WRS Tuning

[thomas]

Maybe this is of interest for those who use the WRS since it came out as Cambo modified some details since then.
This is about the groundglas resp. the groundglas frame.
It's not a brand new feature, actually it has been there since a year or so, but I haven't seen any reports on this here on the forums.
Well, Cambo improved the GG-frame by adding a little clip so that you can fold open the focusing hood:

Why is it a good thing? When your little tech camera does not support the use of a sliding back but you still want to use the groundglas for composition (or focusing) you have to exchange the groundglas with the digiback and vice versa. So you have to fiddle around with a lot of individual parts... camera interface, digiback, groundglas frame, focusing hood, loupe for focusing...
If you want to use a loupe with higher magnification for focusing on the WRS it is not required to take off the focusing hood. You can leave it on the groundglas frame all the time… as you can simply fold open the focusing hood. So this folding mechanism allows you to handle the groundglas frame and the focusing hood as one single part.
As I don't use the finder for compostion (I actually use it before I set up the camera… like a "directors finder") and as I hate to compose on the ****ty LCD of my digital back I always use the groundglas for compostion. I also use it for focusing at close and mid distances.
So this is really a handy little feature of the WRS groundglas frame and I haven't seen anything like that from the other camera makers … so I think it's kind of unique on the WRS...?

I think my snapshots will show how it works.
Note that it is actually intended to be fold open to the left side… but I use it upside down as I want to fold the focusing hood to the right side (as I prefer focusing with my right eye…).

Furthermore... the attached images also show my modified focusing hood.
Cambo uses a focusing hood on the WRS that was originally designed for the sliding backs of their view cameras.
On these cameras they provided certain masks to fit in the inner frame of the fosucing hood. Therefore the inner frame is not rectangular - the corners are slanted (obviously due to the shape of the masks).
I haven't found an image on the web to show this but Don once posted an image of the original groundglas frame (http://forum.getdpi.com/gallery/showimage.php?i=4708&c=114) where you can see the corners:

Well, I just went to a precision mechanics and asked him to cut the inner frame so that it is rectangular (see attachments).
This modification allows me to see the sensor plane plus +/-9mm lateral shift and +/-11mm vertical shift (refering to a 48x36 sensor in horizontal composition) when the focusing hood is mounted. With the focusing hood removed - respectively folded open - the groundglas frame shows +/-16mm lateral and +/-12mm vertical shift.
BTW… I really like the indications on the WRS groundglas (and prefer it over finder masks) as I can see how much movements I need for a certain composition ( http://www.cambo.com/Html/Images/WDS-619-02.jpg ) which comes in handy when stitching. I mostly look at the 48x36 sensor dimensions on the GG although I use a P45, which is slightly larger. The little headroom is fine as it is a kind of safety area and if you apply distortion correction you need some headroom anyway.

Finally... I also just recently replaced the orginal lens of the focusing hood by the front lens of on old (broken) Pentax SMC 1.4/50mm lens.
Gives me quite a bright and crisp view on the groundglas - really nice!
There is always some room for improvements




.

 

[TTLKurtis]

You're so silly - those images are upside down!

(i kid, i kid)

 

[Don Libby]

There were at least two things I didn't like about using this; I always had some light leakage between the viewing hood and the screen however I just draped a scarf over the edges to fix that. The second thing was the lens in the viewing hood. While it enabled me to see the image it was never the clearest image; I actually thought at one time of going old school and using a dark cloth instead of the hood.

I'm only mildly interested in the new prototype sliding back - again I see two concerns for me; using it will add weight and enlarge the overall footprint to a great system and secondly I'd be right back again with the viewing hood. I can see huge advantages to using a sliding back in a studio environment however when you standing outside in a rain forest or on a cliff face like I often find myself then those advantages go away.

Don

glad I was able to help with the images

 

[thomas]

There were at least two things I didn't like about using this; I always had some light leakage between the viewing hood and the screen however I just draped a scarf over the edges to fix that. The second thing was the lens in the viewing hood. While it enabled me to see the image it was never the clearest image; I actually thought at one time of going old school and using a dark cloth instead of the hood.

I'm only mildly interested in the new prototype sliding back - again I see two concerns for me; using it will add weight and enlarge the overall footprint to a great system and secondly I'd be right back again with the viewing hood. I can see huge advantages to using a sliding back in a studio environment however when you standing outside in a rain forest or on a cliff face like I often find myself then those advantages go away.

Don

glad I was able to help with the images

the above mentioned improvements are of course not relevant if your shooting style doesn't require a groundglas (and in this case a camera with sliding back naturally doesn't make sense neither).
But if you need a groundglas the modifications might come in handy.
The folding focusing hood is also an example for a number of little things that sets the WRS apart from similar cameras... workflow-wise. Not that they are indispensable... but really nice to have (if you use the respective features).

 

[Don Libby]

the above mentioned improvements are of course not relevant if your shooting style doesn't require a groundglas (and in this case a camera with sliding back naturally doesn't make sense neither).
But if you need a groundglas the modifications might come in handy.
The folding focusing hood is also an example for a number of little things that sets the WRS apart from similar cameras... workflow-wise. Not that they are indispensable... but really nice to have (if you use the respective features).

I'm in partial agreement with you. I believe I would have used the GG much more if it were easier and I feel the advent of the sliding back is just that. However I'm still stuck with viewing the GG in bright sun and in this case I'd opt for the dark cloth.

I also realized as I wrote the above I wouldn't need this so long as I don't change any of my lenspannels to tilt swing. As soon I do then I'll be lining up at the door for a sliding back.

Don

I still have to wonder how the addition of the sliding back will work with the movement controls...

 

[thomas]

However I'm still stuck with viewing the GG in bright sun and in this case I'd opt for the dark cloth.

I wondered about your comment here. Maybe your copy had a fault... I've never had a problem like this with the focusing hood.
Too, looking at your photo of the GG it seems you didn't use a fresnel glas. Now, this will improve things significantly!
The future (optional) GG of Cambo will be even better (but probably quite expensive).

I also realized as I wrote the above I wouldn't need this so long as I don't change any of my lenspannels to tilt swing. As soon I do then I'll be lining up at the door for a sliding back.

you should try that first. I'd say you can judge about the effects of tilt & swing to some degree but it's impossible to see the real outcome on a groundglas.

I still have to wonder how the addition of the sliding back will work with the movement controls...

think of controls like on the WDS (arTec, Rm3D etc.), not those of the WRS...