shii

shii

Lives in United States United States
Joined on Jul 2, 2001

Comments

Total: 4, showing: 1 – 4
On What is equivalence and why should I care? article (2025 comments in total)
In reply to:

shii: I followed the discussion with great interest but failed to grasp the concept of "total light." In the article it says " ... (while the intensity is the same) because the more (total) light you capture, the less noisy your image, ...". Noise is determined at the pixel level and each pixel does not know how much total light the sensor is capturing. So why would the total light affect noise? Take a Nikon D800, for example. Shoot in FF and then in crop mode. Are we saying the crop mode will have more noise though it is basically the same camera? Comparisons only make sense while we are taking the same picture. The cropped photo will have higher noise only if we move the camera away to keep the same frame but still use the same aperture. But then the DOF will not be the same so it is not the same comparison. So, once again, why does total light matter? Is that to avoid the discussion of having to keep the same frame between FF and cropped?

To Great Bustard: Agree that we need to consider "the whole". When I said "Noise is determined at the pixiel level", I was primarily thinking of image cell design which sets the floor level of noise. I fully understand there are many other factors controlling noise. I stated incorrectly or at least incompletely. We can avoid the complication of more than one sensor/camera by simply restricting ourselves to my example of using the D800 in FF and crop modes. We can also simplify it further by saying that we are taking the picture of a grey card so every pixel sees the same intensity of light. The total amount of light received in crop mode is less but would the noise increase? If not, then why are we saying less total light increases noise? However, we already discussed above that we need to change other elements to get the same image. "Total light" is a convenient way to normalize all attributes but I personally find it misleading. Yet, this is a good article nonetheless.

Direct link | Posted on Jul 9, 2014 at 18:49 UTC
On What is equivalence and why should I care? article (2025 comments in total)
In reply to:

shii: I followed the discussion with great interest but failed to grasp the concept of "total light." In the article it says " ... (while the intensity is the same) because the more (total) light you capture, the less noisy your image, ...". Noise is determined at the pixel level and each pixel does not know how much total light the sensor is capturing. So why would the total light affect noise? Take a Nikon D800, for example. Shoot in FF and then in crop mode. Are we saying the crop mode will have more noise though it is basically the same camera? Comparisons only make sense while we are taking the same picture. The cropped photo will have higher noise only if we move the camera away to keep the same frame but still use the same aperture. But then the DOF will not be the same so it is not the same comparison. So, once again, why does total light matter? Is that to avoid the discussion of having to keep the same frame between FF and cropped?

To mostlyboringphotog: Agreed with your understanding but I just thought "Total Light" might be a convenient way of doing the normalization but it does not reflect the physical process of taking photos and it could be misleading.

To Macs: Agreed. I did not mean pixel was the only factor that determines noise. Bottom line is that if we use the same lens, we need to be taking the photos at different distances and different physical apertures to keep the final images the same.

Direct link | Posted on Jul 9, 2014 at 16:31 UTC
On What is equivalence and why should I care? article (2025 comments in total)

I followed the discussion with great interest but failed to grasp the concept of "total light." In the article it says " ... (while the intensity is the same) because the more (total) light you capture, the less noisy your image, ...". Noise is determined at the pixel level and each pixel does not know how much total light the sensor is capturing. So why would the total light affect noise? Take a Nikon D800, for example. Shoot in FF and then in crop mode. Are we saying the crop mode will have more noise though it is basically the same camera? Comparisons only make sense while we are taking the same picture. The cropped photo will have higher noise only if we move the camera away to keep the same frame but still use the same aperture. But then the DOF will not be the same so it is not the same comparison. So, once again, why does total light matter? Is that to avoid the discussion of having to keep the same frame between FF and cropped?

Direct link | Posted on Jul 9, 2014 at 15:30 UTC as 167th comment | 8 replies
On Just deployed: New dpreview.com forums system article (699 comments in total)

In the forums, can we put a row of buttons for Previous and Next, etc at the bottom of the post/reply? (or move the one at the bottom of the list of posts in the thread up to the top) Right now we have to scroll back to the top of the post to click a button to go to the next post. This is very incinvenient for a long post especially when reading on an iPad. I know there is keyboard shortcut but we cannot do it on the iPad.

I found blue on black difficult to read so I switched to yellow. After switching to a Flat View and then back to Threaded View again, the display stayed blue on black and would not allow me to go to yellow on black anymore. Is that a bug?

Also, sometimes the bullet points disappear altogether. Bug? I am using an iPad.

Direct link | Posted on Oct 5, 2012 at 10:25 UTC as 106th comment
Total: 4, showing: 1 – 4