One of the most popular question on web forums is some variation
on "what should I buy" or "Is it worth it". This article addresses some aspects
of the issues of which 300mm lens to buy and whether IS is worth it! Is it worth
an extra $200 to upgrade from a Canon EF75-300/4-5.6 lens to the EF75-300/4-5.6
IS version? Is it worth the extra $400 to upgrade the EF75-300/4-5.6 IS to an EF
300/4L (used, since it's not made anymore) or $700 to upgrade to a 300/4L IS
lens? I'm not going to directly answer that question because "worth it" is a
highly subjective condition. It depends a lot whether $700 if your life savings
or the amount you'd normally spend on a meal and a bottle of wine. However I will
present some images which might help YOU to make up YOUR mind on the issue.
So let's start off with a shot taken on a typical New Jersey
suburban street, since that's part of my lens testing range!
Above is a full frame shot with a street sign centered. I shot
three frames with IS on and 3 frames with IS off, and the results are shown
Pretty clear that IS works! The top row of images, shot with IS
on, are consistantly sharp. The bottom row of images, shot with IS off,
demonstrate that I can't hold a 300mm lens steady enough at 1/80s to give a sharp
image. Some shots are better, some are worse, but they all show significant
Below is a shot of a cooperative rabbit in my garden. This was
for a comparison of a 300/4L prime lens and the 75-300/4-5.6L, hand held in low
light. The ISO setting on the 10D was ISO 3200. The shutter speed was 1/30s with
the 75-300 wide open at 300mm (f5.6) and 1/80s with the 300/4L wide open (f4), so
the "L" prime had a 1.3 stop advantage. Would this be enough to make the "L"
images better than the IS images?
Below are two typical frames. The noise is due to the ISO 3200
setting. As you can see, the IS image is sharper than the 300 "L" series non-IS
lens image. Note that I did say "typical" frames. If you shoot enough frames,
some will be less sharp, but some will be sharper. If you shot 10 frames with the
"L" lens, it's quite possible that one of them would be better than anything you
could get with the IS lens, though 2 of them might be similar and 7 of them might
be worse! Shoot enough frames hand held at almost any reasonable speed and sooner
or later you'll get a sharp one.
While I think the above images have addressed whether IS works (it does) and
whether and IS lens can beat and "L" series lens in actual use under some
conditions (it can), there remains the question of just how much image quality
you lose going from an EF 300/4L to a 75-300/4-5.6IS under good conditions where
the IS function does not come into play. The images below answer that question.
They were taken using an EOS 10D at ISO 100 with the camera/lens mounted on a
sturdy tripod (Bogen 3051) using a sturdy ballhead (Arca Swiss B1), with a
shutter speed of 1/400s and an aperture of f5.6. IS was not used. The deer was in
my garden and was highly cooperative, since it stood there motionless (the rabbit
moved a bit..) and staring at me while I switched lenses!
Above is the full frame shot. It happens to have been taken with
the 75-300IS, but at this scale the image from the 300/4L would look identical.
The more interesting images are below
You can see from the above shot sthat the image from the 300mm prime "L"
series lens is sharper. Significantly more detail is visible in the fur. Contrast
is higher (blacks or blacker). This isn't a matter of one being in better focus
either. Repeat shots looked the same and from the foreground/background detail in
each image it was evident that focus was the same for both lenses. This is pretty
much the expected result. The image quality of an $800 "L" series prime lens is
better than that of a $400 consumer zoom IS lens (or the equivalent $200 consumer
non-IS zoom lens). For the web (see the small full frame shot above), the
difference doesn't matter, but once you start cropping the image significantly or
making large prints, the difference becomes clear. The difference is even larger
at the edges of the frame, where the 75-300 becomes softer and shows more
chromatic aberration. It it "worth it" to spend $600-$700 for this difference?
Only you know the depth of your wallet. The "L" lens is nicer to use, has
smoother focus, a tripod ring, a built in lens hood, doesn't rotate or extend
duing focus and is a stop faster. All these things come into play along with
image quality when answering the "is it worth it" question. The one stop faster
speed means you can shoot with a shutter speed twice as fast. This means nothing
with a static subject, but if your subject is moving, you want a fast shutter
speed and IS won't help here. Of course the 75-300 also covers the 75-299mm range
that the 300mm prime doesn't, plus it's smaller and lighter. More factors to
consider when asking the "worth it" question.
The conclusion is that IS works. With the 75-300/4-5.6IS lens, you probably
gain at least 2 stops, probably three stops, of hand holdability. Under the
lowest light conditions, the consumer zoom IS lens can outperform an "L" series
non-IS lens (though it wouldn't beat the 300/4L IS lens!). On a tripod, the "L"
lens is a clear winner, but for web images the difference will most likely not be