Other High Quality Telephoto Converter Lenses

This page briefly discusses some high quality telephoto converter lenses: Canon TL-55 1.4X, Olympus TCON-14B 1.45X, Minolta ACT-100 1.5X, Nikon TC-E15ED 1.5X, Nikon TC-E17ED 1.7X, Olympus TCON-17 1.7X, Sony DH1758 and Sony VCL HGD1758 1.7X.

Canon TL-55 1.4X

The Canon TL-55 1.4X is the smallest and lightest converter lens discussed on this page. Its lens power is 1.4X, which brings the FZ-30 maximum focal length to 588mm = 420×1.4. The Canon TL-55 has a rear thread size of 55mm and no front thread. Therefore, it can be directly mounted on a FZ-30. The left image below shows the lens and the right one has a TL-55 directly mounted on a FZ-30.

Olympus TCON-14B

The Olympus TCON-14B is a large and heavy telephoto converter lens with a lens power of 1.45X, which brings the FZ-30 maximum focal length to 609mm = 420×1.45. The TCON-14B has a rear thread size of 62mm and a front thread size of 86mm. Therefore, a 55-62mm step-up ring is needed. The left image below shows the lens and the right one has a TCON-14B mounted on a FZ-30 with the help of a 55-62mm step-up ring.

Minolta ACT-100 1.5X

The Minolta ACT-100 1.5X is also a large and heavy telephoto converter lens with a lens power of 1.5X, which brings the FZ-30 maximum focal length to 630mm = 420×1.5 and is slightly longer than that of the TCON-14B. The Minolta ACT-100 has a rear thread size of 49mm and a 86mm front thread. Therefore, you will need a 55-49mm step-down ring. The left image below shows the lens and the right one has a Minolta ACT-100 mounted on a FZ-30 with the help of a 55-49mm step-down ring.

Nikon TC-E15ED 1.5X

The Nikon TC-E15ED 1.5X is a reasonably light weight and compact telephoto converter lens with a lens power of 1.5X, which brings the FZ-30 maximum focal length to 630mm = 420×1.5. The Nikon TC-E15ED has a rear thread size of 50mm and a 58mm front thread. Since 50mm is not a popular thread size, a special step-down ring is needed to bring the 50mm size to a popular one (e.g., 62mm). Fortunately, Nextphoto and Pemaraal both made a 55-50mm step-down ring for the FZ-30 to directly use the TC-E15ED. Nextphoto also made a 62-50mm step-down ring, which was originally offered for Nikon Coolpix 8800 to use the TC-E15ED. The left image below shows the lens and a Nextphoto 62-50mm step-down ring, while the right one has a TC-E15ED mounted on a FZ-30 with the help of the Nextphoto 62-50 step-down ring and a 55-62mm step-up ring.

The rear glass element of the TC-E15ED is deeply recessed to allow the Nikon Coolpix 5700's lens close to the converter. This is shown in the image below. However, when a TC-E15ED is mounted on a FZ-30, its rear element is farther away from the FZ-30's front glass element (because FZ-30's lens does not extend when zooming in), and, as a result, light fall-off is always possible.

Nikon TC-E17ED 1.7X

The Nikon TC-E17ED 1.7X is a heavy and large telephoto converter lens with a lens power of 1.7X, which brings the FZ-30 maximum focal length to 714mm = 420×1.7. The Nikon TC-E17ED has a rear thread size of 60mm and a front thread of 86mm. Therefore, a 55-60mm step-up ring is required. Brand name 55-60mm step-up rings (e.g., B+W) are usually not cheap and general brand versions are not so easy to be found. You may try Pemaraal for a cheaper version. Otherwise places where you may find 55-60mm step-up rings include the well-known B&H, Filter Connections, and, of course, eBay (occasionally)! The left image below shows the lens, while the right one has a TC-E17ED mounted on a FZ-30 with the help of a B+W 55-60 step-up ring.

