Tele Converter Comparisons
This comparison involves the following five converter lenses: Canon TL-55 1.4X, Olympus TCON-14B 1.45X, Minolta ACT-100 1.5X, Sony VCL HGD1758 1.7X and Olympus TCON-17 1.7X. Details of these lenses can be found here. To yield the best results, the camera is in the aperture-priority mode with a mid-range aperture F5.6 and ISO 50. Other image processing settings are: white balance: Auto, Color Effect: Off, Picture Adjustment: Contrast/low, Sharpness/Low, and Saturation/Std. The camera was on a very sturdy tripod to minimize camera shake. The converter lenses TCON-14B and Sony VCL HGD1758 (with a 62-58mm step-down ring) used the PD62 adapter tube, and the Canon TL-55, Minolta ACT-100 (with a 55-49mm step-down ring) and TCON-17 used a Yoshida 55mm adapter.
It is important to point out that this comparison is about the combo (i.e., the FZ-10 plus a converter) rather than the individual converter lens. The reason is obvious. These converters were designed for other cameras whose lenses may have optical characteristics different from the 35-420mm Leica lens. Therefore, one should not draw a conclusion from this comparison that brand A's converter is better (or worse) than brand B's converter. The conclusion, whether you like it or not, should be brand A's converter performs better than brand B's converter on a FZ-10. It is not universal, and it only applies to my own FZ-10 and my own converter lenses.
A common suggestion is that we should compare all tele-converters at the same focal length. For example, in comparing the Canon TL-55 and TCON-17, we should compare the performance at focal length 588mm = 420mm×1.4 for both lenses rather than 588mm for the Canon TL-55 and 714mm = 420×1.7 for the TCON-17 because it is not fair. As a matter of fact, if we only compare both converters at 588mm, it is really not fair. If we examine the current available zoom lenses, we will find out that the optical quality at a longer focal length of a zoom lens is usually not as good as the optical quality at a shorter focal length, although there are special cases such as many new Nikon zoom lenses, notably the AF-S 12-24mm G F4.0 DX. If we compare Canon TL-55 at 420mm against the TCON-17 at 346mm (of the camera lens), it is likely that the camera lens may have a better image quality at 346mm than the image quality at 420mm, and, as a result, it is not fair to the TL-55. Therefore, this comparison takes a common approach that the camera lens is zoomed all the way in to 420mm so that every converter lens will have a equal base of optical quality. After all, many shooters zoom all the way in when using a tele-converter.
This comparison has three components: very long distance (i.e., infinity focusing), long distance and near minimum focusing distance. Why bother to have separate comparison? The reason is very simple. Most converters are designed and calibrated at infinity. On the other hand, many shooters may use the converter at close and/or near minimum focusing distance. Therefore, it would be more reasonable to compare converters at commonly used focusing distances to evaluate their performance. Note that atmosphere may twist the resolution when shooting at infinity.
