The Canon EF 70-300mm f/4.5-5.6 DO IS USM
Lens is an ultra-compact and very well built telephoto zoom lens
with excellent image stabilization.

I was immediately impressed by the solid build quality of the Canon EF 70-300mm
f/4.5-5.6 DO IS USM Lens. It is not a light lens (1.6 lb / 720g) for its size
(3.2″ x 3.9″ / 82.4mm x 99.9mm – DxL), but the 70-300 DO is very solidly built.
Canon has achieved their goal of compactness – see the comparison pictures below
…

Pictured above from left to right are the
Canon 24-70mm f/2.8 L USM Lens, the Canon EF 70-300 f/4.5-5.6 DO IS USM Lens,
the Canon EF 75-300 f/4-5.6 IS USM Lens and the Canon EF 70-200mm f/2.8 L IS USM
Lens.

As indicated by Canon with the green
stripe, Diffractive Optics (DO) elements were utitized in this lens to obtain
the small size. This is Canon’s second DO lens, the Canon EF 400mm f/4 DO IS USM
Lens being their first. Canon’s web site has a nice graphic illustration of DO
technology.

Size and weight reduction are the big benefits to using Diffractive Optics, but
there are some drawbacks to the current DO technology. The Canon EF 70-300mm
f/4.5-5.6 DO IS USM Lens circular aperture makes out of focus points of light
very round for a 6-blade aperture, but I don’t care for the way the DO makes
points of light into rifle target-like bokeh. Here is an example …

The bullseyes do not show up often in
real use, but a DO-caused bright, blurry halo shows itself more frequently. It
shows up in out of focus areas – especially when the Canon EF 70-300mm f/4.5-5.6
DO IS USM Lens’s aperture is opened up. Some like it and call it dreamy – I
personally don’t like it. Here is an example …

Utilizing Ring USM (Ultrasonic Motor),
the Canon EF 70-300mm f/4.5-5.6 DO IS USM Lens focuses very fast in reasonable
light – faster than the Canon EF 70-300mm non-DO IS USM Lens. Focusing is
internal, FTM (Full Time Manual) focusing is enabled and the front element is
non-rotating (useful when using certain filters or other attachments) – these
are features missing on the similar-focal-length-range Canon EF 70-300mm non-DO
IS USM Lens. The zoom ring is firm and a bit spongy.

Being black and small, the 70-300 DO has a big advantage in the stealth area.
You won’t catch much attention when you are carrying this lens – an important
safety factor for travelers to certain destinations. For some reason, subjects
also tend to feel more comfortable when a little lens is pointed at them.

The Image Stabilization incorporated in the Canon EF 70-300mm f/4.5-5.6 DO IS
USM Lens is Canon’s latest at this time (as always when new lenses released) -
and should be good for about 3 f-stops in handholdability. I found I could get
decent handheld shots with a shutter speed as slow as 1/30th at 300mm. I love
this feature. IS mode 2 is available for panning. The 70-300 DO can detect
the presence of a tripod (when vibrations go below a certain level), but I
generally turn IS off when shooting non-supertelephoto focal length lenses from
a tripod.

Although this lens does not have an especially small diameter, it’s filter size
is only 58mm. Filters for this size tend to be significantly less expensive than
the 77mm size found on many of the zooms in Canon’s L Lens Series.

With a minimum focus distance of 4.6′ (1.4m), the 70-300 DO delivers a maximum
magnification of .19x – a not great but not bad number. Extension tubes nicely
extend the 70-300 DO’s maximum magnification to .26x and .46x for 12mm and 25mm
tubes respectively. The Canon EF 70-300mm f/4.5-5.6 DO IS USM Lens is not
compatible with the Canon Extender 1.4x II or the Canon Extender 2x II.

Chromatic aberration (CA) is well controlled on the Canon EF 70-300mm f/4.5-5.6
DO IS USM Lens – There is noticeably less CA than is present in the older Canon
EF 75-300mm IS USM Lens. Colors are nice. The 70-300 DO exhibits a tendency to
flare and contrast is slightly lower than some of Canon’s better lenses. On the
other hand, vignetting is very well controlled – primarily only
noticeable near 300mm, f/5.6 on a full-frame body. Distortion ranges from some
barrel distortion at 70mm to little distortion at 85mm to pincushion distortion
by 100mm that gets and remains strong from 135mm through 300mm.

My biggest disappointment with the Canon EF 70-300mm f/4.5-5.6 DO IS USM Lens is
the lack of sharpness. The 70-300 DO is very soft wide open – especially
at 300mm – and the corners are much worse. Even the much less expensive Canon EF
70-300mm non-DO IS USM Lens is sharper. The non-DO has an even wider aperture at
some focal lengths (the DO aperture starts at f/4, goes to f/4.5 @ 90mm and to
f/5.6 @ 185mm). Stopping the 70-300 DO down a stop or more improves sharpness
significantly, but even at f/8 I am not totally satisfied with sharpness and
contrast. Canon’s 70-200mm L and 100-400mm L lenses are superior in sharpness to
the 70-300 DO.

The Canon EF 70-300mm f/4.5-5.6 DO IS USM Lens was not given a fast aperture to
begin with, but stopping down to f/8 for a sharp image makes it very slow. Image
Stabilization helps greatly, but not if you want to stop non-panning action.

A zoom lock switch (above) on the Canon
EF 70-300mm f/4.5-5.6 DO IS USM Lens is a nice feature – It prevents the lens
from extending when you don’t want it to. The trade-off is that it makes the
lens slower to put into action. Use it when you want to, don’t use it when you
might need to grab a quick shot.

The Canon EF 70-300mm f/4.5-5.6 DO IS USM Lens is shipped with a Canon ET-65B
Lens Hood and a Canon LP1116 Soft Lens Case (when purchased from a reputable
dealer of course). This lens is not weather sealed.

The price? Too high for the resulting optical performance to me personally. I
really like the Canon EF 70-300mm f/4.5-5.6 DO IS USM Lens’ size, build,
autofocus speed and top-notch IS, but I’m not completely satisfied with the
resulting image quality. As suggested in the review, one of the 70-200 L lenses
such as the Canon EF 70-200mm f/4 L IS Lens or the Canon EF 100-400mm f/4.5-5.6
IS L Lens will deliver far better optical quality. As also mentioned, the Canon
EF 70-300mm non-DO IS USM Lens delivers a sharper image for a much lower price
-but without the high grade features.

The Canon EF 70-300mm f/4.5-5.6 DO IS USM Lens is an excellent travel lens
- having a lens that is easily carryable will get MUCH nicer shots than a lens
left at home because of its size/weight. If this lens’ features are what you
need, then give it a try.