Photography BLOG

With the introduction of the Canon EF
70-300mm f/4-5.6 IS USM Lens, Canon has replaced one of its most popular lenses
and its first image stabilized lens – the Canon EF 75-300mm f/4.5-5.6 IS. The
75-300mm IS lens was popular because of its useful focal length range, small
size, light weight, midrange price and Image Stabilization. The Canon EF
70-300mm f/4-5.6 IS USM Lens improves this overall package (sacrificing
only price somewhat).

Sporting a 3rd generation image stabilizer, the Canon EF 70-300mm f/4-5.6
IS USM Lens is designed to be handholdable at a shutter speed up to 3 f-stops
slower than a non-stabilized lens at the same focal length. “Gyro sensors detect
unwanted vibrations, triggering the corresponding movement of a correcting lens
group perpendicular to the optical axis. This alters the light path, returning
the image to its correct position on the sensor or film plane.” [Canon]

Using the 1/(focal length) rule, this lens can be handheld at 300mm with a
shutter speed of 1/45 of a second (of course, your mileage may vary). I am
getting sharp handheld images consistently at 1/4 or 1/5 second shutter speeds
at 70mm and at 1/25 second at 300mm. None of the 70-300 IS sample pictures (link
below) were taken with a tripod.

Automatic tripod sensing prevents “… feedback loops between the IS sensor and
stabilizer motor vibrations” [Canon]. This implementation of IS includes Mode 1
and 2 stabilization. Use mode 1 (dual axis stabilization) when shooting
stationary subjects and mode 2 (single axis stabilization) when panning with a
moving subject. The IS switches are recessed to prevent accidental changes – a
nice improvement. In my opinion, image stabilization is the best feature of
this lens. It is a significant help when shooting stationary subjects
without a tripod.

Image stabilization is especially helpful to a slow lens. Slow is relative of
course – the Canon EF 70-300mm f/4-5.6 IS USM Lens apertures are typical for a
consumer telephoto zoom lens. The 70-300′s widest aperture starts at f/4 until
around 85mm, then f/4.5, f/5.0 at 135mm and f/5.6 at 200mm. An 8-blade
circular aperture gives the Canon EF 70-300mm f/4-5.6 IS USM Lens a very
good defocused image quality (often referred to as bokeh).

Pictured above are the Canon EF 70-300mm f/4-5.6 IS USM Lens, Canon EF 70-200mm
f/4 L USM Lens and Canon EF 100-400mm f/4.5-5.6 L IS USM Lens.

Weighing 22.2 oz (630g) and measuring 3.0″ (76.5mm) wide and 5.6″(142.8mm) long
(retracted) (essentially the same as the Canon EF 75-300mm f/4.5-5.6 IS USM
Lens), the black Canon EF 70-300mm f/4-5.6 IS USM Lens is relatively small,
light and inconspicuous. A switch locks the 70-300 at 70mm to prevent the
lens from extending when not in use (it will do this). The very useful 70-300mm
focal length will handle portraits, well-lit sports, wildlife and many, many
other photo subjects well.

Pictured above are the Canon EF 70-300mm f/4-5.6 IS USM Lens, Canon EF 70-200mm
f/4 L USM Lens and Canon EF 100-400mm f/4.5-5.6 L IS USM Lens – all shown at
their their maximum focal length extension.

Slow focusing was one of the downfalls of the Canon EF 75-300mm f/4.5-5.6 IS USM
Lens. Canon states that autofocus has been improved in the Canon EF
70-300mm f/4-5.6 IS USM Lens. But, Ring USM (Ultrasonic Motor) is not part of
the package. Improvements in the CPU and AF routines help in the focus
performance increase according to Canon. Accuracy is often more important than
speed. Good thing as actual performance of the Micro USM shows accuracy to be
very good but speed is just OK – not as good as I had hoped. AF motor noise is
not bad.

FTM (Full Time Manual) focus is not provided – you must switch the lens to MF
(Manual Focus) mode to manually focus the lens. To make matters worse, the
70-300 extends about 1″ with focusing. To park the lens compactly, you often
must adjust the focus to minimize the lens length. This means manually turning
AF off, turning the focus ring to retract the lens and turning AF back on (so
you don’t forget next time you use the lens). Of course, if you don’t care about
minimizing the lens length, this attribute will not affect your enjoyment of
this lens.

The Canon EF 70-300mm f/4-5.6 IS USM Lens is not parfocal – you need to refocus
if you change the focal length. Combine a non-parfocal zoom lens with a
rotating front element and you quickly get frustrated Circular Polarizer
Filter users. This is a definite detraction for landscape photography – an
otherwise great use for this lens. Canon’s manual suggests that the front
element should be held while attaching a 58mm filter or the optional Canon
ET-65B lens hood (to prevent it from rotating).

