Basic Daylight Exposure Question

[gabrielh]

Hello everybody!
When using full manual mode (M) on the camera, I understand the equivalent exposures (relations between full fstops and full shutter speed stops and full ISO stops and how to change them without changing the (right) exposure). But how do you start with a photograph? Do you use the rule
shutter speed = 1/ ISO @ f/16
for sunny days? Are do you like other rules?
So, by what do you start for getting the exposure right?
Thanks for your answers!
Gabriel

 

[tsaraleksi]

Easier: just put the camera in Av. Get an idea of what it suggests based upon your depth of field and shutter speed needs. Go from there.

 

[gabrielh]

Thanks tsaraleksi for your answer! I have indeed once thought about this issue too, but it is sometimes cumbersome for you need adjust the shutter speed in the manual mode which the camera gave you in Av. Is there any shortcut (like, you press a key and then change from Av to M) so the camera copies the same aperture and shutter speed it had in Av and uses the same values in M?
Thanks!!

 

[Overread]

where to start with a photo depends what you want the photo to look like

I agree with tsaraleksi (did I get that right?) Start off in aperture priority mode and start to see how depth of field and aperture relate. Also look at the works of others and how they have set their settings for different effects - that can give you an idea of where to start shooting.

For example a landscape shot can be done on a tipod with a long shutterspeed - so you can use a smaller aperture (that means lager f number) to get more depth into the shot. Whilst wildlife you want a fast shutter speed - so to get that you have to use a wider aperture ( smaller f number) - but what if you want to use a bigger aperture? well then you can up your ISO - but beware of the noise it adds to a shot.

That is just an example - different situations require their own settings - it sounds complex, but once you get your head round it its simple. Also try reading Understanding Exposure by Bryan Paterson = that will give you more ideas regarding settings and exposure

 

[gabrielh]

Thanks, Overread, I understand. But I am still puzzled: is finding the "right" exposure in Manual mode then by trial and error? You want a large aperture for a shallow depth of field (example), but by how much? f/4? f/2.8? f/1.4? Or do you try them all three (and some between) and check at your computer which you like most?
Thanks!

 

[JerryPH]

Do you use the rule
shutter speed = 1/ ISO @ f/16
for sunny days? Are do you like other rules?
So, by what do you start for getting the exposure right?
Thanks for your answers!

Hey there.

In the days of film, they made the sunny 16 rule, which doesn't work well in the world of digital. Though we both capture moments in time with film or digital, in the film world you commonly exposed to the right and processed for the shadows... meaning, you lightly overexposed the picture to capture detail in the shadows and brought things down in the darkroom to set the overall exposure properly.

An awesome technique that works simply because film has more dynamic range than what even the most modern digital cameras have.

In all modern digital cameras, we have to think and work differently. We must expose for the MID TONES and process for the highlights. Meaning... because we have a roughly 5 stops of dynamic range (vs 6 to 6.5 in film), we have to be very careful to not blowout (overexpose) anything that is critical to our picture. Once something is blown-out that is data that is forever gone.

The main reason for this is that the meters in our digital cameras are set to meter EVERYTHING to around 18% gray. This is why, if you follow the camera's meter readings, snow looks gray, and black cars come out looking gray-ish. The camera trys to meter EVERYTHING into that 18% gray setting.

So... in the digital world, your meter will try to zero out against the mid-tones and process for the highlights. This is the best way to get reasonably proper exposures... meter against the mid-tones before taking the shot.

Of course ANY method has exceptions and work-arounds depending on what the goals for any picture are. There will be times that one must meter for the darker or lighter tones to get the shot. Knowing WHAT to meter against, therefore, is the first and most important step in knowing how to get a proper exposure.

That's half the fun of photography for me lately... learning what to expose for in any given scene, how to handle complex scenes and how to handle each challenge so that I get the best exposures possible.

It has been repeated here likely a million times... but try to find the book called UNDERSTANDING EXPOSURE by Bryon Peterson... it will open your eyes to a new way of understanding how light works. I recommend this book to all photographers, newbies and experienced alike.