The first comparison examines the performance of each combo when the focusing distance is at infinity. (The focusing distance is at least a mile.) The following are the images shot with various converter lenses. The aperture was set to F5.6 to yield best results, while the shutter speed, which is determined by the camera, was either 1/500 sec or 1/400 sec depending on the lighting condition. ISO was fixed at 50. The camera was on a sturdy tripod and focal length was 420mm (35mm equivalent). From these images, its is clear that the Olympus TCON-17 1.7X has noticeable light fall-off at the corners. Other converter lenses do not noticeable light fall-off.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
| Click on the image to for its full-size version | |
The following shows the center crop of the image. Since the converter lenses have different power, the size of the tower may be different. These images show that other than the Canon TL-55 all converter lenses have high contrast, and the TL-55 image is not as sharp as the other four. All five converters exhibit some degree of chromatic aberration around the black top of the lighthouse tower in the form of purple fringes. The TL-55 seems a little better, and the TCON-17 also shows greenish fringe in the right edge of the tower. In terms of sharpness, it seems the TCON-14B, Minolta ACT-100 and Sony VCL HGD1758 are slightly sharper than the TCON-17, which, in turn, is slightly sharper than the TL-55. Moreover, the Minolta ACT-100 generates a slightly more saturated image.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
The following shows the crops of the new light tower near the upper-left corner. Since the 1.7X converters have a higher power, the new light tower is nearly at the left edge. The Olympus TCON-14B and TCON-17 and Minolta ACT-100 have high contrast, followed by the Sony, followed by the Canon TL-55. Unfortunately, both Olympus TCON converters have serious chromatic aberration in the form of purple and greenish fringes. This reduces the feeling of the sharpness of both lenses. The Sony VCL HGD1758 is a little better; but, chromatic aberration is still very noticeable. The Canon TL-55 shows very little chromatic aberration; however, its resolution is lower than all other lenses. In this test, the best one seems to be the Minolta ACT-100. Its chromatic aberration is much less than the Olympus TCONs and the Sony. But, it does show some greenish fringe. As a result, the Minolta ACT-100 produced a very clean and yet sharp result in the upper-left corner.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X | Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
Next, let us examine the lower right corner. Again, since different lenses have different power, the lower right corner crops are not identical. On the other hand, since we have seen the upper-left corner, there should not be much surprise from the lower-right corner results. Examining the brushes, it is not difficult to see that the Minolta ACT-100 and Olympus TCON-17 performed the best, followed by the Olympus TCON-14B. The Sony VCL HGD1758 is not as good as the TCON-14B as shown. The Canon TL-55 is very soft and blurred.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
The next batch of images are 100% crops of the lower-right center portion of the windows. We would like to see how each lens performs in high contrast and shadow areas. In terms of sharpness, the TCON-14B is the best. Unfortunately, chromatic aberration in the form of purple and greenish fringes is very significant. The Minolta ACT-100 and TCON-17 perform similarly with the TCON-17 slightly better. The TCON-17 (resp., Minolta ACT-100) shows some purple (resp., green) fringes along the white window frames. The Sony is between the TCON-17 and Minolta in terms of sharpness; however, it shows noticeable purple and green fringes. Again, the Canon TL-55 does not exhibit chromatic aberration; however, its image is soft and shows less details.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X |
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| Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
This comparison shows that in terms of center sharpness, the TCON-14B is the best followed by TCON-17 and Sony with Minolta ACT-100 slightly behind. The worst is the Canon TL-55. However, TCON-14B, TCON-17 and Sony 17 all exhibit various degree of chromatic aberration in the form of purple and green fringes. Off center, the Minolta ACT-100 performs the best with just a touch of green fringe. The TCON-17 seems better than the TCON-14B off center. The Sony may be as good as the TCON-14B and slightly behind the TCON-17. The Canon TL-55 is still the last. However, the Canon TL-55 handles chromatic aberration extremely well and beats all the other four miles. Unfortunately, its low sharpness and lower contrast do damage the TL-55's performance significantly.
The second comparison has the subject about 1/3 to 1/2 mile away. The following shows the images taken by each of the five converter lenses. The aperture used was F5.6 with shutter speed about 1/60 sec to 1/100 sec due to lighting fluctuation. ISO was fixed to 50. Again, the Olympus TCON-17 shows some light fall-off at the corners.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
| Click on the image to for its full-size version | |
The following has the 100% crop of the center portion of each image. From these images, we perhaps can immediately notice that TCON-14B and Sony VCL HGD1758 produce a slightly colder tone and that of the TCON-17 is warmer. In terms of sharpness, it seems the TCON-17 and Sony is slightly sharper than the TCON-14B but not by much. It is hard to tell if the Canon TL-55 is sharper than the Minolta ACT-100; however, the contrast of the TL-55 is low. The Minolta ACT-10 rendered the fence very soft, although the window frame, due to higher contrast, looks good and reveals more details than that of the TL-55.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