The glass in the Canon EF 70-300mm f/4-5.6 IS USM Lens (including one UD
element) is new and designed with digital SLRs in mind. Ghosting and flare
caused by reflective imaging sensors are not problems. Although I can’t say I
have much problem with ghosting or flare in most of my good lenses, flat lens
elements can act as mirrors reflecting light back to the sensor. Canon’s MTF
charts indicate a performance improvement over the 75-300 IS – especially
sharpness at 300mm (where the 75-300 IS was weakest). My experience is proving
this out.

The Canon EF 70-300mm f/4-5.6 IS USM Lens has very good center sharpness wide
open at the wide end. Center sharpness decreases slightly as the focal length is
increased to its weakest at 300mm. The lens is soft beyond 200mm. Stopping down
improves sharpness somewhat but it is still weakest at 300mm. Corners are soft
at the ends of the focal length range and do sharpen up as the aperture is
stopped down. The long end of the focal length continues to be the weakest
performing over the range – especially in the vertical orientation. I don’t make
it a habit to formally test lenses in both vertical and horizontal orientations,
but after hearing some reports of an anomaly I did some testing. Shots taken at
the longer focal lengths are indeed sharper in horizontal orientation than in
vertical orientation. I’ll let Canon explain that one.

Update: Canon has addressed the vertical sharpness issue through a
service notice. Canon has performed this work (no charge) on my lens and I am
pleased with the results.

Overall, sharpness is definitely improved from the 75-300 IS.

The Canon EF 70-300mm f/4-5.6 IS USM Lens exhibits barrel distortion (on a full
frame body from 70mm to 120mm or so. Slight pincushion distortion is visible at
300mm. CA and vignetting are well controlled.

The Canon EF 70-300mm f/4-5.6 IS USM Lens’ close focusing distance of 4.9′
(1.5m) matches the Canon EF 300mm f/4 L IS USM Lens’ specs and provides for a
very nice magnification ability (.24x at 300mm). Although it is not compatible
with Canon’s extenders, extension tubes will extend the 70-300 L’s macro
capabilities. A 12mm extension tube will yield a .32x magnification at 300mm
(.22x at 70mm). A 25mm extension tube will yield a .4x magnification at 70mm
(.39x at 300mm). The Canon 500D Closeup Lens is also compatible and results in a
.9x magnification ability at 300mm (.22x at 300mm).

The Canon EF 70-300mm f/4-5.6 IS USM Lens has mediocre build quality. There is a
lot of play in the extending portion of the lens barrel.

The Canon EF 70-300mm f/4-5.6 IS USM Lens functions nicely. Many people will be
completely happy with this lens. But, the 70-300 is not an L Lens. It also does
not cost as much as L lenses. Originally, the Canon EF 70-200mm f/4 L USM Lens
cost less, but the 70-300 price has dropped to slightly less than the 70-200.

Many people are going to carefully consider the choice between the Canon
EF 70-300mm f/4-5.6 IS USM Lens and the Canon EF 70-200mm f/4 L USM Lens as they
cover much of the same focal length range for similar prices.

While the Canon EF 70-300mm f/4-5.6 IS USM Lens is reasonably well built, the
70-200 f/4 L features a significantly higher build quality. The 70-200
f/4 L also features fast and quiet-focusing Ring USM. Image quality is also
better on the L lens – color, contrast and especially sharpness. The L
lens is compatible with Canon’s Extenders. Of course, the 70-200 f/4 requires an
extender to get to 280mm and does not have IS. With the 1.4x attached, the
70-200 f/4 still outperforms the 70-300 at 280mm. Though not important to many,
the Canon EF 70-300mm f/4-5.6 IS USM Lens does not have a distance scale. The
famous Canon Date Code is also missing.

The Canon EF 70-300mm f/4-5.6 IS USM Lens’ big advantage is Image
Stabilization. Even though the 70-300 has a narrower aperture at most
comparable focal lengths, the 3rd generation IS allows it to be handheld under
lower light conditions – if the subject is stationary of course. Also
advantageous is the extra 100mm of focal length range.

These two lenses are similar in size and weight. The Canon EF 70-300mm f/4-5.6
IS USM Lens is .16 lb lighter, the same diameter and 1.2″ shorter (until it is
extended).

My opinion: get the Canon EF 70-200mm f/4 L USM Lens unless you must have
IS or the extra 100mm of focal length.

The Canon EF 100-400mm f/4.5-5.6 L IS USM Lens is another choice for better
image quality in this general focal length range (-30mm on the wide end, +100mm
on the long end). Although not as noticebly better for sharpness as the 70-200
f/4 is, the 100-400 is still a better lens (optically and mechanically) in my
opinion. It is considerably larger, heavier and more expensive.

The Canon EF 70-300mm f/4.5-5.6 DO IS Lensis now in an interesting position in
Canon’s lineup – sharing the basic optical specs of the Canon EF 70-300mm
f/4-5.6 IS USM Lens. Although it is 1.5″ shorter, the DO actually weighs 5.4 oz
more and costs significantly more. The DO is better built and has Ring USM, but
was not impressive to me optically.

The Canon EF 70-300mm f/4-5.6 IS USM Lens is targeted at amateur photographers.
I think this group will find the 70-300 IS appealing.