the same approach by setting the focus on my Hassy at 10' and seeing if the rangefinder targeted at that, but it was just a blur in the viewfinder.


i like that method as well, it acurate, easy and you dont have to take the camera outside to find distant objects ect..and for coupled rangefinder not much else is needed..but for scale focus i find its easy , after colimating the way mentioned, to then check the short distances with GG measured excatly and if need be alter the scale a few mm to be exact--it doesnt matter if the infinity scale is out a few mm and usualy there isnt any exact mark for it anyway

Michael Da Re 01-20-2009 14:35

Just wondering, could this method be applied to adjusting both lenses on a TLR ?

FallisPhoto 01-21-2009 06:37

Quote:

Originally Posted by Michael Da Re (Post 976657)
Just wondering, could this method be applied to adjusting both lenses on a TLR ?

It would take a lot more time, but I don't see why it couldn't.


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