The Manual Mode question and answer thread.

[Aunt Maud]

The Manual Mode question and answer thread.

Please post your troubles and I'll be happy to try and answer them.

[Ham]

When I go into Manuel mode nobody can understand me, except for Meester Fawlty

[Aunt Maud]

When I go into Manuel mode nobody can understand me, except for Meester Fawlty

You need to have a chat with Major Gowen, he'll sort you out.

[T42]

My mode dial has a position that labelled RTFM.

[rogerzilla]

My FM2 only has a manual mode but it does at least have a meter, which is luxury after the M3,

[Jaded]

Dial M for Manual

[LEE]

For me Manual mode and a Tripod are synonymous. (I can't think quickly enough to shoot Manual "on the fly", it's all I can do to make sure I'm in RAW).

For 99% of my other stuff I'll shoot Av in RAW and bracket the exposure (or use Exp compensation...which is sort of manual).

RAW has been a revelation since I got my DSLR a couple of years back.  I now tend to underexpose everything by 1/3 stop or just bracket everything 0, -1, -2.  That seems to give me a decent amount of information for what I want.

I'd be interested to know if I'm missing something by using exp compensation and/or bracketing rather than manual exposure.

[Jaded]

I find the quality of light hitting the sensor in Manual mode is noticeably better than compensated light.

[clarion]

My mode dial has a position that labelled RTFM.

You mean there is a mode other than Manual?  </dark ages>

[Biggsy]

I'd be interested to know if I'm missing something by using exp compensation and/or bracketing rather than manual exposure.

Nothing for normal photography, just the ability to compensate by more stops than your exp compensation provides (if it's limited), or to directly reproduce settings without being affected by the light meter, which you might want for testing or comparison photographs (e.g. with photographs to compare two bike light beams).  Technically the latter can also be done with Av mode + compensation, but manual mode is easier for this.

[Charlotte]

I love shooting manual mode when I'm using on-camera flash at events.  Dark rooms, but with predictable lighting wherever you go means you can assess what the exposure looks like with the meter, dial in something safe like a high ISO, 1/160th and f/5.6 and then bounce a TTL flash off the ceiling or wherever, knowing that your camera will do the maths to get you a good exposure.  If the background is looking too dark, drag the shutter a bit or jack up the ISO and if your subjects are a little hot, dial a bit of minus EV into the flash.  Sorted.

[mike]

What she said.

All my flashed stuff at events is in manual mode. Just dont forget to take it out of auto ISO (took me a lot of swearing to get that figured out)

[David Martin]

The basics:
Exposure is the amount of light hitting the sensor. Total amount of light is limited by two things. 1. The time you collect light for. 2. the size of the light gathering area (aperture).
In auto mode the camera measures the amount of light in the scene and uses an appropriate algorithm to set the shutter speed (time) and aperture (size of the hole).
To make things confusing the shutter speed is normally reported in nths of a second (ie one hundredth) but represented in camera as just the denominator (ie 100). The aperture is reported as an f-stop which is a function of the focal length and actual cross sectional area of the hole. This gives a consistent measure so that f5.6 is the same effective light gathering power across all focal lengths.

If you double the f.stop then the amount of light gathered halves. If you double the shutter speed (go from 1/200 to 2/200, or 1/100) then the amount of light gathered will double

In practiceThe camera meter will indicate what it thinks is the correct exposure. It has a very mechanical view. As a starting point you adjust one of aperture or shutter speed to get the meter to be at 0. Then decide whether some parts of the scene should be lighter or darker (as a rule the meter will be zero for a 'correct'

• exposure when pointed at green grass or typical caucasian skin, both of which approximate 18% grey).

Then adjust from there. If you think the subject is darker than the scene and want more detail there, add more exposure (longer shutter speed - smaller denominator, or smaller f-number - bigger hole.[**]). Or if it is a bright spot that you want detail in (e.g. the moon [***]) then dial in less exposure.

Go and play. Lots.

Experience[****] will have you looking at the scene, at the meter and making the appropriate adjustments from habit.

Or do as I tend to in changeable situations and use an auto mode with exposure compensation.

ISO is a related matter and is the sensitivity of the light detection. If you have a slow ISO then the camera will need more light for a given exposure[*****], a fast iso requires much less light so shutter speeds can be quicker. Iso numbers work by doubling as well, so ISO 100 requires twice as much light as ISO 200.

• given a constant light source - flash is a different game.

[**] to aid the confusion, a smaller aperture is a bigger f-number.
[***] Actually the moon is sunlit with a constant light so can take standard settings of 1/iso at f16 as a starting point. This is the 'sunny 16' rule.
[****] Most of the good photographers on here still take loads of badly exposed photos, but they add to the learning and experience. You won't get the experience without mistakes that you can criticise and learn from.
[*****] There are trade-offs. The signal to noise ratio drops - not a problem for brightly lit bits but shadows then start to look 'grainy'.

