400D and 40D Can't control exposure compensation in Manual mode

[Dream Merchant]

Haha, I've been turning the camera inside out to find the answer the whole night after what you posted earlier. Slept at 4am just trying to figure out what you were meant. I joined photography in the digital age so no idea what Zone System is. Maybe can join you kopi next time?

Alamak!

At least you gave it more than a passing thought! That is a good sign of someone willing to learn and try. :thumbsup:

Photography is still photography lah. The fundamentals are still the same. Only the technology has advanced, but the basic principles are still the same.

To be absolutely frank, I hate talking about technicalities and equipment more than anything else, unless I absolutely have to - either to learn something new or to get a job done. I'd rather TCSS and watch the world go by or go out and make or take photographs (there's a difference).

Lai, lai, next time we all go our lim kopi! Call Uncle Catchlights along - sure got all kinds of interesting stories wan! But you sure u want to be seen with us ah-peks? :bsmilie:

BTW, here's a simplified and fairly easy to understand explanation of the Zone System, and why it's important if you're interested in the highest quality images/prints. It explains or introduces what the Zone System all about in 1 page, whereas a complete study of the Zone System can take several seperate books. Enjoy!

http://www.normankoren.com/zonesystem.html

 

[catchlights]

Most Thursday, between 5.30pm to 6.30pm, I will be at Toa Payoh near Phillip, unless I have shoot on.

can meet for coffee at Kopitiam, 600@Toa Payoh, next to the toa payoh library.

can email me for "meet for coffee"

 

[eeyern]

Lai, lai, next time we all go our lim kopi! Call Uncle Catchlights along - sure got all kinds of interesting stories wan! But you sure u want to be seen with us ah-peks? :bsmilie:

Sure, I will pm both you and Uncle Catchlights after I return from my overseas trip next week. Always happy to meet fellow photographers (ah-pek or non-ah-peks, no problem!) :lovegrin:

 

[nuxnewbie]

Ahhh...I'll just mention it.

What IS exposure compensation, really?

Simply, shifting the perceived exposure value (EV) needed to capture a scene (not the complete answer, but that's too technical and waaay over my head).

Huh? Kong Si Mik?

In Manual, to 'shift' the perception of EV necessary to render a scene as you like it to be, shift the input base values that the camera's metering systems uses to analyse light ... change the ISO settings.

Cinematography Directors, grand old birds and those who grew up on the old meters used to 'think' and 'see' a scene in terms of Luminance and Exposure Values, rather than shutter speed/apeture combinations. Even the exposure meters back then didn't give read-outs like "1/250 and f/8". It would have read something like "EV 14". What shutter speeds and apeture settings you choose to use to capture EV 14 faithfully is then up to you. Talk about control! :bsmilie:

Those who trained in the Zone System might remember shifting ASA settings as one of the fundamental 'methods' of shifting values in a negative (coupled with judicious processing techniques) to yield the max range of useable tonal values in a negative from (visually) total black to total whites. I'm sure I didn't say that entirely in the 'proper' manner, but the crux of the issue is there.

I've heard, there is a technique of metering and capturing for digital that (very loosely) 'mimics' the Zone System, albeit, not in all aspects, but at least what it tries to achieve.

Of course, there's the easy way and just whack Exp Com on your settings. You'll still get better results than relying 100% on your camera's meter especially in difficult lighting situations.

Still don't understand how changing ISO values in a DSLR can result in exposure compensation in manual mode.

You mean by changing ISO, even if the simulated match needle is at 0, the image can be exposed say +/- 1 stop? For film I can understand since the ISO of the photographic medium is independent of the metering, i.e. ISO 400 film is ISO 400 even if the camera setting is switched to ISO 200 or ISO 800. I suppose you're saying for a DSLR it is possible to de-link the sensor and the camera settings?

This thread reminds me of a conversation that I had with a 'lao jiao' driver on ERP. This fella told me there is a way to siam ERP. Thinking that he is very 'lao jiao', i thought his method would involve squeezing in a side alley, driving in opposite directions, masking the IU unit, etc. etc.

His answer?

Drive before 7am.

*faints*

 

[Dream Merchant]

Still don't understand how changing ISO values in a DSLR can result in exposure compensation in manual mode.

This thread reminds me of a conversation that I had with a 'lao jiao' driver on ERP. This fella told me there is a way to siam ERP. Thinking that he is very 'lao jiao', i thought his method would involve squeezing in a side alley, driving in opposite directions, masking the IU unit, etc. etc.

His answer?

Drive before 7am.

*faints*

:bsmilie::bsmilie::bsmilie: Taxi uncle beri d good!


On the latter part of your post ... VERY Good observation.

Exposure compensation comes about with a change of either shutter speed or apeture agaisnt a calculated EV determined by the camera's metering and computing systems, but what determines the basis of 'compensation'?

