Arca-Swiss Binocular Reflex Viewer

I just received the 4x5 version and I'm going to post my observations, together with some photos, over the next couple of days.

My initial reaction is that it is going to speed up composition. I like the fact that it makes it possible to compose without a dark cloth and with an upright image. But I want to experiment a bit to see whether, when it comes to focusing, it is best used for rough focus or whether the magnifiers, when engaged, can really replace a loupe on the ground glass.

I do some work with a chef whose food I photograph. He has good visual sense and is very much involved in composition and overall look. Earlier today, I showed him how the viewer functions, and his reaction was "I love it".

There's one thing that I might mention now. Over the years, there have been suggestions on this forum that the Arca-Swiss Binocular Reflex Viewer works only when one is using the camera in horizontal orientation. When I was trying to decide whether to buy one, those suggestions gave me concern, and I spent a couple of hours on the internet trying to determine whether that was true.

Anyway, the viewer works equally well in both horizontal and vertical orientations. Those who own an Arca-Swiss will know that there is a pin on one side of the ground glass frame, centre, that can be pulled back and that springs back to its normal position when released. There are four small holes, one on each side of the reflex viewer, that are in line with and accept this pin. This is what holds the viewer in place. Over the years, I've wondered what that pin is for. Now I know.

Since 2012 will be a year of important elections both in France, Germany and in the USA, let's start 2012 with a vote : I vote for the Arca Swiss bino viewer and not for the dark cloth ;)

With a bino viewer, your breath will not reach the ground glass. As of January 1-st, this is important in the Northern Hemisphere :D
And you can actually breathe freely ;)

The A/S bino viewer is tiltable so you can adapt it in order to always have a bright band of the image illuminated in the centre of the field, even after applying a shift or a tilt with a wide-angle lens.

I'm short-sighted and suffer from astigmatism so I have to keep my eye glasses on; so I have to use the loupes "on". With the loupes "off" (4x5" Arca Swiss viewer only, the smaller 6x9 has fixed, non-flippable loupes) I cannot see the GG sharp since I also suffer from presbytia ;) however I could flip the loupes "off" and use the "short distance" pair of glasses I use routinely to work with a computer.

The advantage of the bino viewer is the extra comfort you get. Hence you can focus quickly before your eyes get strained.
Apart from extra size and weight (to be compared to the weigth of a dark cloth, some dark cloth have small lead balls ...), the main drawback is that you have to set the height of your camera to a fixed position with respect to your head, whereas the dark cloth + loupe can be used in any position ...

Additional technical info : the 4x5" A/S bino viewer did not change between the 171 and 141 line, so you can attach a used, pre-2002 viewer to any A/S camera with a 4x5" back, be it 171 or 141.
The smaller viewer for 6x9 standards did not change since the 6x9 format frames did not change since the F-line was introduced in 1984

I always found mine good enough for critical focus. Hate a dark cloth.

I used the reflex viewer today outdoors and all I can say is that I should have purchased one years ago. It is such a pleasure to compose right side up, and to compose without a fight between my movements and those of the wind, on one hand, and a dark cloth, on the other.

The image is extremely bright and, as Emmanuel says, one can control the angle of the viewer vis a vis the ground glass to maximize brightness. While it hadn't occurred to me, Emmanuel is also right that the viewer does away with the whole issue, in cold weather, of condensation on the ground glass. As for the viewer's bulk, here too I think that Emmanuel is onto something. It is clearly less bulky than a dark cloth, and no heavier. That said, a dark cloth is malleable, and can be used to swath gear for protection.

For me, the only question at this point is whether I'm just going to use to the reflex viewer for composition and rough focus or whether I'm also going to use it for fine focus. Today, for fine focus, I removed it and used a loupe. Tomorrow, I plan to see how using the viewer's two magnifiers (left and right eye, presumably why it is called a binocular viewer) compare to the use, directly on the ground glass, of a Toyo 3.6x loupe and a Rodenstock 4x loupe.