What is ETTR in photography, and when should you use it?
Summary
TLDRビデオでは、カメラの露出について語り合う。特に、エクスポジション・トゥ・ザ・ライト(ETTR)という概念を解説。ヒストグラムを通じて、画像のトーンがどのように分布するかを示し、露出を右に移動させることで画像の明るさを増やせると説明。RAWファイルでの撮影とポストプロセスの利点、重要なハイライトを維持しながら露出を右に移動させる方法、そしてその技術が状況によって異なる場合があることについても触れている。
Takeaways
- 📸 ETRは「exposure to the right」を意味し、カメラのヒストグラムの明るい側にデータを追加することで画像の明るさを増やします。
- 📈 ヒストグラムの右側にデータを移動させると、画像の質が向上し、デジタルカメラはデフォルトで自然な露出に設定されています。
- 🖼️ RAWファイルを撮影していて、後からソフトウェアで画像の全体的な見た目を変更する場合は、ETRが役立ちます。
- 💡 ETRを活用するには、シャッタースピードを遅くする、絞りを開ける、または実際の光を増やす必要があります。
- 🚫 ETRはISOを使いすぎたり、重要なハイライトを失うことなく、露出を右に押しすぎることはありません。
- 🌟 重要なハイライトを維持しながら露出を右に押しすぎると、画像全体が過曝になり、色飽和度が下がり、全体が明るく見えます。
- 🖌️ ポストプロセスでトーンを下げることで、最初に画像にノイズが少なく、より良い画像品質を得ることができます。
- 🏞️ 風景写真では、カメラがデフォルトでバランスをとろうとし、天空のハイライトを失うことがありますが、ETRはそのリスクを軽減します。
- 📝 ETRは状況によりますが、可能であれば露出を右に押しすぎると、より良い画像品質が得られる可能性があります。
- 📷 カメラメーカーは、RAWファイルのダイナミックレンジを考慮したヒストグラムやETR露出オプションを提供してほしいです。
Q & A
ETTRとはどのような概念ですか?
-ETTRは「Exposure To The Right」の略で、カメラのヒストグラムの右端に露出を向ける技術を指します。これにより、画像の明るさを増やし、デジタルカメラのセンサーにより多くのデータが記録されることで画像の質を向上させることができます。
ヒストグラムとは何ですか?
-ヒストグラムは、カメラで撮影した画像のトーンの分布を表すチャートです。左側は暗いトーンを、右側は明るいトーンを表します。露出を変更することで、これらのトーンをヒストグラムの左右に移動することができます。
RAWファイルとJPEGファイルでETTRの重要性はどのように異なりますか?
-RAWファイルは後処理で大きな変更を加えることができるため、ETTRが特に役立ちます。一方、JPEGファイルは通常、自然な露出で撮影されるため、ETTRはあまり必要ありません。
ETTRを実践する際には、どのような点に注意する必要がありますか?
-ETTRを実践する際には、重要なハイライトを維持しながら露出を右に押し出す必要があります。ただし、ISOを増やしてETTRを行うことは避け、シャッタースピードやアペチャを調整して実際の光をセンサーに当てて露出を右に移動させる必要があります。
ETTRを行うと、画像の質にどのような影響がありますか?
-ETTRを行うと、画像に記録されるデータ量が増大し、ノイズが減少し、画像の質が向上します。特にRAWファイルでは、ノイズを抑えながらもトーンの広いレンジを保持することができます。
モーディなポートレートを撮影する際にETTRは役立ちますか?
-モーディなポートレートでは、シャドウを深くして全体的に暗い雰囲気を出すことが一般的ですが、ETTRを用いることでシャドウ部のノイズを抑えながらもトーンの質を高めることができます。
露出を右に押しすぎるとどのような問題が発生しますか?
-露出を右に押しすぎると、重要なハイライトがセンサーの動的レンジを超えて失われ、復元不可能になる「blooming」现象が起こる可能性があります。
風景写真を撮影する際にETTRはどのように役立ちますか?