 

[Overread]

nope nope - look at your cameras built in light meter - idealy the meter wants to have the arrow in the middle for a "perfect" exposure. So you prioritise your settings according to what you are after - say if your shooting something moving then a fast shutter speed will be important so you start there - then maybe you want little noise - so ISO is low - then you set your aperture to fit - of course you will have to adjust settings to fit since you won't ever get "perfect" shooting conditions.

Of course built into this is experience - that will help tell you what a fast shutter speed really is - which is why I say start in aperture priority mode first since it deals with shutter speed automatically.
However in bright sunlight you might need to make an underexposed shot (exposure arrow to the left of the middle) to prevent your highlights from overexposing.

One of the joys of digitial though is that you can try all the settings -go home and review (post on forums and write a blog is what I do) and you can see from your results what good settings worked - back in the days of film only that is what they did - they read what settings were commonly good - experimented - wasted shots and learnt. Of course if you can get some tutoring you can take advantage of the experience of another to advise and show you in the field as opposed to in the computer after

 

[Josh66]

The "right" exposure is when the needle on the meter lines up with zero.

Chose your aperture, then adjust the shutter speed to get the needle where you want it on the meter.

 

[gabrielh]

Thanks everyone for your answers! I read quit a lot about all these technicalities and heard about the 18% gray metering, but I really don't understand that (yet). Have you got any advice on a book or a website concerning this issue?
Thanks!

 

[Overread]

Understanding Exposure by Bryan Peterson is a good starting point.
For websites you could try:
http://www.ronbigelow.com/articles/articles.htm
specifically :
http://www.ronbigelow.com/articles/exposure/exposure.htm

 

[gabrielh]

Ok! It is sure om my to-read list !

 

[JerryPH]

The "right" exposure is when the needle on the meter lines up with zero.

Is it really? What happens if they point it to the sun, set the meter to that, then point it to the subject?

How about if I set the meter according to the shadows beside the person? How will the person come out looking?

That's part of what I meant by knowing WHAT to meter against.

We can get a little more complex... what do you meter against when you have a bride with a WHITE dress standing beside the groom in a BLACK tuxedo?

How about a snowy mountain slope?

You are "techically" correct in that the camera will always do it's best to set camera settings to try to zero out the meter... however it is not all that often correct in the sense that it will come out "correct".

Let's use the example of the snowy mountain slope. If I follow the camera, the snow will look 18% grey. Now, if when I metered against the snow, and set the meter to read +2 or +3 and the snow is white.

Now if I was taking a picture of a man skiing down that slope and he was wearing a dark jacket, he would be suddenly wearing a gray jacket and the snow would be blown out (with the camera set to meter itself on him). Snow is totally blown out at this point.

If I metered against his dark jacket and set the camera to a -2, he would come out looking GREAT, but the snow (and the rest of the shot), all around him would be darker. However, since the man's jacket was the focus and subject of the shot, I do not care about the snow... and the exposure is now not just technically correct... but ARTISTICALLY correct!

Make sense?

 

[gabrielh]

Ok.. One more question, camera-technical: how do you just meter on the skiing person? Do you use "spot metering" (heard of it, and have tried on my camera, with sometimes big differences with center-weighted or matrix, but don't understand how it really affect the image). And also don't understand what one means with 18% gray. If you stop the meter down -2 or -3 (actually, on what "scale"...?), then the brighter snow will get darker—I follow. But will you get something like 5% gray or more like 30% grey? Is 5% gray lighter or darker than 30% gray?
A lot of questions, thanks for any answers. Love photos!

 

[JerryPH]

You guessed right on the nose... spot metering would do the trick.

As for where that 18% number came from... its from the old days of B&W film. 18% gray is the theoretical middle between black and white. That is what the cameras are set to meter for... mid tones. Now we don't need to meter against a grey card, though that works, but can use known alternatives... like the fact that the palm of the average caucasian is about 1-1.5 stops away from 18% grey in terms of tones.

Spot metering will take the metering from a very small area in the center of your picture. Center weighted uses a bigger circle, perhaps 30-50% of the picture. Evaluative or matrix takes a look at the complete (100%) of the picture and averages it all out.

 

[tsaraleksi]

The key here is that after a while you just get used to what works where and everything gets easier. Because of the oddities of the human eye it's very tough to gauge exposure by just looking, but you can often get pretty close.