Pros: Solid construction, good performance, metal eyepiece adapters.
Cons: Not centered on eyepiece, diopter adjustment easily moves out of focus.
The Hoodman Right Angle Viewer (HRAV) is a multipurpose accessory for SLR cameras designed to both move the viewfinder image to a more comfortable viewing angle and magnify it to make focusing easier. Examples of this use include low to the ground photos, where getting behind the camera may be impossible, and astrophotography, where getting to the viewfinder may be awkward, and the camera is otherwise unable to help with focusing. Note: the HRAV is not able to locate the right angel, despite what the listing says.
The SLR camera has stood the test of time, even to the point of being able to survive the transition to digital photography. Like their film based forbears, the DSLRs use a focusing screen to present an image of the photographic field as seen through the camera's lens. The enduring popularity of this setup is it allows a perfect preview of the image, true real-time focusing, and the dynamic range of your eye, which is far superior to any film or digital detector, to estimate what is there to be seen and if the focus is right.
Unfortunately, this configuration has two major drawbacks:
(1) There is one exit pupil location in the back of the camera.
(2) The viewfinder presents the entire scene with photographic information in small scale, making extremely fine manual focus difficult.
In small consumer cameras, these types of problems have been addressed by presenting the image on a large LCD screen on the back and taking control of the focus away from the photographer and giving it to an automatic setting (at the price of some lag before the photo is taken). But for the SLR, the biggest advantage it has over small cameras is the ability to look through the optics which will take the photo so the human eye's superior dynamic range can evaluate the scene and allow the photographer to make a smart decision about what needs to show up in the final photo and adjust the camera to meet that need.
As for focus, modern digital SLRs have just about univerally added an automatic focus feature, which is generally useful for everyday hand held photography. But when the scene gets complex, the contrast is low, or the objects in it don't have conventional edges, these systems stop working. Examples include scenes in low light, such as under a tree, photographs of large smooth shapes (like one of the old cannons at Fort Monroe in Virginia), or astrophotography, where the telescope has no power connection to the camera, and the scene is made up of points of light. And while a live image on the LCD from the camera's sensor would be useful for focus, this mode would not have the photographer's eye available to determine what the dynamic range was and what the best light settings will be.
Angle viewers are a time tested solution to these problems by attaching to the outlet of the viewfinder. In this mode, the camera now has its image bent 90 degrees from behind it, so if the camera is pointing up, or very low to the ground, it is possible to get a look through the viewfinder.
The second feature built into angle viewers is the ability to magnify the image of the focusing screen to make fine manual focus easier to achieve. As a result, all major camera systems from makes such as Nikon, Canon, Sony, Olympus, or Pentax have removable bezels on their eyepieces to make attaching a angle viewer possible.
Description and Usage
As a maker of general purpose high end camera accessories, Hoodman makes versions of its products to support all of the major SLR camera brands. The Hoodman Right Angle Viewer (HRAV) is an angle viewer made to be used with any of the major brands of SLR cameras. Since the majority of these makes inherited their form factors from film versions, the HRAV is back-compatible to a majority of recent SLR cameras, whether digital or film.
The HRAV comes in a black vinyl pouch with a line drawing of itself monogrammed on the outside in yellow and blue thread. I find I like this since it makes it one of the very few things I have ever owned where the container gave such a clear indication of what went inside. The HRAV itself barely fits inside since the pouch is crammed with a board with various adapters for different cameras attached to it, plus one loose adapter in the pouch. Note, the HRAV didn't support Sony/ Konica Minolta Maxxum or Olympus cameras when it first came out, and this is the reason for the overflow.
In my case, the camera I would be using it with is the now venerable Konica Minolta Maxxum 7D, the direct predecessor to Sony's Alpha series digital SLR cameras (since Sony bought the product line in 2006). This camera has proven itself to be willing to take on a large number of subjects, to the point where I wish Sony had made a more direct equivalent in its Alpha series (the Alpha 350 may be a step in the right direction, but I haven't had a chance to play with one).