-風景写真を撮影する際には、天空などのハイライトを保護しながらも、シャドウ部とミッドトーン部のデータ量を最大化するためにETTRが役立ちます。これにより、後処理でより広い動的レンジを利用することができます。
ETTRは常に適用されるべきですか?
-ETTRは状況によって適用されるべきではありません。シャッタースピードやアペチャが特定の状況で必要になる場合、ETTRは適切ではありません。重要なハイライトを保護する必要がある場合は、露出を減らしてそれらを保護する必要があります。
カメラメーカーに期待されるETTR関連の機能は何ですか?
-カメラメーカーが提供するヒストグラム機能や露出メーターシステムを向上させることで、ETTRをより簡単に実践できるように支援が期待されます。特にRAWファイルの動的レンジを考慮したヒストグラムが便利です。
Outlines
📸 「右に露出」とは?
この段落では、カメラの露出に関する重要な概念「右に露出(ETTR)」について解説しています。右に露出とは、カメラのヒストグラムの明るい側にデータを寄せることにより、画像の明るさを増やし、デジタルカメラがデフォルトで行う自然な露出よりも、より良い画像品質を得る方法です。ヒストグラムの左側は暗いトーンを、右側は明るいトーンを表しており、露出を増やすことで画像が明るくなります。RAWファイルでの撮影やポストプロセスでの調整を行っている場合、この技術は特に役立ちます。ただし、JPEG撮影者はあまりこの技術を気にする必要はありません。
🌅 右に露出する状況とその利点
この段落では、右に露出する状況とその利点を説明しています。特定の状況下では、シャッタースピードやアPERTUREを変更し、ISOを上げることができず、その場合、通常の露出設定を行う必要があります。しかし、状況が許す場合は、露出を増やすことで画像品質を向上させることができます。特に、重要なハイライトを維持しながらも、暗い部分のノイズを抑えるために有効です。一方で、重要なハイライトを失うことなく、画像全体を暗くする必要がある状況では、露出を減らす必要があります。この場合、中間のトーンや影がよりノイズを含んでしまうことになりますが、ポストプロセスで修正することができます。最後に、カメラメーカーに対して、右に露出するための機能やヒストグラムの改善を求める声が挙げられています。
Mindmap
Keywords
💡ETTR
💡ヒストグラム
💡RAWファイル
💡露出
💡シグナル対ノイズ比
💡シャッタースピード
💡絞り
💡ハイライト
💡ノイズ
💡ダイナミックレンジ
Highlights
ETTR(Exposure To The Right)是摄影中的一个重要概念,指的是在不过曝的前提下尽可能向右曝光,以获得更好的图像质量。
直方图是理解ETTR的关键,它显示了图像中不同色调的分布情况。
相机默认曝光倾向于自然平衡,对于JPEG拍摄者来说,ETTR可能不是必需的。
对于RAW文件拍摄者,ETTR有助于在后期处理时获得更好的信号与噪声比。
实际光线是ETTR的关键,需要通过调整快门速度、光圈或使用人工光源来增加传感器的光线。
在ETTR时,应尽量保持重要高光部分不过曝,即使图像看起来过亮。
ETTR有助于减少图像的噪声,提高图像质量,尤其是在后期处理时。
在某些情况下,如需要快速快门或特定光圈,可能无法实施ETTR。
在保护图像中重要部分不丢失细节的情况下,有时需要牺牲一些暗部细节。
ETTR是一个可选的摄影技巧,可以根据拍摄者的需要和场景条件灵活运用。
在某些情况下,如风景摄影中天空过亮,可能需要降低曝光以保护高光部分。
使用三脚架、多重曝光或HDR技术可以在一定程度上扩展动态范围,获得更好的曝光效果。
ETTR是一个有用的工具,但是否使用取决于摄影师对图像质量的追求和场景的实际情况。
呼吁相机制造商提供更好的直方图和曝光辅助功能,以帮助摄影师更好地实施ETTR。
理解相机的曝光原理和背景操作对于获得最佳拍摄结果至关重要。
Transcripts
welcome back deep every TV viewers it is
Chris Nichols here and today we want to
demystify a very important topic about
exposure and that is this term e-ttr now
you know there's a lot of opinions out
there a lot of people saying you should
do it you shouldn't do it and we just
wanted to throw our two cents in because
well we haven't done it yet and we think
it is about time now what does this ettr
business stand for is it exposure
through the retina sounds accurate but
no it's not that is it exposure to is
truly rotten yes it is sometimes it can
be very tricky and that's partly why we
are talking about this today is it
everybody's talking trash about Rico
Pentax I mean yeah sadly too much
they're a great company you cut it out
but really what ETR stands for is
exposure to the right the right of what
well we're really primarily talking
about our histogram when you look at a
histogram on your camera this is a chart
showing you where all the tones in your
image fall and tones on the left side of
the histogram that represents more
towards your darker tones tones on the
right side of the histogram that is more
of your brighter tones and as you change
exposure you can move these tones to the
right or the left of your histogram and
as you move to the right what you're
basically doing is making your photo
look brighter and that is key because as
you add more data to the right side of
your histogram you get some benefits to
your image quality your digital camera
is not by default generally going to
exposed to the right it's by default
going to exposed more to a natural
balanced exposure and that's a very
reasonable decision on the camera
manufacturer's part because you know if
you're starting out you're shooting
jpegs you want those jpegs to look
properly exposed natural colors and so
you know this isn't something you want
to be changing too much afterwards in
post so if you are a JPEG shooter and
that's where you're at right now that's
great but you're probably not going to
need to pay attention to this too much I
mean feel free to I don't know go to
your next video or unsubscribe right I
don't want everyone to do but if you are
now in the stage where you're shooting
raw files and you want to go into your
software afterwards and start making
some changes to the overall look of your
image then there are some benefits that
I want to share with you okay so now we
