(Note: Links below were where I found useful information and represent no other endorsement.)

Questionable stuff in red
How you can help

Tip: Links here are in the icons, not in underlined text

Some General Issues

Dim, upsidedown and backwards images are what confront the LF photographer. While some try to make a virtue of these characteritics most of use wouldn't mind having image displays that look more like the 35mm Nikon and Canon SLR or the MF SLR displays that many of us have used successfully--we just couldn't carry 4 x 5 or 8 x 10 versions of those into the field. So, reflex and magnifying focusing screen viewers are the lightweight, but sometimes bulky contribution to better, but not perfect LF aids for composition and focusing.

While manufacturers name their products differently, there are two basic designs available and I will try to use two naming conventions consistently. A magnifying viewer is generally some kind of hood that shuts out ambient light between the camera's groundglass (GG) and a low power magnifying lens mounted on the back end of the hood. The lens' power is enough to allow a full view of the GG as it is viewed from a point on the optical axis. A reflex viewer has these design components plus a mirror to reflect the GG image up to a magnifying lens mounted at an angle that isn't on the optical axis. The mirror swaps the image 180° vertically, but does not change the image orientation horizontally--it remains reversed right to left.


Examination with viewer          


Examination with loupe          

Now if taking lenses had uniform illumination and the mirror arrangement and the magnification of the image were to be done perfectly, these would both represent a gross improvements, but image illumination -- and therefore focusing difficulty -- takes a double hit in this arrangement, particularly noticeable with short focus lenses. Placing the viewer's magnifying lens at the same relative location as the taking lens only adds more off-axis falloff--darker edges and corners as represented in the intermediate bar in the first figure. In contrast, examining small portions of this GG display with a higher power loupe (second figure), the loupe sees the portion viewed with relatively little off-axis falloff caused by the viewer lens, though falloff from the taking lens is still there. So it is less useful to consider a magnifying or reflex viewer a replacement for rather than a supplement to a loupe.

When designing viewing aids for LF displays, equipment designers have included three features that improve workflow while still supporting both overall image composition and critical examination of edge display.

  • First adding a fresnel lense can reduce apparent image illumination falloff, and becomes increasingly important when using a magnifying or reflex viewer, though it may make loupe examination more difficult.
  • Several makers have attached their magnifying and reflex viewing hoods to an edge hinge on the GG focusing panel. This makes it possible to swing the viewer away to allow easy access to the GG panel for loupe viewing.
  • Some designers may install their reflex mirror in a way that allows changing the vertical viewing angle between top/middle/bottom of the GG display. This comes closer to providing the kind of on-axis view of the GG image we see with a loupe. Strategies for varying mirror angle may include mounting the mirror on pivots within the reflex housing, or by making the entire viewer housing adjustable for angle of view by connecting it to the camera with a flexible bellows.

The installation of a fresnel lens is a sometimes controversial topic among LF photographers. If your camera has a fresnel and groundglass that were installed by its manufacturer, or if it has only groundglass and a fresnel is available as an option, that is likely to be a very good combination. There are other options, however, that you may want to explore, including custom fitted fresnels, different types of groundglass and specialized types of viewing screens. Creating the optimal viewing screen is a function of the texture of the GG, the focal length of the fresnel lens and the focal length of the taking lens. In other words, any single fresnel lens is likely to be a compromise for any but one of your lenses. Since fresnel lenses are made to redirect light rays falling on more distant parts of the GG back toward a central viewing position, they may be good for a magnifying or reflex viewer, but less than ideal when trying to examine edge areas with a loupe. An approach followed by at least one manufacturer--Wista--is to include a fresnel in the reflex viewer that rests on the photographer side of the GG when the viewer is in place. When swung away, the fresnel is no longer in the viewing path. Another strategy for dealing with this problem is to find fresnel mounting arrangements that allow removing the fresnel selectively. Two sources of additional information about fresnels:

     Site article     Wisner article

Very often glasses wearers are attracted to binocular viewers which may be more physically and optically comfortable than monocular viewers. Your success in matching photographic viewing aids to corrective glasses will be dependent on the type of correction they are designed for and their power. This seems to be one of several issues that relate viewer use to photog age. Those of us of a certain age struggle mightily with being able to see the GG and, within some reasonable amount of time and manipulation, to also see the shutter speed and aperture rings. Sometimes critical standards about the niceties of loupe focusing pale...

