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                               CVF 'Spotlight' Series^©

The new CVF Series from STI affords 35mm photographers a fast, easy, and economical way to attain critical daytime visual focusing without guesswork.

While the Series IV 'Stiletto' knife-edge focuser is unsurpassed for deep-sky imaging, it is restricted to night use when a pinpoint source of light is available as a target. On the other hand, daytime focusing through a scope has largely been haphazard since no equivalent device was developed. 35mm photographers - especially those pursuing solar and nature photography - now have an effective alternative in the Critical Visual Focuser Series.

While the CVF was specifically designed to overcome focusing difficulties with Canon EOS and Nikon Digital SLRs, models are available for all 35mm digital and film brands, including Pentax, Olympus, Minolta, and others. Whether digital or film, you will find the CVF essential in your quest for perfect imaging. The CVF is simply the finest visual focuser available today for precision 35mm photography.

              How & Why It Works       Main Features



How & Why It Works

The CVF replaces your entire 35mm film or DSLR camera during critical focusing. This precision calibrated device projects the actual image to be recorded onto a high-resolution 300 grit chemically etched glass focusing screen with a clear 'spot' which is then magnified 16x. Once in focus, the CVF is removed and replaced with your camera to take the actual picture using manual settings. This simple swap-in, swap-out process takes only seconds and guarantees perfect focus every time:

                   1                               2                          3                           4

Attach the CVF                     Focus until sharp           Attach your camera          Frame & Shoot

Designed primarily for solar, nature, lunar, and planetary photography



* Why It Works In a nutshell, the existing view screen in your camera, whether DSLR or film, does not provide enough magnification and contrast for your eye to obtain perfect resolution during focusing. Your eye compensates for an out-of-focus image automatically by up to 3%. Consequently, while focus may appear to be perfect to your eye, it is not at the exact focal plane expected by the film or chip in your camera. The result is a blurry image lacking definition. By providing enhanced contrast with the 'Spotlight' view screen along with high magnification, the CVF radically reduces the error of your eye down to around only .2 %.

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Main Features

* High Magnification minimizes focusing errors caused by the eye itself. Whether nearsighted, farsighted, or astigmatic, high magnification reduces eye error. The 16x adjustable focusing lupe in the CVF guarantees bright and clear images. In fact, CVF light loss is much lower than the camera's own factory viewfinder. No intermediate optical reduction elements or mirrors are in its image train. The image falls directly, and first, on the CVF focusing screen before magnification.
This approach to focusing outperforms built-in DSLR zoom features and add-on devices hands-down. Most eyeglass wearers can even use the CVF without glasses. And, the CVF works at any f/ratio with any scope or lens!

* A 300 Grit 'Spotlight' Optical Glass Viewscreen provides crisp and clear resolution with just the right amount of contrast for easy focusing. The position of the focusing screen is calibrated to the exact backfocus/film-plane distance of your camera to within .001mm of the factory spec using SPC analysis. A calibration quality certificate accompanies each CVF. While the CVF comes pre-calibrated to use out of the box, the position of the focusing screen can easily be adjusted by the user for special applications. We christened it the 'Spotlight' screen since the sharpest image seems to simply pop out at you on the clear spot during focusing. There is no guesswork about where perfect focus is..

* The CVF Bayonet Mount is identical to your camera's and attaches to the very same t-ring. Since the CVF is a standalone device, no special modifications to your camera or other special adapters are ever needed. The CVF is at home in either prime focus or eyepiece projection photography and attaches normally to those adapters just like your camera.  Even larger camera lenses without a fixed infinity stop may also be attached directly to the CVF and pre-focused before attaching to the camera.

* The CVF Modular System - Many different camera brands or lenses may be used with the same CVF body: simply unscrew one bayonet modular mount from the front, and screw in another on the fly. No recalibration is necessary in swapping since the viewscreen is part of the bayonet assembly. Additional modular mounts for all 35mm camera brands are available. You can add on as your requirements change without worry about obsolescence. Note: Series IV 'Stiletto' modular mounts with ronchi screens will also function with the CVF. Just screw one into the CVF body and you're ready for deep-sky imaging!

* The Adjustable Focusing Lupe permits perfect focusing on the 'Spotlight' screen to compensate for differences in individual vision. While the initial position is set at the factory, the lupe focusing eyepiece is easily adjusted by the user. A thumbscrew is simply loosened and the lupe position readjusted and reset. The lupe is a 5-element achromatic design housed in a standard 1.25" diameter housing. Despite the high magnification, it has very comfortable eye relief. This lupe was custom-made by the same manufacturer of Meade,Celestron, and Bushnell optics.

* Focusing Flexibility The CVF can be used effectively for eyepiece projection or prime focus photography. It attaches to the very same t-ring your camera does. No special adapters are needed. It is at home focusing on nature, planetary objects, and sunspots. With care, it can effectively be used for focusing on deep-sky objects as well.
* Solid Construction Materials are used throughout. The CVF body and bayonet mounts are manufactured of solid 6061 aluminum. Lupes are special 5-element designs configured for high contrast at high magnification. Weight: 8 oz
* Technical Support you can count on through our website, email, and product instructions. We want you to take successful photos with the CVF. Proof has to be in the pudding! :)
* Satisfaction Guaranteed with a one-year parts warranty and a 30-day money-back Clear-Sky guarantee.

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