|
The live view has been
introduced some years ago, and nowadays
it is found in nearly all SLRs. I have
begun using it with the 40D, and now I
take all my macro photos using live
view! The live view has several
advantages:
. It is possible to
frame the photo without looking into
viewfinder; this is a great help for
macro, where you often have to frame the
photo from weird angles. Some camera
have even tilting screens, that make the
framing even easier!
. You can
magnify the image by 10x, or even more
in some cameras, for a very precise
manual focus. The angle-finder is no
longer necessary. In the past I used a
lot the Canon Angle-Finder C for macro
photography, to frame a subject from
weird angles, but I didn't like it a
lot: the built quality is average, it
makes more difficult to find the
subject, it makes the viewfinder even
darker, and it has a crappy dioptric
adjustment system (you have to change
the diopter every time that you switch
from 1.25x to 2.5x). The live view is so
much better!
. You can stop down
the lens to the effective aperture (with
the DOF preview button) to check the
depth of field, both on the entire image
or in a 10x magnified area...it is
fantastic to see in real time the effect
of different apertures! And remember
that while the viewfinder becomes
extremely dark if you press the DOF
preview button, the LCD always maintain
the same brightness...I love it!
. You can evaluate immediately the
brightness of the image: it is possible
to simulate the exposure and to view the
histogram in real time! You can see
immediately the effect of exposure
compensation, too.
. In live
view, you can activate a super-imposed
grid, that helps to compose the photo
and to avoid tilted horizons.
.
In some cameras, Live View replaces
Mirror Lock Up (I'm going to explain
in-depth this point in the next
paragraphs)
The only downside of
live view is that is reduces a lot the
battery life; for example, with my
1DsIII I can take about 900 photos when
I don't use live view, while with live
view I can take about 200-250 photos.
For short trips it is not a problem,
while for longer trips it is necessary
to have some spare batteries, or to be
able to charge the battery every day.
Mirror Lock Up
Nowadays, the majority of interchangeable
lens cameras still use the mirror to provide
the image to the view finder; Panasonic has
recently announced the first interchangeable
lenses cameras without mirror (the Panasonic
G1 and Panasonic G HD, that have an
electronic viewfinder), but this kind of
cameras is still a rarity.
With SLR
camera, the mirror is raised just before the
exposure; the movement of the mirror creates
some vibrations that reduce the sharpness of
the image at slow shutter speeds. The Mirror
Lock Up (MLU) allows to avoid this problem:
when MLU is active, you can raise the mirror
some seconds before the exposure. Until some
time ago, MLU was essential for every photo
taken at slow shutter speed, and it was even
more important for macro, where the
magnification emphasizes every minimum
vibration. Nowadays, with some cameras you
no longer need to use MLU, if you shoot in
live view: this is a great advantage, but
not every camera that has live view offers
this possibility.
Mirror lock up is
particularly useful with long lenses: in
this case, the lens is mounted on the tripod
so the camera is "hanging" from the lens,
and every vibration is amplified. If you use
short lenses and you mount the camera
directly on the tripod, the mirror
vibrations are slightly reduced by the
tripod, but they may still be noticeable: I
highly recommend to use either the MLU or
live view. Image stabilization does not
replace the mirror lock up.
You don't
need MLU, instead, if you handhold the
camera (but of course when you are
handholding you use relatively fast shutter
speeds, otherwise the photos will be blurred
by your movements), or when you use flash as
main light (the duration of the flash is
extremely short so it is an equivalent of a
very fast shutter speed).
Different types of
Live View and MLU
Nearly all cameras have Live View, but
there are four main different types of Live
View.
A) The most advanced Live View
implementations (currently found in the
Canon 7D and 5DII) allow to shoot
using the electronic first curtain; in other
words, when you press the shutter the camera
reset electronically the sensor to begin the
exposure, then it closes the physical
shutter curtain to end the exposure. With
this kind of live view, you no longer need
MLU.
B) Another implementation of
live view is found into older Canon cameras
(1DIII, 1DsIII). These cameras don't have
the electronic first curtain; when you press
the shutter the camera closes the physical
curtain to reset the sensor, it opens the
curtain to begin the exposure and it closes
again the curtain the end the exposure. With
this kind of live view, you still need MLU.
C) A third implementation of live view
if found into Nikon and Olympus SLR cameras.
These cameras don't have the electronic
first curtain; when you press the shutter
the camera closes the physical curtain and
turns down the mirror, then it raises the
mirror, it opens the curtain to begin the
exposure and it closes again the curtain the
end the exposure. With this kind of live
view, you still need MLU; moreover, it has a
slight shutter delay (from 1/2" to 1").
D) Some cameras don't have mirror at
all. Of course, in these cameras you don't
need MLU! That said, the only camera of this
type currently in production - the Panasonic
G1 - has not electronic first curtain, so it
may give the same problems of "type B" live
view.
Other than these four types of
live view, there is another type of live
view that use a secondary image sensor
placed into viewfinder. This implementation
has many downsides (poor accuracy,
impossibility to fine tune the focus at
pixel level) and it is currently found only
in the Sony A350; I think it will soon
disappear, replaced by type A or type D live
view.
How does these explanations
translate in practice? I have done a
simple test, that shows clearly the
differences. These images are 100% crops.
All SLR cameras ("A","B","C") - Live
View not active, MLU not active
: when
you press the shutter release, the
camera 1) raises the mirror 2) opens the
shutter for the time necessary for the
exposure 3) closes the shutter to
terminate the exposure. The steps 1
creates some vibrations, that result in
blurred photos, at slow shutter speeds.
All SLR cameras ("A","B","C") - Live
View not active, MLU active
: when you
press the shutter release for the first
time, the camera 1) raises the mirror;
when you press the shutter release for
the second time, the camera 2) opens the
shutter for the time necessary for the
exposure 3) closes the shutter to
terminate the exposure. The step 1
creates some vibrations, but you can
wait few second before pressing again
the shutter release, so the vibrations
are eliminated.
Cameras with Live View "A" - Live
View active, MLU not active
: when you
press the shutter release, the camera 1)
resets the sensor and begins the
exposure 2) closes the shutter to
terminate the exposure. With this type
of Live View you no longer need MLU -
actually, it is even better! It doesn't
require to press two times the shutter
release and wait, as the traditional
MLU.
Cameras with Live View "B" - Live
View active, MLU not active
: when you
press the shutter release, the camera 1)
closes the shutter 2) opens the shutter
for the time necessary for the exposure
3) closes the shutter to terminate the
exposure. The step 1 creates some
vibrations. Even though the mirror is
raised, you still get motion blur; it is
not as bad as the blur caused by the
mirror, but it is clearly visible.
Cameras with Live View "C" - Live
View active, MLU not active
: when
you press the shutter release, the
camera 1) drops the mirror 2) raises the
mirror 3) opens the shutter for the time
necessary for the exposure 4) closes the
shutter to terminate the exposure. The
steps 1 and 2 creates some vibrations,
that results in blurred photos, with
slow shutter speeds.
Do you have
comments or questions?
If you have comments or questions about
this article, feel free to ask in the
Juza
Nature Photography Discussion Forum!
|