The right angle viewer itself is a compact and dense housing with an eyepiece featuring an over-sized conical eye cup. The lower part of the eyepiece is a cylinder with a rubber grip, which smoothly rotates to adjust focus within the eyepiece on the focusing screen. Below this is the diagonal which bends the eyepiece 90 degrees. Between here and the section attached to the camera body the HRAV eyepiece rotates 360 degrees with click stops every 45 degrees. The forebody of the HRAV has a switch for 1X and 2.5X magnification of the focusing screen. Note, the online data says this is 2X, so older units may not have been 2.5X. The front end of this component has a pair of metal ears designed to slide into one of the adapters included with the HRAV for attaching to a camera. Flipping the magnification switch slides one of two lenses in front of the eyepiece.
To attach to a given camera, you first slide on the adapter for that make, or the 19mm universal adapter, and then slide this assembly onto the camera body's eyepiece adapter. In the case of the Maxxum 7D, a horseshoe shaped brow pad needs to come off, first (this fits easily in the HRAV case, so it is easy to keep from losing it).
In use, the eye relief is somewhat limited, so glasses wearers will find themselves tempted to use the diopter adjustment by rotating the eyepiece. Note, if you have astigmatism like me, then you may want to get some glasses which have their lenses come as close to your eyes as possible [note, these tend to look like Teddy Roosevelt's glasses, so practice making a toothy grin].
The diopter adjustment turns out to be critical for anyone using the HRAV, because the focus range it produces is enormous. That combined with the low drag mechanism means every time you use the HRAV, it has to have its eyepiece refocused on the camera's focusing screen. The way to do this is to first point the camera and lens at a bright source (a white wall, the blue sky, or a street light- Never the sun). Pick one of the line elements in the display such as the center focusing box or one of the reticles, then rotate the eyepiece until this pops into focus. I recommend doing this at 2.5X magnification, since the reticles are then easy to see, including their texture within the Fresnel focusing screen. At this point, it is important not to accidentally rotate the eyepiece because that will make focusing the camera impossible. So, if the eyepiece needs to be rotated to a new direction, the way to do it is by grasping the triangular prism base and not by the cylindrical eyepiece.
With this done, it is now possible to use the focusing screen at its highest sensitivity. On the Maxxum 7D, the HRAV does not line up at the true center of the optical system, but is instead off to one side, so the edge of the frame is lost on one end. This is probably the largest annoyance I have found with the HRAV. I will experiment further with the attachment shoes and see if a better fit is possible.
The focusing screen has limitations from its lined Fresnel geometry which casuse the image to be broken along the lines in the screen. This isn't apparent at 1X magnification, but is quite obvious at the 2.5X most photographers would want to use for a critical focus. So, for example, mounting the camera on a 320mm lens (the Astro Tech AT66ED with 0.8X Focal Reducer) and pointing at the bright white star Sirius yields an image where the star appears with the lines of the Fresnel screen through it. It is still readily apparent when the best point of focus is achieved, but the image can't be described as beautiful. On very dim objects, the point of focus reveals itself when dimmer features pop into view or disappear. In daytime scenes, the focusing screen is visible with its pattern of lines on top of the image, and again makes a perfect focus possible, though the really good looking image will be reserved for the camera's sensor.
The HRAV is an effective way to get your eye to the image from the camera's veiw finder, and get to the sharp focus only possible with a magnified image. It is solidly built, and works reasonably well. The main faults I see with it are with the poor centering on the camera eyepiece and the easy turning diopter adjustment which takes it back out of focus. With that said, it works well as a technical aid for difficult shooting angles and low contrast subjects. The fact it comes with a lot of different attachment adapters mean it can follow you to a new camera, even if you change brands. If you find yourself doing photography where you struggle to recognize true focus, this can be the aid to getting there reliably with a minimum of frustration.