As was very keen of you to observe - the sensor in a DSLR is directly connected to the ISO settings, so even if you shift the ISO setting to render a scene as your mind sees it, you have to remember that the sensitivity of the sensor has been changed, bringing you back to square one.

Here's another challenge:

Based on your keen observation, how does a change of ISO settings make exposure compensation possible, in a DSLR, in Manual settings?

The hint is in this post.

 

[night86mare]

Still don't understand how changing ISO values in a DSLR can result in exposure compensation in manual mode.

?!

if i shoot photo at iso 100, f/8, 1/250 second, and it is underexposed by 1 stop or so

and i shoot it again at iso 200, keeping same shutter/aperture settings (i.e. f/8, 1/250 sec).. would the exposure not be increased by 1 stop or so? is this not exposure compensation, albeit in an indirect way? :dunno:

 

[chngpw]

Nice discussion!

I am a ghost in this forum cos there are not much of such discussions on technicalities. Ironically such discussions on technalities are what is necessary to help us become better photographers.


Dream Merchant is so right. In film, ISO would be a way to achieve EC in ANY mode. In this digital age, unfortunately you need a cam (PnS or otherwise) with at least a manual mode.

 

[mrchua]

Mr Chua, Are you sure you're a 'young one'? LOL!

Anymore?

haha i AM a young one! my nickname jus sounds old. haha.

ISO is basically the sensor image's sensitivity to light right? so just basics, a higher ISO setting will allow the sensor to be more sensitive to light (better in dark places, concert halls, night) while lower settings will do you good in daytime (especially under strong sunlight such as up in the mountains).

i've got a question. between aperture priority and manual settings, how is it best that we balance out our settings in manual? is there a recommended procedure we should go about it? how do we balance aperture, shutter, ISO, EV compensation?

thanks in advance.

 

[nuxnewbie]

?!

if i shoot photo at iso 100, f/8, 1/250 second, and it is underexposed by 1 stop or so

and i shoot it again at iso 200, keeping same shutter/aperture settings (i.e. f/8, 1/250 sec).. would the exposure not be increased by 1 stop or so? is this not exposure compensation, albeit in an indirect way? :dunno:

Yes, this i know, and it's really no secret, hence my "Drive at 7am to avoid ERP" rant - all the big hoo-ha over nothing.

I might as well add that I've got another method for exposure compensation while in Manual mode - it's a really, really, really big secret... without changing settings, slap on ND filters of your choice. Unfortunately no solution for positive compensation - maybe start removing lens elements? :sweatsm:

The thread starter mentioned exposure compensation - not changing exposure - so i would think he meant being able to under, or overexpose the shot by a preset amount of EV in manual mode regardless of camera setting, WITHOUT further interference from the photographer (which is pretty much what exposure compensation does in A, S, P modes).

Which is pretty pointless, if you ask me, since you're already in manual.

 

[Fragnatic]

i've got a question. between aperture priority and manual settings, how is it best that we balance out our settings in manual? is there a recommended procedure we should go about it? how do we balance aperture, shutter, ISO, EV compensation?

thanks in advance.

in manual, there is actually not such thing as EV compensation.
(read below for more info)

Yes, this i know, and it's really no secret, hence my "Drive at 7am to avoid ERP" rant - all the big hoo-ha over nothing.

I might as well add that I've got another method for exposure compensation while in Manual mode - it's a really, really, really big secret... without changing settings, slap on ND filters of your choice. Unfortunately no solution for positive compensation - maybe start removing lens elements? :sweatsm:

The thread starter mentioned exposure compensation - not changing exposure - so i would think he meant being able to under, or overexpose the shot by a preset amount of EV in manual mode regardless of camera setting, WITHOUT further interference from the photographer (which is pretty much what exposure compensation does in A, S, P modes).

Which is pretty pointless, if you ask me, since you're already in manual.

yes.


Anyway, for those who still might not know, exposure is controlled by 3 factors. Aperture, Shutter Speed, ISO. that's it.

im not going to mention abt the P mode (or full auto mode)

in the Av (or A) mode, u set the aperture value (and ISO too), the camera will use its metering to find out which is the correct shutter speed in order to achieve a correct exposure.

say at ISO 100, f/5.6, the camera gives a shutter speed of 1/60s.

if u use set the EV compensation by -1, do u notice that the shutter speed actually becomes 1/125s? (with ISO and aperture still remaining at ISO 100, f/5.6)
this is because u instructed the camera to underexpose by 1 stop, thus they increased the shutter speed by 1 stop to allow less light to enter, resulting in a 1-stop underexposure.


in the Tv (or S) mode, u set the shutter speed (and ISO as well), and the camera sets the aperture. if u used EV compensation, they will re-adjust the aperture appropriately to get the intended exposure.