Olympus TCON-17

The Olympus TCON-17 is a light 1.7X converter lens with a plastic barrel. It extends FZ-30's focal length to 714mm = 1.7×420. The TCON-17 has a 55mm rear thread and has no front thread. Therefore, it can be directly used on the FZ-30 without any step rings. The left image below shows the lens and the right one has a TCON-17 on a FZ-30.

Sony VCL-DH1758

This Sony VCL-DH1758 (for Sony H1) is a 1.7X converter lens and is light and small. It extends FZ-30's focal length to 714mm = 1.7×420. The Sony DH1758 1.7X has a 58mm rear thread and has no front thread. Therefore, a 55-58 step-up ring is required. The left image below shows the lens and the right one has a Sony VCL DH1758 on a FZ-30 with the help of a 55-58mm step-up ring.

Sony VCL-HGD1758

This Sony VCL-HGD1758 is a 1.7X converter lens and is one of the heaviest and largest of all converters discussed on this page. The only heavier lens is the Nikon TC-E17ED 1.7X. It extends FZ-30's focal length to 714mm = 1.7×420. The Sony 1.7X has a 58mm rear thread and has no front thread. Therefore, a 55-58 step-up ring is required. The left image below shows the lens and the right one has a Sony VCL HGD1758 on a FZ-30 with the help of a 55-58mm step-up ring.

Light Fall-Off and Vignetting

Light fall-off (i.e., the corners being darker than the center) is likely unavoidable with most teleconverters. The following images were taken at 420mm and F3.7 (i.e., the largest aperture). To illustrate the light fall-off effect, images were underexposed. From these images, one can conclude that all six teleconverters exhibit some degree of light fall-off; however, in general shooting this light fall-off may not be noticeable. Note that due the deeply recessed rear element of the Nikon TC-E15ED 1.5X, its light fall-off may be more obvious than the other teleconverters.

Canon TL-55	Olympus TCON-14B	Konica Minolta ACT-100
Nikon TC-E15ED	Nikon TC-E17ED	Olympus TCON-17
Sony VCL DH1758	Sony VCL HGD1758

Since all teleconverters only exhibit some degree of light fall-off, vignetting (i.e., four black corners) is not a problem at maximum focal length. However, as the camera lens is zoomed back, different teleconverters will eventually have vignetting. To determine the threshold between light fall-off and vignetting, the lens starts at 420mm and zooms back little by light until black corners appear. This is the focal length that starts to cause vignetting. The following table shows the results. Please note that these values are approximates and should not be treated as accurate measurements.

Due to the deeply recessed rear element of the Nikon TC-E15ED, its minimum focal length is considerably higher than those of the others. Although TCON-17 and VCL HGD1758 are both 1.7X teleconverters, the focal length without vignetting of the Sony is shorter than that of the TCON-17. In general, a teleconverter of higher power will have a longer focal length without vignetting.

Minimum Working Distance

The working distance is the distance between the subject and the front element of the lens being used. The minimum working distance is important because it tells us that the subject should at least be placed at a distance longer than the minimum working distance.

Since no published minimum working distance data were available (because it depends on both the camera and the teleconverter being used), actual measurements must be carried out. To do so, the camera with a teleconverter is placed far away to focus on a subject. If focus at that distance is confirmed, the camera-lens combo is moved closer to the subject. This step is repeated until the camera fails to focus. Then, the combo is moved back a little and the process is repeated. Eventually, the closest focusing distance can be determined. The minimum working distance is the shortest focusing distance from the subject to the front element of the teleconverter. The following table shows the results. Note that these values are also approximations rather than accurate results.

In measuring the minimum working distance, I found an interesting fact. With the FZ-30, one can place the camera farther away and gradually move and focus the camera. However, if the camera is placed at a closer distance and moved back, one many not be able to reach the same results. In other words, it is easier to yield the minimum working distance by moving the camera closer to the subject rather than the other way around. In many situations, this process has to be repeated a number of times to determine the "minimum", and each time the "minimum" may be very different. So, the values in the above table can only be used as references and you can certainly come up with a different set of values.

Technical Data

The following technical information is taken from Canon, Minolta. Olympus and Sony user manuals. This information is for the FZ-30 only, and should be different for other cameras.