The following images are the 100% crops of the upper left portion of each image. As you can see, the TCON-14B has serious chromatic aberration, while the other four lenses do not have visible chromatic aberration. Sharpness wise, the Canon TL-55 and TCON-14B are the worst, while the Minolta ACT-100 is the best. But, the TCON-17 looks sharper, mainly due to the TCON-17's light fall-off at the corners. This light fall-off has one or more than one stop of exposure difference, and this difference contributes to higher contrast, which, in turn, gives us a feeling of being sharper. Anyway, the TCON-17 performs very well at the corners even though it has the light fall-off problem. The TCON-14B does not perform well as expect in the corner areas.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
Now, let us examine the center portion of the left edge. The 100% crops are show below. There is no doubt that the Minolta ACT-100 is much much better than the other four. Moreover, you don't see chromatic aberration! Of the remaining four, the TCON-14B and TCON-17 are reasonably sharp; however, chromatic aberration is very visible. This is especially true in TCON-14B's image in which strong green and purple fringes can be seen easily. The Sony 1.7X is not as sharp; however, its chromatic aberration is slightly better than the two TCON converter lenses. The Canon TL-55 seems soft due to its low contrast; however, its chromatic aberration is well under control.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X |
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| Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
In this last comparison, we wish to understand the performance of each combo at its (near) minimum focusing distance. For each converter, the camera is setup to cover the width of a local newspaper. Again, the aperture and ISO used were F5.6 and 50, respectively. Moreover, since the subject has white color, exposure compensation is set to +2/3 stop. The shutter speed, which is selected by the camera in the aperture-priority (A) mode, was either 1/50 or 1/60. Shooting flat subject at close distance is a very challenging job not only for converter lenses but also for other SLR lenses. This is because most camera lenses are designed for moderate distance shooting, and only those macro or micro lenses are designed for shooting in close range. Please note that the image by each of the 1.7X lens has a ghost in the lower right corner. As a result, we shall use the upper-left corner of each image for comparison.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
| Click on the image to for its full-size version | |
The following is the 100% crop of the center portion of each image. There is no doubt that the Sony 1.7X produces the sharpest and highest contrast center portion than the other four do. This is followed by the TCON-14B, although its contrast is lower. The TCON-17 is slightly behind the TCON-14B. The Canon TL-55 performs very good. Its low contrast harms the image quality. Of these five lenses, the Minolta ACT-100 performs the worst. The definition of each letter seems blurred like a little out of focus.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
The following shows the 100% crop of the upper-left corner of each image. Now, the story is completely different from that of the center portion. The Minolta ACT-100 performs the best, beating every other miles. The definition of each letter is as good as its center portion, and there is virtually no chromatic aberration! The TCON-17 is not as sharp as the Minolta ACT-100 and a touch of green fringe appears in the lower part of each letter. But, the TCON-17 is still sharp enough. Then, it comes the TCON-14B. The definition of each letter is still good; however, lower contrast and significant green and some purple fringes makes the image quality lower than those of the Minolta and TCON-17. The Sony 1.7X is better than the TL-55 in terms of contrast and sharpness; however, the Sony shows a touch of purple fringes while the TL-55 seems chromatic aberration free.
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| Canon TL-55 1.4X | Olympus TCON-14B 1.45X | Minolta ACT-100 1.5X |
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| Sony VCL HGD1758 1.7X | Olympus TCON-17 1.7X |
The above comparisons show that there is no converter lens uniformly better than the others in all aspects. As a result, the conclusions below are based on the quality of center, off center and chromatic aberration.
As you can see, there is no clear winner. So, what converter lens should I buy or use? Obviously, if center sharpness is the main concern, the Olympus TCON-14B and Sony VCL HGD1758 are the best choices. The TCON-17 should also be on the top of your list; however, you perhaps have to factor in its light fall-off at the corners. The Minolta ACT-100 is a unique lens because it performs equally well at the center and off center. In fact, in some examples shown above, its off center performance may be slightly better than that of the center area when used with a FZ-10. Hence, if off center image quality is a major concern, you might want to consider the Minolta ACT-100 seriously, since center sharpness can usually be restored with a careful but not very aggressive sharpening. What about the Canon TL-55? It is the cheapest converter lens of the five. Other than its lower contrast and lower resolution, the TL-55 is still a good choice especially that chromatic aberration is well under control.