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Sima SLS-20 2x Telephoto Conversion Lens

The Sima SLS-20 2x Telephoto Conversion Lens is an accessory lens to supplement a camcorder or a digital camera. As the name implies, it changes the magnification of the primary lens by two times. Put it another way, it narrows the vision by 200%, which allows the primary lens to zoom closer to the subject. For example, if the primary lens' focal length is 200mm, this accessory lens converts the field-of-view to the field-of-view of a 400mm lens.

Note: Based on recent testing and comparison, this lens may not be 2x as the manufacturer indicates. It seems to be 1.4x at best. See my "Teleconverter Magnification Comparison" article elsewhere on this web-site for more details.

On a side note, based on a picture of the Kenko SGT-20 2x Teleconverter, this Sima lens seems to look identical to the Kenko version. I suspect that they are the same lens, made by the same original equipment manufacturer (OEM).

The lens is made with coated all glass optics and metal barrel construction. Yet, the lens weights very little compared to other conversion lenses. It has a silver finish with a black rubber grip to aid in the handling of the lens. The lens has a 37mm filter thread for mounting to digital cameras and camcorders. The front of the lens is indented into the barrel with a relatively average curvature. The indention will provide some lens hood protection from stray light. There is a 46mm filter thread in front of the lens for attaching filters.

The lens comes with three step-up rings: 28mm-37mm, 30mm-37mm, and 30.5mm-37mm. The silver metallic finish and gripping ridges of these step-up rings are exactly the same as the Cokin step-up rings. The same manufacturer probably made these rings for the two brands.

In addition to the step-up rings, the lens came with a front lens cap, a rear lens cap, and a carrying pouch. All three items were black. The front and rear lens caps are made to slip onto the lens snuggly. I was quite impressed with its included protections, because the Cokin 0.5x Wide-Angle Conversion Lens that I recently reviewed (see article elsewhere on this site) did not come with any lens cap or carrying pouch.

Unlike other conversion lenses, the Sima lens is made in China and costs only half the price of most conversion lenses that I have seen. Another advantage of this lens over other similar lenses is that this Sima SLS-20 2x Telephoto Conversion Lens has a 46mm filter thread in front. The diameter of the filter thread is small enough where it may be possible to mount other telephoto conversion lenses in front for stacking purposes. I happen to own an Olympus 1.45x telephoto conversion lens (see articles elsewhere on this site) with a 46mm filter thread. As an added bonus, I decided to test the Olympus 1.45x teleconverter with this Sima telephoto lens in this article. Together, the two lenses provide a combined magnification of 2.9x!

During testing with my digital camera, I found that this teleconverter lens has no light-loss. See the Sony DSC-P92 section below for test details.

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Specifications

Magnification:   2.0x
Filter Diameter: 46mm
Mount Thread:    37mm, 28/30/30.5mm with adapter (included)
Dimensions:      48mm x 34mm
Weight:          2.1oz

Panasonic PV-GS50S MiniDV Camcorder

The Sima SLS-20 2x Telephoto Conversion Lens can be mounted on the Panasonic PV-GS50S MiniDV Camcorder with a 27mm-37mm step-up ring. The Panasonic PV-GS50S has a 10x optical zoom capability, which can be greatly enhanced with this 2x teleconverter lens.

Panasonic PV-GS50S with 10x optical zoom.
Panasonic PV-GS50S with Sima SLS-20 attached for a 20x optical zoom.
Panasonic PV-GS50S with Sima SLS-20 and Olympus 1.45x teleconverter attached for a 29x optical zoom.

The 2x teleconverter improved the camcorder zoom to a magnification of 20x and showed great results. I then attached the Olympus 1.45x teleconverter for a significant 29x magnification. It showed even more impressive results. I was extremely satisfied with both configurations.

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Sony DCR-TRV350 Digital8 Handycam

The Sony DCR-TRV350 Digital8 Handycam has amazing zooming capability: 20x optical zoom. Nevertheless, I would like to further enhance the optical zoom of this camcorder. The Sony DCR-TRV350 has a 37mm filter thread, therefore the Sima SLS-20 2x Telephoto Conversion Lens can be mounted directly to this camcorder.

Sony DCR-TRV350 with 20x optical zoom.
Sony DCR-TRV350 with Sima SLS-20 attached for a 40x optical zoom.
Sony DCR-TRV350 with Sima SLS-20 and Olympus 1.45x teleconverter attached for a 58x optical zoom.

While shooting with the 2x teleconverter, the Sony DCR-TRV350 focused normally and the image in the electronic viewfinder looks fine. However, upon reviewing the pictures, I found the images to have a highlight soft-focus effect. Adding the Olympus 1.45x teleconverter helped lessen the problem, but gotten similar result. I am not sure what is causing this problem, but these configurations may be only useful for specialized situations, such as glamour shots, dreamy portraitures, or artful naked nudes.

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Sony DSC-P92 Digital Camera / Sony VAD-PEA Lens Adapter

The Sony DSC-P92 digital camera does not have any filter threads for attaching accessory lenses. However, with a Sony VAD-PEA lens adapter (reviewed elsewhere on this site), filters and accessory lenses can be attached to this digital camera. The Sony VAD-PEA has a 30mm filter thread. The include Sima 30mm-37mm step-up ring can be used to attach the Sima SLS-20 2x Telephoto Conversion Lens to the Sony VAD-PEA lens adapter.

Sony DSC-P92 at full optical zoom.
Sony DSC-P92 with Sima SLS-20 attached.
Sony DSC-P92 with Sima SLS-20 and Olympus 1.45x teleconverter attached.

The 2x teleconverter improved the digital camera zoom and showed great results. I then attached the Olympus 1.45x teleconverter for a very significant magnification. It showed quite an impressive result as well. I was extremely satisfied with both configurations.

The Sima SLS-20 showed no light-loss on my Sony DSC-P92. Although the Sony DSC-P92 does not allow manual adjustment of aperture or shutter speed, it does display both parameters during metering. I completed the light-loss test with a uniform patch of grass under bright sunlight. The DSC-P92 displayed f/10 and 1/320 on its electronic viewfinder with and without the Sima SLS-20 2x teleconverter. From my previous tests (documented in another article), I already known that the Olympus 1.45x teleconverter also has no light-loss. So it was no surprise when I stack the Olympus 1.45x teleconverter on the Sima 2x teleconverter and saw the same f/10 aperture and 1/320 shutter speed when metering on the same patch of grass. I am super pleased to have two stackable teleconverter lenses that does not reduce the light gathering capability of my camera.

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Copyright © 2004 by Chieh Cheng. All Rights Reserved.