are willing to shoot raw and we're
willing to add more actual light to the
sensor at the time of taking the
photograph you know what we're trying to
do here is get a better signal to noise
ratio just get more data across all of
our tones so that we start out with less
noise in the first place now the key
thing is we need actual light what I
mean by that is we cannot expose to the
right using ISO we need actual light
coming to the sensor so that means that
we can slow down our shutter speed that
means that we can open up our aperture
or if you're using artificial lights
like right now Jordan's going to turn
these lights up we're actually going to
boost the actual artificial light
exposure and that's getting again that
actual light to the sensor now when you
look at me now I don't look properly
exposed right I'm washed out color
saturations down everything looks too
bright but that's okay the key thing is
we want to push our exposure as far to
the right as possible while still
keeping the highlights that are
important to us I don't want you to feel
like you have to maintain every single
highlight in the image if there's things
in there that you are fine with
completely losing like the sun or
intensely bright street lights in the
background or something fine but push it
as far to the right as you can using
actual light while still maintaining the
highlights that are important to you and
your photograph all right so it's one
thing to talk about it but now let's
show you some practical examples and the
first thing I want to talk about is like
a moody portrait and this is where we
actually do want to end up with more of
a low-key look deeper Shadows a darker
overall feel and that's wonderful
there's nothing wrong with that but
there's a couple ways that we can do
this so one way is we simply give the
camera less light right we under expose
the image until it looks Moody and deep
and if I was shooting at jpeg that's
probably what I'd want to do but by
providing the sensor less light we are
going to start out with more noise and
on top of that let's say that we want to
raise some of those Shadows afterwards
you know we're going to go into
Photoshop we're going to brighten some
of the stuff up that might have been too
dark well you're not adding noise doing
that but you're certainly revealing the
inherent noise that was there present in
the first place okay now let's look at
exposing to the right using that
technique so I'm going to add actual
light I'm going to slow down my shutter
speed open up my aperture and we can see
here the photo doesn't have that deep
Moody look okay it looks Overexposed I'm
making sure that I only add enough light
that I still have the highlights that
are important to me maintained now when
I go to my post processing software I'm
going to bring down all of those tones
to where I finally want it to end up and
the benefit here is a couple things
first off by adding more light we
started out with less noise in the image
the second thing is by bringing my tones
down to where I want them to be moody
I'm not raising anything and making any
noise there even more visible so now
we're still getting beautiful highlights
we're getting nice Deep Shadows and just
overall we have better image quality
okay so let's take a look at the two
images now and when we start looking at
the the noise is it a humongous
difference no and I mean that's not
really the point the point is that one
of these though does have more tonal
quality and less noise to begin with and
so you know we start to ask ourselves is
this something that's important to do
well the first thing I want to point out
is you can't always do this okay there
are situations where you need a fast
shutter speed you need a specific
aperture and you might have to crank
your ISO and that's fine in those
situations do what you would normally do
but when you have the opportunity to add
more light by doing an aperture change
or shutter speed change or perhaps
raising the natural light that's in the
environment that can be a really