so, in M mode, u are in control of all 3. ISO, aperture and shutter speed. no such thing as a EV compensation since the camera is not allowed to adjust any of the 3. so u as the photographer will have to adjust these 3 values to ur liking to achieve what u want. the arrow in the exposure bar will tell u, at ur current settings, u all achieve what kinda exposure as compared to the camera's metering.

for eg.: the camera's metering reads that at ISO 100, f/5.6, 1/60s, it will be properly exposed. but for manual (since u r in control of all 3 factors), u set them to be ISO 200, f/5.6, 1/60s. the arrow will show a +1 in the EV. maybe u didnt like the photo to be overexposed by 1 stop, but u want it be to be 1 stop underexposed, so u gotta adjust the ISO, aperture, and/or shutter speed in such a way so that less light will be captured. which is to either drop the ISO, decrease the aperture size (increase F-value) or increase the shutter speed.

 

[night86mare]

Yes, this i know, and it's really no secret, hence my "Drive at 7am to avoid ERP" rant - all the big hoo-ha over nothing.

I might as well add that I've got another method for exposure compensation while in Manual mode - it's a really, really, really big secret... without changing settings, slap on ND filters of your choice. Unfortunately no solution for positive compensation - maybe start removing lens elements? :sweatsm:

The thread starter mentioned exposure compensation - not changing exposure - so i would think he meant being able to under, or overexpose the shot by a preset amount of EV in manual mode regardless of camera setting, WITHOUT further interference from the photographer (which is pretty much what exposure compensation does in A, S, P modes).

Which is pretty pointless, if you ask me, since you're already in manual.

not true, got solution for positive compensation.. it's called a flash. selective positive compensation though. :bsmilie: only areas reachable by the flash depending on strength.

well there are other considerations other than keeping the iso the same.. just that people don't usually want to change the iso, due to quality matters. i'm sure you won't want the camera to auto-compensate the iso to 3200 with current technology.. horror when you pixel peep..

aiya, nothing wrong with adding a little drama what.. why so uptight?

 

[night86mare]

for eg.: the camera's metering reads that at ISO 100, f/5.6, 1/60s, it will be properly exposed. but for manual (since u r in control of all 3 factors), u set them to be ISO 200, f/5.6, 1/60s. the arrow will show a +1 in the EV. maybe u didnt like the photo to be overexposed by 1 stop, but u want it be to be 1 stop underexposed, so u gotta adjust the ISO, aperture, and/or shutter speed in such a way so that less light will be captured. which is to either drop the ISO, decrease the aperture size (increase F-value) or increase the shutter speed.

someone here once used an analogy that i remember now and then

light is like water, and for proper exposure you need to fill a cup, the photo
aperture is the hole through which the water pours, shutter speed is how long the water is poured for.. and iso is the speed at which the water pours.

after that you can sort of visualise how the light works to "fill the photo" i hope.. though it doesn't encompass matters such as depth of field. an unfilled cup is undesirable, just as an overfilled cup is desirable.

 

[calebk]

I might add that the camera compensating for constant over/underexposure contradicts the whole idea of having your camera on manual exposure, doesn't it?

The whole idea of having your camera on Manual exposure is you have all the control - the camera does not decide anything for you WRT exposure. It meters for you; that's it.

 

[mrchua]

someone here once used an analogy that i remember now and then

light is like water, and for proper exposure you need to fill a cup, the photo
aperture is the hole through which the water pours, shutter speed is how long the water is poured for.. and iso is the speed at which the water pours.

after that you can sort of visualise how the light works to "fill the photo" i hope.. though it doesn't encompass matters such as depth of field. an unfilled cup is undesirable, just as an overfilled cup is desirable.

imagine a bucket to be filled with water with a hose.

the aperture - diameter of the hose
shutter speed - time taken to let the water flow through the hose.
ISO - speed at which water is flowing through the hose

http://www.photoxels.com/tutorial_exposure.html

hope this helps.

 

[eeyern]

Thanks everyone for the great advice. I have learnt so much about exposure last weekend shooting for a friend's wedding. Wah, you can really learn so much from shooting an event. My arms and legs are aching from all the kneeling, standing, jumping and rolling. Need more exercise

 

[Fragnatic]

Thanks everyone for the great advice. I have learnt so much about exposure last weekend shooting for a friend's wedding. Wah, you can really learn so much from shooting an event. My arms and legs are aching from all the kneeling, standing, jumping and rolling. Need more exercise

of cos. nth beats experience and shooting more. of cos ur basics are impt as well.

wah, u firing rifle and trying to hide frm the crossfire? y need rolling? :bsmilie:

 

[xunjas]

Thanks everyone for the great advice. I have learnt so much about exposure last weekend shooting for a friend's wedding. Wah, you can really learn so much from shooting an event. My arms and legs are aching from all the kneeling, standing, jumping and rolling. Need more exercise

shoot more n get fit~~ ;p