In general, fitting a reflex or magnifying viewer to a camera is a function of the size of the "well" that holds the groundglass. Unlike standardization of filmholder dimensions, there seems to be little that is standard about the focusing frame. The safest way to approach this is to buy a viewer made by the manufacturer of your camera, but you may like the design of a viewer of another brand or the manufacturer of your camera may not make a viewer. Some viewers will fit more than one brand of camera or can be modified to fit others. I have tried to address compatibility in the chart below by finding forum posts that report success or failure. This table can be made more useful by showing those viewers that are designed for one camera that will fit another out of the box or with minor modifications. If you can add to our common knowledge about non-standard fitting, send me your tale and I will summarize it for the table. If you know of additional reflex or magnifying viewer not shown, including custom or DIY items, please send an image and whatever information you have about the viewer and I will include it here. I am willing to publish as independent pages with attribution--longer summaries that you write, with images. If you have an explanation and images of a project, but no experience with Web pages, I'll work with you to create a page that will document your project. If you already have a page, just send me the url and I will create an entry in the table that is linked to your page.

You may note that while the page title includes medium format viewers for view, technical and field cameras, there are no examples of MF SLR finders here. The primary thrust of this site is to identify and describe equipment that supports standards movements. Except for the occassional MF SLR lens that has rise/fall/shift capabilities, this is not a feature that is promoted in MF SLR design. Few LF SLRs, primarily the Graflex models, had movements on the front standard. It might be argued that a MF or LF technical camera with a reflex viewer and a sliding or rotating GG/RH back comes close to providing this functionality.

The table below attempts to pull together on one page information I've gleaned from LF forums, from documentation published by equipment manufacturers and dealers, and from comments made to me by visitors to this page. For convenience I have tried to provide links to information sources.

Thanks to Peter Lewitt for his contributions to this page.


Opinions about specific viewers and viewers in general


Arca Swiss M Monolith 6 x 9 with binocular reflex viewer

Binocular Reflex Viewer

Available in
6 x 9cm and 4 x 5 in models

Arca Swiss

View Camera Store
(download Arca Swiss .pdf brochure)

Precision Camera Works
(general information)

Arca Swiss follows the general design strategy of highly compatible--within their system--components. The binocular eye mask and lens units can be used on either of the two reflex finder units or either of the two viewing bellows which form straight through magnifying viewers. The reflex units come with their own dedicated bellows which allow the entire reflex structsure, including its stationary mirror, to shift on the vertical viewing axis--think back tilt on the average LF camera. The angle of the mirror to the GG is changed by extending the viewer housing away from its mounting plate that is connected to the focusing frame.

The 4 x 5 viewer attaches to the focusing frame with a lip and pin arrangement; the 6 x 9 uses a different kind of mounting.

The finder can be collapsed and disassembled for transport, though the reflex housing piece is itself large.

Because of the cost and complexity of this viewer and the means of attaching it, modification to fit a non-Arca camera would likely be not very cost-effective.
However, if you have done this we'd be glad to know of the experience.

  Monocular Magnifying Viewer Cambo I know these were made but don't currently have a picture of one

Monocular reflex viewer

4 x 5


Calumet Photo

Currently a search of the Calumet Photo site for "reflex viewer" produced no matches.

Viewing hood attaches to Cambo/Calumet 4 x 5 viewing frames using a metal tab on one side and a sliding lock on the other. The rear section rotates to allow vertical or horizontal viewing for either stationary or rotating backs.

The footprint of the Cambo viewer is
5 1/2 x 4 9/16.


General: If the inside dimensions of your viewing frame are larger than the dimensions of the viewer, you may be able to add spacers made of sheet aluminum or preformed aluminum L or U rail to attach it to whatever fastening arrangement there is on your focusing frame. Velcro fastening has worked.

These viewers are made of either aluminum or structural plastic either of which might be modified by simple machining techniques to change their shapes.

One of the simplest and most successful redesigns is to replace the international G focusing frame with a Cambo focusing frame. This will work on most Graphics, but will not work on Wista technicals.
Other stories of success or failure?

Ebony: Can be made to fit by adding some metal extensions so that the Cambo is the same shape as the Ebony GG.

Ebony: New clamps to attach Cambo viewer
S. K. Grimes

Reflex Viewer

for 4 x 5

 Cambo An older Cambo binocular hood for Cambo viewing frames.
Attaches like Cambo monocular hood?
Monocular Reflex Viewer Chamonix

This viewer appears to be in the style of the Cambo viewer, but with a distinctly different mounting flange that is fastened to the GG panel with four machine screws. Like the Cambo, its viewer housing rotates 360° .

While this viewer might be adapted, because of its mounting flange, it probably will not fit any other back out of the box.

Folding Hood Chamonix

I have not generally shown folding viewing hoods here, but this one is unusual enough to warrant interest. Its length greatly limits the amount of ambient light that enters to viewing slit.

Does it have an optic?



Revolving duplex back for
2 1/4 x 3 1/4 international G back
(Horseman Rotary Back)


(no longer manufactured)

Originally made for Horseman VH/VH-R 6 x 9 cameras with international back. Two ports on back plate accept a 6 x ? rollholder and one of two GG options: a 6 x 9 GG panel or a reflex viewing hood with its own GG.

