AmateurPhotographer

Technical
Support
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l ExpErt advicE l tips l tricks l hacks l know-how
How to find ISO 3,200
QIn your review of the
Canon EOS 5D as a
second-hand camera (AP
23 April), you state that the ISO
can be extended to 3,200. I have
owned an EOS 5D for years, but
never found out how to extend the
ISO beyond 1,600. How is this
achieved? The camera has given
me good service, and I cannot
understand why anyone would
want anything more modern.
What’s the point in bigger and
bigger file sizes, when 12MP will
do very nicely? Andrew Redding
AHere’s how you enable
extended ISO settings on
the EOS 5D. Press Menu,
scroll down to Custom Functions,
press Set to enter. Then select
Function 08 (ISO Expansion),
press Set, and change it to 1:On.
Now, when pressing the ISO
button, you’ll be able to access
two new settings: H, which is ISO
3,200, and L, which is ISO 50.
ISO 3,200 is distinctly noisy –
much more so than what we’d
consider acceptable from a
full-frame camera these days.
ISO 50 will result in highlights
that clip to white earlier.
I appreciate your point about
file sizes. Despite its relatively
lowly 12.8-million-pixel
resolution, I’ve made very nice
prints of up to 20x30in using the
EOS 5D. But time moves on and
the newer models are much
better cameras in every regard;
the EOS 5D Mark III has much
better high ISO performance, a
Extended settings of ISO 50 and
3,200 are available on the EOS 5D
vastly better AF system, tougher
body, much quieter shutter, and
modern features such as live view
and video recording. These are
all good reasons to update. But
if none of these is important to
you, then the EOS 5D is still a
perfectly capable camera despite
its age. Andy Westlake
Focal-length rule
QThere’s a common rule for
the slowest shutter speed
you can use to handhold
a lens being about 1/focal length
(so 1/50sec for a 50mm lens,
1/125sec for a 135mm lens and
so on). I always thought I was quite
good at holding a camera steady,
but I’ve been looking critically at
pictures taken on my Canon EOS
70D and found it doesn’t seem to
work any more. Indeed, with my
50mm lens, I usually have to shoot
at closer to 1/125sec for really
sharp pictures. Was the rule
wrong, or am I now getting older
and shakier? Paul Templeton
AThere are a couple of
factors at play here. When
using cameras that don’t
have full-frame sensors, the rule
of thumb has to change, and you
need to use the equivalent focal
length of the lens rather than the
actual focal length. In practice,
this means limiting speeds of
1/90sec for a 50mm lens, and
1/250sec for a 135mm.
However, there are further
complications. First, if you want
a picture that’s completely sharp
when viewing it on-screen at the
pixel level, you’ll probably need to
shoot at faster speeds, as you’re
looking at them in more detail
than we did with film. Second,
because telephoto lenses are
rather larger and heavier, and
therefore less easy to handhold,
you’ll probably need to use even
faster speeds to get really sharp
pictures. Overall, this goes some
way to explaining your personal
observations. Andy Westlake
Digital medium format has
never been mainstream,
and has its limitations
Digital back for medium format
QI’d like to return to medium-format film photography, but
also have the ability to shoot digital. Can you suggest a
second-hand camera that can take both a film and digi
back? Also, can you suggest a digital back that can produce a
decent 15x15in print – I don’t need a monster like the Phase
One, which featured in AP 9 April. J W Bryan
AIt’s possible to get digital backs for Hasselblad, Mamiya
645AF, or Contax 645AF cameras at least. As for
making a decent 15x15in print, if we work on the
principle of printing at a resolution of 300 pixels per inch to
ensure critical sharpness, any back of 27MP or better should do
fine, taking into account the crop from a 4:3 image. At a slightly
less stringent 240ppi, 18MP should be sufficient (and you’d
probably only see any difference when looking at prints closely).
However, it’s questionable whether using digital medium
format is a good idea. It’s never been mainstream, so backs are
relatively difficult to find on the used market. You’re likely to pay
a minimum of £1,500 for one in good condition from a dealer,
and probably more. You can get a used 20-24MP full-frame
CSC or DSLR for significantly less. Pair it with a decent lens,
and you’ll still be able to make very nice 15x15in prints.
Medium-format backs also overwhelmingly use CCDs, so
have poor high ISO performance. This means that they’re not
especially versatile – no handheld low-light shooting, despite
the large sensors. Most medium-format sensors also have a
significant field-of-view crop compared to 645 film, similar to
APS-C vs full-frame SLRs and with a comparable impact on
how your lenses behave. However, unlike for APS-C, there are
no wideangle lenses specifically designed for the crop sensors.
Of course, there’s still a certain amount to be said for using
medium-format film. But when it comes to digital, it just
doesn’t look very practical, I’m afraid. Andy Westlake
© Hannes Grobe
subscribe 0330 333 1113 I www.amateurphotographer.co.uk I 14 May 2016 55