Increasing the EX3 viewfinder image size for Nikon lenses
 

The very handy “expanded focus” function does not work with Nikon lenses. As a result I have been experimenting with a stronger eye-piece that permanently enlarges the image by a very useful amount. Since I have not altered the camera in any way it can be replaced by the original loupe at any time. The new loupe is attached and removed in the same way as the original. It can also be raised for an unaided view of the screen

The extra magnification makes it easier to see fine subject detail in the image. The shorter focal length of the lens used means that the eye position is 2.5” (63 mm) further forward than with the original loupe. When handholding the camera some of the camera’s weight can now be taken by the operator’s shoulder and the side of the camera becomes the cheek pad.

The photographs show a single support tube that has three functions. One function is as a lens support, a single screw clamp permits both a forward / back movement and a rotational movement of the tube. The rocker type lens cradle is positioned under a suitable section of the lens, the rod is then rotated until the rocker is carrying some of the weight of the lens and the screw tightened. Very quick and easy.

The tube also acts as a support for the left hand. The sliding black collar on the support tube is placed in the web between thumb and forefinger. This leaves the fingers in a position where they can be used to tweak the lens controls. When using this grip there is no torsion on the right hand.

As the tube is parallel to the optic axis it can be used as a sight to facilitate finding the subject when using a long lens.
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Actually, the expanded screen focus assist function works just fine. Assign a button to it and you can use it when the dedicated expanded screen focus assist button gets removed with the stock lens.

I can vouch for Les reply, although when assigned to a button the expanded view time seems to be a lot shorter than with the stock lens

That's both an interesting loupe and an interesting mount you have there. Any plans to go into production?

Hi Vincent and Les,

I have not found a way of using an assign switch for "expanded focus" with Nikon lenses on my EX3. An advantage of increasing the viewfinder magnification with a shorter focal length is that the image is enlarged the whole time. Furthermore I can see the whole field and not just a portion of it as when "expanded focus" is in operation.

Alastair,

Go into the menu and under the "Options" menu select Assign Button, Select which button you want to assign the Expand Focus to and click it. A list of about 17 options will appear, scroll down and select Expand Focus. It's as simple as that.

Of course if your viewfinder works for you, then stick with that, it's probably a better option.

Just hold the assigned button down until you are done focusing.

Thanks for the advice, in the past I managed to reassign the last shot delete, so I knew how to do it once.

Yes the viewfinder does work for me, when I now use the original it is like peering down a long tube at a distant view. Is is likely to be packed away with the cheek pad and carry strap.

The project started by removing the original loupe and examining the screen with any available lens. A focal length of around 4" (100 mm) seemed ideal. I ended up with a choice - one being an old slide projector lens and the other was originally for doubling the magnification of a stereo dissecting microscope. I used the latter because it was easier to attach. It is also a very bright lens and covers the required field. If you try experimenting make sure you test the lens both ways.

Oops, I made a mistake here. Holding the button longer does to make the expanded focus view stay on longer. It must be a I thought ti did because I always got it focused before it quit. Sorry about the misinformation.