Chronically Under-Exposed shots in 4/3 cameras

[rasdeep]

i would think images recover from under exposure better than from over exposure. Dun take my word for it. Go test it out yourself.

under exposure when corrected will always have higher noise level compared to properly or over exposed images (if the data does not get clipped)

 

[Oly5050]

under exposure when corrected will always have higher noise level compared to properly or over exposed images (if the data does not get clipped)

Correct me if i am wrong but i find that the recovery from underexposure gives more natural results compared to overexposure. If u recover from overexposure, the image looks a little over-contrasty and artificial, for lack of a better word to describe it. As for noise, it depends on the image, whether fundamentally the light was good enuff etc, and also depends on the software u use. If it is 1/3 to 2/3 underexposure, there is really not much noise. Even picasa can recover 2/3 without any significant noise. However, if light was poor right at the beginning and the image is underexposed badly, of course the results will be bad. My experience after using picasa extensively and LR3, is that i much prefer the results from recovering from underexposure than from overexposure. I guess people who are noise-averse may choose to prefer to recover from overexposure. Is that correct?

 

[elgkh]

I prefer to recover from over-exposure, and would rather add contrast than deal with noise.

 

[rasdeep]

its not exactly about that but majority of the tonal values are recorded in the first few brightest stops of dynamic range hence you are losing a lot of data if you exposed to the left (ETTL).. The trick is usually to ETTR where you get most of your tonal values. i dont pretend to be an expert in this area but you can read more about it here and why ETTR makes more sense than ETTL

Expose Right

However, ETTL has it uses when you are trying to "push" iso, eg pic shot at ISO1600 with -1EV but PP adjusted to 0EV digitally pushed the pic to an ISO3200 equivalent. This trick has been used frequently back in the days where most cameras have ISO1600 as the limit hence pushing -1 to -2 EV to gain ISO3200-ISO6400 equivalent has been useful.

Also, from what i understand, digitally "pushed" ISO has higher SNR compared to adjusting the analog gain from the sensor itself. Hence some camera eg Nikon has the "HI" ISO level which means the ISO is "digitally" pushed as compared to "analog". Not sure if i can explain this clear enough

Correct me if i am wrong but i find that the recovery from underexposure gives more natural results compared to overexposure. If u recover from overexposure, the image looks a little over-contrasty and artificial, for lack of a better word to describe it. As for noise, it depends on the image, whether fundamentally the light was good enuff etc, and also depends on the software u use. If it is 1/3 to 2/3 underexposure, there is really not much noise. Even picasa can recover 2/3 without any significant noise. However, if light was poor right at the beginning and the image is underexposed badly, of course the results will be bad. My experience after using picasa extensively and LR3, is that i much prefer the results from recovering from underexposure than from overexposure. I guess people who are noise-averse may choose to prefer to recover from overexposure. Is that correct?

 

[pinholecam]

I dun know abt panny but I have a couple hundred shots from my friend's gf1 and I din remember having to correct exposure. Also he does not know anything about post and I have seen his photos and the exposure always seems ok. On the hand, it's not uncommon to see under exposures from oly. Anyway this should not be about who is better. I apologise. It's just tat I found I could not recover some stuff in post for some perfectly exposed shots from the x10.

So, there is no right or wrong or who is better. It is wat the manufacturer or you choose to have. Perfect exposure every time but risk losing some highlights occasionally OR chronically underexposed shots and having to fix exposure in nearly all the time. At first I thought it was a problem, but now I can see the reason for it. That is all. Just highlighting my ignorance from that.

I still really dunno which I prefer. I enjoy now not having to correct exposure all the time, (saves me a lot of time), but in the occasional times that I have some blown bits, I do wish the camera had underexposed a bit.

Ok. I see.
Don't get me wrong, I brought up G3/GF1 just as a comparative example. Not trying to say its any better or worse.

I tend to favour getting an underexposed photo rather than a blown one.
G3 only recovers 1stop overexposure and probably 2.5-3 stops from underexposure in RAW.
Almost all digital cameras have this characteristic (ie. recover more from the left than the right).
Being slightly under also gives faster shutter speeds.
The trade off is of course noise when recovering the underexposed parts.
This is one of the reasons why a camera with very low noise footprint and DR like the K5 is so incredible; its underexposed parts can take the punishment being pushed up in exposure during PP w/o showing off as much noise.

 

[Oly5050]

its not exactly about that but majority of the tonal values are recorded in the first few brightest stops of dynamic range hence you are losing a lot of data if you exposed to the left (ETTL).. The trick is usually to ETTR where you get most of your tonal values. i dont pretend to be an expert in this area but you can read more about it here and why ETTR makes more sense than ETTL

Expose Right

However, ETTL has it uses when you are trying to "push" iso, eg pic shot at ISO1600 with -1EV but PP adjusted to 0EV digitally pushed the pic to an ISO3200 equivalent. This trick has been used frequently back in the days where most cameras have ISO1600 as the limit hence pushing -1 to -2 EV to gain ISO3200-ISO6400 equivalent has been useful.

Also, from what i understand, digitally "pushed" ISO has higher SNR compared to adjusting the analog gain from the sensor itself. Hence some camera eg Nikon has the "HI" ISO level which means the ISO is "digitally" pushed as compared to "analog". Not sure if i can explain this clear enough

Good link and interesting stuff. Definately useful and educational. But only applies to RAW and I shoot JPEG nearly all the time. But will definately take that into consideration in those few times when I really really need that range and quality.