Is there a point of learning Aperture,ISO,Shutter speed?

rsbones · Nov 11, 2011

The funny thing is that sensor and software technology is advancing so much that there are now cameras that can be treated basically ISO-less. Their read noise curves are so flat that there is NO ADVANTAGE gained by shooting at higher ISO compared with just shooting at base ISO (usually 100 or 200) and then just boosting the image "exposure" on the computer later. And there is an advantage to doing it on the computer because you can both lighten the image to reveal shadow detail and preserve the highlights, too (whereas shooting at higher iso on the camera would have permanently clipped the highlights, never to be recovered).

So if whoever it was who joked rhetorically about shooting a concert at ISO 100 owned a Nikon D7000 or any of the other "isoless" cameras, he could have done just that and once he developed the image on the computer, no one would have know the difference. With this kind of camera, one is (within a quite wide step range) free to choose aperture based on the dof he wants, shutter speed based on the motion stop/blur he wants, and then worry about the resulting image brightness later when he "develops" the images with his raw converter. The only downside is the jpg produced for your camera lcd will be too dark to see! (manufacturers could easily fix this by treating the Iso as meta data only: i.e. it'd be in the jpg so the preview image on camera would show you something viewable, but once you download to the computer it wouldn't be a permanent part of the raw data).

As this type of sensor becomes more common, there will need to be a new edition of "Understanding Exposure"!

unpopular · Nov 11, 2011

^^ I think in 15 years, people will be looking at this sentiment as ironic. I think that ISO-less is a huge exaggeration, that is likely where we are heading - imagine a a camera that records an effective HDR image at 32-bit in one exposure with ISO in the six digits with a SNR similar to today's ISO 100 - but I don't think that's where we're at.

Significant noise - albeit less than previous digital cameras and even film always starts around ISO 3200, and if I were to guess, ISO 3200 has similar SNR as ISO 400 film - which is suitable for some applications, but not all applications. When cameras can perform equally well at ISOs in six digits, as they do at their native ISO, then maybe.

However, when cameras do perform in such a way that sensitivity can provide adjustment in any any lighting circumstance and does not affect image quality, it will change how we think of exposure time as something which is only responsible for capturing or freezing movement, similar to how we normally think of aperture controlling depth of field and the perception of space.

Now, one question - is ISO set at time of capture or time of conversion? Is there any analog amplification in-camera, or is ISO determined by the software in a similar fashion as the "exposure slider"?

rsbones · Nov 12, 2011

ISO is part of "processing". It has always been so, even with film. Setting a film camera at iso 800 instead of iso 100 (without changing aperture or shutter speed) did not in any way alter what the camera did or the way the image was captured on the film. That's why it really shouldn't be consider as part of the "exposure". However, in digital cameras currently this "processing" is done as default by the cameras before it puts the image into a format that can be read/displayed by computers. So altering the iso setting of the camera does permanently alter the image.

It really shouldn't, and in the near future perhaps it will not and we will be able to set the iso at whatever we want, the camera will spit out jpgs that match that setting, but the camera will not alter the raw file and will simply allow the raw file to capture the full amount of light available at the given aperture and shutter speed setting (without clipping anything out like it currently does) and leave it up to us to determine how bright we want the image to be and what we want to appear in the dynamic range available, with no noise penalty!

memento · Nov 12, 2011

:energizerbunnygif:

unpopular · Nov 12, 2011

rsbones said:
ISO is part of "processing". It has always been so, even with film. Setting a film camera at iso 800 instead of iso 100 (without changing aperture or shutter speed) did not in any way alter what the camera did or the way the image was captured on the film. That's why it really shouldn't be consider as part of the "exposure".

RE film, that is not at all accurate. ISO is set by the character of the film, primarily the size of the grain determines the sensitivity of the film. Setting the ISO calibrates the meter to the film, but you process higher ISO film similarly to lower ISO film, and, provided what you are sayings is accurate, digital ISO increases are more like push processing (yikes!). In film it wasn't considered a part of exposure because it was constant.

Because camera sensors measure one pixel at a time in either axis (right?) it seems you could place an analog amplifier at the outputs. I have no idea if this would produce a better noise profile than arrhythmically doing it in the post processor. My guess would be that this would produce more noise since you are not only amplifying the noise from the sensor itself, but also introducing noise from the amplifier.

But now that I think of it, that does make sense since sensitivity is determined by the physical properties of the capacitor array at the front of the ccd. The only way to change sensitivity would be to either permit the user to switch the CCD out for one that is more sensitive, or to somehow change the physical qualities of the sensor with an electric charge.

ETA:

However, Wikipedia says otherwise:

For digital photo cameras ("digital still cameras"), an exposure index (EI) rating—commonly called ISO setting—is specified by the manufacturer such that the sRGB image files produced by the camera will have a lightness similar to what would be obtained with film of the same EI rating at the same exposure. The usual design is that the camera's parameters for interpreting the sensor data values into sRGB values are fixed, and a number of different EI choices are accommodated by varying the sensor's signal gain in the analog realm, prior to conversion to digital

If this is the case, then improved ISO relates to lower noise in analog amplification. Being that sensor chemistry is pretty fixed to what technologies are available (a ccd device can only "hold" as many electrons as its physical capabilities permit), making less noisy gain output would be much more practical for sensor manufacturers to accomplish.

mknittle · Nov 12, 2011

Matrixgravity said:
Oh ok, so Manual is for accurate exposure. I understand that.. But the one thing that bothers me is that.. There doesn't seem like you can do much with a Camera once you learn how to properly use it.. Like, technique wise. Like I said, from what I understand the two primary techniques you can apply in Manual is using Depth Of Field to create interesting shots, and create Bokeh as well. But is there anything else you can do?..

are you for real? this is not philosophy.

unpopular · Nov 12, 2011

mknittle said:
are you for real? this is not philosophy.

Is there anything less philosophic than communicating ones own world view ... I think if anything this guy could use a little philosophy. He seems to be approaching photography like its a jigsaw puzzle.

xnoirox · Nov 16, 2011

On auto setting the camera doesn't always give you the right exposure. For ex. it might expose your subject but over-expose other elements of your photo. So if you want to tone down the brightness on your background elements, throw it in manual and adjust accordingly. I prefer manual a lot of the time for practice, and I seem to get better exposures a majority of the time.

ann · Nov 16, 2011

The OP ever come back and review any of this

KmH · Nov 16, 2011

According to their profile, the OP was last on active on the forum 2 days after starting the thread:
Last Activity - 10-27-2011 07:45 PM

That does not preclude the OP from lurking.

tevo · Nov 16, 2011

KmH said:
According to their profile, the OP was last on active on the forum 2 days after starting the thread:
Last Activity - 10-27-2011 07:45 PM

That does not preclude the OP from lurking.

WHY WOULD YOU BUMP THIS THREAD. WHY.

ann · Nov 16, 2011

My fault, It is amazing that this has been going on so long and the OP has never checked back, but a lot of us seem to have had a great time anyway.

BlairWright · Nov 16, 2011

nope, no point at all.

The best advice I can give you is this.. Grab a point n shoot, register your business and start shooting weddings immediately!

ok... I had to add to this 19 page thread *check*

Overread · Nov 16, 2011

tevo said:
KmH said:

According to their profile, the OP was last on active on the forum 2 days after starting the thread:
Last Activity - 10-27-2011 07:45 PM

That does not preclude the OP from lurking.

Click to expand...

WHY WOULD YOU BUMP THIS THREAD. WHY.