Viewing/film positions are controlled by a lever that lets the plate assembly revolve. Plate attaches to camera using Graflok bars.

Note: In theory, these should fit any 2 1/4 x 3 1/4 international G back. Horseman's specs for slots on Graflok accessories--where the Graflok bars slide into the back adapter--is slightly thicker than Graflex's for early Graphic holders. Attachment of Horseman accessories to Pacemaker Crown Graphic 23 is difficult and tentative. No problem attaching Horseman back accessories on Graflex XL's (23) Graflok back..

Because the rotating back maintains a common camera-to-adapter distance between the GG panel and rollholder mount, this should not be an issue using this adapter on non-Horseman cameras..

Horseman Rotary Back design effectively increases extension by about 25mm

Revolving duplex 6 x 9 back for
4 x 5 international G back
(Horseman Rotary Back)


(no longer manufactured)

This is basically the same back as above but made to mount on Horseman 4 x 5 technical cameras with international G back. Two ports on the back plate accept 6 x ? rollholders and one of two GG options: a 6 x 9 GG panel or a reflex viewing hood with its own GG.

Viewing/film positions are controlled by a lever that lets the plate assembly revolve. Plate attaches to camera using Graflok bars.

Like the 6 x 9 version for the 6 x 9 mount, this 6 x 9 version for the 4 x 5 mount does not mount to the 4 x 5 Pacemaker Grahics. The adapter will attach to the Super Graphic back.

Horseman Rotary Back design effectively increases extension
by about 40mm


6 x 9 Reflex finder


(no longer manufactured)

, fresnels & lens length

Originally made for Horseman VH/VH-R 6 x 9 with or without the rotary back, or the Horseman 4 x 5 cameras (HD & FA) with the 4 x 5 version of the rotary back. Eyepiece section rotates for vertical/horizontal orientation. Viewer has its own integrated GG and expects to attach to Graflok port with no GG viewing frame.

The reflex viewer itself should be usable on most cameras with 6 x 9 international backs, but see below.

Note: Horseman's spec for slots on Graflok accessories--where the Graflok bars slide into--is slightly thicker than Graflex's for the Graphic holders. Attachment of Horseman accessories to Pacemaker Crown Graphic 23 is difficult and tentative. No problem attaching Horseman back accessories on Graflex XL's later Graflok back or Super Graphic..

4 x 5 Folding Binocular


This folding binocular viewer uses sissors braces to establish the distance between the view lenses and the GG, then compresses for travel. Magnifying glasses use 3 diopter lenses.


Binocular viewer

for 4 x 5


This item has been discontinued with much other well-designed Horseman LF film equipment. Available rarely on the auction market.

Cambo & Horseman viewers


Horseman binocular reflex viewers w/pix

Folding binocular viewer. Suggestion that it fits Sinars.

This viewer has gotten consistently good reviews.

"Mounts on Horseman standard, as well as 14 x 14cm standard cameras."
B&J Professional Catalog


Horseman viewer can be modified by Ebony to fit their cameras.

Reportedly fits Toyo VX125 with little or no modification.

Fits Sinar P2/F2/F1 without mods.

Fits Toyo, possibly with minor adjustments.


9 x 12 and 6.5 x 9 Technikas with Reflex Viewers

Monocular Reflex Viewer
for Technika 23


B&H Photo


From B&H

"With 4-way adjustable reflex housing, for vertical and horizontal viewing. Ideal for critical observation of the entire groundglass image. Shows upright image. Includes 2x magnifier covers for groundglass area."

Viewer is hinged to the GG frame on one side and can be swung away for loupe focusing. The base of the mirror/optic housing is square and can be attached to the larger housing in horizontal or vertical orientations.

Linhof viewers are/have been available for 6.5 x 9, 9 x 12 and 13 x 18cm models.

Badger Graphic lists a:
Right Angle Hood 4X5
(no image)




Magnifying finder


Viewers on Technikas

I've found these items on the Linhof site in a list of accessories for 6 x 9 and 4 x 5 Technikas; these items may be components of magnifying and reflex viewers.

  • Focusing Bellows 23 002504
  • Basic Lighthood 23 001611
  • Magnifier Viewing System 8x8 for Basic Lighthood 002757


Binocular Reflex Viewer Polaroid MP4

Originally fit a copy camera; occassionally available on eBay

Adaptation for 4x5 Speed Graphic
Illustrated How-To


Monocular reflex viewer

4 x 5

 Shen-Hao This appears to be of very similar construction to the Cambo T20 reflex viewer, but I have no information about how it mounts to the Shen-Hao cameras. Looking at the focusing panels of a couple of the Shen-Hao cameras, it isn't obvious how these viewers would attach. 
Binocular Reflex viewer  Sinar This substantial reflex viewer has a rigid plastic eye mask. The reflex structure includes a moveable mirror.
Is this possibly an older version than the current one shown below?
Modular viewing options Sinar

Like Arca Swiss, Sinar uses a modular approach combining elements to create viewers with different capabilities.