positive thing to do so when you can use
this technique is it really worth doing
the extra steps
I mean in the end I think that's
entirely up to you you know we're
spending a lot of money to get the
latest sensor to get brighter lenses and
that's all because we're trying to seek
better image quality if there's a
situation where you can do it for free
just by adding more light to the actual
exposure in the first place why not do
it there are some situations where
exposing to the right but keeping the
highlights that you really want might
actually mean that you're under exposing
the image let's take a look an example
here so now we've got a landscape with a
bright sky and you know what we're going
to deal with is the camera by default
again trying to balance everything right
trying to get some of the Shadow detail
in the foreground trying to get some of
the highlights in the sky but it's
letting some of those highlights go and
this might be a situation where you say
actually those highlights are really
important to me when highlights get too
much light and they blow out beyond the
dynamic range the sensors cable
recording they're gone forever there's
no getting them back so in a situation
like that we're actually going to bring
the exposure down okay now the first
thing you want to do is if your ISO is
raised you'd want to drop that but
assuming that's at its lowest now we're
actually going to close down our
aperture or speed up our shutter speed
or both and what we're going to do is
bring the exposure down we're going to
watch that histogram and we're going to
make sure that the parts of the scene
that we want protected are actually
within range now does that mean that by
reducing the amount of light getting in
the sensor those mid tones and shadows
that go darker are going to get less
data we're going to get more noise in
them yes unfortunately it does but we
cannot recover blown highlights we can
to some degree recover Dark Shadows
they're going to start out more noisy
than before and when we raise them up in
post-processing software we're going to
reveal all of that noise and that's just
the way it is but sometimes you have to
make decisions to really protect what's
important to you in the photograph and
frankly if you can do it use a tripod
use multiple exposures you know HDR take
some exposures darker some for the
midtone some for brighter tones put them
together and then you just get a really
nice expanded dynamic range to play with
but otherwise if you've only got one
shot at it you got to make an important
decision and that's why we're showing
you this in the end I don't want you to
feel like you have to do this I just
want it to be a tool that is an option
at your disposal and I just think it
it's important to understand
how exposure works and what your camera
is doing in the background anyways just
so you can get the best result possible
for you whatever that may be the other
thing I want to ask for is actually from
the manufacturers we could use some help
here because I think it would be very
useful with the modern metering systems
in the camera to have options like do
you want to expose to the right in this
situation that might be a nice little
function that you could just turn on and
then not have to really mess around with
knowing all of the stuff yourself
another thing would be really important
is better histograms because currently
the histogram that we're using to judge
all these exposures is based on the JPEG
but you actually have a little bit more
range than what the jpeg is giving you
your raw files have a little bit of
extra space and so that should be really
nice to have the manufacturers provide a
histogram that shows you what your raw
file can do as far as keeping those
highlights safe and how far you can go
with your exposures so that we'd like
the manufacturers to do but otherwise
please leave your comments below as
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that as well thanks so much for joining
us we'll see you soon with more deep
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