[clarion]

A pretty clear explanation,  David.

Oddly, I learned most about exposure by using aperture priority mode, which is still my preferred approach.

[Jaded]

Manual is very useful at gigs.

"Correct" exposure is different now from what it used to be. With better sensors this change will continue.

[Tewdric]

An important concept to get your head around with digital sensors is what their failure modes are when over and under exposed.

If you blow your highlights there is nothing to recover  - no informtion at all beyond level 256 for an 8 bit jpg capture for example.

Low light capture is more forgiving but bringing up the levels of dark shadows very quickly introduces noise and starts to look unnatural.

Things are improving with every new generation of sensor but are nowhere near perfect yet.

This is pretty much the opposite of how neg film behaved, where burning in apparently white skies for ages would eventually yield some detail.

A good skill to master is judging the tonal range of a scene and it's good to get to know how many stops range your camera can record.  If your scene has too broad a spread of tones you need to manage it with neutral density filtration, lighting,  masking or HDR combination of multiple exposures.  Renting a Pentax spotmeter for a weekend helps with this as our brains are very good at compensating for real world tonal variation, making scene assessment tricky.

The most important thing is not to blow your highlights.  An easily accessible histogram display either in thecorner of your finder or as a one touch review option is a really good idea.

[frankly frankie]

Exposure is the amount of light hitting the sensor.

... per sensor area, to be pedantic about it.  (The larger the sensor, the more light you need for the same exposure, all else being equal.)

That aside - I'm a great believer in exposing for the light conditions, and not for the subject.  Manual mode is one good way to do this, whereas relying on auto-exposure at half-press is more likely to expose for the subject primarily.

[Charlotte]

If you blow your highlights there is nothing to recover  - no informtion at all beyond level 256 for an 8 bit jpg capture for example.

This is completely true.  Paradoxically though, whilst being careful not to blow your highlights, for maximum dynamic range and signal to noise ratio, you also need to make sure that you're exposing as far to the right of your histogram as you can.  In other words, deliberately overexpose, but not so much as to be unable to recover it in post. 

Warning: this technique is risky and not to be undertaken when the shot really matters unless you've practiced it safely beforehand and you know your camera's capabilities very well indeed...

https://en.wikipedia.org/wiki/Exposing_to_the_right

[Woofage]

If you blow your highlights there is nothing to recover  - no informtion at all beyond level 256 for an 8 bit jpg capture for example.

This is completely true.  Paradoxically though, whilst being careful not to blow your highlights, for maximum dynamic range and signal to noise ratio, you also need to make sure that you're exposing as far to the right of your histogram as you can.  In other words, deliberately overexpose, but not so much as to be unable to recover it in post. 

Warning: this technique is risky and not to be undertaken when the shot really matters unless you've practiced it safely beforehand and you know your camera's capabilities very well indeed...

https://en.wikipedia.org/wiki/Exposing_to_the_right

I learned about this only recently but it makes total sense when you think about it. In the days of fillum, I would always nudge the exp down a bit for slides and up a bit for negs for best results but with digital you have much more freedom in PP.

[Woofage]

Manual is very useful at gigs.

Defo. The photo below was taken on Miss W's Canon Powershot in manual mode (OOC JPEG). The exposure was a total guess (well, an educated one). Unfortunately the camera battery died immediately after (you did pack spares, didn't you, Miss W?...) so no chance of any more that night .

Untitled by pencyclist, on Flickr

"Correct" exposure is different now from what it used to be. With better sensors this change will continue.

This too.

[David Martin]

Exposure is the amount of light hitting the sensor.

... per sensor area, to be pedantic about it.  (The larger the sensor, the more light you need for the same exposure, all else being equal.)

Except that the numbers all balance out as you need a longer focal length to get the same image on a larger sensor, so the difference in total light is masked by the relative nature of the f-stop.

[David Martin]

Correct exposure is like beauty - in the eye of the beholder. I am quite tolerant of various exposures - there is no one absolutely correct exposure.

But Manual mode is about how to coerce the machinery into doing the job you want it to do, rather than auto modes where it does the job the design engineer thought might do it for you

[Jaded]

Surely no one uses just auto modes per se. They use compensation and/or spot metering.

Sometimes though, getting a photograph is more important than getting the exposure perfect. No design engineer has yet come up with an algorithm for timing and composition.

[David Martin]

Timing yes, how about smile mode?

[Jaded]

Doesn't work with landscapes.