Questions tagged [digital-iso]

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7
votes
7answers
3k views

Is there any reason to change the ISO manually?

Here's my understanding so far. When taking a photo with a digital camera, there are some tradeoffs: Aperture size: bigger aperture lets in more light, smaller aperture means less blurring in space. ...
2
votes
6answers
183 views

What is the physical cause of increasing noise at high ISO?

Which is the physical cause of the increasing noise at high iso? I know that Iso represents the sensor/film sensitivity to light: at lower iso we need an higher exposure time to get the image of the ...
4
votes
1answer
147 views

Doubling ISO vs summing pixel values from 2 shots - different?

How much different is doubling the ISO vs. summing the pixel values from 2 shots? (at a very basic level, ignoring fancy image processing, image compression, etc) When taking a shot of the night sky (...
0
votes
1answer
122 views

How does digital ISO work electronically? One amplifier or many? [duplicate]

As I understand the way ISO boosting works in a digital sensor, is that the voltage coming from each pixel is boosted (or suppressed) by an analog amplifier. So, for example, if the native sensitivity ...
0
votes
1answer
237 views

Greenish color with photography in dim/low light

It always happens when I do photography in low/dim light. The photo comes out greenish. The colour is slightly light green. It is taken from a dark room facing the sky coming from a roof window. I ...
8
votes
4answers
3k views

Digital ISO vs Post-Exposure Correction

As far as I know, a ISO setting on a DSLR camera corresponds to a mixture of both analog and digital settings set before a shot is taken and governs how much amplification the incidence luminosity is ...
44
votes
10answers
2k views

Should higher ISOs really be preferred (all other things being equal)?

My understanding of the ISO setting on digital cameras is that, unlike film-cameras, changing the ISO does not evoke any physical change in the camera. Rather, it simply tells the camera to multiply ...
9
votes
3answers
1k views

Variable ISO Sensor: Possible and/or Useful?

This answer to the question about how ISO is implemented in digital cameras seems to imply that each photosite (i.e., pixel) can have its ISO set independently. If this is true, then I would think ...
5
votes
3answers
774 views

What is preventing sensor ISOs from going lower than 100? [duplicate]

Possible Duplicate: Why can't the ISO level on most digital cameras be set below 80 So, take your typical DSLR sensor. It probably tops out at anywhere between 1600 - 6400 ISO. The reason ...
32
votes
4answers
5k views

Why can't the ISO level on most digital cameras be set below 80?

Why is it that the ISO level on most digital cameras doesn't seem to go lower than ISO 80? I understand (vaguely) that the sensors adjust the gain in order to achieve the equivalent of a high ISO ...
9
votes
0answers
595 views

What does expanded ISO mean?

Especially with regards to image quality. I am particularly interested in when you expand to a lower ISO, say 50 rather than 100. Generally the standard high ISO is too noisy, with the expanded ISO ...
53
votes
8answers
41k views

What does “expanded ISO” mean?

The ISO specification for the Canon EOS 7D reads as follows: High ISO For handheld shooting in low light, the EOS 7D offers ISO speeds of up to 6400. Expandable to ISO 12800, for low light ...
13
votes
1answer
368 views

What factors determine the lowest ISO for a camera?

With the introduction of the Nikon D7000, one of its advantages over the D90 is that its lowest "true" ISO is 100 instead of 200. What does this mean though, what had to change in the the ...
23
votes
5answers
23k views

What is meant by the “native ISO” when talking about DSLRs?

The new Nikon D7000 is out, and a lot of previews has touted the "native iso" of D7000 to be 100. What does this actually mean? I'm assuming it means it performs at its best at iso 100, which means ...