Polaroid 110B - adjusting focus after installation of Graflock Back

I am in the process of converting a 110B to 4 x5. I have attached a graflock

back to the rear door of the camera. The graflock back is positioned up against

the rear door of the camera (on the left side atleast)ie. it cannot be moved

any closer to the lens. In this position it is approximately 36mm further back

from the original film plane.

 

As I understand it, I should then reposition and fix the front standard 36mm

further back for the modified camera to focus properly.

 

I have read in previous posts on this subject that the film plane should be

moved back by approximately one inch (25mm).

 

My question. Is 36mm too far?

The only way to do this properly is to use a ground glass. Use the one that came with your Graflok back.

 

While looking though the ground glass at a far distant object, move the front standard forward and back until the object comes into focus. Secure the front standard at this point. The camera is then calibrated for infinity for that lens. It will be real close to 36mm back from its original spot.

 

Here is an example:

 

http://www.rolandandcaroline.co.uk/focadj.html

 

There is a fancier way of doing this mentioned here:

 

http://elekm.net/zeiss-ikon/repair/collimate/

Brett:

 

It is not clear what you are doing. You mention that you are positioning the Graflok back against the back door of the camera.

 

Typically the "back door" is cut up with a hacksaw to the dimensions of the Graflok. The Graflok is centered with the lens axis. Then it is glued/screwed somehow to the back door.

 

As to finding the distance for infinity focusing, this may vary depending on the position of the Graflok. There is a cure for this, just collimate the lens on the camera using another camera.

 

The way that this is done is by marking a pencil line on the GG of the Graflok, then by taking another camera and putting it in front of the Polaroid lens. This camera setting is at infinity. Look through and you will see the line on the GG. This may be blurry, to make it sharp, move the front standard of the 110B forwards or backwards until it is. Mark carefully this position, this is the infinity setting for the 110B lens.

 

If I recall, the back door of the 110B needs to be cut up so that it allows for the 4x5 image to be fully projected.

Sorry if I didnt explain myself clearly enough. The Graflock back has been mounted on/in the back door of the camera. I have cut an appropriately sized hole in the back door with the graflock back centred over the lens. The graflock back is actually resting on the left side against the remainder of the camera's back door. The result is that the graflock back will be about 36mm further back from the original film plane. Does it really make any difference whether it is 25mm or 36mm or greater?

 

And thank you for the links and description for collimating the lens.

Brett:

 

Since you are at it, a good idea is to remove the "red button" which is on the left side of the back of the camera. This will eliminate a sore thumb in the future and make the use of the camera more enjoyable.

Before mounting the Graflok back to the camera you need to determine if the new location will allow the light coming through the lens to cover 4x5 completely. Too close and it will vignette.

 

Diwan: Did you mount your back even with the bump on the left side? Or was it shimmed out further?

Frank:

 

Cannot fully understand your question. What I did is to cut up the back door of the camera for full 4x5 image projection. To this back, I fitted my film holder device. I have full 4x5 image.

 

I did not cut up the "red button" because I did not feel to go get a jewelers saw. I should have done so, but I do not use that camera anymore, it is a brick.

 

I have been using only the newer version that has the RF in the middle of the camera and is much much brighter, has also the shutter release on the body, not in the akward position of the shutter release as found on the 110. Much easier focusing with this new camera which is lightweight, this thing is a feather.

 

I do not use the Rodenstock lens anymore, I fitted a newer lens that, as I just found out, leaves the Ysarex miles behind. More contrast and very good sharpness at all apertures. My shutter now goes to 1/500sec ~ a true 1/300sec.

 

Oh! I fitted a neck strap to the camera, so now I look like a tourist, hehehe...

Hi Brett.....your back door should look like this. I no longer convert Polars in this fashion as it is rather involved. If you position the Graflok in exactly the right place, then fit a 150mm lens, the front standard can remain untouched, (although some modification to the rangefinder cam is then needed). Moving the standard back toward the camera body can incur some problems when closing, so if you use the 127mm, keep the distance from the original film plane to the Graflok to a minimum. I have a CD which explains how to do everything. Cheers.<div></div>

Here`s a pic showing a method used when fitting a Graflok. Only a distance of 21mm is needed, perhaps less. An easy method of checking the minimum distance can be seen by sighting from each corner of the 4x5 frame. If you can see the entire rear element in all four corners, vignetting won`t occur. In the case of fitting a 90mm Angulon, this distance must be substantially less. This is due to a 90mm being so wide as to shoot the tip of the camera`s front door at infinity, or the tip of the bed when focus is racked forward.

If the film plane is set rearward too far, (without using a longer focal length lens) then some difficulty may be experienced when closing the front door. This is due to the geometry of the front support struts being altered by setting thew front standard too far aft. At present a 150mm seems the limit for this compact 4x5 folder.

Cheers, Dean. (no alias needed)............

You can find further FREE info by visiting my website: Razzledog`s Camera Homepage. (Google)<div></div>

Project finished. Thanks for the assistance. First couple of shots out of the beast. <a href="http://www.photo.net/photodb/folder?folder_id=669092">110B + Fuji 100C</a>