The Holding Tank

Hardware

Lens Tests

| EF 28mm f1.8 USM | EF 50mm f1.4 USM | EF 100mm f2.8 Macro USM |

| EF 180mm f3.5L Macro | EF 180mm f3.5L Macro + EF 1.4X II | EF 180mm f3.5L Macro + EF 2X II |

Image Stabilizer Tests

| EF 300mm f4L IS | EF 24-105mm f4L IS |

EF 300mm f4L IS

| EF 300mm f4L IS | EF 300mm f4L IS + 1.4XII | EF 300mm f4L IS + 2XII |

Content

Introduction

The EF 300mm f4L IS has IS performance has been evaluated with the basic lens (No TC) and with the two Canon teleconverters (teleextenders) EF 1.4X II and EF 2X II).

Please select the Test Group from the above menu for more detailed results.

Summary data for each focal length are under the appropriate headings later on this page with an overall summary section below.

Summary

The results are summered below normalized to the ideal shutter speed of 1/(focal_length X crop factor) in stops for piecewise linear regression trend to the data for all three focal lengths.

So the IS is effective for all three cases although the Mode 2 should be used in preference if a monopod is used.

Using handheld Mode 1 for a sharpness criteria of 35 lp/mm we see a reducing trend of advantage.

No TC:     3.1 stops

1.4X:        2.2 stops

2X:            1.1 stops

With No TC

The results are summered below normalized to the ideal shutter speed of 1/(focal_length X crop factor) in stops. So for a 100mm lens on a 20D the "safe" IS off speed is 1/160 which will be labeled 0 stops. +1 stops above this speed is 1/320 and 1 stop below (-1 stop) is 1/80.

Both the data and a piecewise linear regression trend to the data are shown.

It can be seen that IS handheld gives around 3 stops advantage over most of the sharpness range, from these results it seems that M2 may be a better choice strangely.

On the monopod M2 has a consistent advantage over M1 between 0.5 and 2 stops over IS off depending on sharpness.

With EF 1.4X II

The results are summered below normalized to the ideal shutter speed of 1/(focal_length X crop factor) in stops.

Both the data and a piecewise linear regression trend to the data are shown.

Based on these results when handheld the advantage with Mode 1 is about 2 stops, perhaps a little more, but this advantage disappears quickly when the shutter speed drops 3 stops below the critical shutter speed. Using Mode 1 gave no advantage in these tests.

With a monopod both Mode 1 and Mode 2 gave a fairly consistent 1.5-2 stop advantage. The sharpness of the image degrading gracefully with and without IS as the shutter speed dropped in contrast to the handheld case.

With EF 2X II

The results are summered below normalized to the ideal shutter speed of 1/(focal_length X crop factor) in stops.

Both the data and a piecewise linear regression trend to the data are shown.

The actual stops advantage of IS depends on the sharpness required in some cases, this is shown on the next plot as a function of the MTF 50% point in line pairs per millimeter. Note that 30 lp/mm is soft and 45 lp/mm is close to the lenses optical performance on a tripod. The output graph sharpness range is limited to only 35lp/mm due to the limited range of test results due to exposure value compromises.

We can see from this chart that handheld the IS advantage is fairly constant 2.7 stops for Mode 1 and 2 stops for Mode 2.

For the monopod case Mode 1 is detrimental but Mode 2 provides some advantage although this is a diminishing return as a function of image sharpness.

It is likely the trend for handheld would extended 1 or 2 stops further towards faster shutter speeds. The Monopod however suggest that above 1 or 2 stops below the guide shutter speed of 1/960 (0 stops on data chart x axis) it would be best to turn off the IS.

Last Updated 05/06/2008

All material is supplied as is and without warranty, use at your own risk.

All opinions stated are the authors own.

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