Standard Viewing Package:

  • Wide Angle Bellows
  • Multipurpose Standard
  • Bellows hood mask

Deluxe Viewing Package

  • Wide Angle Bellows
  • Multipurpose Standard
  • Bellows hood mask

Bino Reflex Housing

  • Lighthood w/Lightdrop
  • Bellows reflex housing with adjustable mirror

Bino Magnifier Board
shown with bellows, bellows clips, joint rod and lighthood




Monocular magnifying viewer

for 4 x 5



B&H Photo

Swing away monocular magnifying viewer

From Toyo site:
"Toyo Fresnel Lenses
Fits under ground glass for bright, even illumination with all lenses fromwide angle to telephoto."

Monocular magnifying viewer

(Toyo Mono Hood)
for 6 x 9



Viewer with 1.5x magnification.
Presumably will attach to slider accessory back (below)

Appears to swing up or down when the camera is in horizontal position.

 4 x 5 Binocular Reflex Viewer


B&H Photo

Found this on B & H site. "Fits all Toyo 4 x 5 cameras"
Slider accessory back
4 x 5


B&H Photo

Duplex back for 6 x 9 components for use on 4 x 5 cameras with an international G back (according to B&H). Ports for 6 x 9 RH with auto dark slide and 6 x 9 GG. Rollholder is attached to accessory back using Graflok bars. Not clear how a magnifying or reflex viewer would attach to accessory back..

Because of design of the Graflok flange, it is likely that this unit significantly increases extension.

Balloon Focusing Hood


B&H Photo

A balloon type focusing hood attached to a frame that attaches to the Toyo focusing frame.

Binocular Reflex Viewer

8 x 10



Binocular reflex viewer for 8 x 10 Toyo and possibly others.

Wista viewer mounting detail

Duplex accessory back

Monocular magnifying viewer
4 x 5


B&H Photo


Duplex accessory back probably fits only Wista 4 x 5 technicals, since it replaces the entire 4 x 5 back on the camera. Unlike other accessory backs that attach using G back sliding attachment bars and thus create significant extension, the Wista attachment doesn't change extension significantly. Good news for using short lenses. Swapping the 4 x 5 and the sliding back is a simple operation--30 seconds.

Viewing/film positions are selected by pressing a lever and raising/lowering the frames. Viewing frame has 6 x 9 GG with 6 x 7 markings and accepts either a conventional folding hood or a magnifying viewing hood. Film frame has an auto dark slide and accepts at least Wista, Horseman and Graphic 6 x ? (120) rollholders.

Magnifying viewing hood attaches to a hinged assembly on the duplex back, here shown on the left in the detail. Hood swings away for loupe access to the GG. Magnifying viewing hood seems unlikey to fit other backs. It has a primary eyepiece and a concave condenser element. It is more like a large loupe that presents a bright view of the center of the field than an effective compositional view. Imaging at the edges is quite distorted, so it is no substitute for a loupe . It is very effective for short focus lenses. Viewer has a heavy optical element and weighs about 1 pound.

Duplex accessory back, rollholders and viewing hood sold as separate Wista accessories.

Folding monocular reflex viewer
for 4 x 5


B&H Photo

Folding monocular viewer:

No. 4565 for Wista technical
No. 4566 for Wista field
No. 4567 for Linhof

At least the Wista technicals version attaches with a right-mounted pivot hinge, and swings away for loupe focusing. Can be stored in the folded position on the camera. No information about how it attaches to Wista field or Linhof (presumably Technika) .

Has removeable fresnel to improve focusing with some lenses.

This is an outstanding viewer--compact, optically bright and convenient for loupe use. Only down side is that it only fits Wistas or Technikas. Ed.

In the way that Wista back accessories mount and dismount, it would be possible to swap the reflex viewer and the sliding magnifier in seconds.

Sliding magnifier


B&H Photo

Attachment that holds a loupe in contact with GG and can be adjusted to any part of the image. Swings away on right mounted pivot.

No 1005 for 45 technical
No 1006 for Field 45
No. 1007 for Linhof


Binocular reflex viewer


B&H Photo

Binocular viewer that has an adjustable mirror for flexibility in maximizing brightness over vertical sections of of the image.

Here is Wista's explanation:

"Mirror movement solves the problem of losing brightness of focusing screen when taking indoor shots, especially when camera is tilted"



04/27/2011 22:52